+++ /dev/null
-diff -ruN linux-2.4.18/drivers/md/Config.in linux/drivers/md/Config.in
---- linux-2.4.18/drivers/md/Config.in Fri Sep 14 22:22:18 2001
-+++ linux/drivers/md/Config.in Tue Apr 23 22:39:09 2002
-@@ -14,5 +14,6 @@
- dep_tristate ' Multipath I/O support' CONFIG_MD_MULTIPATH $CONFIG_BLK_DEV_MD
-
- dep_tristate ' Logical volume manager (LVM) support' CONFIG_BLK_DEV_LVM $CONFIG_MD
-+dep_tristate ' Device mapper support' CONFIG_BLK_DEV_DM $CONFIG_MD
-
- endmenu
-diff -ruN linux-2.4.18/drivers/md/Makefile linux/drivers/md/Makefile
---- linux-2.4.18/drivers/md/Makefile Thu Dec 6 15:57:55 2001
-+++ linux/drivers/md/Makefile Tue Apr 23 22:39:09 2002
-@@ -4,9 +4,12 @@
-
- O_TARGET := mddev.o
-
--export-objs := md.o xor.o
-+export-objs := md.o xor.o dm-table.o dm-target.o kcopyd.o
- list-multi := lvm-mod.o
- lvm-mod-objs := lvm.o lvm-snap.o lvm-fs.o
-+dm-mod-objs := dm.o dm-table.o dm-target.o dm-ioctl.o \
-+ dm-linear.o dm-stripe.o dm-snapshot.o dm-exception-store.o \
-+ kcopyd.o
-
- # Note: link order is important. All raid personalities
- # and xor.o must come before md.o, as they each initialise
-@@ -20,8 +23,12 @@
- obj-$(CONFIG_MD_MULTIPATH) += multipath.o
- obj-$(CONFIG_BLK_DEV_MD) += md.o
- obj-$(CONFIG_BLK_DEV_LVM) += lvm-mod.o
-+obj-$(CONFIG_BLK_DEV_DM) += dm-mod.o
-
- include $(TOPDIR)/Rules.make
-
- lvm-mod.o: $(lvm-mod-objs)
- $(LD) -r -o $@ $(lvm-mod-objs)
-+
-+dm-mod.o: $(dm-mod-objs)
-+ $(LD) -r -o $@ $(dm-mod-objs)
-diff -ruN linux-2.4.18/drivers/md/dm-exception-store.c linux/drivers/md/dm-exception-store.c
---- linux-2.4.18/drivers/md/dm-exception-store.c Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm-exception-store.c Tue Apr 23 21:54:20 2002
-@@ -0,0 +1,720 @@
-+/*
-+ * dm-snapshot.c
-+ *
-+ * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#include "dm-snapshot.h"
-+
-+#define SECTOR_SIZE 512
-+
-+/*
-+ * Magic for persistent snapshots: "SnAp" - Feeble isn't it.
-+ */
-+#define SNAP_MAGIC 0x70416e53
-+
-+/*
-+ * The on-disk version of the metadata. Only applicable to
-+ * persistent snapshots.
-+ * There is no backward or forward compatibility implemented, snapshots
-+ * with different disk versions than the kernel will not be usable. It is
-+ * expected that "lvcreate" will blank out the start of the COW device
-+ * before calling the snapshot constructor.
-+ */
-+#define SNAPSHOT_DISK_VERSION 1
-+
-+/*
-+ * Metadata format: (please keep this up-to-date!)
-+ * Persistent snapshots have a 1 block header (see below for structure) at
-+ * the very start of the device. The COW metadata starts at
-+ * .start_of_exceptions.
-+ *
-+ * COW metadata is stored in blocks that are "extent-size" sectors long as
-+ * an array of disk_exception structures in Little-Endian format.
-+ * The last entry in this array has rsector_new set to 0 (this cannot be a
-+ * legal redirection as the header is here) and if rsector_org has a value
-+ * it is the sector number of the next COW metadata sector on the disk. if
-+ * rsector_org is also zero then this is the end of the COW metadata.
-+ *
-+ * The metadata is written in hardblocksize lumps rather than in units of
-+ * extents for efficiency so don't expect a whole extent to be zeroed out
-+ * at any time.
-+ *
-+ * Non-persistent snapshots simple have redirected blocks stored
-+ * (in chunk_size sectors) from hard block 1 to avoid inadvertantly
-+ * creating a bad header.
-+ */
-+
-+/*
-+ * Internal snapshot structure
-+ */
-+struct persistent_info {
-+ /* Size of extents used for COW blocks */
-+ long extent_size;
-+
-+ /* Number of the next free sector for COW/data */
-+ unsigned long next_free_sector;
-+
-+ /* Where the metadata starts */
-+ unsigned long start_of_exceptions;
-+
-+ /* Where we are currently writing the metadata */
-+ unsigned long current_metadata_sector;
-+
-+ /* Index into disk_cow array */
-+ int current_metadata_entry;
-+
-+ /* Index into mythical extent array */
-+ int current_metadata_number;
-+
-+ /* Number of metadata entries in the disk_cow array */
-+ int highest_metadata_entry;
-+
-+ /* Number of metadata entries per hard disk block */
-+ int md_entries_per_block;
-+
-+ int full;
-+
-+ /* kiobuf for doing I/O to header & metadata */
-+ struct kiobuf *cow_iobuf;
-+
-+ /*
-+ * Disk extent with COW data in it. as an array of
-+ * exception tables. The first one points to the next
-+ * block of metadata or 0 if this is the last
-+ */
-+ struct disk_exception *disk_cow;
-+};
-+
-+/*
-+ * An array of these is held in each disk block. LE format
-+ */
-+struct disk_exception {
-+ uint64_t rsector_org;
-+ uint64_t rsector_new;
-+};
-+
-+/*
-+ * Structure of a (persistent) snapshot header on disk. in LE format
-+ */
-+struct snap_disk_header {
-+ uint32_t magic;
-+
-+ /* Simple, incrementing version. no backward compatibility */
-+ uint32_t version;
-+
-+ /* In 512 byte sectors */
-+ uint32_t chunk_size;
-+
-+ /* In 512 byte sectors */
-+ uint32_t extent_size;
-+ uint64_t start_of_exceptions;
-+ uint32_t full;
-+};
-+
-+static inline struct persistent_info *get_info(struct exception_store *store)
-+{
-+ return (struct persistent_info *) store->context;
-+}
-+
-+/*
-+ * READ or WRITE some blocks to/from a device
-+ */
-+static int do_io(int rw, struct kiobuf *iobuf, kdev_t dev,
-+ unsigned long start, int nr_sectors)
-+{
-+ int i, sectors_per_block, nr_blocks;
-+ int blocksize = get_hardsect_size(dev);
-+ int status;
-+
-+ sectors_per_block = blocksize / SECTOR_SIZE;
-+
-+ nr_blocks = nr_sectors / sectors_per_block;
-+ start /= sectors_per_block;
-+
-+ for (i = 0; i < nr_blocks; i++)
-+ iobuf->blocks[i] = start++;
-+
-+ iobuf->length = nr_sectors << 9;
-+
-+ status = brw_kiovec(rw, 1, &iobuf, dev, iobuf->blocks, blocksize);
-+ return (status != (nr_sectors << 9));
-+}
-+
-+/*
-+ * Write the latest COW metadata block.
-+ */
-+static int write_metadata(struct dm_snapshot *s, struct persistent_info *pi)
-+{
-+ kdev_t dev = s->cow->dev;
-+ int blocksize = get_hardsect_size(dev);
-+ int writesize = blocksize / SECTOR_SIZE;
-+
-+ if (do_io(WRITE, pi->cow_iobuf, dev,
-+ pi->current_metadata_sector, writesize) != 0) {
-+ DMERR("Error writing COW block");
-+ return -1;
-+ }
-+
-+ return 0;
-+}
-+
-+/*
-+ * Allocate a kiobuf. This is the only code nicked from the old
-+ * snapshot driver and I've changed it anyway.
-+ */
-+static int alloc_iobuf_pages(struct kiobuf *iobuf, int nr_sectors)
-+{
-+ int nr_pages, r, i;
-+
-+ if (nr_sectors > KIO_MAX_SECTORS)
-+ return -1;
-+
-+ nr_pages = nr_sectors / (PAGE_SIZE / SECTOR_SIZE);
-+ r = expand_kiobuf(iobuf, nr_pages);
-+ if (r)
-+ goto out;
-+
-+ r = -ENOMEM;
-+ iobuf->locked = 1;
-+ iobuf->nr_pages = 0;
-+ for (i = 0; i < nr_pages; i++) {
-+ struct page *page;
-+
-+ page = alloc_page(GFP_KERNEL);
-+ if (!page)
-+ goto out;
-+
-+ iobuf->maplist[i] = page;
-+ LockPage(page);
-+ iobuf->nr_pages++;
-+ }
-+
-+ iobuf->offset = 0;
-+ r = 0;
-+
-+ out:
-+ return r;
-+}
-+
-+/*
-+ * Read on-disk COW metadata and populate the hash table.
-+ */
-+static int read_metadata(struct dm_snapshot *s, struct persistent_info *pi)
-+{
-+ int status;
-+ int i;
-+ int entry = 0;
-+ int map_page = 0;
-+ int nr_sectors = pi->extent_size;
-+ kdev_t dev = s->cow->dev;
-+ int blocksize = get_hardsect_size(dev);
-+ unsigned long cur_sector = pi->start_of_exceptions;
-+ unsigned long last_sector;
-+ unsigned long first_free_sector = 0;
-+ int entries_per_page = PAGE_SIZE / sizeof(struct disk_exception);
-+ struct disk_exception *cow_block;
-+ struct kiobuf *read_iobuf;
-+ int r = 0;
-+ int devsize = get_dev_size(dev);
-+
-+ /*
-+ * Allocate our own iovec for this operation 'cos the
-+ * others are way too small.
-+ */
-+ if (alloc_kiovec(1, &read_iobuf)) {
-+ DMERR("Error allocating iobuf for %s", kdevname(dev));
-+ return -1;
-+ }
-+
-+ if (alloc_iobuf_pages(read_iobuf, pi->extent_size)) {
-+ DMERR("Error allocating iobuf space for %s", kdevname(dev));
-+ free_kiovec(1, &read_iobuf);
-+ return -1;
-+ }
-+ cow_block = page_address(read_iobuf->maplist[0]);
-+
-+ do {
-+ /* Make sure the chain does not go off the end of
-+ * the device, or backwards */
-+ if (cur_sector > devsize || cur_sector < first_free_sector) {
-+ DMERR("COW table chain pointers are inconsistent, "
-+ "can't activate snapshot");
-+ r = -1;
-+ goto out;
-+ }
-+
-+ first_free_sector = max(first_free_sector,
-+ cur_sector + pi->extent_size);
-+ status = do_io(READ, read_iobuf, dev, cur_sector, nr_sectors);
-+ if (status == 0) {
-+ map_page = 0;
-+ entry = 0;
-+
-+ cow_block = page_address(read_iobuf->maplist[0]);
-+
-+ /* Now populate the hash table from this data */
-+ for (i = 0; i <= pi->highest_metadata_entry &&
-+ cow_block[entry].rsector_new != 0; i++) {
-+
-+ chunk_t old =
-+ sector_to_chunk(s,
-+ le64_to_cpu(cow_block
-+ [entry].
-+ rsector_org));
-+ chunk_t new =
-+ sector_to_chunk(s,
-+ le64_to_cpu(cow_block
-+ [entry].
-+ rsector_new));
-+
-+ if ((r = dm_add_exception(s, old, new)))
-+ goto out;
-+
-+ first_free_sector = max(first_free_sector,
-+ (unsigned
-+ long) (le64_to_cpu
-+ (cow_block
-+ [entry].
-+ rsector_new) +
-+ s->chunk_size));
-+
-+ /* Do we need to move onto the next page? */
-+ if (++entry >= entries_per_page) {
-+ entry = 0;
-+ cow_block =
-+ page_address(read_iobuf->
-+ maplist[++map_page]);
-+ }
-+ }
-+ } else {
-+ DMERR("Error reading COW metadata for %s",
-+ kdevname(dev));
-+ r = -1;
-+ goto out;
-+ }
-+ last_sector = cur_sector;
-+ cur_sector = le64_to_cpu(cow_block[entry].rsector_org);
-+
-+ } while (cur_sector != 0);
-+
-+ pi->current_metadata_sector = last_sector +
-+ map_page * PAGE_SIZE / SECTOR_SIZE +
-+ entry / (SECTOR_SIZE / sizeof(struct disk_exception));
-+ pi->current_metadata_entry = entry;
-+ pi->current_metadata_number = i;
-+ pi->next_free_sector = first_free_sector;
-+
-+ /* Copy last block into cow_iobuf */
-+ memcpy(pi->disk_cow, (char *) ((long) &cow_block[entry] -
-+ ((long) &cow_block[entry] &
-+ (blocksize - 1))), blocksize);
-+
-+ out:
-+ unmap_kiobuf(read_iobuf);
-+ free_kiovec(1, &read_iobuf);
-+
-+ return r;
-+}
-+
-+/*
-+ * Read the snapshot volume header, returns 0 only if it read OK
-+ * and it was valid. returns 1 if no header was found, -1 on
-+ * error. All fields are checked against the snapshot structure
-+ * itself to make sure we don't corrupt the data.
-+ */
-+static int read_header(struct dm_snapshot *s, struct persistent_info *pi)
-+{
-+ int status;
-+ struct snap_disk_header *header;
-+ kdev_t dev = s->cow->dev;
-+ int blocksize = get_hardsect_size(dev);
-+ unsigned long devsize;
-+
-+ /* Get it */
-+ status = do_io(READ, pi->cow_iobuf, dev, 0L, blocksize / SECTOR_SIZE);
-+ if (status != 0) {
-+ DMERR("Snapshot dev %s error reading header", kdevname(dev));
-+ return -1;
-+ }
-+
-+ header = (struct snap_disk_header *)
-+ page_address(pi->cow_iobuf->maplist[0]);
-+
-+ /*
-+ * Check the magic. It's OK if this fails, we just create
-+ * a new snapshot header and start from scratch.
-+ */
-+ if (le32_to_cpu(header->magic) != SNAP_MAGIC) {
-+ return 1;
-+ }
-+
-+ /* Check the version matches */
-+ if (le32_to_cpu(header->version) != SNAPSHOT_DISK_VERSION) {
-+ DMWARN("Snapshot dev %s version mismatch. Stored: %d, "
-+ "driver: %d", kdevname(dev),
-+ le32_to_cpu(header->version), SNAPSHOT_DISK_VERSION);
-+ return -1;
-+ }
-+
-+ /* Check the chunk sizes match */
-+ if (le32_to_cpu(header->chunk_size) != s->chunk_size) {
-+ DMWARN("Snapshot dev %s chunk size mismatch. Stored: %d, "
-+ "requested: %ld", kdevname(dev),
-+ le32_to_cpu(header->chunk_size), s->chunk_size);
-+ return -1;
-+ }
-+
-+ /* Check the extent sizes match */
-+ if (le32_to_cpu(header->extent_size) != pi->extent_size) {
-+ DMWARN("Snapshot dev %s extent size mismatch. Stored: %d, "
-+ "requested: %ld", kdevname(dev),
-+ le32_to_cpu(header->extent_size), pi->extent_size);
-+ return -1;
-+ }
-+
-+ /* Get the rest of the data */
-+ pi->start_of_exceptions = le64_to_cpu(header->start_of_exceptions);
-+ if (header->full) {
-+ DMWARN("Snapshot dev %s is full. It cannot be used",
-+ kdevname(dev));
-+ return -1;
-+ }
-+
-+ /* Validate against the size of the volume */
-+ devsize = get_dev_size(dev);
-+ if (pi->start_of_exceptions > devsize) {
-+ DMWARN("Snapshot metadata error on %s. start exceptions > "
-+ "device size (%ld > %ld)",
-+ kdevname(dev), pi->start_of_exceptions, devsize);
-+ return -1;
-+ }
-+
-+ /* Read metadata into the hash table and update pointers */
-+ return read_metadata(s, pi);
-+}
-+
-+/*
-+ * Write (or update) the header. The only time we should need to
-+ * do an update is when the snapshot becomes full.
-+ */
-+static int write_header(struct dm_snapshot *s, struct persistent_info *pi)
-+{
-+ struct snap_disk_header *header;
-+ struct kiobuf *head_iobuf;
-+ kdev_t dev = s->cow->dev;
-+ int blocksize = get_hardsect_size(dev);
-+ int status;
-+
-+ /*
-+ * Allocate our own iobuf for this so we don't corrupt
-+ * any of the other writes that may be going on.
-+ */
-+ if (alloc_kiovec(1, &head_iobuf)) {
-+ DMERR("Error allocating iobuf for header on %s", kdevname(dev));
-+ return -1;
-+ }
-+
-+ if (alloc_iobuf_pages(head_iobuf, PAGE_SIZE / SECTOR_SIZE)) {
-+ DMERR("Error allocating iobuf space for header on %s",
-+ kdevname(dev));
-+ free_kiovec(1, &head_iobuf);
-+ return -1;
-+ }
-+
-+ header = (struct snap_disk_header *)
-+ page_address(head_iobuf->maplist[0]);
-+
-+ header->magic = cpu_to_le32(SNAP_MAGIC);
-+ header->version = cpu_to_le32(SNAPSHOT_DISK_VERSION);
-+ header->chunk_size = cpu_to_le32(s->chunk_size);
-+ header->extent_size = cpu_to_le32(pi->extent_size);
-+ header->full = cpu_to_le32(pi->full);
-+
-+ header->start_of_exceptions = cpu_to_le64(pi->start_of_exceptions);
-+
-+ /* Must write at least a full block */
-+ status = do_io(WRITE, head_iobuf, dev, 0, blocksize / SECTOR_SIZE);
-+
-+ unmap_kiobuf(head_iobuf);
-+ free_kiovec(1, &head_iobuf);
-+ return status;
-+}
-+
-+static void destroy_persistent(struct exception_store *store)
-+{
-+ struct persistent_info *pi = get_info(store);
-+ unmap_kiobuf(pi->cow_iobuf);
-+ free_kiovec(1, &pi->cow_iobuf);
-+ kfree(pi);
-+}
-+
-+static int init_persistent(struct exception_store *store, int blocksize,
-+ unsigned long extent_size, void **context)
-+{
-+ struct persistent_info *pi = get_info(store);
-+ struct dm_snapshot *s = store->snap;
-+ int status;
-+
-+ *context = "Error in disk header";
-+ /* Check for a header on disk and create a new one if not */
-+ if ((status = read_header(s, pi)) == 1) {
-+
-+ /* Write a new header */
-+ pi->start_of_exceptions = pi->next_free_sector;
-+ pi->next_free_sector += pi->extent_size;
-+ pi->current_metadata_sector = pi->start_of_exceptions;
-+ pi->current_metadata_entry = 0;
-+ pi->current_metadata_number = 0;
-+
-+ *context = "Unable to write snapshot header";
-+ if (write_header(s, pi) != 0) {
-+ DMERR("Error writing header to snapshot volume %s",
-+ kdevname(s->cow->dev));
-+ goto free_ret;
-+ }
-+
-+ /* Write a blank metadata block to the device */
-+ if (write_metadata(s, pi) != 0) {
-+ DMERR("Error writing initial COW table to "
-+ "snapshot volume %s", kdevname(s->cow->dev));
-+ goto free_ret;
-+ }
-+ }
-+
-+ /*
-+ * There is a header but it doesn't match - fail so we
-+ * don't destroy what might be useful data on disk. If
-+ * the user really wants to use this COW device for a
-+ * snapshot then the first sector should be zeroed out
-+ * first.
-+ */
-+ if (status == -1)
-+ goto free_ret;
-+
-+ return 0;
-+
-+ free_ret:
-+ unmap_kiobuf(pi->cow_iobuf);
-+ free_kiovec(1, &pi->cow_iobuf);
-+ return -1;
-+}
-+
-+/*
-+ * Finds a suitable destination for the exception.
-+ */
-+static int prepare_persistent(struct exception_store *store,
-+ struct exception *e)
-+{
-+ struct persistent_info *pi = get_info(store);
-+ struct dm_snapshot *s = store->snap;
-+ offset_t dev_size;
-+
-+ /*
-+ * Check for full snapshot. Doing the size calculation here means that
-+ * the COW device can be resized without us being told
-+ */
-+ dev_size = get_dev_size(s->cow->dev);
-+ if (pi->next_free_sector + s->chunk_size >= dev_size) {
-+ /* Snapshot is full, we can't use it */
-+ DMWARN("Snapshot %s is full (sec=%ld, size=%ld)",
-+ kdevname(s->cow->dev),
-+ pi->next_free_sector + s->chunk_size, dev_size);
-+ pi->full = 1;
-+
-+ /* Mark it full on the device */
-+ write_header(s, pi);
-+
-+ return -1;
-+
-+ } else {
-+ e->new_chunk = sector_to_chunk(s, pi->next_free_sector);
-+ pi->next_free_sector += s->chunk_size;
-+ }
-+
-+ return 0;
-+}
-+
-+/*
-+ * Add a new exception entry to the on-disk metadata.
-+ */
-+static int commit_persistent(struct exception_store *store, struct exception *e)
-+{
-+ struct persistent_info *pi = get_info(store);
-+ struct dm_snapshot *s = store->snap;
-+
-+ int i = pi->current_metadata_entry++;
-+ unsigned long next_md_block = pi->current_metadata_sector;
-+
-+ pi->current_metadata_number++;
-+
-+ /* Update copy of disk COW */
-+ pi->disk_cow[i].rsector_org =
-+ cpu_to_le64(chunk_to_sector(s, e->old_chunk));
-+ pi->disk_cow[i].rsector_new =
-+ cpu_to_le64(chunk_to_sector(s, e->new_chunk));
-+
-+ /* Have we filled this extent ? */
-+ if (pi->current_metadata_number >= pi->highest_metadata_entry) {
-+ /* Fill in pointer to next metadata extent */
-+ i++;
-+ pi->current_metadata_entry++;
-+
-+ next_md_block = pi->next_free_sector;
-+ pi->next_free_sector += pi->extent_size;
-+
-+ pi->disk_cow[i].rsector_org = cpu_to_le64(next_md_block);
-+ pi->disk_cow[i].rsector_new = 0;
-+ }
-+
-+ /* Commit to disk */
-+ if (write_metadata(s, pi)) {
-+ pi->full = 1; /* Failed. don't try again */
-+ return -1;
-+ }
-+
-+ /*
-+ * Write a new (empty) metadata block if we are at the
-+ * end of an existing block so that read_metadata finds a
-+ * terminating zero entry.
-+ */
-+ if (pi->current_metadata_entry == pi->md_entries_per_block) {
-+ memset(pi->disk_cow, 0, PAGE_SIZE);
-+ pi->current_metadata_sector = next_md_block;
-+
-+ /*
-+ * If this is also the end of an extent then go
-+ * back to the start.
-+ */
-+ if (pi->current_metadata_number >= pi->highest_metadata_entry) {
-+ pi->current_metadata_number = 0;
-+
-+ } else {
-+ int blocksize = get_hardsect_size(s->cow->dev);
-+ pi->current_metadata_sector += blocksize / SECTOR_SIZE;
-+ }
-+
-+ pi->current_metadata_entry = 0;
-+ if (write_metadata(s, pi) != 0) {
-+ pi->full = 1;
-+ return -1;
-+ }
-+ }
-+
-+ return 0;
-+}
-+
-+/*
-+ * Sets the full flag in the metadata. A quick hack for now.
-+ */
-+static void drop_persistent(struct exception_store *store)
-+{
-+ get_info(store)->full = 1;
-+ write_header(store->snap, get_info(store));
-+}
-+
-+int dm_create_persistent(struct exception_store *store, struct dm_snapshot *s,
-+ int blocksize, offset_t extent_size, void **error)
-+{
-+ struct persistent_info *pi;
-+ int i, r;
-+ int cow_sectors;
-+
-+ pi = kmalloc(sizeof(*pi), GFP_KERNEL);
-+ if (!pi)
-+ return -ENOMEM;
-+
-+ memset(store, 0, sizeof(*store));
-+ store->destroy = destroy_persistent;
-+ store->init = init_persistent;
-+ store->prepare_exception = prepare_persistent;
-+ store->commit_exception = commit_persistent;
-+ store->drop_snapshot = drop_persistent;
-+ store->snap = s;
-+ store->context = pi;
-+
-+ pi->extent_size = extent_size;
-+
-+ /* Leave the first block alone */
-+ pi->next_free_sector = blocksize / SECTOR_SIZE;
-+ pi->disk_cow = NULL;
-+
-+ pi->highest_metadata_entry = (pi->extent_size * SECTOR_SIZE) /
-+ sizeof(struct disk_exception) - 1;
-+ pi->md_entries_per_block = blocksize / sizeof(struct disk_exception);
-+
-+ /* Allocate and set up iobuf for metadata I/O */
-+ *error = "Unable to allocate COW iovec";
-+ if ((r = alloc_kiovec(1, &pi->cow_iobuf)))
-+ return r;
-+
-+ /*
-+ * Allocate space for the COW buffer. It should be at
-+ * least PAGE_SIZE.
-+ */
-+ cow_sectors = blocksize / SECTOR_SIZE + PAGE_SIZE / SECTOR_SIZE;
-+ *error = "Unable to allocate COW I/O buffer space";
-+ if ((r = alloc_iobuf_pages(pi->cow_iobuf, cow_sectors))) {
-+ free_kiovec(1, &pi->cow_iobuf);
-+ return r;
-+ }
-+
-+ for (i = 0; i < pi->cow_iobuf->nr_pages; i++)
-+ memset(page_address(pi->cow_iobuf->maplist[i]), 0, PAGE_SIZE);
-+
-+ pi->disk_cow = page_address(pi->cow_iobuf->maplist[0]);
-+ return 0;
-+}
-+
-+/*
-+ * Implementation of the store for non-persistent snapshots.
-+ */
-+struct transient_c {
-+ offset_t next_free;
-+};
-+
-+void destroy_transient(struct exception_store *store)
-+{
-+ kfree(store->context);
-+}
-+
-+int prepare_transient(struct exception_store *store, struct exception *e)
-+{
-+ struct transient_c *tc = (struct transient_c *) store->context;
-+ offset_t size = get_dev_size(store->snap->cow->dev);
-+
-+ if (size < (tc->next_free + store->snap->chunk_size))
-+ return -1;
-+
-+ e->new_chunk = sector_to_chunk(store->snap, tc->next_free);
-+ tc->next_free += store->snap->chunk_size;
-+
-+#if 0
-+ DMWARN("Preparing exception, chunk %lu -> %lu.",
-+ (unsigned long) e->old_chunk, (unsigned long) e->new_chunk);
-+#endif
-+
-+ return 0;
-+}
-+
-+int dm_create_transient(struct exception_store *store,
-+ struct dm_snapshot *s, int blocksize, void **error)
-+{
-+ struct transient_c *tc;
-+
-+ memset(store, 0, sizeof(*store));
-+ store->destroy = destroy_transient;
-+ store->prepare_exception = prepare_transient;
-+ store->snap = s;
-+
-+ tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
-+ if (!tc)
-+ return -ENOMEM;
-+
-+ tc->next_free = 0;
-+ store->context = tc;
-+
-+ return 0;
-+}
-diff -ruN linux-2.4.18/drivers/md/dm-ioctl.c linux/drivers/md/dm-ioctl.c
---- linux-2.4.18/drivers/md/dm-ioctl.c Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm-ioctl.c Tue Apr 23 21:51:57 2002
-@@ -0,0 +1,588 @@
-+/*
-+ * Copyright (C) 2001 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#include "dm.h"
-+
-+#include <linux/miscdevice.h>
-+#include <linux/dm-ioctl.h>
-+#include <linux/init.h>
-+
-+static void free_params(struct dm_ioctl *param)
-+{
-+ vfree(param);
-+}
-+
-+static int version(struct dm_ioctl *user)
-+{
-+ return copy_to_user(user, DM_DRIVER_VERSION, sizeof(DM_DRIVER_VERSION));
-+}
-+
-+static int copy_params(struct dm_ioctl *user, struct dm_ioctl **param)
-+{
-+ struct dm_ioctl tmp, *dmi;
-+
-+ if (copy_from_user(&tmp, user, sizeof(tmp)))
-+ return -EFAULT;
-+
-+ if (strcmp(DM_IOCTL_VERSION, tmp.version)) {
-+ DMWARN("struct dm_ioctl version incompatible");
-+ return -EINVAL;
-+ }
-+
-+ if (tmp.data_size < sizeof(tmp))
-+ return -EINVAL;
-+
-+ dmi = (struct dm_ioctl *) vmalloc(tmp.data_size);
-+ if (!dmi)
-+ return -ENOMEM;
-+
-+ if (copy_from_user(dmi, user, tmp.data_size)) {
-+ vfree(dmi);
-+ return -EFAULT;
-+ }
-+
-+ *param = dmi;
-+ return 0;
-+}
-+
-+static int validate_params(uint cmd, struct dm_ioctl *param)
-+{
-+ /* Unless creating, either name of uuid but not both */
-+ if (cmd != DM_CREATE_CMD) {
-+ if ((!*param->uuid && !*param->name) ||
-+ (*param->uuid && *param->name)) {
-+ DMWARN("one of name or uuid must be supplied");
-+ return -EINVAL;
-+ }
-+ }
-+
-+ /* Ensure strings are terminated */
-+ param->name[DM_NAME_LEN - 1] = '\0';
-+ param->uuid[DM_UUID_LEN - 1] = '\0';
-+
-+ return 0;
-+}
-+
-+/*
-+ * Check a string doesn't overrun the chunk of
-+ * memory we copied from userland.
-+ */
-+static int valid_str(char *str, void *begin, void *end)
-+{
-+ while (((void *) str >= begin) && ((void *) str < end))
-+ if (!*str++)
-+ return 0;
-+
-+ return -EINVAL;
-+}
-+
-+static int next_target(struct dm_target_spec *last, unsigned long next,
-+ void *begin, void *end,
-+ struct dm_target_spec **spec, char **params)
-+{
-+ *spec = (struct dm_target_spec *)
-+ ((unsigned char *) last + next);
-+ *params = (char *) (*spec + 1);
-+
-+ if (*spec < (last + 1) || ((void *) *spec > end))
-+ return -EINVAL;
-+
-+ return valid_str(*params, begin, end);
-+}
-+
-+/*
-+ * Checks to see if there's a gap in the table.
-+ * Returns true iff there is a gap.
-+ */
-+static int gap(struct dm_table *table, struct dm_target_spec *spec)
-+{
-+ if (!table->num_targets)
-+ return (spec->sector_start > 0) ? 1 : 0;
-+
-+ if (spec->sector_start != table->highs[table->num_targets - 1] + 1)
-+ return 1;
-+
-+ return 0;
-+}
-+
-+static int populate_table(struct dm_table *table, struct dm_ioctl *args)
-+{
-+ int i = 0, r, first = 1, argc;
-+ struct dm_target_spec *spec;
-+ char *params, *argv[MAX_ARGS];
-+ struct target_type *ttype;
-+ void *context, *begin, *end;
-+ offset_t highs = 0;
-+
-+ if (!args->target_count) {
-+ DMWARN("populate_table: no targets specified");
-+ return -EINVAL;
-+ }
-+
-+ begin = (void *) args;
-+ end = begin + args->data_size;
-+
-+#define PARSE_ERROR(msg) {DMWARN(msg); return -EINVAL;}
-+
-+ for (i = 0; i < args->target_count; i++) {
-+
-+ r = first ? next_target((struct dm_target_spec *) args,
-+ args->data_start,
-+ begin, end, &spec, ¶ms) :
-+ next_target(spec, spec->next, begin, end, &spec, ¶ms);
-+
-+ if (r)
-+ PARSE_ERROR("unable to find target");
-+
-+ /* Look up the target type */
-+ ttype = dm_get_target_type(spec->target_type);
-+ if (!ttype)
-+ PARSE_ERROR("unable to find target type");
-+
-+ if (gap(table, spec))
-+ PARSE_ERROR("gap in target ranges");
-+
-+ /* Split up the parameter list */
-+ if (split_args(MAX_ARGS, &argc, argv, params) < 0)
-+ PARSE_ERROR("Too many arguments");
-+
-+ /* Build the target */
-+ if (ttype->ctr(table, spec->sector_start, spec->length,
-+ argc, argv, &context)) {
-+ DMWARN("%s: target constructor failed",
-+ (char *) context);
-+ return -EINVAL;
-+ }
-+
-+ /* Add the target to the table */
-+ highs = spec->sector_start + (spec->length - 1);
-+ if (dm_table_add_target(table, highs, ttype, context))
-+ PARSE_ERROR("internal error adding target to table");
-+
-+ first = 0;
-+ }
-+
-+#undef PARSE_ERROR
-+
-+ r = dm_table_complete(table);
-+ return r;
-+}
-+
-+/*
-+ * Round up the ptr to the next 'align' boundary. Obviously
-+ * 'align' must be a power of 2.
-+ */
-+static inline void *align_ptr(void *ptr, unsigned int align)
-+{
-+ align--;
-+ return (void *) (((unsigned long) (ptr + align)) & ~align);
-+}
-+
-+/*
-+ * Copies a dm_ioctl and an optional additional payload to
-+ * userland.
-+ */
-+static int results_to_user(struct dm_ioctl *user, struct dm_ioctl *param,
-+ void *data, unsigned long len)
-+{
-+ int r;
-+ void *ptr = NULL;
-+
-+ strncpy(param->version, DM_IOCTL_VERSION, sizeof(param->version));
-+
-+ if (data) {
-+ ptr = align_ptr(user + 1, sizeof(unsigned long));
-+ param->data_start = ptr - (void *) user;
-+ }
-+
-+ r = copy_to_user(user, param, sizeof(*param));
-+ if (r)
-+ return r;
-+
-+ if (data) {
-+ if (param->data_start + len > param->data_size)
-+ return -ENOSPC;
-+ r = copy_to_user(ptr, data, len);
-+ }
-+
-+ return r;
-+}
-+
-+/*
-+ * Fills in a dm_ioctl structure, ready for sending back to
-+ * userland.
-+ */
-+static void __info(struct mapped_device *md, struct dm_ioctl *param)
-+{
-+ param->flags = DM_EXISTS_FLAG;
-+ if (md->suspended)
-+ param->flags |= DM_SUSPEND_FLAG;
-+ if (md->read_only)
-+ param->flags |= DM_READONLY_FLAG;
-+
-+ strncpy(param->name, md->name, sizeof(param->name));
-+
-+ if (md->uuid)
-+ strncpy(param->uuid, md->uuid, sizeof(param->uuid) - 1);
-+ else
-+ param->uuid[0] = '\0';
-+
-+ param->open_count = md->use_count;
-+ param->dev = kdev_t_to_nr(md->dev);
-+ param->target_count = md->map->num_targets;
-+}
-+
-+/*
-+ * Always use UUID for lookups if it's present, otherwise use name.
-+ */
-+static inline char *lookup_name(struct dm_ioctl *param)
-+{
-+ return (*param->uuid) ? param->uuid : param->name;
-+}
-+
-+static inline int lookup_type(struct dm_ioctl *param)
-+{
-+ return (*param->uuid) ? DM_LOOKUP_BY_UUID : DM_LOOKUP_BY_NAME;
-+}
-+
-+/*
-+ * Copies device info back to user space, used by
-+ * the create and info ioctls.
-+ */
-+static int info(struct dm_ioctl *param, struct dm_ioctl *user)
-+{
-+ struct mapped_device *md;
-+
-+ param->flags = 0;
-+
-+ md = dm_get_name_r(lookup_name(param), lookup_type(param));
-+ if (!md)
-+ /*
-+ * Device not found - returns cleared exists flag.
-+ */
-+ goto out;
-+
-+ __info(md, param);
-+ dm_put_r(md);
-+
-+ out:
-+ return results_to_user(user, param, NULL, 0);
-+}
-+
-+/*
-+ * Retrieves a list of devices used by a particular dm device.
-+ */
-+static int dep(struct dm_ioctl *param, struct dm_ioctl *user)
-+{
-+ int count, r;
-+ struct mapped_device *md;
-+ struct list_head *tmp;
-+ size_t len = 0;
-+ struct dm_target_deps *deps = NULL;
-+
-+ md = dm_get_name_r(lookup_name(param), lookup_type(param));
-+ if (!md)
-+ goto out;
-+
-+ /*
-+ * Setup the basic dm_ioctl structure.
-+ */
-+ __info(md, param);
-+
-+ /*
-+ * Count the devices.
-+ */
-+ count = 0;
-+ list_for_each(tmp, &md->map->devices)
-+ count++;
-+
-+ /*
-+ * Allocate a kernel space version of the dm_target_status
-+ * struct.
-+ */
-+ len = sizeof(*deps) + (sizeof(*deps->dev) * count);
-+ deps = kmalloc(len, GFP_KERNEL);
-+ if (!deps) {
-+ dm_put_r(md);
-+ return -ENOMEM;
-+ }
-+
-+ /*
-+ * Fill in the devices.
-+ */
-+ deps->count = count;
-+ count = 0;
-+ list_for_each(tmp, &md->map->devices) {
-+ struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
-+ deps->dev[count++] = kdev_t_to_nr(dd->dev);
-+ }
-+ dm_put_r(md);
-+
-+ out:
-+ r = results_to_user(user, param, deps, len);
-+
-+ kfree(deps);
-+ return r;
-+}
-+
-+static int create(struct dm_ioctl *param, struct dm_ioctl *user)
-+{
-+ int r, ro;
-+ struct dm_table *t;
-+ int minor;
-+
-+ r = dm_table_create(&t);
-+ if (r)
-+ return r;
-+
-+ r = populate_table(t, param);
-+ if (r) {
-+ dm_table_destroy(t);
-+ return r;
-+ }
-+
-+ minor = (param->flags & DM_PERSISTENT_DEV_FLAG) ?
-+ MINOR(to_kdev_t(param->dev)) : -1;
-+
-+ ro = (param->flags & DM_READONLY_FLAG) ? 1 : 0;
-+
-+ r = dm_create(param->name, param->uuid, minor, ro, t);
-+ if (r) {
-+ dm_table_destroy(t);
-+ return r;
-+ }
-+
-+ r = info(param, user);
-+ return r;
-+}
-+
-+static int remove(struct dm_ioctl *param)
-+{
-+ int r;
-+ struct mapped_device *md;
-+
-+ md = dm_get_name_w(lookup_name(param), lookup_type(param));
-+ if (!md)
-+ return -ENXIO;
-+
-+ r = dm_destroy(md);
-+ dm_put_w(md);
-+ if (!r)
-+ kfree(md);
-+
-+ return r;
-+}
-+
-+static int suspend(struct dm_ioctl *param)
-+{
-+ int r;
-+ struct mapped_device *md;
-+
-+ md = dm_get_name_w(lookup_name(param), lookup_type(param));
-+ if (!md)
-+ return -ENXIO;
-+
-+ r = (param->flags & DM_SUSPEND_FLAG) ? dm_suspend(md) : dm_resume(md);
-+ dm_put_w(md);
-+
-+ return r;
-+}
-+
-+static int reload(struct dm_ioctl *param, struct dm_ioctl *user)
-+{
-+ int r;
-+ struct mapped_device *md;
-+ struct dm_table *t;
-+
-+ r = dm_table_create(&t);
-+ if (r)
-+ return r;
-+
-+ r = populate_table(t, param);
-+ if (r) {
-+ dm_table_destroy(t);
-+ return r;
-+ }
-+
-+ md = dm_get_name_w(lookup_name(param), lookup_type(param));
-+ if (!md) {
-+ dm_table_destroy(t);
-+ return -ENXIO;
-+ }
-+
-+ r = dm_swap_table(md, t);
-+ if (r) {
-+ dm_put_w(md);
-+ dm_table_destroy(t);
-+ return r;
-+ }
-+
-+ dm_set_ro(md, (param->flags & DM_READONLY_FLAG) ? 1 : 0);
-+ dm_put_w(md);
-+
-+ r = info(param, user);
-+ return r;
-+}
-+
-+static int rename(struct dm_ioctl *param)
-+{
-+ char *newname = (char *) param + param->data_start;
-+
-+ if (valid_str(newname, (void *) param,
-+ (void *) param + param->data_size) ||
-+ dm_set_name(lookup_name(param), lookup_type(param), newname)) {
-+ DMWARN("Invalid new logical volume name supplied.");
-+ return -EINVAL;
-+ }
-+
-+ return 0;
-+}
-+
-+static int ctl_open(struct inode *inode, struct file *file)
-+{
-+ /* only root can open this */
-+ if (!capable(CAP_SYS_ADMIN))
-+ return -EACCES;
-+
-+ MOD_INC_USE_COUNT;
-+
-+ return 0;
-+}
-+
-+static int ctl_close(struct inode *inode, struct file *file)
-+{
-+ MOD_DEC_USE_COUNT;
-+ return 0;
-+}
-+
-+static int ctl_ioctl(struct inode *inode, struct file *file,
-+ uint command, ulong u)
-+{
-+ int r = 0;
-+ struct dm_ioctl *param;
-+ struct dm_ioctl *user = (struct dm_ioctl *) u;
-+ uint cmd = _IOC_NR(command);
-+
-+ /* Process commands without params first - always return version */
-+ switch (cmd) {
-+ case DM_REMOVE_ALL_CMD:
-+ dm_destroy_all();
-+ case DM_VERSION_CMD:
-+ return version(user);
-+ default:
-+ break;
-+ }
-+
-+ r = copy_params(user, ¶m);
-+ if (r)
-+ goto err;
-+
-+ r = validate_params(cmd, param);
-+ if (r) {
-+ free_params(param);
-+ goto err;
-+ }
-+
-+ switch (cmd) {
-+ case DM_INFO_CMD:
-+ r = info(param, user);
-+ break;
-+
-+ case DM_SUSPEND_CMD:
-+ r = suspend(param);
-+ break;
-+
-+ case DM_CREATE_CMD:
-+ r = create(param, user);
-+ break;
-+
-+ case DM_RELOAD_CMD:
-+ r = reload(param, user);
-+ break;
-+
-+ case DM_REMOVE_CMD:
-+ r = remove(param);
-+ break;
-+
-+ case DM_RENAME_CMD:
-+ r = rename(param);
-+ break;
-+
-+ case DM_DEPS_CMD:
-+ r = dep(param, user);
-+ break;
-+
-+ default:
-+ DMWARN("dm_ctl_ioctl: unknown command 0x%x", command);
-+ r = -EINVAL;
-+ }
-+
-+ free_params(param);
-+ return r;
-+
-+ err:
-+ version(user);
-+ return r;
-+}
-+
-+static struct file_operations _ctl_fops = {
-+ open: ctl_open,
-+ release: ctl_close,
-+ ioctl: ctl_ioctl,
-+ owner: THIS_MODULE,
-+};
-+
-+static devfs_handle_t _ctl_handle;
-+
-+static struct miscdevice _dm_misc = {
-+ minor: MISC_DYNAMIC_MINOR,
-+ name: DM_NAME,
-+ fops: &_ctl_fops
-+};
-+
-+/* Create misc character device and link to DM_DIR/control */
-+int __init dm_interface_init(void)
-+{
-+ int r;
-+ char rname[64];
-+
-+ r = misc_register(&_dm_misc);
-+ if (r) {
-+ DMERR("misc_register failed for control device");
-+ return r;
-+ }
-+
-+ r = devfs_generate_path(_dm_misc.devfs_handle, rname + 3,
-+ sizeof rname - 3);
-+ if (r == -ENOSYS)
-+ return 0; /* devfs not present */
-+
-+ if (r < 0) {
-+ DMERR("devfs_generate_path failed for control device");
-+ goto failed;
-+ }
-+
-+ strncpy(rname + r, "../", 3);
-+ r = devfs_mk_symlink(NULL, DM_DIR "/control",
-+ DEVFS_FL_DEFAULT, rname + r, &_ctl_handle, NULL);
-+ if (r) {
-+ DMERR("devfs_mk_symlink failed for control device");
-+ goto failed;
-+ }
-+ devfs_auto_unregister(_dm_misc.devfs_handle, _ctl_handle);
-+
-+ return 0;
-+
-+ failed:
-+ misc_deregister(&_dm_misc);
-+ return r;
-+}
-+
-+void dm_interface_exit(void)
-+{
-+ if (misc_deregister(&_dm_misc) < 0)
-+ DMERR("misc_deregister failed for control device");
-+}
-diff -ruN linux-2.4.18/drivers/md/dm-linear.c linux/drivers/md/dm-linear.c
---- linux-2.4.18/drivers/md/dm-linear.c Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm-linear.c Tue Jan 15 19:53:55 2002
-@@ -0,0 +1,105 @@
-+/*
-+ * Copyright (C) 2001 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#include "dm.h"
-+
-+#include <linux/module.h>
-+#include <linux/init.h>
-+#include <linux/blkdev.h>
-+
-+/*
-+ * Linear: maps a linear range of a device.
-+ */
-+struct linear_c {
-+ long delta; /* FIXME: we need a signed offset type */
-+ struct dm_dev *dev;
-+};
-+
-+/*
-+ * Construct a linear mapping: <dev_path> <offset>
-+ */
-+static int linear_ctr(struct dm_table *t, offset_t b, offset_t l,
-+ int argc, char **argv, void **context)
-+{
-+ struct linear_c *lc;
-+ unsigned long start; /* FIXME: unsigned long long */
-+ char *end;
-+
-+ if (argc != 2) {
-+ *context = "dm-linear: Not enough arguments";
-+ return -EINVAL;
-+ }
-+
-+ lc = kmalloc(sizeof(*lc), GFP_KERNEL);
-+ if (lc == NULL) {
-+ *context = "dm-linear: Cannot allocate linear context";
-+ return -ENOMEM;
-+ }
-+
-+ start = simple_strtoul(argv[1], &end, 10);
-+ if (*end) {
-+ *context = "dm-linear: Invalid device sector";
-+ goto bad;
-+ }
-+
-+ if (dm_table_get_device(t, argv[0], start, l, &lc->dev)) {
-+ *context = "dm-linear: Device lookup failed";
-+ goto bad;
-+ }
-+
-+ lc->delta = (int) start - (int) b;
-+ *context = lc;
-+ return 0;
-+
-+ bad:
-+ kfree(lc);
-+ return -EINVAL;
-+}
-+
-+static void linear_dtr(struct dm_table *t, void *c)
-+{
-+ struct linear_c *lc = (struct linear_c *) c;
-+
-+ dm_table_put_device(t, lc->dev);
-+ kfree(c);
-+}
-+
-+static int linear_map(struct buffer_head *bh, int rw, void *context)
-+{
-+ struct linear_c *lc = (struct linear_c *) context;
-+
-+ bh->b_rdev = lc->dev->dev;
-+ bh->b_rsector = bh->b_rsector + lc->delta;
-+
-+ return 1;
-+}
-+
-+static struct target_type linear_target = {
-+ name: "linear",
-+ module: THIS_MODULE,
-+ ctr: linear_ctr,
-+ dtr: linear_dtr,
-+ map: linear_map,
-+};
-+
-+int __init dm_linear_init(void)
-+{
-+ int r = dm_register_target(&linear_target);
-+
-+ if (r < 0)
-+ DMERR("linear: register failed %d", r);
-+
-+ return r;
-+}
-+
-+void dm_linear_exit(void)
-+{
-+ int r = dm_unregister_target(&linear_target);
-+
-+ if (r < 0)
-+ DMERR("linear: unregister failed %d", r);
-+}
-+
-diff -ruN linux-2.4.18/drivers/md/dm-mirror.c linux/drivers/md/dm-mirror.c
---- linux-2.4.18/drivers/md/dm-mirror.c Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm-mirror.c Tue Apr 23 22:13:47 2002
-@@ -0,0 +1,299 @@
-+/*
-+ * Copyright (C) 2002 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#include "dm.h"
-+#include "kcopyd.h"
-+
-+#include <linux/module.h>
-+#include <linux/init.h>
-+#include <linux/blkdev.h>
-+
-+/* kcopyd priority of mirror operations */
-+#define MIRROR_COPY_PRIORITY 5
-+
-+static kmem_cache_t *bh_cachep;
-+
-+/*
-+ * Mirror: maps a mirror range of a device.
-+ */
-+struct mirror_c {
-+ struct dm_dev *fromdev;
-+ struct dm_dev *todev;
-+
-+ unsigned long from_delta;
-+ unsigned long to_delta;
-+
-+ unsigned long frompos;
-+ unsigned long topos;
-+
-+ unsigned long got_to;
-+ struct rw_semaphore lock;
-+ struct buffer_head *bhstring;
-+ int error;
-+};
-+
-+/* Called when a duplicating I/O has finished */
-+static void mirror_end_io(struct buffer_head *bh, int uptodate)
-+{
-+ struct mirror_c *lc = (struct mirror_c *) bh->b_private;
-+
-+ /* Flag error if it failed */
-+ if (!uptodate) {
-+ DMERR("Mirror copy to %s failed", kdevname(lc->todev->dev));
-+ lc->error = 1;
-+ dm_notify(lc); /* TODO: interface ?? */
-+ }
-+ kmem_cache_free(bh_cachep, bh);
-+}
-+
-+static void mirror_bh(struct mirror_c *mc, struct buffer_head *bh)
-+{
-+ struct buffer_head *dbh = kmem_cache_alloc(bh_cachep, GFP_NOIO);
-+ if (dbh) {
-+ *dbh = *bh;
-+ dbh->b_rdev = mc->todev->dev;
-+ dbh->b_rsector = bh->b_rsector - mc->from_delta + mc->to_delta;
-+ dbh->b_end_io = mirror_end_io;
-+ dbh->b_private = mc;
-+
-+ generic_make_request(WRITE, dbh);
-+ } else {
-+ DMERR("kmem_cache_alloc failed for mirror bh");
-+ mc->error = 1;
-+ }
-+}
-+
-+/* Called when the copy I/O has finished */
-+static void copy_callback(copy_cb_reason_t reason, void *context, long arg)
-+{
-+ struct mirror_c *lc = (struct mirror_c *) context;
-+ struct buffer_head *bh;
-+
-+ if (reason == COPY_CB_FAILED_READ || reason == COPY_CB_FAILED_WRITE) {
-+ DMERR("Mirror block %s on %s failed, sector %ld",
-+ reason == COPY_CB_FAILED_READ ? "read" : "write",
-+ reason == COPY_CB_FAILED_READ ?
-+ kdevname(lc->fromdev->dev) :
-+ kdevname(lc->todev->dev), arg);
-+ lc->error = 1;
-+ return;
-+ }
-+
-+ if (reason == COPY_CB_COMPLETE) {
-+ /* Say we've finished */
-+ dm_notify(lc); /* TODO: interface ?? */
-+ }
-+
-+ if (reason == COPY_CB_PROGRESS) {
-+ dm_notify(lc); /* TODO: interface ?? */
-+ }
-+
-+ /* Submit, and mirror any pending BHs */
-+ down_write(&lc->lock);
-+ lc->got_to = arg;
-+
-+ bh = lc->bhstring;
-+ lc->bhstring = NULL;
-+ up_write(&lc->lock);
-+
-+ while (bh) {
-+ struct buffer_head *nextbh = bh->b_reqnext;
-+ bh->b_reqnext = NULL;
-+ generic_make_request(WRITE, bh);
-+ mirror_bh(lc, bh);
-+ bh = nextbh;
-+ }
-+}
-+
-+/*
-+ * Construct a mirror mapping: <dev_path1> <offset> <dev_path2> <offset> <throttle> [<priority>]
-+ */
-+static int mirror_ctr(struct dm_table *t, offset_t b, offset_t l,
-+ int argc, char **argv, void **context)
-+{
-+ struct mirror_c *lc;
-+ unsigned long offset1, offset2;
-+ char *value;
-+ int priority = MIRROR_COPY_PRIORITY;
-+ int throttle;
-+ struct kcopyd_region src, dest;
-+
-+ if (argc <= 4) {
-+ *context = "dm-mirror: Not enough arguments";
-+ return -EINVAL;
-+ }
-+
-+ lc = kmalloc(sizeof(*lc), GFP_KERNEL);
-+ if (lc == NULL) {
-+ *context = "dm-mirror: Cannot allocate mirror context";
-+ return -ENOMEM;
-+ }
-+
-+ if (dm_table_get_device(t, argv[0], 0, l, &lc->fromdev)) {
-+ *context = "dm-mirror: Device lookup failed";
-+ goto bad;
-+ }
-+
-+ offset1 = simple_strtoul(argv[1], &value, 10);
-+ if (value == NULL) {
-+ *context = "Invalid offset for dev1";
-+ dm_table_put_device(t, lc->fromdev);
-+ goto bad;
-+ }
-+
-+ if (dm_table_get_device(t, argv[2], 0, l, &lc->todev)) {
-+ *context = "dm-mirror: Device lookup failed";
-+ dm_table_put_device(t, lc->fromdev);
-+ goto bad;
-+ }
-+
-+ offset2 = simple_strtoul(argv[3], &value, 10);
-+ if (value == NULL) {
-+ *context = "Invalid offset for dev2";
-+ goto bad_put;
-+ }
-+
-+ throttle = simple_strtoul(argv[4], &value, 10);
-+ if (value == NULL) {
-+ *context = "Invalid throttle value";
-+ goto bad_put;
-+ }
-+
-+ if (argc > 5) {
-+ priority = simple_strtoul(argv[5], &value, 10);
-+ if (value == NULL) {
-+ *context = "Invalid priority value";
-+ goto bad_put;
-+ }
-+ }
-+
-+ lc->from_delta = (int) offset1 - (int) b;
-+ lc->to_delta = (int) offset2 - (int) b;
-+ lc->frompos = offset1;
-+ lc->topos = offset2;
-+ lc->error = 0;
-+ lc->bhstring = NULL;
-+ init_rwsem(&lc->lock);
-+ *context = lc;
-+
-+ /* Tell kcopyd to do the biz */
-+ src.dev = lc->fromdev->dev;
-+ src.sector = offset1;
-+ src.count = l - offset1;
-+
-+ dest.dev = lc->todev->dev;
-+ dest.sector = offset2;
-+ dest.count = l - offset1;
-+
-+ if (kcopyd_copy(&src, &dest, priority, 0, copy_callback, lc)) {
-+ DMERR("block copy call failed");
-+ dm_table_put_device(t, lc->fromdev);
-+ dm_table_put_device(t, lc->todev);
-+ goto bad;
-+ }
-+ return 0;
-+
-+ bad_put:
-+ dm_table_put_device(t, lc->fromdev);
-+ dm_table_put_device(t, lc->todev);
-+ bad:
-+ kfree(lc);
-+ return -EINVAL;
-+}
-+
-+static void mirror_dtr(struct dm_table *t, void *c)
-+{
-+ struct mirror_c *lc = (struct mirror_c *) c;
-+
-+ dm_table_put_device(t, lc->fromdev);
-+ dm_table_put_device(t, lc->todev);
-+ kfree(c);
-+}
-+
-+static int mirror_map(struct buffer_head *bh, int rw, void *context)
-+{
-+ struct mirror_c *lc = (struct mirror_c *) context;
-+
-+ bh->b_rdev = lc->fromdev->dev;
-+ bh->b_rsector = bh->b_rsector + lc->from_delta;
-+
-+ if (rw == WRITE) {
-+ down_write(&lc->lock);
-+
-+ /*
-+ * If this area is in flight then save it until it's
-+ * commited to the mirror disk and then submit it and
-+ * its mirror.
-+ */
-+ if (bh->b_rsector > lc->got_to &&
-+ bh->b_rsector <= lc->got_to + KIO_MAX_SECTORS) {
-+ bh->b_reqnext = lc->bhstring;
-+ lc->bhstring = bh;
-+ up_write(&lc->lock);
-+ return 0;
-+ }
-+
-+ /*
-+ * If we've already copied this block then duplicate
-+ * it to the mirror device
-+ */
-+ if (bh->b_rsector < lc->got_to) {
-+ /* Schedule copy of I/O to other target */
-+ mirror_bh(lc, bh);
-+ }
-+ up_write(&lc->lock);
-+ }
-+ return 1;
-+}
-+
-+static struct target_type mirror_target = {
-+ name: "mirror",
-+ module: THIS_MODULE,
-+ ctr: mirror_ctr,
-+ dtr: mirror_dtr,
-+ map: mirror_map,
-+};
-+
-+int __init dm_mirror_init(void)
-+{
-+ int r;
-+
-+ bh_cachep = kmem_cache_create("dm-mirror",
-+ sizeof(struct buffer_head),
-+ __alignof__(struct buffer_head),
-+ 0, NULL, NULL);
-+ if (!bh_cachep) {
-+ return -1;
-+ }
-+
-+ r = dm_register_target(&mirror_target);
-+ if (r < 0) {
-+ DMERR("mirror: register failed %d", r);
-+ kmem_cache_destroy(bh_cachep);
-+ }
-+ return r;
-+}
-+
-+void dm_mirror_exit(void)
-+{
-+ int r = dm_unregister_target(&mirror_target);
-+
-+ if (r < 0)
-+ DMERR("mirror: unregister failed %d", r);
-+
-+ kmem_cache_destroy(bh_cachep);
-+}
-+
-+/*
-+ * Overrides for Emacs so that we follow Linus's tabbing style.
-+ * Emacs will notice this stuff at the end of the file and automatically
-+ * adjust the settings for this buffer only. This must remain at the end
-+ * of the file.
-+ * ---------------------------------------------------------------------------
-+ * Local variables:
-+ * c-file-style: "linux"
-+ * End:
-+ */
-diff -ruN linux-2.4.18/drivers/md/dm-snapshot.c linux/drivers/md/dm-snapshot.c
---- linux-2.4.18/drivers/md/dm-snapshot.c Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm-snapshot.c Tue Apr 23 22:07:45 2002
-@@ -0,0 +1,1080 @@
-+/*
-+ * dm-snapshot.c
-+ *
-+ * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#include <linux/config.h>
-+#include <linux/module.h>
-+#include <linux/init.h>
-+#include <linux/slab.h>
-+#include <linux/list.h>
-+#include <linux/fs.h>
-+#include <linux/blkdev.h>
-+#include <linux/mempool.h>
-+#include <linux/device-mapper.h>
-+
-+#include "dm-snapshot.h"
-+#include "kcopyd.h"
-+
-+/*
-+ * FIXME: Remove this before release.
-+ */
-+#if 0
-+#define DMDEBUG(x...) DMWARN( ## x)
-+#else
-+#define DMDEBUG(x...)
-+#endif
-+
-+/*
-+ * Hard sector size used all over the kernel
-+ */
-+#define SECTOR_SIZE 512
-+
-+/*
-+ * kcopyd priority of snapshot operations
-+ */
-+#define SNAPSHOT_COPY_PRIORITY 2
-+
-+struct pending_exception {
-+ struct exception e;
-+
-+ /*
-+ * Origin buffers waiting for this to complete are held
-+ * in a list (using b_reqnext).
-+ */
-+ struct buffer_head *origin_bhs;
-+ struct buffer_head *snapshot_bhs;
-+
-+ /*
-+ * Other pending_exceptions that are processing this
-+ * chunk. When this list is empty, we know we can
-+ * complete the origins.
-+ */
-+ struct list_head siblings;
-+
-+ /* Pointer back to snapshot context */
-+ struct dm_snapshot *snap;
-+
-+ /*
-+ * 1 indicates the exception has already been sent to
-+ * kcopyd.
-+ */
-+ int started;
-+};
-+
-+/*
-+ * Hash table mapping origin volumes to lists of snapshots and
-+ * a lock to protect it
-+ */
-+static kmem_cache_t *exception_cache;
-+static kmem_cache_t *pending_cache;
-+static mempool_t *pending_pool;
-+
-+/*
-+ * One of these per registered origin, held in the snapshot_origins hash
-+ */
-+struct origin {
-+ /* The origin device */
-+ kdev_t dev;
-+
-+ struct list_head hash_list;
-+
-+ /* List of snapshots for this origin */
-+ struct list_head snapshots;
-+};
-+
-+/*
-+ * Useful macro for running the store functions. Use
-+ * store_int_fn if you want the return value.
-+ */
-+#define store_fn(snap, fn, args...) \
-+ if ((snap)->store. ## fn) \
-+ (snap)->store. ## fn ( &(snap)->store , ## args )
-+
-+#define store_int_fn(snap, fn, args...) \
-+ (((snap)->store. ## fn) ? \
-+ ((snap)->store. ## fn ( &(snap)->store , ## args )) : 0)
-+
-+/*
-+ * Size of the hash table for origin volumes. If we make this
-+ * the size of the minors list then it should be nearly perfect
-+ */
-+#define ORIGIN_HASH_SIZE 256
-+#define ORIGIN_MASK 0xFF
-+static struct list_head *_origins;
-+static struct rw_semaphore _origins_lock;
-+
-+static int init_origin_hash(void)
-+{
-+ int i;
-+
-+ _origins = kmalloc(ORIGIN_HASH_SIZE * sizeof(struct list_head),
-+ GFP_KERNEL);
-+ if (!_origins) {
-+ DMERR("Device mapper: Snapshot: unable to allocate memory");
-+ return -ENOMEM;
-+ }
-+
-+ for (i = 0; i < ORIGIN_HASH_SIZE; i++)
-+ INIT_LIST_HEAD(_origins + i);
-+ init_rwsem(&_origins_lock);
-+
-+ return 0;
-+}
-+
-+static void exit_origin_hash(void)
-+{
-+ kfree(_origins);
-+}
-+
-+static inline unsigned int origin_hash(kdev_t dev)
-+{
-+ return MINOR(dev) & ORIGIN_MASK;
-+}
-+
-+static struct origin *__lookup_origin(kdev_t origin)
-+{
-+ struct list_head *slist;
-+ struct list_head *ol;
-+ struct origin *o;
-+
-+ ol = &_origins[origin_hash(origin)];
-+ list_for_each(slist, ol) {
-+ o = list_entry(slist, struct origin, hash_list);
-+
-+ if (o->dev == origin)
-+ return o;
-+ }
-+
-+ return NULL;
-+}
-+
-+static void __insert_origin(struct origin *o)
-+{
-+ struct list_head *sl = &_origins[origin_hash(o->dev)];
-+ list_add_tail(&o->hash_list, sl);
-+}
-+
-+/*
-+ * Make a note of the snapshot and its origin so we can look it
-+ * up when the origin has a write on it.
-+ */
-+static int register_snapshot(struct dm_snapshot *snap)
-+{
-+ struct origin *o;
-+ kdev_t dev = snap->origin->dev;
-+
-+ down_write(&_origins_lock);
-+ o = __lookup_origin(dev);
-+
-+ if (!o) {
-+ /* New origin */
-+ o = kmalloc(sizeof(*o), GFP_KERNEL);
-+ if (!o) {
-+ up_write(&_origins_lock);
-+ return -ENOMEM;
-+ }
-+
-+ /* Initialise the struct */
-+ INIT_LIST_HEAD(&o->snapshots);
-+ o->dev = dev;
-+
-+ __insert_origin(o);
-+ }
-+
-+ list_add_tail(&snap->list, &o->snapshots);
-+
-+ up_write(&_origins_lock);
-+ return 0;
-+}
-+
-+static void unregister_snapshot(struct dm_snapshot *s)
-+{
-+ struct origin *o;
-+
-+ down_write(&_origins_lock);
-+ o = __lookup_origin(s->origin->dev);
-+
-+ list_del(&s->list);
-+ if (list_empty(&o->snapshots)) {
-+ list_del(&o->hash_list);
-+ kfree(o);
-+ }
-+
-+ up_write(&_origins_lock);
-+}
-+
-+/*
-+ * Implementation of the exception hash tables.
-+ */
-+static int init_exception_table(struct exception_table *et, uint32_t size)
-+{
-+ int i;
-+
-+ et->hash_mask = size - 1;
-+ et->table = vmalloc(sizeof(struct list_head) * (size));
-+ if (!et->table)
-+ return -ENOMEM;
-+
-+ for (i = 0; i < size; i++)
-+ INIT_LIST_HEAD(et->table + i);
-+
-+ return 0;
-+}
-+
-+static void exit_exception_table(struct exception_table *et, kmem_cache_t * mem)
-+{
-+ struct list_head *slot, *entry, *temp;
-+ struct exception *ex;
-+ int i, size;
-+
-+ size = et->hash_mask + 1;
-+ for (i = 0; i < size; i++) {
-+ slot = et->table + i;
-+
-+ list_for_each_safe(entry, temp, slot) {
-+ ex = list_entry(entry, struct exception, hash_list);
-+ kmem_cache_free(mem, ex);
-+ }
-+ }
-+
-+ vfree(et->table);
-+}
-+
-+/*
-+ * FIXME: check how this hash fn is performing.
-+ */
-+static inline uint32_t exception_hash(struct exception_table *et, chunk_t chunk)
-+{
-+ return chunk & et->hash_mask;
-+}
-+
-+static void insert_exception(struct exception_table *eh, struct exception *e)
-+{
-+ struct list_head *l = &eh->table[exception_hash(eh, e->old_chunk)];
-+ list_add(&e->hash_list, l);
-+}
-+
-+static inline void remove_exception(struct exception *e)
-+{
-+ list_del(&e->hash_list);
-+}
-+
-+/*
-+ * Return the exception data for a sector, or NULL if not
-+ * remapped.
-+ */
-+static struct exception *lookup_exception(struct exception_table *et,
-+ chunk_t chunk)
-+{
-+ struct list_head *slot, *el;
-+ struct exception *e;
-+
-+ slot = &et->table[exception_hash(et, chunk)];
-+ list_for_each(el, slot) {
-+ e = list_entry(el, struct exception, hash_list);
-+ if (e->old_chunk == chunk)
-+ return e;
-+ }
-+
-+ return NULL;
-+}
-+
-+static inline struct exception *alloc_exception(void)
-+{
-+ return kmem_cache_alloc(exception_cache, GFP_NOIO);
-+}
-+
-+static inline void free_exception(struct exception *e)
-+{
-+ kmem_cache_free(exception_cache, e);
-+}
-+
-+static inline struct pending_exception *alloc_pending_exception(void)
-+{
-+ return mempool_alloc(pending_pool, GFP_NOIO);
-+}
-+
-+static inline void free_pending_exception(struct pending_exception *pe)
-+{
-+ mempool_free(pe, pending_pool);
-+}
-+
-+int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new)
-+{
-+ struct exception *e;
-+
-+ e = alloc_exception();
-+ if (!e)
-+ return -ENOMEM;
-+
-+ e->old_chunk = old;
-+ e->new_chunk = new;
-+ insert_exception(&s->complete, e);
-+ return 0;
-+}
-+
-+/*
-+ * Hard coded magic.
-+ */
-+static int calc_max_buckets(void)
-+{
-+ unsigned long mem;
-+
-+ mem = num_physpages << PAGE_SHIFT;
-+ mem /= 50;
-+ mem /= sizeof(struct list_head);
-+
-+ return mem;
-+}
-+
-+/*
-+ * Rounds a number down to a power of 2.
-+ */
-+static inline uint32_t round_down(uint32_t n)
-+{
-+ while (n & (n - 1))
-+ n &= (n - 1);
-+ return n;
-+}
-+
-+/*
-+ * Allocate room for a suitable hash table.
-+ */
-+static int init_hash_tables(struct dm_snapshot *s)
-+{
-+ offset_t hash_size, cow_dev_size, origin_dev_size, max_buckets;
-+
-+ /*
-+ * Calculate based on the size of the original volume or
-+ * the COW volume...
-+ */
-+ cow_dev_size = get_dev_size(s->cow->dev);
-+ origin_dev_size = get_dev_size(s->origin->dev);
-+ max_buckets = calc_max_buckets();
-+
-+ hash_size = min(origin_dev_size, cow_dev_size) / s->chunk_size;
-+ hash_size = min(hash_size, max_buckets);
-+
-+ /* Round it down to a power of 2 */
-+ hash_size = round_down(hash_size);
-+ if (init_exception_table(&s->complete, hash_size))
-+ return -ENOMEM;
-+
-+ /*
-+ * Allocate hash table for in-flight exceptions
-+ * Make this smaller than the real hash table
-+ */
-+ hash_size >>= 3;
-+ if (!hash_size)
-+ hash_size = 64;
-+
-+ if (init_exception_table(&s->pending, hash_size)) {
-+ exit_exception_table(&s->complete, exception_cache);
-+ return -ENOMEM;
-+ }
-+
-+ return 0;
-+}
-+
-+/*
-+ * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n>
-+ * <chunk-size> <extent-size>
-+ */
-+static int snapshot_ctr(struct dm_table *t, offset_t b, offset_t l,
-+ int argc, char **argv, void **context)
-+{
-+ struct dm_snapshot *s;
-+ unsigned long chunk_size;
-+ unsigned long extent_size = 0L;
-+ int r = -EINVAL;
-+ char *persistent;
-+ char *origin_path;
-+ char *cow_path;
-+ char *value;
-+ int blocksize;
-+
-+ if (argc < 4) {
-+ *context = "dm-snapshot: Not enough arguments";
-+ r = -EINVAL;
-+ goto bad;
-+ }
-+
-+ origin_path = argv[0];
-+ cow_path = argv[1];
-+ persistent = argv[2];
-+
-+ if ((*persistent & 0x5f) != 'P' && (*persistent & 0x5f) != 'N') {
-+ *context = "Persistent flag is not P or N";
-+ r = -EINVAL;
-+ goto bad;
-+ }
-+
-+ chunk_size = simple_strtoul(argv[3], &value, 10);
-+ if (chunk_size == 0 || value == NULL) {
-+ *context = "Invalid chunk size";
-+ r = -EINVAL;
-+ goto bad;
-+ }
-+
-+ /* Get the extent size for persistent snapshots */
-+ if ((*persistent & 0x5f) == 'P') {
-+ if (argc < 5) {
-+ *context = "No extent size specified";
-+ r = -EINVAL;
-+ goto bad;
-+ }
-+
-+ extent_size = simple_strtoul(argv[4], &value, 10);
-+ if (extent_size == 0 || value == NULL) {
-+ *context = "Invalid extent size";
-+ r = -EINVAL;
-+ goto bad;
-+ }
-+ }
-+
-+ s = kmalloc(sizeof(*s), GFP_KERNEL);
-+ if (s == NULL) {
-+ *context = "Cannot allocate snapshot context private structure";
-+ r = -ENOMEM;
-+ goto bad;
-+ }
-+
-+ r = dm_table_get_device(t, origin_path, 0, 0, &s->origin);
-+ if (r) {
-+ *context = "Cannot get origin device";
-+ goto bad_free;
-+ }
-+
-+ r = dm_table_get_device(t, cow_path, 0, 0, &s->cow);
-+ if (r) {
-+ dm_table_put_device(t, s->origin);
-+ *context = "Cannot get COW device";
-+ goto bad_free;
-+ }
-+
-+ /* Validate the extent and chunk sizes against the device block size */
-+ blocksize = get_hardsect_size(s->cow->dev);
-+ if (chunk_size % (blocksize / SECTOR_SIZE)) {
-+ *context = "Chunk size is not a multiple of device blocksize";
-+ r = -EINVAL;
-+ goto bad_putdev;
-+ }
-+
-+ if (extent_size % (blocksize / SECTOR_SIZE)) {
-+ *context = "Extent size is not a multiple of device blocksize";
-+ r = -EINVAL;
-+ goto bad_putdev;
-+ }
-+
-+ /* Check the sizes are small enough to fit in one kiovec */
-+ if (chunk_size > KIO_MAX_SECTORS) {
-+ *context = "Chunk size is too big";
-+ r = -EINVAL;
-+ goto bad_putdev;
-+ }
-+
-+ if (extent_size > KIO_MAX_SECTORS) {
-+ *context = "Extent size is too big";
-+ r = -EINVAL;
-+ goto bad_putdev;
-+ }
-+
-+ /* Check chunk_size is a power of 2 */
-+ if (chunk_size & (chunk_size - 1)) {
-+ *context = "Chunk size is not a power of 2";
-+ r = -EINVAL;
-+ goto bad_putdev;
-+ }
-+
-+ s->chunk_size = chunk_size;
-+ s->chunk_mask = chunk_size - 1;
-+ for (s->chunk_shift = 0; chunk_size;
-+ s->chunk_shift++, chunk_size >>= 1)
-+ ;
-+ s->chunk_shift--;
-+
-+ s->valid = 1;
-+ init_rwsem(&s->lock);
-+
-+ /* Allocate hash table for COW data */
-+ if (init_hash_tables(s)) {
-+ *context = "Unable to allocate hash table space";
-+ r = -ENOMEM;
-+ goto bad_putdev;
-+ }
-+
-+ /*
-+ * Check the persistent flag - done here because we need the iobuf
-+ * to check the LV header
-+ */
-+#if 0
-+ if ((*persistent & 0x5f) == 'P')
-+ r = dm_create_persistent(&s->store, s, blocksize,
-+ extent_size, context);
-+ else
-+#endif
-+ r = dm_create_transient(&s->store, s, blocksize, context);
-+
-+ if (r) {
-+ *context = "Couldn't create exception store";
-+ r = -EINVAL;
-+ goto bad_free1;
-+ }
-+
-+ /* Allocate the COW iobuf and set associated variables */
-+ r = store_int_fn(s, init, blocksize, extent_size, context);
-+ if (r) {
-+ *context = "Couldn't initialise exception store";
-+ goto bad_free1;
-+ }
-+
-+ /* Flush IO to the origin device */
-+#if LVM_VFS_ENHANCEMENT
-+ fsync_dev_lockfs(s->origin->dev);
-+#else
-+ fsync_dev(s->origin->dev);
-+#endif
-+
-+ /* Add snapshot to the list of snapshots for this origin */
-+ if (register_snapshot(s)) {
-+ r = -EINVAL;
-+ *context = "Cannot register snapshot origin";
-+ goto bad_free2;
-+ }
-+#if LVM_VFS_ENHANCEMENT
-+ unlockfs(s->origin->dev);
-+#endif
-+
-+ *context = s;
-+ return 0;
-+
-+ bad_free2:
-+ store_fn(s, destroy);
-+
-+ bad_free1:
-+ exit_exception_table(&s->pending, pending_cache);
-+ exit_exception_table(&s->complete, exception_cache);
-+
-+ bad_putdev:
-+ dm_table_put_device(t, s->cow);
-+ dm_table_put_device(t, s->origin);
-+
-+ bad_free:
-+ kfree(s);
-+
-+ bad:
-+ return r;
-+}
-+
-+static void snapshot_dtr(struct dm_table *t, void *context)
-+{
-+ struct dm_snapshot *s = (struct dm_snapshot *) context;
-+
-+ unregister_snapshot(s);
-+
-+ exit_exception_table(&s->pending, pending_cache);
-+ exit_exception_table(&s->complete, exception_cache);
-+
-+ /* Deallocate memory used */
-+ store_fn(s, destroy);
-+
-+ dm_table_put_device(t, s->origin);
-+ dm_table_put_device(t, s->cow);
-+ kfree(s);
-+}
-+
-+/*
-+ * We hold lists of buffer_heads, using the b_reqnext field.
-+ */
-+static void queue_buffer(struct buffer_head **queue, struct buffer_head *bh)
-+{
-+ bh->b_reqnext = *queue;
-+ *queue = bh;
-+}
-+
-+/*
-+ * Flush a list of buffers.
-+ */
-+static void flush_buffers(struct buffer_head *bh)
-+{
-+ struct buffer_head *n;
-+
-+ DMDEBUG("begin flush");
-+ while (bh) {
-+ n = bh->b_reqnext;
-+ bh->b_reqnext = NULL;
-+ DMDEBUG("flushing %p", bh);
-+ generic_make_request(WRITE, bh);
-+ bh = n;
-+ }
-+
-+ run_task_queue(&tq_disk);
-+}
-+
-+/*
-+ * Error a list of buffers.
-+ */
-+static void error_buffers(struct buffer_head *bh)
-+{
-+ struct buffer_head *n;
-+
-+ while (bh) {
-+ n = bh->b_reqnext;
-+ bh->b_reqnext = NULL;
-+ buffer_IO_error(bh);
-+ bh = n;
-+ }
-+}
-+
-+/*
-+ * Called when the copy I/O has finished
-+ */
-+static void copy_callback(int err, void *context)
-+{
-+ struct pending_exception *pe = (struct pending_exception *) context;
-+ struct dm_snapshot *s = pe->snap;
-+ struct exception *e;
-+
-+ if (!err) {
-+ /* Update the metadata if we are persistent */
-+ store_fn(s, commit_exception, &pe->e);
-+
-+ e = alloc_exception();
-+ if (!e) {
-+ /* FIXME: what do we do now ? */
-+ return;
-+ }
-+
-+ /*
-+ * Add a proper exception, and remove the
-+ * inflight exception from the list.
-+ */
-+ down_write(&pe->snap->lock);
-+
-+ memcpy(e, &pe->e, sizeof(*e));
-+ insert_exception(&s->complete, e);
-+ remove_exception(&pe->e);
-+
-+ /* Submit any pending write BHs */
-+ up_write(&pe->snap->lock);
-+
-+ flush_buffers(pe->snapshot_bhs);
-+ DMDEBUG("Exception completed successfully.");
-+
-+ } else {
-+ /* Read/write error - snapshot is unusable */
-+ DMERR("Error reading/writing snapshot");
-+
-+ down_write(&pe->snap->lock);
-+ store_fn(pe->snap, drop_snapshot);
-+ pe->snap->valid = 0;
-+ remove_exception(&pe->e);
-+ up_write(&pe->snap->lock);
-+
-+ error_buffers(pe->snapshot_bhs);
-+
-+ DMDEBUG("Exception failed.");
-+ }
-+
-+ if (list_empty(&pe->siblings))
-+ flush_buffers(pe->origin_bhs);
-+ else
-+ list_del(&pe->siblings);
-+
-+ free_pending_exception(pe);
-+}
-+
-+/*
-+ * Dispatches the copy operation to kcopyd.
-+ */
-+static inline void start_copy(struct pending_exception *pe)
-+{
-+ struct dm_snapshot *s = pe->snap;
-+ struct kcopyd_region src, dest;
-+
-+ src.dev = s->origin->dev;
-+ src.sector = chunk_to_sector(s, pe->e.old_chunk);
-+ src.count = s->chunk_size;
-+
-+ dest.dev = s->cow->dev;
-+ dest.sector = chunk_to_sector(s, pe->e.new_chunk);
-+ dest.count = s->chunk_size;
-+
-+ if (!pe->started) {
-+ /* Hand over to kcopyd */
-+ kcopyd_copy(&src, &dest, copy_callback, pe);
-+ pe->started = 1;
-+ }
-+}
-+
-+/*
-+ * Looks to see if this snapshot already has a pending exception
-+ * for this chunk, otherwise it allocates a new one and inserts
-+ * it into the pending table.
-+ */
-+static struct pending_exception *find_pending_exception(struct dm_snapshot *s,
-+ struct buffer_head *bh)
-+{
-+ struct exception *e;
-+ struct pending_exception *pe;
-+ chunk_t chunk = sector_to_chunk(s, bh->b_rsector);
-+
-+ /*
-+ * Is there a pending exception for this already ?
-+ */
-+ e = lookup_exception(&s->pending, chunk);
-+ if (e) {
-+ /* cast the exception to a pending exception */
-+ pe = list_entry(e, struct pending_exception, e);
-+
-+ } else {
-+ /* Create a new pending exception */
-+ pe = alloc_pending_exception();
-+ if (!pe) {
-+ DMWARN("Couldn't allocate pending exception.");
-+ return NULL;
-+ }
-+
-+ pe->e.old_chunk = chunk;
-+ pe->origin_bhs = pe->snapshot_bhs = NULL;
-+ INIT_LIST_HEAD(&pe->siblings);
-+ pe->snap = s;
-+ pe->started = 0;
-+
-+ if (store_int_fn(s, prepare_exception, &pe->e)) {
-+ free_pending_exception(pe);
-+ s->valid = 0;
-+ return NULL;
-+ }
-+
-+ insert_exception(&s->pending, &pe->e);
-+ }
-+
-+ return pe;
-+}
-+
-+static inline void remap_exception(struct dm_snapshot *s, struct exception *e,
-+ struct buffer_head *bh)
-+{
-+ bh->b_rdev = s->cow->dev;
-+ bh->b_rsector = chunk_to_sector(s, e->new_chunk) +
-+ (bh->b_rsector & s->chunk_mask);
-+}
-+
-+static int snapshot_map(struct buffer_head *bh, int rw, void *context)
-+{
-+ struct exception *e;
-+ struct dm_snapshot *s = (struct dm_snapshot *) context;
-+ int r = 1;
-+ chunk_t chunk;
-+ struct pending_exception *pe;
-+
-+ chunk = sector_to_chunk(s, bh->b_rsector);
-+
-+ /* Full snapshots are not usable */
-+ if (!s->valid)
-+ return -1;
-+
-+ /*
-+ * Write to snapshot - higher level takes care of RW/RO
-+ * flags so we should only get this if we are
-+ * writeable.
-+ */
-+ if (rw == WRITE) {
-+
-+ down_write(&s->lock);
-+
-+ /* If the block is already remapped - use that, else remap it */
-+ e = lookup_exception(&s->complete, chunk);
-+ if (e)
-+ remap_exception(s, e, bh);
-+
-+ else {
-+ pe = find_pending_exception(s, bh);
-+
-+ if (!pe) {
-+ store_fn(s, drop_snapshot);
-+ s->valid = 0;
-+ }
-+
-+ queue_buffer(&pe->snapshot_bhs, bh);
-+ start_copy(pe);
-+ r = 0;
-+ }
-+
-+ up_write(&s->lock);
-+
-+ } else {
-+ /*
-+ * FIXME: this read path scares me because we
-+ * always use the origin when we have a pending
-+ * exception. However I can't think of a
-+ * situation where this is wrong - ejt.
-+ */
-+
-+ /* Do reads */
-+ down_read(&s->lock);
-+
-+ /* See if it it has been remapped */
-+ e = lookup_exception(&s->complete, chunk);
-+ if (e)
-+ remap_exception(s, e, bh);
-+ else
-+ bh->b_rdev = s->origin->dev;
-+
-+ up_read(&s->lock);
-+ }
-+
-+ return r;
-+}
-+
-+static int __origin_write(struct list_head *snapshots, struct buffer_head *bh)
-+{
-+ int r = 1;
-+ struct list_head *sl;
-+ struct dm_snapshot *snap;
-+ struct exception *e;
-+ struct pending_exception *pe, *last = NULL;
-+ chunk_t chunk;
-+
-+ /* Do all the snapshots on this origin */
-+ list_for_each(sl, snapshots) {
-+ snap = list_entry(sl, struct dm_snapshot, list);
-+
-+ /* Only deal with valid snapshots */
-+ if (!snap->valid)
-+ continue;
-+
-+ down_write(&snap->lock);
-+
-+ /*
-+ * Remember, different snapshots can have
-+ * different chunk sizes.
-+ */
-+ chunk = sector_to_chunk(snap, bh->b_rsector);
-+
-+ /*
-+ * Check exception table to see if block
-+ * is already remapped in this snapshot
-+ * and trigger an exception if not.
-+ */
-+ e = lookup_exception(&snap->complete, chunk);
-+ if (!e) {
-+ pe = find_pending_exception(snap, bh);
-+ if (!pe) {
-+ store_fn(snap, drop_snapshot);
-+ snap->valid = 0;
-+ } else {
-+
-+ if (last)
-+ list_splice(&pe->siblings,
-+ &last->siblings);
-+
-+ last = pe;
-+ r = 0;
-+ }
-+ }
-+
-+ up_write(&snap->lock);
-+ }
-+
-+ /*
-+ * Now that we have a complete pe list we can start the copying.
-+ */
-+ if (last) {
-+ pe = last;
-+ do {
-+ down_write(&pe->snap->lock);
-+ queue_buffer(&pe->origin_bhs, bh);
-+ start_copy(pe);
-+ up_write(&pe->snap->lock);
-+ pe = list_entry(pe->siblings.next,
-+ struct pending_exception, siblings);
-+
-+ } while (pe != last);
-+ }
-+
-+ return r;
-+}
-+
-+/*
-+ * Called on a write from the origin driver.
-+ */
-+int do_origin(struct dm_dev *origin, struct buffer_head *bh)
-+{
-+ struct origin *o;
-+ int r;
-+
-+ down_read(&_origins_lock);
-+ o = __lookup_origin(origin->dev);
-+ if (!o)
-+ BUG();
-+
-+ r = __origin_write(&o->snapshots, bh);
-+ up_read(&_origins_lock);
-+
-+ return r;
-+}
-+
-+/*
-+ * Origin: maps a linear range of a device, with hooks for snapshotting.
-+ */
-+
-+/*
-+ * Construct an origin mapping: <dev_path>
-+ * The context for an origin is merely a 'struct dm_dev *'
-+ * pointing to the real device.
-+ */
-+static int origin_ctr(struct dm_table *t, offset_t b, offset_t l,
-+ int argc, char **argv, void **context)
-+{
-+ int r;
-+ struct dm_dev *dev;
-+
-+ if (argc != 1) {
-+ *context = "dm-origin: incorrect number of arguments";
-+ return -EINVAL;
-+ }
-+
-+ r = dm_table_get_device(t, argv[0], 0, l, &dev);
-+ if (r) {
-+ *context = "Cannot get target device";
-+ return r;
-+ }
-+
-+ *context = dev;
-+
-+ return 0;
-+}
-+
-+static void origin_dtr(struct dm_table *t, void *c)
-+{
-+ struct dm_dev *dev = (struct dm_dev *) c;
-+ dm_table_put_device(t, dev);
-+}
-+
-+static int origin_map(struct buffer_head *bh, int rw, void *context)
-+{
-+ struct dm_dev *dev = (struct dm_dev *) context;
-+ bh->b_rdev = dev->dev;
-+
-+ /* Only tell snapshots if this is a write */
-+ return (rw == WRITE) ? do_origin(dev, bh) : 1;
-+}
-+
-+static struct target_type origin_target = {
-+ name: "snapshot-origin",
-+ module: THIS_MODULE,
-+ ctr: origin_ctr,
-+ dtr: origin_dtr,
-+ map: origin_map,
-+ err: NULL
-+};
-+
-+static struct target_type snapshot_target = {
-+ name: "snapshot",
-+ module: THIS_MODULE,
-+ ctr: snapshot_ctr,
-+ dtr: snapshot_dtr,
-+ map: snapshot_map,
-+ err: NULL
-+};
-+
-+int __init dm_snapshot_init(void)
-+{
-+ int r;
-+
-+ r = dm_register_target(&snapshot_target);
-+ if (r) {
-+ DMERR("snapshot target register failed %d", r);
-+ return r;
-+ }
-+
-+ r = dm_register_target(&origin_target);
-+ if (r < 0) {
-+ DMERR("Device mapper: Origin: register failed %d\n", r);
-+ goto bad1;
-+ }
-+
-+ r = init_origin_hash();
-+ if (r) {
-+ DMERR("init_origin_hash failed.");
-+ goto bad2;
-+ }
-+
-+ exception_cache = kmem_cache_create("dm-snapshot-ex",
-+ sizeof(struct exception),
-+ __alignof__(struct exception),
-+ 0, NULL, NULL);
-+ if (!exception_cache) {
-+ DMERR("Couldn't create exception cache.");
-+ r = -ENOMEM;
-+ goto bad3;
-+ }
-+
-+ pending_cache =
-+ kmem_cache_create("dm-snapshot-in",
-+ sizeof(struct pending_exception),
-+ __alignof__(struct pending_exception),
-+ 0, NULL, NULL);
-+ if (!pending_cache) {
-+ DMERR("Couldn't create pending cache.");
-+ r = -ENOMEM;
-+ goto bad4;
-+ }
-+
-+ pending_pool = mempool_create(128, mempool_alloc_slab,
-+ mempool_free_slab, pending_cache);
-+ if (!pending_pool) {
-+ DMERR("Couldn't create pending pool.");
-+ r = -ENOMEM;
-+ goto bad5;
-+ }
-+
-+ return 0;
-+
-+ bad5:
-+ kmem_cache_destroy(pending_cache);
-+ bad4:
-+ kmem_cache_destroy(exception_cache);
-+ bad3:
-+ exit_origin_hash();
-+ bad2:
-+ dm_unregister_target(&origin_target);
-+ bad1:
-+ dm_unregister_target(&snapshot_target);
-+ return r;
-+}
-+
-+void dm_snapshot_exit(void)
-+{
-+ int r;
-+
-+ r = dm_unregister_target(&snapshot_target);
-+ if (r)
-+ DMERR("snapshot unregister failed %d", r);
-+
-+ r = dm_unregister_target(&origin_target);
-+ if (r)
-+ DMERR("origin unregister failed %d", r);
-+
-+ exit_origin_hash();
-+ mempool_destroy(pending_pool);
-+ kmem_cache_destroy(pending_cache);
-+ kmem_cache_destroy(exception_cache);
-+}
-+
-+/*
-+ * Overrides for Emacs so that we follow Linus's tabbing style.
-+ * Emacs will notice this stuff at the end of the file and automatically
-+ * adjust the settings for this buffer only. This must remain at the end
-+ * of the file.
-+ * ---------------------------------------------------------------------------
-+ * Local variables:
-+ * c-file-style: "linux"
-+ * End:
-+ */
-diff -ruN linux-2.4.18/drivers/md/dm-snapshot.h linux/drivers/md/dm-snapshot.h
---- linux-2.4.18/drivers/md/dm-snapshot.h Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm-snapshot.h Tue Apr 23 22:23:32 2002
-@@ -0,0 +1,144 @@
-+/*
-+ * dm-snapshot.c
-+ *
-+ * Copyright (C) 2001-2002 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#ifndef DM_SNAPSHOT_H
-+#define DM_SNAPSHOT_H
-+
-+#include "dm.h"
-+#include <linux/blkdev.h>
-+
-+struct exception_table {
-+ uint32_t hash_mask;
-+ struct list_head *table;
-+};
-+
-+/*
-+ * The snapshot code deals with largish chunks of the disk at a
-+ * time. Typically 64k - 256k.
-+ */
-+/* FIXME: can we get away with limiting these to a uint32_t ? */
-+typedef offset_t chunk_t;
-+
-+/*
-+ * An exception is used where an old chunk of data has been
-+ * replaced by a new one.
-+ */
-+struct exception {
-+ struct list_head hash_list;
-+
-+ chunk_t old_chunk;
-+ chunk_t new_chunk;
-+};
-+
-+/*
-+ * Abstraction to handle the meta/layout of exception stores (the
-+ * COW device).
-+ */
-+struct exception_store {
-+
-+ /*
-+ * Destroys this object when you've finished with it.
-+ */
-+ void (*destroy)(struct exception_store *store);
-+
-+ /*
-+ * Read the metadata and populate the snapshot.
-+ */
-+ int (*init)(struct exception_store *store,
-+ int blocksize, unsigned long extent_size, void **context);
-+
-+ /*
-+ * Find somewhere to store the next exception.
-+ */
-+ int (*prepare_exception)(struct exception_store *store,
-+ struct exception *e);
-+
-+ /*
-+ * Update the metadata with this exception.
-+ */
-+ int (*commit_exception)(struct exception_store *store,
-+ struct exception *e);
-+
-+ /*
-+ * The snapshot is invalid, note this in the metadata.
-+ */
-+ void (*drop_snapshot)(struct exception_store *store);
-+
-+ struct dm_snapshot *snap;
-+ void *context;
-+};
-+
-+struct dm_snapshot {
-+ struct rw_semaphore lock;
-+
-+ struct dm_dev *origin;
-+ struct dm_dev *cow;
-+
-+ /* List of snapshots per Origin */
-+ struct list_head list;
-+
-+ /* Size of data blocks saved - must be a power of 2 */
-+ chunk_t chunk_size;
-+ chunk_t chunk_mask;
-+ chunk_t chunk_shift;
-+
-+ /* You can't use a snapshot if this is 0 (e.g. if full) */
-+ int valid;
-+
-+ struct exception_table pending;
-+ struct exception_table complete;
-+
-+ /* The on disk metadata handler */
-+ struct exception_store store;
-+};
-+
-+/*
-+ * Used by the exception stores to load exceptions hen
-+ * initialising.
-+ */
-+int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new);
-+
-+/*
-+ * Constructor and destructor for the default persistent
-+ * store.
-+ */
-+int dm_create_persistent(struct exception_store *store,
-+ struct dm_snapshot *s,
-+ int blocksize,
-+ offset_t extent_size,
-+ void **error);
-+
-+int dm_create_transient(struct exception_store *store,
-+ struct dm_snapshot *s,
-+ int blocksize, void **error);
-+
-+/*
-+ * Return the number of sectors in the device.
-+ */
-+static inline offset_t get_dev_size(kdev_t dev)
-+{
-+ int *sizes;
-+
-+ sizes = blk_size[MAJOR(dev)];
-+ if (sizes)
-+ return sizes[MINOR(dev)] << 1;
-+
-+ return 0;
-+}
-+
-+static inline chunk_t sector_to_chunk(struct dm_snapshot *s, offset_t sector)
-+{
-+ return (sector & ~s->chunk_mask) >> s->chunk_shift;
-+}
-+
-+static inline offset_t chunk_to_sector(struct dm_snapshot *s, chunk_t chunk)
-+{
-+ return chunk << s->chunk_shift;
-+}
-+
-+#endif
-diff -ruN linux-2.4.18/drivers/md/dm-stripe.c linux/drivers/md/dm-stripe.c
---- linux-2.4.18/drivers/md/dm-stripe.c Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm-stripe.c Thu Jan 31 17:50:20 2002
-@@ -0,0 +1,202 @@
-+/*
-+ * Copyright (C) 2001 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#include "dm.h"
-+
-+#include <linux/module.h>
-+#include <linux/init.h>
-+#include <linux/blkdev.h>
-+
-+struct stripe {
-+ struct dm_dev *dev;
-+ offset_t physical_start;
-+};
-+
-+struct stripe_c {
-+ offset_t logical_start;
-+ uint32_t stripes;
-+
-+ /* The size of this target / num. stripes */
-+ uint32_t stripe_width;
-+
-+ /* stripe chunk size */
-+ uint32_t chunk_shift;
-+ offset_t chunk_mask;
-+
-+ struct stripe stripe[0];
-+};
-+
-+static inline struct stripe_c *alloc_context(int stripes)
-+{
-+ size_t len = sizeof(struct stripe_c) +
-+ (sizeof(struct stripe) * stripes);
-+
-+ return kmalloc(len, GFP_KERNEL);
-+}
-+
-+/*
-+ * Parse a single <dev> <sector> pair
-+ */
-+static int get_stripe(struct dm_table *t, struct stripe_c *sc,
-+ int stripe, char **argv)
-+{
-+ char *end;
-+ unsigned long start;
-+
-+ start = simple_strtoul(argv[1], &end, 10);
-+ if (*end)
-+ return -EINVAL;
-+
-+ if (dm_table_get_device(t, argv[0], start, sc->stripe_width,
-+ &sc->stripe[stripe].dev))
-+ return -ENXIO;
-+
-+ sc->stripe[stripe].physical_start = start;
-+ return 0;
-+}
-+
-+/*
-+ * Construct a striped mapping.
-+ * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
-+ */
-+static int stripe_ctr(struct dm_table *t, offset_t b, offset_t l,
-+ int argc, char **argv, void **context)
-+{
-+ struct stripe_c *sc;
-+ uint32_t stripes;
-+ uint32_t chunk_size;
-+ char *end;
-+ int r, i;
-+
-+ if (argc < 2) {
-+ *context = "dm-stripe: Not enough arguments";
-+ return -EINVAL;
-+ }
-+
-+ stripes = simple_strtoul(argv[0], &end, 10);
-+ if (*end) {
-+ *context = "dm-stripe: Invalid stripe count";
-+ return -EINVAL;
-+ }
-+
-+ chunk_size =simple_strtoul(argv[1], &end, 10);
-+ if (*end) {
-+ *context = "dm-stripe: Invalid chunk_size";
-+ return -EINVAL;
-+ }
-+
-+ if (l % stripes) {
-+ *context = "dm-stripe: Target length not divisable by "
-+ "number of stripes";
-+ return -EINVAL;
-+ }
-+
-+ sc = alloc_context(stripes);
-+ if (!sc) {
-+ *context = "dm-stripe: Memory allocation for striped context "
-+ "failed";
-+ return -ENOMEM;
-+ }
-+
-+ sc->logical_start = b;
-+ sc->stripes = stripes;
-+ sc->stripe_width = l / stripes;
-+
-+ /*
-+ * chunk_size is a power of two
-+ */
-+ if (!chunk_size || (chunk_size & (chunk_size - 1))) {
-+ *context = "dm-stripe: Invalid chunk size";
-+ kfree(sc);
-+ return -EINVAL;
-+ }
-+
-+ sc->chunk_mask = chunk_size - 1;
-+ for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++)
-+ chunk_size >>= 1;
-+ sc->chunk_shift--;
-+
-+ /*
-+ * Get the stripe destinations.
-+ */
-+ for (i = 0; i < stripes; i++) {
-+ if (argc < 2) {
-+ *context = "dm-stripe: Not enough destinations "
-+ "specified";
-+ kfree(sc);
-+ return -EINVAL;
-+ }
-+
-+ argv += 2;
-+
-+ r = get_stripe(t, sc, i, argv);
-+ if (r < 0) {
-+ *context = "dm-stripe: Couldn't parse stripe "
-+ "destination";
-+ while (i--)
-+ dm_table_put_device(t, sc->stripe[i].dev);
-+ kfree(sc);
-+ return r;
-+ }
-+ }
-+
-+ *context = sc;
-+ return 0;
-+}
-+
-+static void stripe_dtr(struct dm_table *t, void *c)
-+{
-+ unsigned int i;
-+ struct stripe_c *sc = (struct stripe_c *) c;
-+
-+ for (i = 0; i < sc->stripes; i++)
-+ dm_table_put_device(t, sc->stripe[i].dev);
-+
-+ kfree(sc);
-+}
-+
-+static int stripe_map(struct buffer_head *bh, int rw, void *context)
-+{
-+ struct stripe_c *sc = (struct stripe_c *) context;
-+
-+ offset_t offset = bh->b_rsector - sc->logical_start;
-+ uint32_t chunk = (uint32_t) (offset >> sc->chunk_shift);
-+ uint32_t stripe = chunk % sc->stripes; /* 32bit modulus */
-+ chunk = chunk / sc->stripes;
-+
-+ bh->b_rdev = sc->stripe[stripe].dev->dev;
-+ bh->b_rsector = sc->stripe[stripe].physical_start +
-+ (chunk << sc->chunk_shift) + (offset & sc->chunk_mask);
-+ return 1;
-+}
-+
-+static struct target_type stripe_target = {
-+ name: "striped",
-+ module: THIS_MODULE,
-+ ctr: stripe_ctr,
-+ dtr: stripe_dtr,
-+ map: stripe_map,
-+};
-+
-+int __init dm_stripe_init(void)
-+{
-+ int r;
-+
-+ r = dm_register_target(&stripe_target);
-+ if (r < 0)
-+ DMWARN("striped target registration failed");
-+
-+ return r;
-+}
-+
-+void dm_stripe_exit(void)
-+{
-+ if (dm_unregister_target(&stripe_target))
-+ DMWARN("striped target unregistration failed");
-+
-+ return;
-+}
-+
-diff -ruN linux-2.4.18/drivers/md/dm-table.c linux/drivers/md/dm-table.c
---- linux-2.4.18/drivers/md/dm-table.c Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm-table.c Tue Apr 23 21:48:53 2002
-@@ -0,0 +1,404 @@
-+/*
-+ * Copyright (C) 2001 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#include "dm.h"
-+
-+#include <linux/blkdev.h>
-+
-+/* ceiling(n / size) * size */
-+static inline unsigned long round_up(unsigned long n, unsigned long size)
-+{
-+ unsigned long r = n % size;
-+ return n + (r ? (size - r) : 0);
-+}
-+
-+/* ceiling(n / size) */
-+static inline unsigned long div_up(unsigned long n, unsigned long size)
-+{
-+ return round_up(n, size) / size;
-+}
-+
-+/* similar to ceiling(log_size(n)) */
-+static uint int_log(unsigned long n, unsigned long base)
-+{
-+ int result = 0;
-+
-+ while (n > 1) {
-+ n = div_up(n, base);
-+ result++;
-+ }
-+
-+ return result;
-+}
-+
-+/*
-+ * return the highest key that you could lookup
-+ * from the n'th node on level l of the btree.
-+ */
-+static offset_t high(struct dm_table *t, int l, int n)
-+{
-+ for (; l < t->depth - 1; l++)
-+ n = get_child(n, CHILDREN_PER_NODE - 1);
-+
-+ if (n >= t->counts[l])
-+ return (offset_t) - 1;
-+
-+ return get_node(t, l, n)[KEYS_PER_NODE - 1];
-+}
-+
-+/*
-+ * fills in a level of the btree based on the
-+ * highs of the level below it.
-+ */
-+static int setup_btree_index(int l, struct dm_table *t)
-+{
-+ int n, k;
-+ offset_t *node;
-+
-+ for (n = 0; n < t->counts[l]; n++) {
-+ node = get_node(t, l, n);
-+
-+ for (k = 0; k < KEYS_PER_NODE; k++)
-+ node[k] = high(t, l + 1, get_child(n, k));
-+ }
-+
-+ return 0;
-+}
-+
-+/*
-+ * highs, and targets are managed as dynamic
-+ * arrays during a table load.
-+ */
-+static int alloc_targets(struct dm_table *t, int num)
-+{
-+ offset_t *n_highs;
-+ struct target *n_targets;
-+ int n = t->num_targets;
-+ unsigned long size = (sizeof(struct target) + sizeof(offset_t)) * num;
-+
-+ n_highs = (offset_t *) vmalloc(size);
-+ if (!n_highs)
-+ return -ENOMEM;
-+
-+ memset(n_highs, 0, size);
-+
-+ n_targets = (struct target *) (n_highs + num);
-+
-+ if (n) {
-+ memcpy(n_highs, t->highs, sizeof(*n_highs) * n);
-+ memcpy(n_targets, t->targets, sizeof(*n_targets) * n);
-+ }
-+
-+ memset(n_highs + n, -1, sizeof(*n_highs) * (num - n));
-+ if (t->highs)
-+ vfree(t->highs);
-+
-+ t->num_allocated = num;
-+ t->highs = n_highs;
-+ t->targets = n_targets;
-+
-+ return 0;
-+}
-+
-+int dm_table_create(struct dm_table **result)
-+{
-+ struct dm_table *t = kmalloc(sizeof(struct dm_table), GFP_NOIO);
-+
-+ if (!t)
-+ return -ENOMEM;
-+
-+ memset(t, 0, sizeof(*t));
-+ INIT_LIST_HEAD(&t->devices);
-+
-+ /* allocate a single node's worth of targets to begin with */
-+ if (alloc_targets(t, KEYS_PER_NODE)) {
-+ kfree(t);
-+ t = NULL;
-+ return -ENOMEM;
-+ }
-+
-+ *result = t;
-+ return 0;
-+}
-+
-+static void free_devices(struct list_head *devices)
-+{
-+ struct list_head *tmp, *next;
-+
-+ for (tmp = devices->next; tmp != devices; tmp = next) {
-+ struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
-+ next = tmp->next;
-+ kfree(dd);
-+ }
-+}
-+
-+void dm_table_destroy(struct dm_table *t)
-+{
-+ int i;
-+
-+ /* free the indexes (see dm_table_complete) */
-+ if (t->depth >= 2)
-+ vfree(t->index[t->depth - 2]);
-+
-+ /* free the targets */
-+ for (i = 0; i < t->num_targets; i++) {
-+ struct target *tgt = &t->targets[i];
-+
-+ dm_put_target_type(t->targets[i].type);
-+
-+ if (tgt->type->dtr)
-+ tgt->type->dtr(t, tgt->private);
-+ }
-+
-+ vfree(t->highs);
-+
-+ /* free the device list */
-+ if (t->devices.next != &t->devices) {
-+ DMWARN("devices still present during destroy: "
-+ "dm_table_remove_device calls missing");
-+
-+ free_devices(&t->devices);
-+ }
-+
-+ kfree(t);
-+}
-+
-+/*
-+ * Checks to see if we need to extend highs or targets.
-+ */
-+static inline int check_space(struct dm_table *t)
-+{
-+ if (t->num_targets >= t->num_allocated)
-+ return alloc_targets(t, t->num_allocated * 2);
-+
-+ return 0;
-+}
-+
-+/*
-+ * Convert a device path to a kdev_t.
-+ */
-+int lookup_device(const char *path, kdev_t *dev)
-+{
-+ int r;
-+ struct nameidata nd;
-+ struct inode *inode;
-+
-+ if (!path_init(path, LOOKUP_FOLLOW, &nd))
-+ return 0;
-+
-+ if ((r = path_walk(path, &nd)))
-+ goto bad;
-+
-+ inode = nd.dentry->d_inode;
-+ if (!inode) {
-+ r = -ENOENT;
-+ goto bad;
-+ }
-+
-+ if (!S_ISBLK(inode->i_mode)) {
-+ r = -EINVAL;
-+ goto bad;
-+ }
-+
-+ *dev = inode->i_rdev;
-+
-+ bad:
-+ path_release(&nd);
-+ return r;
-+}
-+
-+/*
-+ * See if we've already got a device in the list.
-+ */
-+static struct dm_dev *find_device(struct list_head *l, kdev_t dev)
-+{
-+ struct list_head *tmp;
-+
-+ list_for_each(tmp, l) {
-+ struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
-+ if (dd->dev == dev)
-+ return dd;
-+ }
-+
-+ return NULL;
-+}
-+
-+/*
-+ * Open a device so we can use it as a map destination.
-+ */
-+static int open_dev(struct dm_dev *d)
-+{
-+ int err;
-+
-+ if (d->bd)
-+ BUG();
-+
-+ if (!(d->bd = bdget(kdev_t_to_nr(d->dev))))
-+ return -ENOMEM;
-+
-+ if ((err = blkdev_get(d->bd, FMODE_READ | FMODE_WRITE, 0, BDEV_FILE)))
-+ return err;
-+
-+ return 0;
-+}
-+
-+/*
-+ * Close a device that we've been using.
-+ */
-+static void close_dev(struct dm_dev *d)
-+{
-+ if (!d->bd)
-+ return;
-+
-+ blkdev_put(d->bd, BDEV_FILE);
-+ d->bd = NULL;
-+}
-+
-+/*
-+ * If possible (ie. blk_size[major] is set), this
-+ * checks an area of a destination device is
-+ * valid.
-+ */
-+static int check_device_area(kdev_t dev, offset_t start, offset_t len)
-+{
-+ int *sizes;
-+ offset_t dev_size;
-+
-+ if (!(sizes = blk_size[MAJOR(dev)]) || !(dev_size = sizes[MINOR(dev)]))
-+ /* we don't know the device details,
-+ * so give the benefit of the doubt */
-+ return 1;
-+
-+ /* convert to 512-byte sectors */
-+ dev_size <<= 1;
-+
-+ return ((start < dev_size) && (len <= (dev_size - start)));
-+}
-+
-+/*
-+ * Add a device to the list, or just increment the usage count
-+ * if it's already present.
-+ */
-+int dm_table_get_device(struct dm_table *t, const char *path,
-+ offset_t start, offset_t len, struct dm_dev **result)
-+{
-+ int r;
-+ kdev_t dev;
-+ struct dm_dev *dd;
-+
-+ /* convert the path to a device */
-+ if ((r = lookup_device(path, &dev)))
-+ return r;
-+
-+ dd = find_device(&t->devices, dev);
-+ if (!dd) {
-+ dd = kmalloc(sizeof(*dd), GFP_KERNEL);
-+ if (!dd)
-+ return -ENOMEM;
-+
-+ dd->dev = dev;
-+ dd->bd = NULL;
-+
-+ if ((r = open_dev(dd))) {
-+ kfree(dd);
-+ return r;
-+ }
-+
-+ atomic_set(&dd->count, 0);
-+ list_add(&dd->list, &t->devices);
-+ }
-+ atomic_inc(&dd->count);
-+
-+ if (!check_device_area(dd->dev, start, len)) {
-+ DMWARN("device %s too small for target", path);
-+ dm_table_put_device(t, dd);
-+ return -EINVAL;
-+ }
-+
-+ *result = dd;
-+
-+ return 0;
-+}
-+
-+/*
-+ * Decrement a devices use count and remove it if neccessary.
-+ */
-+void dm_table_put_device(struct dm_table *t, struct dm_dev *dd)
-+{
-+ if (atomic_dec_and_test(&dd->count)) {
-+ close_dev(dd);
-+ list_del(&dd->list);
-+ kfree(dd);
-+ }
-+}
-+
-+/*
-+ * Adds a target to the map
-+ */
-+int dm_table_add_target(struct dm_table *t, offset_t highs,
-+ struct target_type *type, void *private)
-+{
-+ int r, n;
-+
-+ if ((r = check_space(t)))
-+ return r;
-+
-+ n = t->num_targets++;
-+ t->highs[n] = highs;
-+ t->targets[n].type = type;
-+ t->targets[n].private = private;
-+
-+ return 0;
-+}
-+
-+static int setup_indexes(struct dm_table *t)
-+{
-+ int i, total = 0;
-+ offset_t *indexes;
-+
-+ /* allocate the space for *all* the indexes */
-+ for (i = t->depth - 2; i >= 0; i--) {
-+ t->counts[i] = div_up(t->counts[i + 1], CHILDREN_PER_NODE);
-+ total += t->counts[i];
-+ }
-+
-+ indexes = (offset_t *) vmalloc((unsigned long)NODE_SIZE * total);
-+ if (!indexes)
-+ return -ENOMEM;
-+
-+ /* set up internal nodes, bottom-up */
-+ for (i = t->depth - 2, total = 0; i >= 0; i--) {
-+ t->index[i] = indexes;
-+ indexes += (KEYS_PER_NODE * t->counts[i]);
-+ setup_btree_index(i, t);
-+ }
-+
-+ return 0;
-+}
-+
-+/*
-+ * Builds the btree to index the map
-+ */
-+int dm_table_complete(struct dm_table *t)
-+{
-+ int leaf_nodes, r = 0;
-+
-+ /* how many indexes will the btree have ? */
-+ leaf_nodes = div_up(t->num_targets, KEYS_PER_NODE);
-+ t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
-+
-+ /* leaf layer has already been set up */
-+ t->counts[t->depth - 1] = leaf_nodes;
-+ t->index[t->depth - 1] = t->highs;
-+
-+ if (t->depth >= 2)
-+ r = setup_indexes(t);
-+
-+ return r;
-+}
-+
-+EXPORT_SYMBOL(dm_table_get_device);
-+EXPORT_SYMBOL(dm_table_put_device);
-diff -ruN linux-2.4.18/drivers/md/dm-target.c linux/drivers/md/dm-target.c
---- linux-2.4.18/drivers/md/dm-target.c Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm-target.c Tue Jan 8 17:57:45 2002
-@@ -0,0 +1,241 @@
-+/*
-+ * Copyright (C) 2001 Sistina Software (UK) Limited
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#include "dm.h"
-+
-+#include <linux/kmod.h>
-+
-+struct tt_internal {
-+ struct target_type tt;
-+
-+ struct list_head list;
-+ long use;
-+};
-+
-+static LIST_HEAD(_targets);
-+static rwlock_t _lock = RW_LOCK_UNLOCKED;
-+
-+#define DM_MOD_NAME_SIZE 32
-+
-+/*
-+ * Destructively splits up the argument list to pass to ctr.
-+ */
-+int split_args(int max, int *argc, char **argv, char *input)
-+{
-+ char *start, *end = input, *out;
-+ *argc = 0;
-+
-+ while (1) {
-+ start = end;
-+
-+ /* Skip whitespace */
-+ while (*start && isspace(*start))
-+ start++;
-+
-+ if (!*start)
-+ break; /* success, we hit the end */
-+
-+ /* 'out' is used to remove any back-quotes */
-+ end = out = start;
-+ while (*end) {
-+ /* Everything apart from '\0' can be quoted */
-+ if (*end == '\\' && *(end + 1)) {
-+ *out++ = *(end + 1);
-+ end += 2;
-+ continue;
-+ }
-+
-+ if (isspace(*end))
-+ break; /* end of token */
-+
-+ *out++ = *end++;
-+ }
-+
-+ /* have we already filled the array ? */
-+ if ((*argc + 1) > max)
-+ return -EINVAL;
-+
-+ /* we know this is whitespace */
-+ if (*end)
-+ end++;
-+
-+ /* terminate the string and put it in the array */
-+ *out = '\0';
-+ argv[*argc] = start;
-+ (*argc)++;
-+ }
-+
-+ return 0;
-+}
-+
-+static inline struct tt_internal *__find_target_type(const char *name)
-+{
-+ struct list_head *tih;
-+ struct tt_internal *ti;
-+
-+ list_for_each(tih, &_targets) {
-+ ti = list_entry(tih, struct tt_internal, list);
-+
-+ if (!strcmp(name, ti->tt.name))
-+ return ti;
-+ }
-+
-+ return NULL;
-+}
-+
-+static struct tt_internal *get_target_type(const char *name)
-+{
-+ struct tt_internal *ti;
-+
-+ read_lock(&_lock);
-+ ti = __find_target_type(name);
-+
-+ if (ti) {
-+ if (ti->use == 0 && ti->tt.module)
-+ __MOD_INC_USE_COUNT(ti->tt.module);
-+ ti->use++;
-+ }
-+ read_unlock(&_lock);
-+
-+ return ti;
-+}
-+
-+static void load_module(const char *name)
-+{
-+ char module_name[DM_MOD_NAME_SIZE] = "dm-";
-+
-+ /* Length check for strcat() below */
-+ if (strlen(name) > (DM_MOD_NAME_SIZE - 4))
-+ return;
-+
-+ strcat(module_name, name);
-+ request_module(module_name);
-+
-+ return;
-+}
-+
-+struct target_type *dm_get_target_type(const char *name)
-+{
-+ struct tt_internal *ti = get_target_type(name);
-+
-+ if (!ti) {
-+ load_module(name);
-+ ti = get_target_type(name);
-+ }
-+
-+ return ti ? &ti->tt : NULL;
-+}
-+
-+void dm_put_target_type(struct target_type *t)
-+{
-+ struct tt_internal *ti = (struct tt_internal *) t;
-+
-+ read_lock(&_lock);
-+ if (--ti->use == 0 && ti->tt.module)
-+ __MOD_DEC_USE_COUNT(ti->tt.module);
-+
-+ if (ti->use < 0)
-+ BUG();
-+ read_unlock(&_lock);
-+
-+ return;
-+}
-+
-+static struct tt_internal *alloc_target(struct target_type *t)
-+{
-+ struct tt_internal *ti = kmalloc(sizeof(*ti), GFP_KERNEL);
-+
-+ if (ti) {
-+ memset(ti, 0, sizeof(*ti));
-+ ti->tt = *t;
-+ }
-+
-+ return ti;
-+}
-+
-+int dm_register_target(struct target_type *t)
-+{
-+ int rv = 0;
-+ struct tt_internal *ti = alloc_target(t);
-+
-+ if (!ti)
-+ return -ENOMEM;
-+
-+ write_lock(&_lock);
-+ if (__find_target_type(t->name))
-+ rv = -EEXIST;
-+ else
-+ list_add(&ti->list, &_targets);
-+
-+ write_unlock(&_lock);
-+ return rv;
-+}
-+
-+int dm_unregister_target(struct target_type *t)
-+{
-+ struct tt_internal *ti;
-+
-+ write_lock(&_lock);
-+ if (!(ti = __find_target_type(t->name))) {
-+ write_unlock(&_lock);
-+ return -EINVAL;
-+ }
-+
-+ if (ti->use) {
-+ write_unlock(&_lock);
-+ return -ETXTBSY;
-+ }
-+
-+ list_del(&ti->list);
-+ kfree(ti);
-+
-+ write_unlock(&_lock);
-+ return 0;
-+}
-+
-+/*
-+ * io-err: always fails an io, useful for bringing
-+ * up LV's that have holes in them.
-+ */
-+static int io_err_ctr(struct dm_table *t, offset_t b, offset_t l,
-+ int argc, char **args, void **context)
-+{
-+ *context = NULL;
-+ return 0;
-+}
-+
-+static void io_err_dtr(struct dm_table *t, void *c)
-+{
-+ /* empty */
-+ return;
-+}
-+
-+static int io_err_map(struct buffer_head *bh, int rw, void *context)
-+{
-+ buffer_IO_error(bh);
-+ return 0;
-+}
-+
-+static struct target_type error_target = {
-+ name: "error",
-+ ctr: io_err_ctr,
-+ dtr: io_err_dtr,
-+ map: io_err_map,
-+};
-+
-+int dm_target_init(void)
-+{
-+ return dm_register_target(&error_target);
-+}
-+
-+void dm_target_exit(void)
-+{
-+ if (dm_unregister_target(&error_target))
-+ DMWARN("error target unregistration failed");
-+}
-+
-+EXPORT_SYMBOL(dm_register_target);
-+EXPORT_SYMBOL(dm_unregister_target);
-diff -ruN linux-2.4.18/drivers/md/dm.c linux/drivers/md/dm.c
---- linux-2.4.18/drivers/md/dm.c Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm.c Tue Apr 23 22:38:53 2002
-@@ -0,0 +1,1154 @@
-+/*
-+ * Copyright (C) 2001 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#include "dm.h"
-+#include "kcopyd.h"
-+
-+#include <linux/blk.h>
-+#include <linux/blkpg.h>
-+
-+/* we only need this for the lv_bmap struct definition, not happy */
-+#include <linux/lvm.h>
-+
-+#define DEFAULT_READ_AHEAD 64
-+
-+static const char *_name = DM_NAME;
-+static const char *_version = "0.94.10-ioctl (2002-04-23)";
-+static const char *_email = "lvm-devel@lists.sistina.com";
-+
-+static int major = 0;
-+static int _major = 0;
-+
-+struct io_hook {
-+ struct mapped_device *md;
-+ struct target *target;
-+ int rw;
-+
-+ void (*end_io) (struct buffer_head * bh, int uptodate);
-+ void *context;
-+};
-+
-+static kmem_cache_t *_io_hook_cache;
-+
-+static struct mapped_device *_devs[MAX_DEVICES];
-+static struct rw_semaphore _dev_locks[MAX_DEVICES];
-+
-+/*
-+ * This lock is only held by dm_create and dm_set_name to avoid
-+ * race conditions where someone else may create a device with
-+ * the same name.
-+ */
-+static spinlock_t _create_lock = SPIN_LOCK_UNLOCKED;
-+
-+/* block device arrays */
-+static int _block_size[MAX_DEVICES];
-+static int _blksize_size[MAX_DEVICES];
-+static int _hardsect_size[MAX_DEVICES];
-+
-+static devfs_handle_t _dev_dir;
-+
-+static int request(request_queue_t * q, int rw, struct buffer_head *bh);
-+static int dm_user_bmap(struct inode *inode, struct lv_bmap *lvb);
-+
-+/*
-+ * Protect the mapped_devices referenced from _dev[]
-+ */
-+struct mapped_device *dm_get_r(int minor)
-+{
-+ struct mapped_device *md;
-+
-+ if (minor >= MAX_DEVICES)
-+ return NULL;
-+
-+ down_read(_dev_locks + minor);
-+ md = _devs[minor];
-+ if (!md)
-+ up_read(_dev_locks + minor);
-+ return md;
-+}
-+
-+struct mapped_device *dm_get_w(int minor)
-+{
-+ struct mapped_device *md;
-+
-+ if (minor >= MAX_DEVICES)
-+ return NULL;
-+
-+ down_write(_dev_locks + minor);
-+ md = _devs[minor];
-+ if (!md)
-+ up_write(_dev_locks + minor);
-+ return md;
-+}
-+
-+static int namecmp(struct mapped_device *md, const char *name, int nametype)
-+{
-+ switch (nametype) {
-+ case DM_LOOKUP_BY_NAME:
-+ return strcmp(md->name, name);
-+ break;
-+
-+ case DM_LOOKUP_BY_UUID:
-+ if (!md->uuid)
-+ return -1; /* never equal */
-+
-+ return strcmp(md->uuid, name);
-+ break;
-+
-+ default:
-+ DMWARN("Unknown comparison type in namecmp: %d", nametype);
-+ BUG();
-+ }
-+
-+ return -1;
-+}
-+
-+/*
-+ * The interface (eg, ioctl) will probably access the devices
-+ * through these slow 'by name' locks, this needs improving at
-+ * some point if people start playing with *large* numbers of dm
-+ * devices.
-+ */
-+struct mapped_device *dm_get_name_r(const char *name, int nametype)
-+{
-+ int i;
-+ struct mapped_device *md;
-+
-+ for (i = 0; i < MAX_DEVICES; i++) {
-+ md = dm_get_r(i);
-+ if (md) {
-+ if (!namecmp(md, name, nametype))
-+ return md;
-+
-+ dm_put_r(md);
-+ }
-+ }
-+
-+ return NULL;
-+}
-+
-+struct mapped_device *dm_get_name_w(const char *name, int nametype)
-+{
-+ int i;
-+ struct mapped_device *md;
-+
-+ /*
-+ * To avoid getting write locks on all the devices we try
-+ * and promote a read lock to a write lock, this can
-+ * fail, in which case we just start again.
-+ */
-+
-+ restart:
-+ for (i = 0; i < MAX_DEVICES; i++) {
-+ md = dm_get_r(i);
-+ if (!md)
-+ continue;
-+
-+ if (namecmp(md, name, nametype)) {
-+ dm_put_r(md);
-+ continue;
-+ }
-+
-+ /* found it */
-+ dm_put_r(md);
-+
-+ md = dm_get_w(i);
-+ if (!md)
-+ goto restart;
-+
-+ if (namecmp(md, name, nametype)) {
-+ dm_put_w(md);
-+ goto restart;
-+ }
-+
-+ return md;
-+ }
-+
-+ return NULL;
-+}
-+
-+void dm_put_r(struct mapped_device *md)
-+{
-+ int minor = MINOR(md->dev);
-+
-+ if (minor >= MAX_DEVICES)
-+ return;
-+
-+ up_read(_dev_locks + minor);
-+}
-+
-+void dm_put_w(struct mapped_device *md)
-+{
-+ int minor = MINOR(md->dev);
-+
-+ if (minor >= MAX_DEVICES)
-+ return;
-+
-+ up_write(_dev_locks + minor);
-+}
-+
-+/*
-+ * Setup and tear down the driver
-+ */
-+static __init void init_locks(void)
-+{
-+ int i;
-+
-+ for (i = 0; i < MAX_DEVICES; i++)
-+ init_rwsem(_dev_locks + i);
-+}
-+
-+static __init int local_init(void)
-+{
-+ int r;
-+
-+ init_locks();
-+
-+ /* allocate a slab for the io-hooks */
-+ if (!_io_hook_cache &&
-+ !(_io_hook_cache = kmem_cache_create("dm io hooks",
-+ sizeof(struct io_hook),
-+ 0, 0, NULL, NULL)))
-+ return -ENOMEM;
-+
-+ _major = major;
-+ r = devfs_register_blkdev(_major, _name, &dm_blk_dops);
-+ if (r < 0) {
-+ DMERR("register_blkdev failed");
-+ kmem_cache_destroy(_io_hook_cache);
-+ return r;
-+ }
-+
-+ if (!_major)
-+ _major = r;
-+
-+ /* set up the arrays */
-+ read_ahead[_major] = DEFAULT_READ_AHEAD;
-+ blk_size[_major] = _block_size;
-+ blksize_size[_major] = _blksize_size;
-+ hardsect_size[_major] = _hardsect_size;
-+
-+ blk_queue_make_request(BLK_DEFAULT_QUEUE(_major), request);
-+
-+ _dev_dir = devfs_mk_dir(0, DM_DIR, NULL);
-+
-+ DMINFO("%s initialised: %s", _version, _email);
-+ return 0;
-+}
-+
-+static void local_exit(void)
-+{
-+ if (kmem_cache_destroy(_io_hook_cache))
-+ DMWARN("io_hooks still allocated during unregistration");
-+ _io_hook_cache = NULL;
-+
-+ if (devfs_unregister_blkdev(_major, _name) < 0)
-+ DMERR("devfs_unregister_blkdev failed");
-+
-+ read_ahead[_major] = 0;
-+ blk_size[_major] = NULL;
-+ blksize_size[_major] = NULL;
-+ hardsect_size[_major] = NULL;
-+ _major = 0;
-+
-+ DMINFO("%s cleaned up", _version);
-+}
-+
-+/*
-+ * We have a lot of init/exit functions, so it seems easier to
-+ * store them in an array. The disposable macro 'xx'
-+ * expands a prefix into a pair of function names.
-+ */
-+static struct {
-+ int (*init)(void);
-+ void (*exit)(void);
-+
-+} _inits[] = {
-+#define xx(n) {n ## _init, n ## _exit},
-+ xx(local)
-+ xx(dm_target)
-+ xx(dm_linear)
-+ xx(dm_stripe)
-+ xx(kcopyd)
-+ xx(dm_snapshot)
-+ xx(dm_interface)
-+#undef xx
-+};
-+
-+static int __init dm_init(void)
-+{
-+ const int count = sizeof(_inits) / sizeof(*_inits);
-+
-+ int r, i;
-+
-+ for (i = 0; i < count; i++) {
-+ r = _inits[i].init();
-+ if (r)
-+ goto bad;
-+ }
-+
-+ return 0;
-+
-+ bad:
-+ while (i--)
-+ _inits[i].exit();
-+
-+ return r;
-+}
-+
-+static void __exit dm_exit(void)
-+{
-+ int i = sizeof(_inits) / sizeof(*_inits);
-+
-+ dm_destroy_all();
-+ while (i--)
-+ _inits[i].exit();
-+}
-+
-+/*
-+ * Block device functions
-+ */
-+static int dm_blk_open(struct inode *inode, struct file *file)
-+{
-+ struct mapped_device *md;
-+
-+ md = dm_get_w(MINOR(inode->i_rdev));
-+ if (!md)
-+ return -ENXIO;
-+
-+ md->use_count++;
-+ dm_put_w(md);
-+
-+ return 0;
-+}
-+
-+static int dm_blk_close(struct inode *inode, struct file *file)
-+{
-+ struct mapped_device *md;
-+
-+ md = dm_get_w(MINOR(inode->i_rdev));
-+ if (!md)
-+ return -ENXIO;
-+
-+ if (md->use_count < 1)
-+ DMWARN("incorrect reference count found in mapped_device");
-+
-+ md->use_count--;
-+ dm_put_w(md);
-+
-+ return 0;
-+}
-+
-+/* In 512-byte units */
-+#define VOLUME_SIZE(minor) (_block_size[(minor)] << 1)
-+
-+static int dm_blk_ioctl(struct inode *inode, struct file *file,
-+ uint command, unsigned long a)
-+{
-+ int minor = MINOR(inode->i_rdev);
-+ long size;
-+
-+ if (minor >= MAX_DEVICES)
-+ return -ENXIO;
-+
-+ switch (command) {
-+ case BLKSSZGET:
-+ case BLKBSZGET:
-+ case BLKROGET:
-+ case BLKROSET:
-+ case BLKRASET:
-+ case BLKRAGET:
-+ case BLKFLSBUF:
-+#if 0 /* Future stacking block device */
-+ case BLKELVSET:
-+ case BLKELVGET:
-+#endif
-+ return blk_ioctl(inode->i_rdev, command, a);
-+ break;
-+
-+ case BLKGETSIZE:
-+ size = VOLUME_SIZE(minor);
-+ if (copy_to_user((void *) a, &size, sizeof(long)))
-+ return -EFAULT;
-+ break;
-+
-+ case BLKGETSIZE64:
-+ size = VOLUME_SIZE(minor);
-+ if (put_user((u64) size, (u64 *) a))
-+ return -EFAULT;
-+ break;
-+
-+ case BLKRRPART:
-+ return -EINVAL;
-+
-+ case LV_BMAP:
-+ return dm_user_bmap(inode, (struct lv_bmap *) a);
-+
-+ default:
-+ DMWARN("unknown block ioctl 0x%x", command);
-+ return -EINVAL;
-+ }
-+
-+ return 0;
-+}
-+
-+static inline struct io_hook *alloc_io_hook(void)
-+{
-+ return kmem_cache_alloc(_io_hook_cache, GFP_NOIO);
-+}
-+
-+static inline void free_io_hook(struct io_hook *ih)
-+{
-+ kmem_cache_free(_io_hook_cache, ih);
-+}
-+
-+/*
-+ * FIXME: We need to decide if deferred_io's need
-+ * their own slab, I say no for now since they are
-+ * only used when the device is suspended.
-+ */
-+static inline struct deferred_io *alloc_deferred(void)
-+{
-+ return kmalloc(sizeof(struct deferred_io), GFP_NOIO);
-+}
-+
-+static inline void free_deferred(struct deferred_io *di)
-+{
-+ kfree(di);
-+}
-+
-+/*
-+ * Call a target's optional error function if an I/O failed.
-+ */
-+static inline int call_err_fn(struct io_hook *ih, struct buffer_head *bh)
-+{
-+ dm_err_fn err = ih->target->type->err;
-+
-+ if (err)
-+ return err(bh, ih->rw, ih->target->private);
-+
-+ return 0;
-+}
-+
-+/*
-+ * bh->b_end_io routine that decrements the pending count
-+ * and then calls the original bh->b_end_io fn.
-+ */
-+static void dec_pending(struct buffer_head *bh, int uptodate)
-+{
-+ struct io_hook *ih = bh->b_bdev_private;
-+
-+ if (!uptodate && call_err_fn(ih, bh))
-+ return;
-+
-+ if (atomic_dec_and_test(&ih->md->pending))
-+ /* nudge anyone waiting on suspend queue */
-+ wake_up(&ih->md->wait);
-+
-+ bh->b_end_io = ih->end_io;
-+ bh->b_bdev_private = ih->context;
-+ free_io_hook(ih);
-+
-+ bh->b_end_io(bh, uptodate);
-+}
-+
-+/*
-+ * Add the bh to the list of deferred io.
-+ */
-+static int queue_io(struct buffer_head *bh, int rw)
-+{
-+ struct deferred_io *di = alloc_deferred();
-+ struct mapped_device *md;
-+
-+ if (!di)
-+ return -ENOMEM;
-+
-+ md = dm_get_w(MINOR(bh->b_rdev));
-+ if (!md) {
-+ free_deferred(di);
-+ return -ENXIO;
-+ }
-+
-+ if (!md->suspended) {
-+ dm_put_w(md);
-+ free_deferred(di);
-+ return 1;
-+ }
-+
-+ di->bh = bh;
-+ di->rw = rw;
-+ di->next = md->deferred;
-+ md->deferred = di;
-+
-+ dm_put_w(md);
-+
-+ return 0; /* deferred successfully */
-+}
-+
-+/*
-+ * Do the bh mapping for a given leaf
-+ */
-+static inline int __map_buffer(struct mapped_device *md,
-+ struct buffer_head *bh, int rw, int leaf)
-+{
-+ int r;
-+ dm_map_fn fn;
-+ void *context;
-+ struct io_hook *ih = NULL;
-+ struct target *ti = md->map->targets + leaf;
-+
-+ fn = ti->type->map;
-+ context = ti->private;
-+
-+ ih = alloc_io_hook();
-+
-+ if (!ih)
-+ return -1;
-+
-+ ih->md = md;
-+ ih->rw = rw;
-+ ih->target = ti;
-+ ih->end_io = bh->b_end_io;
-+ ih->context = bh->b_bdev_private;
-+
-+ r = fn(bh, rw, context);
-+
-+ if (r > 0) {
-+ /* hook the end io request fn */
-+ atomic_inc(&md->pending);
-+ bh->b_end_io = dec_pending;
-+ bh->b_bdev_private = ih;
-+
-+ } else if (r == 0)
-+ /* we don't need to hook */
-+ free_io_hook(ih);
-+
-+ else if (r < 0) {
-+ free_io_hook(ih);
-+ return -1;
-+ }
-+
-+ return r;
-+}
-+
-+/*
-+ * Search the btree for the correct target.
-+ */
-+static inline int __find_node(struct dm_table *t, struct buffer_head *bh)
-+{
-+ int l, n = 0, k = 0;
-+ offset_t *node;
-+
-+ for (l = 0; l < t->depth; l++) {
-+ n = get_child(n, k);
-+ node = get_node(t, l, n);
-+
-+ for (k = 0; k < KEYS_PER_NODE; k++)
-+ if (node[k] >= bh->b_rsector)
-+ break;
-+ }
-+
-+ return (KEYS_PER_NODE * n) + k;
-+}
-+
-+static int request(request_queue_t * q, int rw, struct buffer_head *bh)
-+{
-+ struct mapped_device *md;
-+ int r, minor = MINOR(bh->b_rdev);
-+
-+ md = dm_get_r(minor);
-+ if (!md) {
-+ buffer_IO_error(bh);
-+ return 0;
-+ }
-+
-+ /*
-+ * If we're suspended we have to queue
-+ * this io for later.
-+ */
-+ while (md->suspended) {
-+ dm_put_r(md);
-+
-+ if (rw == READA)
-+ goto bad_no_lock;
-+
-+ r = queue_io(bh, rw);
-+
-+ if (r < 0)
-+ goto bad_no_lock;
-+
-+ else if (r == 0)
-+ return 0; /* deferred successfully */
-+
-+ /*
-+ * We're in a while loop, because someone could suspend
-+ * before we get to the following read lock.
-+ */
-+ md = dm_get_r(minor);
-+ if (!md) {
-+ buffer_IO_error(bh);
-+ return 0;
-+ }
-+ }
-+
-+ if ((r = __map_buffer(md, bh, rw, __find_node(md->map, bh))) < 0)
-+ goto bad;
-+
-+ dm_put_r(md);
-+ return r;
-+
-+ bad:
-+ dm_put_r(md);
-+
-+ bad_no_lock:
-+ buffer_IO_error(bh);
-+ return 0;
-+}
-+
-+static int check_dev_size(int minor, unsigned long block)
-+{
-+ /* FIXME: check this */
-+ unsigned long max_sector = (_block_size[minor] << 1) + 1;
-+ unsigned long sector = (block + 1) * (_blksize_size[minor] >> 9);
-+
-+ return (sector > max_sector) ? 0 : 1;
-+}
-+
-+/*
-+ * Creates a dummy buffer head and maps it (for lilo).
-+ */
-+static int do_bmap(kdev_t dev, unsigned long block,
-+ kdev_t * r_dev, unsigned long *r_block)
-+{
-+ struct mapped_device *md;
-+ struct buffer_head bh;
-+ int minor = MINOR(dev), r;
-+ struct target *t;
-+
-+ md = dm_get_r(minor);
-+ if (!md)
-+ return -ENXIO;
-+
-+ if (md->suspended) {
-+ dm_put_r(md);
-+ return -EPERM;
-+ }
-+
-+ if (!check_dev_size(minor, block)) {
-+ dm_put_r(md);
-+ return -EINVAL;
-+ }
-+
-+ /* setup dummy bh */
-+ memset(&bh, 0, sizeof(bh));
-+ bh.b_blocknr = block;
-+ bh.b_dev = bh.b_rdev = dev;
-+ bh.b_size = _blksize_size[minor];
-+ bh.b_rsector = block * (bh.b_size >> 9);
-+
-+ /* find target */
-+ t = md->map->targets + __find_node(md->map, &bh);
-+
-+ /* do the mapping */
-+ r = t->type->map(&bh, READ, t->private);
-+
-+ *r_dev = bh.b_rdev;
-+ *r_block = bh.b_rsector / (bh.b_size >> 9);
-+
-+ dm_put_r(md);
-+ return r;
-+}
-+
-+/*
-+ * Marshals arguments and results between user and kernel space.
-+ */
-+static int dm_user_bmap(struct inode *inode, struct lv_bmap *lvb)
-+{
-+ unsigned long block, r_block;
-+ kdev_t r_dev;
-+ int r;
-+
-+ if (get_user(block, &lvb->lv_block))
-+ return -EFAULT;
-+
-+ if ((r = do_bmap(inode->i_rdev, block, &r_dev, &r_block)))
-+ return r;
-+
-+ if (put_user(kdev_t_to_nr(r_dev), &lvb->lv_dev) ||
-+ put_user(r_block, &lvb->lv_block))
-+ return -EFAULT;
-+
-+ return 0;
-+}
-+
-+/*
-+ * See if the device with a specific minor # is free. The write
-+ * lock is held when it returns successfully.
-+ */
-+static inline int specific_dev(int minor, struct mapped_device *md)
-+{
-+ if (minor >= MAX_DEVICES) {
-+ DMWARN("request for a mapped_device beyond MAX_DEVICES (%d)",
-+ MAX_DEVICES);
-+ return -1;
-+ }
-+
-+ down_write(_dev_locks + minor);
-+ if (_devs[minor]) {
-+ /* in use */
-+ up_write(_dev_locks + minor);
-+ return -1;
-+ }
-+
-+ return minor;
-+}
-+
-+/*
-+ * Find the first free device. Again the write lock is held on
-+ * success.
-+ */
-+static int any_old_dev(struct mapped_device *md)
-+{
-+ int i;
-+
-+ for (i = 0; i < MAX_DEVICES; i++)
-+ if (specific_dev(i, md) != -1)
-+ return i;
-+
-+ return -1;
-+}
-+
-+/*
-+ * Allocate and initialise a blank device.
-+ * Caller must ensure uuid is null-terminated.
-+ * Device is returned with a write lock held.
-+ */
-+static struct mapped_device *alloc_dev(const char *name, const char *uuid,
-+ int minor)
-+{
-+ struct mapped_device *md = kmalloc(sizeof(*md), GFP_KERNEL);
-+ int len;
-+
-+ if (!md) {
-+ DMWARN("unable to allocate device, out of memory.");
-+ return NULL;
-+ }
-+
-+ memset(md, 0, sizeof(*md));
-+
-+ /*
-+ * This grabs the write lock if it succeeds.
-+ */
-+ minor = (minor < 0) ? any_old_dev(md) : specific_dev(minor, md);
-+ if (minor < 0) {
-+ kfree(md);
-+ return NULL;
-+ }
-+
-+ md->dev = MKDEV(_major, minor);
-+ md->suspended = 0;
-+
-+ strncpy(md->name, name, sizeof(md->name) - 1);
-+ md->name[sizeof(md->name) - 1] = '\0';
-+
-+ /*
-+ * Copy in the uuid.
-+ */
-+ if (uuid && *uuid) {
-+ len = strlen(uuid) + 1;
-+ if (!(md->uuid = kmalloc(len, GFP_KERNEL))) {
-+ DMWARN("unable to allocate uuid - out of memory.");
-+ kfree(md);
-+ return NULL;
-+ }
-+ strcpy(md->uuid, uuid);
-+ }
-+
-+ init_waitqueue_head(&md->wait);
-+ return md;
-+}
-+
-+static int __register_device(struct mapped_device *md)
-+{
-+ md->devfs_entry =
-+ devfs_register(_dev_dir, md->name, DEVFS_FL_CURRENT_OWNER,
-+ MAJOR(md->dev), MINOR(md->dev),
-+ S_IFBLK | S_IRUSR | S_IWUSR | S_IRGRP,
-+ &dm_blk_dops, NULL);
-+
-+ return 0;
-+}
-+
-+static int __unregister_device(struct mapped_device *md)
-+{
-+ devfs_unregister(md->devfs_entry);
-+ return 0;
-+}
-+
-+/*
-+ * The hardsect size for a mapped device is the smallest hardsect size
-+ * from the devices it maps onto.
-+ */
-+static int __find_hardsect_size(struct list_head *devices)
-+{
-+ int result = INT_MAX, size;
-+ struct list_head *tmp;
-+
-+ list_for_each(tmp, devices) {
-+ struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
-+ size = get_hardsect_size(dd->dev);
-+ if (size < result)
-+ result = size;
-+ }
-+ return result;
-+}
-+
-+/*
-+ * Bind a table to the device.
-+ */
-+static int __bind(struct mapped_device *md, struct dm_table *t)
-+{
-+ int minor = MINOR(md->dev);
-+
-+ md->map = t;
-+
-+ if (!t->num_targets) {
-+ _block_size[minor] = 0;
-+ _blksize_size[minor] = BLOCK_SIZE;
-+ _hardsect_size[minor] = 0;
-+ return 0;
-+ }
-+
-+ /* in k */
-+ _block_size[minor] = (t->highs[t->num_targets - 1] + 1) >> 1;
-+
-+ _blksize_size[minor] = BLOCK_SIZE;
-+ _hardsect_size[minor] = __find_hardsect_size(&t->devices);
-+ register_disk(NULL, md->dev, 1, &dm_blk_dops, _block_size[minor]);
-+
-+ return 0;
-+}
-+
-+static void __unbind(struct mapped_device *md)
-+{
-+ int minor = MINOR(md->dev);
-+
-+ dm_table_destroy(md->map);
-+ md->map = NULL;
-+
-+ _block_size[minor] = 0;
-+ _blksize_size[minor] = 0;
-+ _hardsect_size[minor] = 0;
-+}
-+
-+static int check_name(const char *name)
-+{
-+ struct mapped_device *md;
-+
-+ if (strchr(name, '/') || strlen(name) > DM_NAME_LEN) {
-+ DMWARN("invalid device name");
-+ return -1;
-+ }
-+
-+ md = dm_get_name_r(name, DM_LOOKUP_BY_NAME);
-+ if (md) {
-+ dm_put_r(md);
-+ DMWARN("device name already in use");
-+ return -1;
-+ }
-+
-+ return 0;
-+}
-+
-+static int check_uuid(const char *uuid)
-+{
-+ struct mapped_device *md;
-+
-+ if (uuid) {
-+ md = dm_get_name_r(uuid, DM_LOOKUP_BY_UUID);
-+ if (md) {
-+ dm_put_r(md);
-+ DMWARN("device uuid already in use");
-+ return -1;
-+ }
-+ }
-+
-+ return 0;
-+}
-+
-+/*
-+ * Constructor for a new device.
-+ */
-+int dm_create(const char *name, const char *uuid, int minor, int ro,
-+ struct dm_table *table)
-+{
-+ int r;
-+ struct mapped_device *md;
-+
-+ spin_lock(&_create_lock);
-+ if (check_name(name) || check_uuid(uuid)) {
-+ spin_unlock(&_create_lock);
-+ return -EINVAL;
-+ }
-+
-+ md = alloc_dev(name, uuid, minor);
-+ if (!md) {
-+ spin_unlock(&_create_lock);
-+ return -ENXIO;
-+ }
-+ minor = MINOR(md->dev);
-+ _devs[minor] = md;
-+
-+ r = __register_device(md);
-+ if (r)
-+ goto err;
-+
-+ r = __bind(md, table);
-+ if (r)
-+ goto err;
-+
-+ dm_set_ro(md, ro);
-+
-+ spin_unlock(&_create_lock);
-+ dm_put_w(md);
-+ return 0;
-+
-+ err:
-+ _devs[minor] = NULL;
-+ if (md->uuid)
-+ kfree(md->uuid);
-+
-+ dm_put_w(md);
-+ kfree(md);
-+ spin_unlock(&_create_lock);
-+ return r;
-+}
-+
-+/*
-+ * Renames the device. No lock held.
-+ */
-+int dm_set_name(const char *name, int nametype, const char *newname)
-+{
-+ int r;
-+ struct mapped_device *md;
-+
-+ spin_lock(&_create_lock);
-+ if (check_name(newname) < 0) {
-+ spin_unlock(&_create_lock);
-+ return -EINVAL;
-+ }
-+
-+ md = dm_get_name_w(name, nametype);
-+ if (!md) {
-+ spin_unlock(&_create_lock);
-+ return -ENXIO;
-+ }
-+
-+ r = __unregister_device(md);
-+ if (r)
-+ goto out;
-+
-+ strcpy(md->name, newname);
-+ r = __register_device(md);
-+
-+ out:
-+ dm_put_w(md);
-+ spin_unlock(&_create_lock);
-+ return r;
-+}
-+
-+/*
-+ * Destructor for the device. You cannot destroy an open
-+ * device. Write lock must be held before calling.
-+ * Caller must dm_put_w(md) then kfree(md) if call was successful.
-+ */
-+int dm_destroy(struct mapped_device *md)
-+{
-+ int minor, r;
-+
-+ if (md->use_count)
-+ return -EPERM;
-+
-+ r = __unregister_device(md);
-+ if (r)
-+ return r;
-+
-+ minor = MINOR(md->dev);
-+ _devs[minor] = NULL;
-+ __unbind(md);
-+
-+ if (md->uuid)
-+ kfree(md->uuid);
-+
-+ return 0;
-+}
-+
-+/*
-+ * Destroy all devices - except open ones
-+ */
-+void dm_destroy_all(void)
-+{
-+ int i, some_destroyed, r;
-+ struct mapped_device *md;
-+
-+ do {
-+ some_destroyed = 0;
-+ for (i = 0; i < MAX_DEVICES; i++) {
-+ md = dm_get_w(i);
-+ if (!md)
-+ continue;
-+
-+ r = dm_destroy(md);
-+ dm_put_w(md);
-+
-+ if (!r) {
-+ kfree(md);
-+ some_destroyed = 1;
-+ }
-+ }
-+ } while (some_destroyed);
-+}
-+
-+/*
-+ * Sets or clears the read-only flag for the device. Write lock
-+ * must be held.
-+ */
-+void dm_set_ro(struct mapped_device *md, int ro)
-+{
-+ md->read_only = ro;
-+ set_device_ro(md->dev, ro);
-+}
-+
-+/*
-+ * A target is notifying us of some event
-+ */
-+void dm_notify(void *target)
-+{
-+}
-+
-+/*
-+ * Requeue the deferred buffer_heads by calling generic_make_request.
-+ */
-+static void flush_deferred_io(struct deferred_io *c)
-+{
-+ struct deferred_io *n;
-+
-+ while (c) {
-+ n = c->next;
-+ generic_make_request(c->rw, c->bh);
-+ free_deferred(c);
-+ c = n;
-+ }
-+}
-+
-+/*
-+ * Swap in a new table (destroying old one). Write lock must be
-+ * held.
-+ */
-+int dm_swap_table(struct mapped_device *md, struct dm_table *table)
-+{
-+ int r;
-+
-+ /* device must be suspended */
-+ if (!md->suspended)
-+ return -EPERM;
-+
-+ __unbind(md);
-+
-+ r = __bind(md, table);
-+ if (r)
-+ return r;
-+
-+ return 0;
-+}
-+
-+/*
-+ * We need to be able to change a mapping table under a mounted
-+ * filesystem. for example we might want to move some data in
-+ * the background. Before the table can be swapped with
-+ * dm_bind_table, dm_suspend must be called to flush any in
-+ * flight buffer_heads and ensure that any further io gets
-+ * deferred. Write lock must be held.
-+ */
-+int dm_suspend(struct mapped_device *md)
-+{
-+ int minor = MINOR(md->dev);
-+ DECLARE_WAITQUEUE(wait, current);
-+
-+ if (md->suspended)
-+ return -EINVAL;
-+
-+ md->suspended = 1;
-+ dm_put_w(md);
-+
-+ /* wait for all the pending io to flush */
-+ add_wait_queue(&md->wait, &wait);
-+ current->state = TASK_UNINTERRUPTIBLE;
-+ do {
-+ md = dm_get_w(minor);
-+ if (!md) {
-+ /* Caller expects to free this lock. Yuck. */
-+ down_write(_dev_locks + minor);
-+ return -ENXIO;
-+ }
-+
-+ if (!atomic_read(&md->pending))
-+ break;
-+
-+ dm_put_w(md);
-+ schedule();
-+
-+ } while (1);
-+
-+ current->state = TASK_RUNNING;
-+ remove_wait_queue(&md->wait, &wait);
-+
-+ return 0;
-+}
-+
-+int dm_resume(struct mapped_device *md)
-+{
-+ int minor = MINOR(md->dev);
-+ struct deferred_io *def;
-+
-+ if (!md->suspended || !md->map->num_targets)
-+ return -EINVAL;
-+
-+ md->suspended = 0;
-+ def = md->deferred;
-+ md->deferred = NULL;
-+
-+ dm_put_w(md);
-+ flush_deferred_io(def);
-+ run_task_queue(&tq_disk);
-+
-+ if (!dm_get_w(minor)) {
-+ /* FIXME: yuck */
-+ down_write(_dev_locks + minor);
-+ return -ENXIO;
-+ }
-+
-+ return 0;
-+}
-+
-+struct block_device_operations dm_blk_dops = {
-+ open: dm_blk_open,
-+ release: dm_blk_close,
-+ ioctl: dm_blk_ioctl,
-+ owner: THIS_MODULE
-+};
-+
-+/*
-+ * module hooks
-+ */
-+module_init(dm_init);
-+module_exit(dm_exit);
-+
-+MODULE_PARM(major, "i");
-+MODULE_PARM_DESC(major, "The major number of the device mapper");
-+MODULE_DESCRIPTION(DM_NAME " driver");
-+MODULE_AUTHOR("Joe Thornber <thornber@sistina.com>");
-+MODULE_LICENSE("GPL");
-diff -ruN linux-2.4.18/drivers/md/dm.h linux/drivers/md/dm.h
---- linux-2.4.18/drivers/md/dm.h Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/dm.h Tue Apr 23 22:23:30 2002
-@@ -0,0 +1,220 @@
-+/*
-+ * Internal header file for device mapper
-+ *
-+ * Copyright (C) 2001 Sistina Software
-+ *
-+ * This file is released under the LGPL.
-+ */
-+
-+#ifndef DM_INTERNAL_H
-+#define DM_INTERNAL_H
-+
-+#include <linux/config.h>
-+#include <linux/version.h>
-+#include <linux/major.h>
-+#include <linux/iobuf.h>
-+#include <linux/module.h>
-+#include <linux/fs.h>
-+#include <linux/slab.h>
-+#include <linux/vmalloc.h>
-+#include <linux/compatmac.h>
-+#include <linux/cache.h>
-+#include <linux/devfs_fs_kernel.h>
-+#include <linux/ctype.h>
-+#include <linux/device-mapper.h>
-+#include <linux/list.h>
-+#include <linux/init.h>
-+
-+#define DM_NAME "device-mapper" /* Name for messaging */
-+#define MAX_DEPTH 16
-+#define NODE_SIZE L1_CACHE_BYTES
-+#define KEYS_PER_NODE (NODE_SIZE / sizeof(offset_t))
-+#define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
-+#define MAX_ARGS 32
-+#define MAX_DEVICES 256
-+
-+/*
-+ * List of devices that a metadevice uses and should open/close.
-+ */
-+struct dm_dev {
-+ atomic_t count;
-+ struct list_head list;
-+
-+ kdev_t dev;
-+ struct block_device *bd;
-+};
-+
-+/*
-+ * I/O that had to be deferred while we were suspended
-+ */
-+struct deferred_io {
-+ int rw;
-+ struct buffer_head *bh;
-+ struct deferred_io *next;
-+};
-+
-+/*
-+ * Btree leaf - this does the actual mapping
-+ */
-+struct target {
-+ struct target_type *type;
-+ void *private;
-+};
-+
-+/*
-+ * The btree
-+ */
-+struct dm_table {
-+ /* btree table */
-+ int depth;
-+ int counts[MAX_DEPTH]; /* in nodes */
-+ offset_t *index[MAX_DEPTH];
-+
-+ int num_targets;
-+ int num_allocated;
-+ offset_t *highs;
-+ struct target *targets;
-+
-+ /* a list of devices used by this table */
-+ struct list_head devices;
-+};
-+
-+/*
-+ * The actual device struct
-+ */
-+struct mapped_device {
-+ kdev_t dev;
-+ char name[DM_NAME_LEN];
-+ char *uuid;
-+
-+ int use_count;
-+ int suspended;
-+ int read_only;
-+
-+ /* a list of io's that arrived while we were suspended */
-+ atomic_t pending;
-+ wait_queue_head_t wait;
-+ struct deferred_io *deferred;
-+
-+ struct dm_table *map;
-+
-+ /* used by dm-fs.c */
-+ devfs_handle_t devfs_entry;
-+};
-+
-+extern struct block_device_operations dm_blk_dops;
-+
-+/* dm-target.c */
-+int dm_target_init(void);
-+struct target_type *dm_get_target_type(const char *name);
-+void dm_put_target_type(struct target_type *t);
-+void dm_target_exit(void);
-+
-+/*
-+ * Destructively splits argument list to pass to ctr.
-+ */
-+int split_args(int max, int *argc, char **argv, char *input);
-+
-+/* dm.c */
-+struct mapped_device *dm_get_r(int minor);
-+struct mapped_device *dm_get_w(int minor);
-+
-+/*
-+ * There are two ways to lookup a device.
-+ */
-+enum {
-+ DM_LOOKUP_BY_NAME,
-+ DM_LOOKUP_BY_UUID
-+};
-+
-+struct mapped_device *dm_get_name_r(const char *name, int nametype);
-+struct mapped_device *dm_get_name_w(const char *name, int nametype);
-+
-+void dm_put_r(struct mapped_device *md);
-+void dm_put_w(struct mapped_device *md);
-+
-+/*
-+ * Call with no lock.
-+ */
-+int dm_create(const char *name, const char *uuid, int minor, int ro,
-+ struct dm_table *table);
-+int dm_set_name(const char *name, int nametype, const char *newname);
-+void dm_destroy_all(void);
-+
-+/*
-+ * You must have the write lock before calling the remaining md
-+ * methods.
-+ */
-+int dm_destroy(struct mapped_device *md);
-+void dm_set_ro(struct mapped_device *md, int ro);
-+
-+/*
-+ * The device must be suspended before calling this method.
-+ */
-+int dm_swap_table(struct mapped_device *md, struct dm_table *t);
-+
-+/*
-+ * A device can still be used while suspended, but I/O is deferred.
-+ */
-+int dm_suspend(struct mapped_device *md);
-+int dm_resume(struct mapped_device *md);
-+
-+/*
-+ * Event notification
-+ */
-+void dm_notify(void *target);
-+
-+/* dm-table.c */
-+int dm_table_create(struct dm_table **result);
-+void dm_table_destroy(struct dm_table *t);
-+
-+int dm_table_add_target(struct dm_table *t, offset_t highs,
-+ struct target_type *type, void *private);
-+int dm_table_complete(struct dm_table *t);
-+
-+/* Snapshots */
-+int dm_snapshot_init(void);
-+void dm_snapshot_exit(void);
-+
-+/* dm-mirror.c */
-+int dm_mirror_init(void);
-+void dm_mirror_exit(void);
-+
-+#define DMWARN(f, x...) printk(KERN_WARNING DM_NAME ": " f "\n" , ## x)
-+#define DMERR(f, x...) printk(KERN_ERR DM_NAME ": " f "\n" , ## x)
-+#define DMINFO(f, x...) printk(KERN_INFO DM_NAME ": " f "\n" , ## x)
-+
-+/*
-+ * Calculate the index of the child node of the n'th node k'th key.
-+ */
-+static inline int get_child(int n, int k)
-+{
-+ return (n * CHILDREN_PER_NODE) + k;
-+}
-+
-+/*
-+ * Return the n'th node of level l from table t.
-+ */
-+static inline offset_t *get_node(struct dm_table *t, int l, int n)
-+{
-+ return t->index[l] + (n * KEYS_PER_NODE);
-+}
-+
-+/*
-+ * The device-mapper can be driven through one of two interfaces;
-+ * ioctl or filesystem, depending which patch you have applied.
-+ */
-+int __init dm_interface_init(void);
-+void dm_interface_exit(void);
-+
-+/*
-+ * Targets for linear and striped mappings
-+ */
-+
-+int dm_linear_init(void);
-+void dm_linear_exit(void);
-+
-+int dm_stripe_init(void);
-+void dm_stripe_exit(void);
-+
-+#endif
-diff -ruN linux-2.4.18/drivers/md/kcopyd.c linux/drivers/md/kcopyd.c
---- linux-2.4.18/drivers/md/kcopyd.c Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/kcopyd.c Tue Apr 23 22:28:13 2002
-@@ -0,0 +1,779 @@
-+/*
-+ * Copyright (C) 2002 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#include <linux/config.h>
-+#include <linux/module.h>
-+#include <linux/init.h>
-+#include <linux/slab.h>
-+#include <linux/list.h>
-+#include <linux/fs.h>
-+#include <linux/blkdev.h>
-+#include <linux/device-mapper.h>
-+#include <linux/mempool.h>
-+#include <asm/atomic.h>
-+
-+#include "kcopyd.h"
-+
-+/* FIXME: this is only needed for the DMERR macros */
-+#include "dm.h"
-+
-+/*
-+ * Hard sector size used all over the kernel.
-+ */
-+#define SECTOR_SIZE 512
-+#define SECTOR_SHIFT 9
-+static int wake_kcopyd(void);
-+
-+/*-----------------------------------------------------------------
-+ * We reserve our own pool of preallocated pages that are
-+ * only used for kcopyd io.
-+ *---------------------------------------------------------------*/
-+
-+/*
-+ * FIXME: This should be configurable.
-+ */
-+#define NUM_PAGES 512
-+
-+static DECLARE_MUTEX(_pages_lock);
-+static int _num_free_pages;
-+static struct page *_pages_array[NUM_PAGES];
-+
-+static __init int init_pages(void)
-+{
-+ int i;
-+ struct page *p;
-+
-+ for (i = 0; i < NUM_PAGES; i++) {
-+ p = alloc_page(GFP_KERNEL);
-+ if (!p)
-+ goto bad;
-+
-+ LockPage(p);
-+ _pages_array[i] = p;
-+ }
-+
-+ _num_free_pages = NUM_PAGES;
-+ return 0;
-+
-+ bad:
-+ while (i--)
-+ __free_page(_pages_array[i]);
-+ return -ENOMEM;
-+}
-+
-+static void exit_pages(void)
-+{
-+ int i;
-+ struct page *p;
-+
-+ for (i = 0; i < NUM_PAGES; i++) {
-+ p = _pages_array[i];
-+ UnlockPage(p);
-+ __free_page(p);
-+ }
-+
-+ _num_free_pages = 0;
-+}
-+
-+static int kcopyd_get_pages(int num, struct page **result)
-+{
-+ int i;
-+
-+ down(&_pages_lock);
-+ if (_num_free_pages < num) {
-+ up(&_pages_lock);
-+ return -ENOMEM;
-+ }
-+
-+ for (i = 0; i < num; i++) {
-+ _num_free_pages--;
-+ result[i] = _pages_array[_num_free_pages];
-+ }
-+ up(&_pages_lock);
-+
-+ return 0;
-+}
-+
-+static void kcopyd_free_pages(int num, struct page **result)
-+{
-+ int i;
-+
-+ down(&_pages_lock);
-+ for (i = 0; i < num; i++)
-+ _pages_array[_num_free_pages++] = result[i];
-+ up(&_pages_lock);
-+}
-+
-+/*-----------------------------------------------------------------
-+ * We keep our own private pool of buffer_heads. These are just
-+ * held in a list on the b_reqnext field.
-+ *---------------------------------------------------------------*/
-+
-+/*
-+ * Make sure we have enough buffers to always keep the pages
-+ * occupied. So we assume the worst case scenario where blocks
-+ * are the size of a single sector.
-+ */
-+#define NUM_BUFFERS NUM_PAGES * (PAGE_SIZE / SECTOR_SIZE)
-+
-+static spinlock_t _buffer_lock = SPIN_LOCK_UNLOCKED;
-+static struct buffer_head *_all_buffers;
-+static struct buffer_head *_free_buffers;
-+
-+static __init int init_buffers(void)
-+{
-+ int i;
-+ struct buffer_head *buffers;
-+ size_t s = sizeof(struct buffer_head) * NUM_BUFFERS;
-+
-+ /*
-+ * FIXME: this should be a vmalloc.
-+ */
-+ buffers = vmalloc(s);
-+ if (!buffers) {
-+ DMWARN("Couldn't allocate buffer heads.");
-+ return -ENOMEM;
-+ }
-+
-+ memset(buffers, 0, s);
-+ for (i = 0; i < NUM_BUFFERS; i++) {
-+ if (i < NUM_BUFFERS - 1)
-+ buffers[i].b_reqnext = &buffers[i + 1];
-+ init_waitqueue_head(&buffers[i].b_wait);
-+ INIT_LIST_HEAD(&buffers[i].b_inode_buffers);
-+ }
-+
-+ _all_buffers = _free_buffers = buffers;
-+ return 0;
-+}
-+
-+static void exit_buffers(void)
-+{
-+ vfree(_all_buffers);
-+}
-+
-+static struct buffer_head *alloc_buffer(void)
-+{
-+ int state = current->state;
-+ struct buffer_head *r;
-+
-+ set_current_state(TASK_UNINTERRUPTIBLE);
-+ spin_lock(&_buffer_lock);
-+
-+ if (!_free_buffers)
-+ r = NULL;
-+ else {
-+ r = _free_buffers;
-+ _free_buffers = _free_buffers->b_reqnext;
-+ r->b_reqnext = NULL;
-+ }
-+
-+ spin_unlock(&_buffer_lock);
-+ set_current_state(state);
-+
-+ return r;
-+}
-+
-+/*
-+ * Only called from interrupt context.
-+ */
-+static void free_buffer(struct buffer_head *bh)
-+{
-+ spin_lock(&_buffer_lock);
-+ bh->b_reqnext = _free_buffers;
-+ _free_buffers = bh;
-+ spin_unlock(&_buffer_lock);
-+}
-+
-+/*-----------------------------------------------------------------
-+ * kcopyd_jobs need to be allocated by the *clients* of kcopyd,
-+ * for this reason we use a mempool to prevent the client from
-+ * ever having to do io (which could cause a
-+ * deadlock).
-+ *---------------------------------------------------------------*/
-+#define MIN_JOBS NUM_PAGES
-+
-+static kmem_cache_t *_job_cache = NULL;
-+static mempool_t *_job_pool = NULL;
-+
-+/*
-+ * We maintain three lists of jobs:
-+ *
-+ * i) jobs waiting for pages
-+ * ii) jobs that have pages, and are waiting for the io to be issued.
-+ * iii) jobs that have completed.
-+ *
-+ * All three of these are protected by job_lock.
-+ */
-+
-+static spinlock_t _job_lock = SPIN_LOCK_UNLOCKED;
-+
-+static LIST_HEAD(_complete_jobs);
-+static LIST_HEAD(_io_jobs);
-+static LIST_HEAD(_pages_jobs);
-+
-+static __init int init_jobs(void)
-+{
-+ INIT_LIST_HEAD(&_complete_jobs);
-+ INIT_LIST_HEAD(&_io_jobs);
-+ INIT_LIST_HEAD(&_pages_jobs);
-+
-+ _job_cache = kmem_cache_create("kcopyd-jobs", sizeof(struct kcopyd_job),
-+ __alignof__(struct kcopyd_job),
-+ 0, NULL, NULL);
-+ if (!_job_cache)
-+ return -ENOMEM;
-+
-+ _job_pool = mempool_create(MIN_JOBS,
-+ mempool_alloc_slab,
-+ mempool_free_slab, _job_cache);
-+ if (!_job_pool) {
-+ kmem_cache_destroy(_job_cache);
-+ return -ENOMEM;
-+ }
-+
-+ return 0;
-+}
-+
-+static void exit_jobs(void)
-+{
-+ mempool_destroy(_job_pool);
-+ kmem_cache_destroy(_job_cache);
-+}
-+
-+struct kcopyd_job *kcopyd_alloc_job(void)
-+{
-+ struct kcopyd_job *job;
-+
-+ job = mempool_alloc(_job_pool, GFP_KERNEL);;
-+ if (!job)
-+ return NULL;
-+
-+ memset(job, 0, sizeof(*job));
-+ return job;
-+}
-+
-+void kcopyd_free_job(struct kcopyd_job *job)
-+{
-+ mempool_free(job, _job_pool);
-+}
-+
-+/*
-+ * Functions to push and pop a job onto the head of a given job
-+ * list.
-+ */
-+static inline struct kcopyd_job *__pop(struct list_head *jobs)
-+{
-+ struct kcopyd_job *job = NULL;
-+
-+ spin_lock(&_job_lock);
-+ if (!list_empty(jobs)) {
-+ job = list_entry(jobs->next, struct kcopyd_job, list);
-+ list_del(&job->list);
-+ }
-+ spin_unlock(&_job_lock);
-+
-+ return job;
-+}
-+
-+static struct kcopyd_job *pop(struct list_head *jobs)
-+{
-+ int state = current->state;
-+ struct kcopyd_job *job;
-+
-+ set_current_state(TASK_UNINTERRUPTIBLE);
-+ job = __pop(jobs);
-+ set_current_state(state);
-+ return job;
-+}
-+
-+static inline void __push(struct list_head *jobs, struct kcopyd_job *job)
-+{
-+ spin_lock(&_job_lock);
-+ list_add(&job->list, jobs);
-+ spin_unlock(&_job_lock);
-+}
-+
-+static void push(struct list_head *jobs, struct kcopyd_job *job)
-+{
-+ int state = current->state;
-+
-+ set_current_state(TASK_UNINTERRUPTIBLE);
-+ __push(jobs, job);
-+ set_current_state(state);
-+}
-+
-+/*
-+ * Completion function for one of our buffers.
-+ */
-+static void end_bh(struct buffer_head *bh, int uptodate)
-+{
-+ struct kcopyd_job *job = bh->b_private;
-+
-+ mark_buffer_uptodate(bh, uptodate);
-+ unlock_buffer(bh);
-+
-+ if (!uptodate)
-+ job->err = -EIO;
-+
-+ /* are we the last ? */
-+ if (atomic_dec_and_test(&job->nr_incomplete)) {
-+ __push(&_complete_jobs, job);
-+ wake_kcopyd();
-+ }
-+
-+ free_buffer(bh);
-+}
-+
-+static void dispatch_bh(struct kcopyd_job *job,
-+ struct buffer_head *bh, int block)
-+{
-+ int p;
-+
-+ /*
-+ * Add in the job offset
-+ */
-+ block += job->offset >> job->block_shift;
-+ bh->b_blocknr = (job->disk.sector >> job->block_shift) + block;
-+
-+ p = block >> job->bpp_shift;
-+ block &= job->bpp_mask;
-+
-+ bh->b_dev = B_FREE;
-+ bh->b_size = job->block_size;
-+ set_bh_page(bh, job->pages[p],
-+ (block << job->block_shift) << SECTOR_SHIFT);
-+ bh->b_this_page = bh;
-+
-+ init_buffer(bh, end_bh, job);
-+
-+ bh->b_dev = job->disk.dev;
-+ bh->b_state = ((1 << BH_Mapped) | (1 << BH_Lock) | (1 << BH_Req));
-+
-+ set_bit(BH_Uptodate, &bh->b_state);
-+ if (job->rw == WRITE)
-+ clear_bit(BH_Dirty, &bh->b_state);
-+
-+ submit_bh(job->rw, bh);
-+}
-+
-+/*
-+ * These three functions process 1 item from the corresponding
-+ * job list.
-+ *
-+ * They return:
-+ * < 0: error
-+ * 0: success
-+ * > 0: can't process yet.
-+ */
-+static int run_complete_job(struct kcopyd_job *job)
-+{
-+ job->callback(job);
-+ return 0;
-+}
-+
-+/*
-+ * Request io on as many buffer heads as we can currently get for
-+ * a particular job.
-+ */
-+static int run_io_job(struct kcopyd_job *job)
-+{
-+ unsigned int block;
-+ struct buffer_head *bh;
-+
-+ for (block = atomic_read(&job->nr_requested);
-+ block < job->nr_blocks; block++) {
-+ bh = alloc_buffer();
-+ if (!bh)
-+ break;
-+
-+ atomic_inc(&job->nr_requested);
-+ dispatch_bh(job, bh, block);
-+ }
-+
-+ return (block == job->nr_blocks) ? 0 : 1;
-+}
-+
-+static int run_pages_job(struct kcopyd_job *job)
-+{
-+ int r;
-+
-+ job->nr_pages = (job->disk.count + job->offset) /
-+ (PAGE_SIZE / SECTOR_SIZE);
-+ r = kcopyd_get_pages(job->nr_pages, job->pages);
-+ if (!r) {
-+ /* this job is ready for io */
-+ push(&_io_jobs, job);
-+ return 0;
-+ }
-+
-+ if (r == -ENOMEM)
-+ /* can complete now */
-+ return 1;
-+
-+ return r;
-+}
-+
-+/*
-+ * Run through a list for as long as possible. Returns the count
-+ * of successful jobs.
-+ */
-+static int process_jobs(struct list_head *jobs, int (*fn) (struct kcopyd_job *))
-+{
-+ struct kcopyd_job *job;
-+ int r, count = 0;
-+
-+ while ((job = pop(jobs))) {
-+
-+ r = fn(job);
-+
-+ if (r < 0) {
-+ /* error this rogue job */
-+ job->err = r;
-+ push(&_complete_jobs, job);
-+ break;
-+ }
-+
-+ if (r > 0) {
-+ /*
-+ * We couldn't service this job ATM, so
-+ * push this job back onto the list.
-+ */
-+ push(jobs, job);
-+ break;
-+ }
-+
-+ count++;
-+ }
-+
-+ return count;
-+}
-+
-+/*
-+ * kcopyd does this every time it's woken up.
-+ */
-+static void do_work(void)
-+{
-+ int count;
-+
-+ /*
-+ * We loop round until there is no more work to do.
-+ */
-+ do {
-+ count = process_jobs(&_complete_jobs, run_complete_job);
-+ count += process_jobs(&_io_jobs, run_io_job);
-+ count += process_jobs(&_pages_jobs, run_pages_job);
-+
-+ } while (count);
-+
-+ run_task_queue(&tq_disk);
-+}
-+
-+/*-----------------------------------------------------------------
-+ * The daemon
-+ *---------------------------------------------------------------*/
-+static struct task_struct *_kcopyd_task;
-+static atomic_t _kcopyd_must_die;
-+static DECLARE_MUTEX(_run_lock);
-+static DECLARE_WAIT_QUEUE_HEAD(_job_queue);
-+
-+/*
-+ * A day in the life of a little daemon.
-+ */
-+static void kcopyd_cycle(void)
-+{
-+ DECLARE_WAITQUEUE(wq, current);
-+
-+ set_current_state(TASK_INTERRUPTIBLE);
-+ add_wait_queue(&_job_queue, &wq);
-+
-+ do_work();
-+ schedule();
-+
-+ set_current_state(TASK_RUNNING);
-+ remove_wait_queue(&_job_queue, &wq);
-+}
-+
-+static int kcopyd(void *start_lock)
-+{
-+ daemonize();
-+ strcpy(current->comm, "kcopyd");
-+ _kcopyd_task = current;
-+ atomic_set(&_kcopyd_must_die, 0);
-+ down(&_run_lock);
-+ up((struct semaphore *) start_lock);
-+
-+ while (!atomic_read(&_kcopyd_must_die))
-+ kcopyd_cycle();
-+
-+ up(&_run_lock);
-+ DMINFO("kcopyd shutting down");
-+ return 0;
-+}
-+
-+static int start_daemon(void)
-+{
-+ static pid_t pid = 0;
-+ DECLARE_MUTEX(start_lock);
-+
-+ down(&start_lock);
-+ pid = kernel_thread(kcopyd, &start_lock, 0);
-+ if (pid <= 0) {
-+ DMERR("Failed to start kcopyd thread");
-+ return -EAGAIN;
-+ }
-+
-+ /*
-+ * wait for the daemon to up this mutex.
-+ */
-+ down(&start_lock);
-+ DMINFO("Started kcopyd thread");
-+
-+ return 0;
-+}
-+
-+static int stop_daemon(void)
-+{
-+ if (_kcopyd_task) {
-+ atomic_set(&_kcopyd_must_die, 1);
-+ wake_kcopyd();
-+ down(&_run_lock);
-+ }
-+
-+ return 0;
-+}
-+
-+static int wake_kcopyd(void)
-+{
-+ int r = 0;
-+
-+ /* Start the thread if we don't have one already */
-+ if (!_kcopyd_task)
-+ r = start_daemon();
-+
-+ if (!r)
-+ wake_up_interruptible(&_job_queue);
-+
-+ return r;
-+}
-+
-+static int calc_shift(unsigned int n)
-+{
-+ int s;
-+
-+ for (s = 0; n; s++, n >>= 1)
-+ ;
-+
-+ return --s;
-+}
-+
-+static void calc_block_sizes(struct kcopyd_job *job)
-+{
-+ job->block_size = get_hardsect_size(job->disk.dev);
-+ job->block_shift = calc_shift(job->block_size / SECTOR_SIZE);
-+ job->bpp_shift = PAGE_SHIFT - job->block_shift - SECTOR_SHIFT;
-+ job->bpp_mask = (1 << job->bpp_shift) - 1;
-+ job->nr_blocks = job->disk.count >> job->block_shift;
-+ atomic_set(&job->nr_requested, 0);
-+ atomic_set(&job->nr_incomplete, job->nr_blocks);
-+}
-+
-+int kcopyd_io(struct kcopyd_job *job)
-+{
-+ calc_block_sizes(job);
-+ push(job->pages[0] ? &_io_jobs : &_pages_jobs, job);
-+ wake_kcopyd();
-+ return 0;
-+}
-+
-+/*-----------------------------------------------------------------
-+ * The copier is implemented on top of the simpler async io
-+ * daemon above.
-+ *---------------------------------------------------------------*/
-+struct copy_info {
-+ kcopyd_notify_fn notify;
-+ void *notify_context;
-+
-+ struct kcopyd_region to;
-+};
-+
-+#define MIN_INFOS 128
-+static kmem_cache_t *_copy_cache = NULL;
-+static mempool_t *_copy_pool = NULL;
-+
-+static __init int init_copier(void)
-+{
-+ _copy_cache = kmem_cache_create("kcopyd-info",
-+ sizeof(struct copy_info),
-+ __alignof__(struct copy_info),
-+ 0, NULL, NULL);
-+ if (!_copy_cache)
-+ return -ENOMEM;
-+
-+ _copy_pool = mempool_create(MIN_INFOS,
-+ mempool_alloc_slab,
-+ mempool_free_slab, _copy_cache);
-+ if (!_copy_pool) {
-+ kmem_cache_destroy(_copy_cache);
-+ return -ENOMEM;
-+ }
-+
-+ return 0;
-+}
-+
-+static void exit_copier(void)
-+{
-+ if (_copy_pool)
-+ mempool_destroy(_copy_pool);
-+
-+ if (_copy_cache)
-+ kmem_cache_destroy(_copy_cache);
-+}
-+
-+static inline struct copy_info *alloc_copy_info(void)
-+{
-+ return mempool_alloc(_copy_pool, GFP_KERNEL);
-+}
-+
-+static inline void free_copy_info(struct copy_info *info)
-+{
-+ mempool_free(info, _copy_pool);
-+}
-+
-+void copy_complete(struct kcopyd_job *job)
-+{
-+ struct copy_info *info = (struct copy_info *) job->context;
-+
-+ if (info->notify)
-+ info->notify(job->err, info->notify_context);
-+
-+ free_copy_info(info);
-+ kcopyd_free_pages(job->nr_pages, job->pages);
-+ kcopyd_free_job(job);
-+}
-+
-+/*
-+ * These callback functions implement the state machine that copies regions.
-+ * FIXME: handle large regions.
-+ */
-+void copy_write(struct kcopyd_job *job)
-+{
-+ struct copy_info *info = (struct copy_info *) job->context;
-+
-+ if (job->err && info->notify) {
-+ info->notify(job->err, job->context);
-+ kcopyd_free_job(job);
-+ free_copy_info(info);
-+ return;
-+ }
-+
-+ job->rw = WRITE;
-+ memcpy(&job->disk, &info->to, sizeof(job->disk));
-+ job->callback = copy_complete;
-+ job->context = info;
-+
-+ /*
-+ * Queue the write.
-+ */
-+ kcopyd_io(job);
-+}
-+
-+int kcopyd_copy(struct kcopyd_region *from,
-+ struct kcopyd_region *to, kcopyd_notify_fn fn, void *context)
-+{
-+ struct copy_info *info;
-+ struct kcopyd_job *job;
-+
-+ /*
-+ * Allocate a new copy_info.
-+ */
-+ info = alloc_copy_info();
-+ if (!info)
-+ return -ENOMEM;
-+
-+ job = kcopyd_alloc_job();
-+ if (!job) {
-+ free_copy_info(info);
-+ return -ENOMEM;
-+ }
-+
-+ /*
-+ * set up for the read.
-+ */
-+ info->notify = fn;
-+ info->notify_context = context;
-+ memcpy(&info->to, to, sizeof(*to));
-+
-+ job->rw = READ;
-+ memcpy(&job->disk, from, sizeof(*from));
-+
-+ job->offset = 0;
-+ calc_block_sizes(job);
-+ job->callback = copy_write;
-+ job->context = info;
-+
-+ /*
-+ * Trigger job.
-+ */
-+ kcopyd_io(job);
-+ return 0;
-+}
-+
-+/*-----------------------------------------------------------------
-+ * Unit setup
-+ *---------------------------------------------------------------*/
-+static struct {
-+ int (*init) (void);
-+ void (*exit) (void);
-+
-+} _inits[] = {
-+#define xx(n) { init_ ## n, exit_ ## n}
-+ xx(pages),
-+ xx(buffers),
-+ xx(jobs),
-+ xx(copier)
-+#undef xx
-+};
-+
-+static int _has_initialised = 0;
-+
-+int __init kcopyd_init(void)
-+{
-+ const int count = sizeof(_inits) / sizeof(*_inits);
-+
-+ int r, i;
-+
-+ if (_has_initialised)
-+ return 0;
-+
-+ for (i = 0; i < count; i++) {
-+ r = _inits[i].init();
-+ if (r)
-+ goto bad;
-+ }
-+
-+ _has_initialised = 1;
-+ return 0;
-+
-+ bad:
-+ while (i--)
-+ _inits[i].exit();
-+
-+ return r;
-+}
-+
-+void kcopyd_exit(void)
-+{
-+ int i = sizeof(_inits) / sizeof(*_inits);
-+
-+ if (stop_daemon())
-+ DMWARN("Couldn't stop kcopyd.");
-+
-+ while (i--)
-+ _inits[i].exit();
-+
-+ _has_initialised = 0;
-+}
-diff -ruN linux-2.4.18/drivers/md/kcopyd.h linux/drivers/md/kcopyd.h
---- linux-2.4.18/drivers/md/kcopyd.h Thu Jan 1 01:00:00 1970
-+++ linux/drivers/md/kcopyd.h Tue Apr 23 22:23:30 2002
-@@ -0,0 +1,96 @@
-+/*
-+ * Copyright (C) 2001 Sistina Software
-+ *
-+ * This file is released under the GPL.
-+ */
-+
-+#ifndef DM_KCOPYD_H
-+#define DM_KCOPYD_H
-+
-+/*
-+ * Needed for the definition of offset_t.
-+ */
-+#include <linux/device-mapper.h>
-+#include <linux/iobuf.h>
-+
-+struct kcopyd_region {
-+ kdev_t dev;
-+ offset_t sector;
-+ offset_t count;
-+};
-+
-+#define MAX_KCOPYD_PAGES 128
-+
-+struct kcopyd_job {
-+ struct list_head list;
-+
-+ /*
-+ * Error state of the job.
-+ */
-+ int err;
-+
-+ /*
-+ * Either READ or WRITE
-+ */
-+ int rw;
-+
-+ /*
-+ * The source or destination for the transfer.
-+ */
-+ struct kcopyd_region disk;
-+
-+ int nr_pages;
-+ struct page *pages[MAX_KCOPYD_PAGES];
-+
-+ /*
-+ * Shifts and masks that will be useful when dispatching
-+ * each buffer_head.
-+ */
-+ offset_t offset;
-+ offset_t block_size;
-+ offset_t block_shift;
-+ offset_t bpp_shift; /* blocks per page */
-+ offset_t bpp_mask;
-+
-+ /*
-+ * nr_blocks is how many buffer heads will have to be
-+ * displatched to service this job, nr_requested is how
-+ * many have been dispatched and nr_complete is how many
-+ * have come back.
-+ */
-+ unsigned int nr_blocks;
-+ atomic_t nr_requested;
-+ atomic_t nr_incomplete;
-+
-+ /*
-+ * Set this to ensure you are notified when the job has
-+ * completed. 'context' is for callback to use.
-+ */
-+ void (*callback) (struct kcopyd_job *job);
-+ void *context;
-+};
-+
-+/*
-+ * Low level async io routines.
-+ */
-+struct kcopyd_job *kcopyd_alloc_job(void);
-+void kcopyd_free_job(struct kcopyd_job *job);
-+
-+int kcopyd_queue_job(struct kcopyd_job *job);
-+
-+/*
-+ * Submit a copy job to kcopyd. This is built on top of the
-+ * previous three fns.
-+ */
-+typedef void (*kcopyd_notify_fn) (int err, void *context);
-+
-+int kcopyd_copy(struct kcopyd_region *from,
-+ struct kcopyd_region *to, kcopyd_notify_fn fn, void *context);
-+
-+/*
-+ * Setup/teardown.
-+ */
-+int kcopyd_init(void);
-+void kcopyd_exit(void);
-+
-+#endif
-diff -ruN linux-2.4.18/include/linux/device-mapper.h linux/include/linux/device-mapper.h
---- linux-2.4.18/include/linux/device-mapper.h Thu Jan 1 01:00:00 1970
-+++ linux/include/linux/device-mapper.h Thu Mar 7 16:56:22 2002
-@@ -0,0 +1,59 @@
-+/*
-+ * Copyright (C) 2001 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the LGPL.
-+ */
-+
-+#ifndef _LINUX_DEVICE_MAPPER_H
-+#define _LINUX_DEVICE_MAPPER_H
-+
-+#define DM_DIR "device-mapper" /* Slashes not supported */
-+#define DM_MAX_TYPE_NAME 16
-+#define DM_NAME_LEN 128
-+#define DM_UUID_LEN 129
-+
-+#ifdef __KERNEL__
-+
-+struct dm_table;
-+struct dm_dev;
-+typedef unsigned long offset_t;
-+
-+
-+/*
-+ * Prototypes for functions for a target
-+ */
-+typedef int (*dm_ctr_fn)(struct dm_table *t, offset_t b, offset_t l,
-+ int argc, char **argv, void **context);
-+typedef void (*dm_dtr_fn)(struct dm_table *t, void *c);
-+typedef int (*dm_map_fn)(struct buffer_head *bh, int rw, void *context);
-+typedef int (*dm_err_fn)(struct buffer_head *bh, int rw, void *context);
-+
-+
-+void dm_error(const char *message);
-+
-+/*
-+ * Constructors should call these functions to ensure destination devices
-+ * are opened/closed correctly
-+ */
-+int dm_table_get_device(struct dm_table *t, const char *path,
-+ offset_t start, offset_t len, struct dm_dev **result);
-+void dm_table_put_device(struct dm_table *table, struct dm_dev *d);
-+
-+/*
-+ * Information about a target type
-+ */
-+struct target_type {
-+ const char *name;
-+ struct module *module;
-+ dm_ctr_fn ctr;
-+ dm_dtr_fn dtr;
-+ dm_map_fn map;
-+ dm_err_fn err;
-+};
-+
-+int dm_register_target(struct target_type *t);
-+int dm_unregister_target(struct target_type *t);
-+
-+#endif /* __KERNEL__ */
-+
-+#endif /* _LINUX_DEVICE_MAPPER_H */
-diff -ruN linux-2.4.18/include/linux/dm-ioctl.h linux/include/linux/dm-ioctl.h
---- linux-2.4.18/include/linux/dm-ioctl.h Thu Jan 1 01:00:00 1970
-+++ linux/include/linux/dm-ioctl.h Tue Apr 23 22:38:54 2002
-@@ -0,0 +1,103 @@
-+/*
-+ * Copyright (C) 2001 Sistina Software (UK) Limited.
-+ *
-+ * This file is released under the LGPL.
-+ */
-+
-+#ifndef _LINUX_DM_IOCTL_H
-+#define _LINUX_DM_IOCTL_H
-+
-+#include "device-mapper.h"
-+
-+/*
-+ * Implements a traditional ioctl interface to the device mapper.
-+ */
-+
-+/*
-+ * All ioctl arguments consist of a single chunk of memory, with
-+ * this structure at the start.
-+ */
-+struct dm_ioctl {
-+ char version[16];
-+
-+ unsigned long data_size; /* total size of data passed in
-+ * including this struct */
-+
-+ unsigned long data_start; /* offset to start of data
-+ * relative to start of this struct */
-+
-+ char name[DM_NAME_LEN]; /* device name */
-+
-+ unsigned int target_count; /* in/out */
-+ unsigned int open_count; /* out */
-+ unsigned int flags; /* in/out */
-+
-+ __kernel_dev_t dev; /* in/out */
-+
-+ char uuid[DM_UUID_LEN]; /* unique identifier for
-+ * the block device */
-+};
-+
-+/*
-+ * Used to specify tables. These structures appear after the
-+ * dm_ioctl.
-+ */
-+struct dm_target_spec {
-+ int32_t status; /* used when reading from kernel only */
-+ unsigned long long sector_start;
-+ unsigned long long length;
-+
-+ char target_type[DM_MAX_TYPE_NAME];
-+
-+ unsigned long next; /* offset in bytes to next target_spec */
-+
-+ /*
-+ * Parameter string starts immediately after this object.
-+ * Be careful to add padding after string to ensure correct
-+ * alignment of subsequent dm_target_spec.
-+ */
-+};
-+
-+/*
-+ * Used to retrieve the target dependencies.
-+ */
-+struct dm_target_deps {
-+ unsigned int count;
-+
-+ __kernel_dev_t dev[0]; /* out */
-+};
-+
-+#define DM_IOCTL 0xfd
-+
-+enum {
-+ DM_CREATE_CMD = 0,
-+ DM_REMOVE_CMD,
-+ DM_SUSPEND_CMD,
-+ DM_RELOAD_CMD,
-+ DM_INFO_CMD,
-+ DM_RENAME_CMD,
-+ DM_VERSION_CMD,
-+ DM_DEPS_CMD,
-+ DM_REMOVE_ALL_CMD
-+};
-+
-+#define DM_CREATE _IOWR(DM_IOCTL, DM_CREATE_CMD, struct dm_ioctl)
-+#define DM_REMOVE _IOW(DM_IOCTL, DM_REMOVE_CMD, struct dm_ioctl)
-+#define DM_SUSPEND _IOW(DM_IOCTL, DM_SUSPEND_CMD, struct dm_ioctl)
-+#define DM_RELOAD _IOW(DM_IOCTL, DM_RELOAD_CMD, struct dm_ioctl)
-+#define DM_INFO _IOWR(DM_IOCTL, DM_INFO_CMD, struct dm_ioctl)
-+#define DM_RENAME _IOW(DM_IOCTL, DM_RENAME_CMD, struct dm_ioctl)
-+#define DM_VERSION _IOR(DM_IOCTL, DM_VERSION_CMD, struct dm_ioctl)
-+#define DM_DEPS _IOR(DM_IOCTL, DM_DEPS_CMD, struct dm_ioctl)
-+#define DM_REMOVE_ALL _IOR(DM_IOCTL, DM_REMOVE_ALL_CMD, struct dm_ioctl)
-+
-+#define DM_IOCTL_VERSION "0.94"
-+#define DM_DRIVER_VERSION "0.94.10-ioctl (2002-04-23)"
-+
-+/* Status bits */
-+#define DM_READONLY_FLAG 0x00000001
-+#define DM_SUSPEND_FLAG 0x00000002
-+#define DM_EXISTS_FLAG 0x00000004
-+#define DM_PERSISTENT_DEV_FLAG 0x00000008
-+
-+#endif /* _LINUX_DM_IOCTL_H */
-diff -ruN linux-2.4.18/include/linux/fs.h linux/include/linux/fs.h
---- linux-2.4.18/include/linux/fs.h Mon Mar 4 17:42:19 2002
-+++ linux/include/linux/fs.h Tue Apr 23 22:39:09 2002
-@@ -258,7 +258,10 @@
- char * b_data; /* pointer to data block */
- struct page *b_page; /* the page this bh is mapped to */
- void (*b_end_io)(struct buffer_head *bh, int uptodate); /* I/O completion */
-- void *b_private; /* reserved for b_end_io */
-+ void *b_private; /* reserved for b_end_io, also used by ext3 */
-+ void *b_bdev_private; /* a hack to get around ext3 using b_private
-+ * after handing the buffer_head to the
-+ * block layer */
-
- unsigned long b_rsector; /* Real buffer location on disk */
- wait_queue_head_t b_wait;
-diff -ruN linux-2.4.18/include/linux/mempool.h linux/include/linux/mempool.h
---- linux-2.4.18/include/linux/mempool.h Thu Jan 1 01:00:00 1970
-+++ linux/include/linux/mempool.h Tue Apr 23 22:39:09 2002
-@@ -0,0 +1,41 @@
-+/*
-+ * memory buffer pool support
-+ */
-+#ifndef _LINUX_MEMPOOL_H
-+#define _LINUX_MEMPOOL_H
-+
-+#include <linux/list.h>
-+#include <linux/wait.h>
-+
-+struct mempool_s;
-+typedef struct mempool_s mempool_t;
-+
-+typedef void * (mempool_alloc_t)(int gfp_mask, void *pool_data);
-+typedef void (mempool_free_t)(void *element, void *pool_data);
-+
-+struct mempool_s {
-+ spinlock_t lock;
-+ int min_nr, curr_nr;
-+ struct list_head elements;
-+
-+ void *pool_data;
-+ mempool_alloc_t *alloc;
-+ mempool_free_t *free;
-+ wait_queue_head_t wait;
-+};
-+extern mempool_t * mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
-+ mempool_free_t *free_fn, void *pool_data);
-+extern void mempool_resize(mempool_t *pool, int new_min_nr, int gfp_mask);
-+extern void mempool_destroy(mempool_t *pool);
-+extern void * mempool_alloc(mempool_t *pool, int gfp_mask);
-+extern void mempool_free(void *element, mempool_t *pool);
-+
-+
-+/*
-+ * A mempool_alloc_t and mempool_free_t that get the memory from
-+ * a slab that is passed in through pool_data.
-+ */
-+void *mempool_alloc_slab(int gfp_mask, void *pool_data);
-+void mempool_free_slab(void *element, void *pool_data);
-+
-+#endif /* _LINUX_MEMPOOL_H */
-diff -ruN linux-2.4.18/mm/Makefile linux/mm/Makefile
---- linux-2.4.18/mm/Makefile Wed Oct 24 23:21:18 2001
-+++ linux/mm/Makefile Tue Apr 23 22:39:09 2002
-@@ -9,12 +9,12 @@
-
- O_TARGET := mm.o
-
--export-objs := shmem.o filemap.o
-+export-objs := shmem.o filemap.o memory.o page_alloc.o mempool.o
-
- obj-y := memory.o mmap.o filemap.o mprotect.o mlock.o mremap.o \
- vmalloc.o slab.o bootmem.o swap.o vmscan.o page_io.o \
- page_alloc.o swap_state.o swapfile.o numa.o oom_kill.o \
-- shmem.o
-+ shmem.o mempool.o
-
- obj-$(CONFIG_HIGHMEM) += highmem.o
-
-diff -ruN linux-2.4.18/mm/mempool.c linux/mm/mempool.c
---- linux-2.4.18/mm/mempool.c Thu Jan 1 01:00:00 1970
-+++ linux/mm/mempool.c Tue Apr 23 22:39:09 2002
-@@ -0,0 +1,295 @@
-+/*
-+ * linux/mm/mempool.c
-+ *
-+ * memory buffer pool support. Such pools are mostly used
-+ * for guaranteed, deadlock-free memory allocations during
-+ * extreme VM load.
-+ *
-+ * started by Ingo Molnar, Copyright (C) 2001
-+ */
-+
-+#include <linux/mm.h>
-+#include <linux/slab.h>
-+#include <linux/module.h>
-+#include <linux/mempool.h>
-+#include <linux/compiler.h>
-+
-+/**
-+ * mempool_create - create a memory pool
-+ * @min_nr: the minimum number of elements guaranteed to be
-+ * allocated for this pool.
-+ * @alloc_fn: user-defined element-allocation function.
-+ * @free_fn: user-defined element-freeing function.
-+ * @pool_data: optional private data available to the user-defined functions.
-+ *
-+ * this function creates and allocates a guaranteed size, preallocated
-+ * memory pool. The pool can be used from the mempool_alloc and mempool_free
-+ * functions. This function might sleep. Both the alloc_fn() and the free_fn()
-+ * functions might sleep - as long as the mempool_alloc function is not called
-+ * from IRQ contexts. The element allocated by alloc_fn() must be able to
-+ * hold a struct list_head. (8 bytes on x86.)
-+ */
-+mempool_t * mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
-+ mempool_free_t *free_fn, void *pool_data)
-+{
-+ mempool_t *pool;
-+ int i;
-+
-+ pool = kmalloc(sizeof(*pool), GFP_KERNEL);
-+ if (!pool)
-+ return NULL;
-+ memset(pool, 0, sizeof(*pool));
-+
-+ spin_lock_init(&pool->lock);
-+ pool->min_nr = min_nr;
-+ pool->pool_data = pool_data;
-+ INIT_LIST_HEAD(&pool->elements);
-+ init_waitqueue_head(&pool->wait);
-+ pool->alloc = alloc_fn;
-+ pool->free = free_fn;
-+
-+ /*
-+ * First pre-allocate the guaranteed number of buffers.
-+ */
-+ for (i = 0; i < min_nr; i++) {
-+ void *element;
-+ struct list_head *tmp;
-+ element = pool->alloc(GFP_KERNEL, pool->pool_data);
-+
-+ if (unlikely(!element)) {
-+ /*
-+ * Not enough memory - free the allocated ones
-+ * and return:
-+ */
-+ list_for_each(tmp, &pool->elements) {
-+ element = tmp;
-+ pool->free(element, pool->pool_data);
-+ }
-+ kfree(pool);
-+
-+ return NULL;
-+ }
-+ tmp = element;
-+ list_add(tmp, &pool->elements);
-+ pool->curr_nr++;
-+ }
-+ return pool;
-+}
-+
-+/**
-+ * mempool_resize - resize an existing memory pool
-+ * @pool: pointer to the memory pool which was allocated via
-+ * mempool_create().
-+ * @new_min_nr: the new minimum number of elements guaranteed to be
-+ * allocated for this pool.
-+ * @gfp_mask: the usual allocation bitmask.
-+ *
-+ * This function shrinks/grows the pool. In the case of growing,
-+ * it cannot be guaranteed that the pool will be grown to the new
-+ * size immediately, but new mempool_free() calls will refill it.
-+ *
-+ * Note, the caller must guarantee that no mempool_destroy is called
-+ * while this function is running. mempool_alloc() & mempool_free()
-+ * might be called (eg. from IRQ contexts) while this function executes.
-+ */
-+void mempool_resize(mempool_t *pool, int new_min_nr, int gfp_mask)
-+{
-+ int delta;
-+ void *element;
-+ unsigned long flags;
-+ struct list_head *tmp;
-+
-+ if (new_min_nr <= 0)
-+ BUG();
-+
-+ spin_lock_irqsave(&pool->lock, flags);
-+ if (new_min_nr < pool->min_nr) {
-+ pool->min_nr = new_min_nr;
-+ /*
-+ * Free possible excess elements.
-+ */
-+ while (pool->curr_nr > pool->min_nr) {
-+ tmp = pool->elements.next;
-+ if (tmp == &pool->elements)
-+ BUG();
-+ list_del(tmp);
-+ element = tmp;
-+ pool->curr_nr--;
-+ spin_unlock_irqrestore(&pool->lock, flags);
-+
-+ pool->free(element, pool->pool_data);
-+
-+ spin_lock_irqsave(&pool->lock, flags);
-+ }
-+ spin_unlock_irqrestore(&pool->lock, flags);
-+ return;
-+ }
-+ delta = new_min_nr - pool->min_nr;
-+ pool->min_nr = new_min_nr;
-+ spin_unlock_irqrestore(&pool->lock, flags);
-+
-+ /*
-+ * We refill the pool up to the new treshold - but we dont
-+ * (cannot) guarantee that the refill succeeds.
-+ */
-+ while (delta) {
-+ element = pool->alloc(gfp_mask, pool->pool_data);
-+ if (!element)
-+ break;
-+ mempool_free(element, pool);
-+ delta--;
-+ }
-+}
-+
-+/**
-+ * mempool_destroy - deallocate a memory pool
-+ * @pool: pointer to the memory pool which was allocated via
-+ * mempool_create().
-+ *
-+ * this function only sleeps if the free_fn() function sleeps. The caller
-+ * has to guarantee that no mempool_alloc() nor mempool_free() happens in
-+ * this pool when calling this function.
-+ */
-+void mempool_destroy(mempool_t *pool)
-+{
-+ void *element;
-+ struct list_head *head, *tmp;
-+
-+ if (!pool)
-+ return;
-+
-+ head = &pool->elements;
-+ for (tmp = head->next; tmp != head; ) {
-+ element = tmp;
-+ tmp = tmp->next;
-+ pool->free(element, pool->pool_data);
-+ pool->curr_nr--;
-+ }
-+ if (pool->curr_nr)
-+ BUG();
-+ kfree(pool);
-+}
-+
-+/**
-+ * mempool_alloc - allocate an element from a specific memory pool
-+ * @pool: pointer to the memory pool which was allocated via
-+ * mempool_create().
-+ * @gfp_mask: the usual allocation bitmask.
-+ *
-+ * this function only sleeps if the alloc_fn function sleeps or
-+ * returns NULL. Note that due to preallocation, this function
-+ * *never* fails when called from process contexts. (it might
-+ * fail if called from an IRQ context.)
-+ */
-+void * mempool_alloc(mempool_t *pool, int gfp_mask)
-+{
-+ void *element;
-+ unsigned long flags;
-+ struct list_head *tmp;
-+ int curr_nr;
-+ DECLARE_WAITQUEUE(wait, current);
-+ int gfp_nowait = gfp_mask & ~(__GFP_WAIT | __GFP_IO);
-+
-+repeat_alloc:
-+ element = pool->alloc(gfp_nowait, pool->pool_data);
-+ if (likely(element != NULL))
-+ return element;
-+
-+ /*
-+ * If the pool is less than 50% full then try harder
-+ * to allocate an element:
-+ */
-+ if ((gfp_mask != gfp_nowait) && (pool->curr_nr <= pool->min_nr/2)) {
-+ element = pool->alloc(gfp_mask, pool->pool_data);
-+ if (likely(element != NULL))
-+ return element;
-+ }
-+
-+ /*
-+ * Kick the VM at this point.
-+ */
-+ wakeup_bdflush();
-+
-+ spin_lock_irqsave(&pool->lock, flags);
-+ if (likely(pool->curr_nr)) {
-+ tmp = pool->elements.next;
-+ list_del(tmp);
-+ element = tmp;
-+ pool->curr_nr--;
-+ spin_unlock_irqrestore(&pool->lock, flags);
-+ return element;
-+ }
-+ spin_unlock_irqrestore(&pool->lock, flags);
-+
-+ /* We must not sleep in the GFP_ATOMIC case */
-+ if (gfp_mask == gfp_nowait)
-+ return NULL;
-+
-+ run_task_queue(&tq_disk);
-+
-+ add_wait_queue_exclusive(&pool->wait, &wait);
-+ set_task_state(current, TASK_UNINTERRUPTIBLE);
-+
-+ spin_lock_irqsave(&pool->lock, flags);
-+ curr_nr = pool->curr_nr;
-+ spin_unlock_irqrestore(&pool->lock, flags);
-+
-+ if (!curr_nr)
-+ schedule();
-+
-+ current->state = TASK_RUNNING;
-+ remove_wait_queue(&pool->wait, &wait);
-+
-+ goto repeat_alloc;
-+}
-+
-+/**
-+ * mempool_free - return an element to the pool.
-+ * @element: pool element pointer.
-+ * @pool: pointer to the memory pool which was allocated via
-+ * mempool_create().
-+ *
-+ * this function only sleeps if the free_fn() function sleeps.
-+ */
-+void mempool_free(void *element, mempool_t *pool)
-+{
-+ unsigned long flags;
-+
-+ if (pool->curr_nr < pool->min_nr) {
-+ spin_lock_irqsave(&pool->lock, flags);
-+ if (pool->curr_nr < pool->min_nr) {
-+ list_add(element, &pool->elements);
-+ pool->curr_nr++;
-+ spin_unlock_irqrestore(&pool->lock, flags);
-+ wake_up(&pool->wait);
-+ return;
-+ }
-+ spin_unlock_irqrestore(&pool->lock, flags);
-+ }
-+ pool->free(element, pool->pool_data);
-+}
-+
-+/*
-+ * A commonly used alloc and free fn.
-+ */
-+void *mempool_alloc_slab(int gfp_mask, void *pool_data)
-+{
-+ kmem_cache_t *mem = (kmem_cache_t *) pool_data;
-+ return kmem_cache_alloc(mem, gfp_mask);
-+}
-+
-+void mempool_free_slab(void *element, void *pool_data)
-+{
-+ kmem_cache_t *mem = (kmem_cache_t *) pool_data;
-+ kmem_cache_free(mem, element);
-+}
-+
-+
-+EXPORT_SYMBOL(mempool_create);
-+EXPORT_SYMBOL(mempool_resize);
-+EXPORT_SYMBOL(mempool_destroy);
-+EXPORT_SYMBOL(mempool_alloc);
-+EXPORT_SYMBOL(mempool_free);
-+EXPORT_SYMBOL(mempool_alloc_slab);
-+EXPORT_SYMBOL(mempool_free_slab);
-+
git://sourceware.org / dm.git / commitdiff