Hi.
The attached patch addresses a deadlock possible in the ext2 file system
implementation. This deadlock occurs when a file is removed from an ext2
file system which was mounted with the "sync" mount option.
The problem is that ext2_xattr_delete_inode() was invoking the routine,
sync_dirty_buffer(), using a buffer head which was previously locked via
lock_buffer(). The first thing that sync_dirty_buffer() does is to lock
the buffer head that it was passed. It does this via lock_buffer(). Oops.
The solution is to unlock the buffer head in ext2_xattr_delete_inode()
before invoking sync_dirty_buffer(). This makes the code in
ext2_xattr_delete_inode() obey the same locking rules as all other
callers of sync_dirty_buffer() in the ext2 file system implementation.
Thanx...
ps
Signed-off-by: Peter Staubach <[email protected]>
--- linux-2.6.15.x86_64/fs/ext2/xattr.c.org
+++ linux-2.6.15.x86_64/fs/ext2/xattr.c
@@ -792,18 +792,20 @@ ext2_xattr_delete_inode(struct inode *in
ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1);
get_bh(bh);
bforget(bh);
+ unlock_buffer(bh);
} else {
HDR(bh)->h_refcount = cpu_to_le32(
le32_to_cpu(HDR(bh)->h_refcount) - 1);
if (ce)
mb_cache_entry_release(ce);
+ ea_bdebug(bh, "refcount now=%d",
+ le32_to_cpu(HDR(bh)->h_refcount));
+ unlock_buffer(bh);
mark_buffer_dirty(bh);
if (IS_SYNC(inode))
sync_dirty_buffer(bh);
DQUOT_FREE_BLOCK(inode, 1);
}
- ea_bdebug(bh, "refcount now=%d", le32_to_cpu(HDR(bh)->h_refcount) - 1);
- unlock_buffer(bh);
EXT2_I(inode)->i_file_acl = 0;
cleanup:
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
