Remove snapshot extent_size parameter

Ensure chunk size >= page size

diff --git a/kernel/common/dm-snapshot.c b/kernel/common/dm-snapshot.c
index 07cfdae090f42669ea5c8c74d65bd60eb4780f16..536184772a3d7109053121ed14062d21e1d1c364 100644 (file)
--- a/kernel/common/dm-snapshot.c
+++ b/kernel/common/dm-snapshot.c
@@ -380,15 +380,13 @@ static int init_hash_tables(struct dm_snapshot *s)
 }
 
 /*
- * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n>
- * <chunk-size>
+ * Construct a snapshot mapping: <origin_dev> <COW-dev> <p/n> <chunk-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;
@@ -397,7 +395,7 @@ static int snapshot_ctr(struct dm_table *t, offset_t b, offset_t l,
        int blocksize;
 
        if (argc < 4) {
-               *context = "dm-snapshot: Not enough arguments";
+               *context = "dm-snapshot: requires exactly 4 arguments";
                r = -EINVAL;
                goto bad;
        }
@@ -419,22 +417,6 @@ static int snapshot_ctr(struct dm_table *t, offset_t b, offset_t l,
                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";
@@ -455,7 +437,11 @@ static int snapshot_ctr(struct dm_table *t, offset_t b, offset_t l,
                goto bad_free;
        }
 
-       /* Validate the extent and chunk sizes against the device block size */
+       /* Chunk size must be multiple of page size. If it's wrong, fix it */
+       if (chunk_size < (PAGE_SIZE / SECTOR_SIZE))
+               chunk_size = PAGE_SIZE / SECTOR_SIZE;
+
+       /* Validate the chunk size 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";
@@ -463,12 +449,6 @@ static int snapshot_ctr(struct dm_table *t, offset_t b, offset_t l,
                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";
@@ -476,12 +456,6 @@ static int snapshot_ctr(struct dm_table *t, offset_t b, offset_t l,
                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";