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Re: JFFS2 Garbage Collection Error? (NO! rbtree.c bug)
>
> That's great! Are there any other [similar] issues like this in that
> code?
Actually, there is one other thing that I had to do to get my tests to
run. Perhaps David can comment...
If on a JFFS2 file you were to:
open();
write( fd, buf, 100 );
close();
an then
open();
read( fd, buf, 50 );
read( fd, buf, 50 ); /* This would fail */
close();
The second read was failing for me. I had to comment out a check in the
JFFS2 read.c file. I am not sure what it was doing, but I can't run
with it in.
Take a look at the code below. Hopefully my mail client will not munge
it too hard. Look for my "#if 0"
Scott
from: packages/fs/jffs2/current/src/read.c
int jffs2_read_inode_range(struct jffs2_sb_info *c, struct
jffs2_inode_info *f,
unsigned char *buf, uint32_t offset, uint32_t len)
{
uint32_t end = offset + len;
struct jffs2_node_frag *frag;
int ret;
D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n",
f->inocache->ino, offset, offset+len));
frag = jffs2_lookup_node_frag(&f->fragtree, offset);
/* XXX FIXME: Where a single physical node actually shows up in two
frags, we read it twice. Don't do that. */
/* Now we're pointing at the first frag which overlaps our page */
while(offset < end) {
D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end));
if (!frag || frag->ofs > offset) {
uint32_t holesize = end - offset;
if (frag) {
D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset));
holesize = min(holesize, frag->ofs - offset);
D1(jffs2_print_frag_list(f));
}
D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize));
memset(buf, 0, holesize);
buf += holesize;
offset += holesize;
continue;
#if 0
/* SCOTT - This had to be taken out to get tests to run.
Seems like it is checking for overlap, but perhaps there
is a logic problem somewhere because when I print the frag_list
I don't see any overlap. */
} else if (frag->ofs < offset && (offset & (PAGE_CACHE_SIZE-1)) != 0) {
D1(printk(KERN_NOTICE "Eep. Overlap in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n",
f->inocache->ino, frag->ofs, offset));
D1(jffs2_print_frag_list(f));
memset(buf, 0, end - offset);
return -EIO;
#endif
} else if (!frag->node) {
uint32_t holeend = min(end, frag->ofs + frag->size);
D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size));
memset(buf, 0, holeend - offset);
buf += holeend - offset;
offset = holeend;
frag = frag_next(frag);
continue;
} else {
uint32_t readlen;
uint32_t fragofs; /* offset within the frag to start reading */
fragofs = offset - frag->ofs;
readlen = min(frag->size - fragofs, end - offset);
D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n",
frag->ofs+fragofs, frag->ofs+fragofs+readlen,
ref_offset(frag->node->raw), ref_flags(frag->node->raw)));
ret = jffs2_read_dnode(c, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
D2(printk(KERN_DEBUG "node read done\n"));
if (ret) {
D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret));
memset(buf, 0, readlen);
return ret;
}
buf += readlen;
offset += readlen;
frag = frag_next(frag);
D2(printk(KERN_DEBUG "node read was OK. Looping\n"));
}
}
return 0;
}
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