+++ /dev/null
-Date: Mon, 23 Oct 2006 15:45:05 -0500
-From: Eric Sandeen <sandeen@redhat.com>
-Subject: [PATCH RHEL5] - handle ext3 directory corruption better
-
-This is for BZ 209907 <https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=209907>: kernel Soft lockup detected on corrupted ext3 filesystem.
-
-This patch is now in -mm.
-
-I've been using Steve Grubb's purely evil "fsfuzzer" tool, at
-http://people.redhat.com/sgrubb/files/fsfuzzer-0.4.tar.gz
-
-Basically it makes a filesystem, splats some random bits over it, then
-tries to mount it and do some simple filesystem actions.
-
-At best, the filesystem catches the corruption gracefully. At worst,
-things spin out of control.
-
-As you might guess, we found a couple places in ext3 where things spin out
-of control :)
-
-First, we had a corrupted directory that was never checked for
-consistency... it was corrupt, and pointed to another bad "entry" of
-length 0. The for() loop looped forever, since the length of
-ext3_next_entry(de) was 0, and we kept looking at the same pointer over and
-over and over and over... I modeled this check and subsequent action on
-what is done for other directory types in ext3_readdir...
-
-(adding this check adds some computational expense; I am testing a followup
-patch to reduce the number of times we check and re-check these directory
-entries, in all cases. Thanks for the idea, Andreas).
-
-Next we had a root directory inode which had a corrupted size, claimed to
-be > 200M on a 4M filesystem. There was only really 1 block in the
-directory, but because the size was so large, readdir kept coming back for
-more, spewing thousands of printk's along the way.
-
-Per Andreas' suggestion, if we're in this read error condition and we're
-trying to read an offset which is greater than i_blocks worth of bytes,
-stop trying, and break out of the loop.
-
-With these two changes fsfuzz test survives quite well on ext3.
-
-Signed-off-by: Eric Sandeen <sandeen@redhat.com>
-Cc: <linux-ext4@vger.kernel.org>
-Signed-off-by: Andrew Morton <akpm@osdl.org>
----
-
- fs/ext3/dir.c | 3 +++
- fs/ext3/namei.c | 9 +++++++++
- 2 files changed, 12 insertions(+)
-
-Index: linux-2.6.18-1.2732.el5/fs/ext3/dir.c
-===================================================================
---- linux-2.6.18-1.2732.el5.orig/fs/ext3/dir.c
-+++ linux-2.6.18-1.2732.el5/fs/ext3/dir.c
-@@ -151,6 +151,9 @@ static int ext3_readdir(struct file * fi
- ext3_error (sb, "ext3_readdir",
- "directory #%lu contains a hole at offset %lu",
- inode->i_ino, (unsigned long)filp->f_pos);
-+ /* corrupt size? Maybe no more blocks to read */
-+ if (filp->f_pos > inode->i_blocks << 9)
-+ break;
- filp->f_pos += sb->s_blocksize - offset;
- continue;
- }
-Index: linux-2.6.18-1.2732.el5/fs/ext3/namei.c
-===================================================================
---- linux-2.6.18-1.2732.el5.orig/fs/ext3/namei.c
-+++ linux-2.6.18-1.2732.el5/fs/ext3/namei.c
-@@ -551,6 +551,15 @@ static int htree_dirblock_to_tree(struct
- dir->i_sb->s_blocksize -
- EXT3_DIR_REC_LEN(0));
- for (; de < top; de = ext3_next_entry(de)) {
-+ if (!ext3_check_dir_entry("htree_dirblock_to_tree", dir, de, bh,
-+ (block<<EXT3_BLOCK_SIZE_BITS(dir->i_sb))
-+ +((char *)de - bh->b_data))) {
-+ /* On error, skip the f_pos to the next block. */
-+ dir_file->f_pos = (dir_file->f_pos |
-+ (dir->i_sb->s_blocksize - 1)) + 1;
-+ brelse (bh);
-+ return count;
-+ }
- ext3fs_dirhash(de->name, de->name_len, hinfo);
- if ((hinfo->hash < start_hash) ||
- ((hinfo->hash == start_hash) &&
-
git://git.whamcloud.com / fs / lustre-release.git / blobdiff