The patch titled
Subject: nilfs2: fix infinite loop in nilfs_mdt_get_block()
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
nilfs2-fix-infinite-loop-in-nilfs_mdt_get_block.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/nilfs2-fix-infinite-loop-in-nilfs_mdt_get_block.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Subject: nilfs2: fix infinite loop in nilfs_mdt_get_block()
Date: Mon, 1 May 2023 04:30:46 +0900
If the disk image that nilfs2 mounts is corrupted and a virtual block
address obtained by block lookup for a metadata file is invalid,
nilfs_bmap_lookup_at_level() may return the same internal return code as
-ENOENT, meaning the block does not exist in the metadata file.
This duplication of return codes confuses nilfs_mdt_get_block(), causing
it to read and create a metadata block indefinitely.
In particular, if this happens to the inode metadata file, ifile,
semaphore i_rwsem can be left held, causing task hangs in lock_mount.
Fix this issue by making nilfs_bmap_lookup_at_level() treat virtual block
address translation failures with -ENOENT as metadata corruption instead
of returning the error code.
Link: https://lkml.kernel.org/r/20230430193046.6769-1-konishi.ryusuke@xxxxxxxxx
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Tested-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Reported-by: syzbot+221d75710bde87fa0e97@xxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://syzkaller.appspot.com/bug?extid=221d75710bde87fa0e97
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/bmap.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
--- a/fs/nilfs2/bmap.c~nilfs2-fix-infinite-loop-in-nilfs_mdt_get_block
+++ a/fs/nilfs2/bmap.c
@@ -67,20 +67,28 @@ int nilfs_bmap_lookup_at_level(struct ni
down_read(&bmap->b_sem);
ret = bmap->b_ops->bop_lookup(bmap, key, level, ptrp);
- if (ret < 0) {
- ret = nilfs_bmap_convert_error(bmap, __func__, ret);
+ if (ret < 0)
goto out;
- }
+
if (NILFS_BMAP_USE_VBN(bmap)) {
ret = nilfs_dat_translate(nilfs_bmap_get_dat(bmap), *ptrp,
&blocknr);
if (!ret)
*ptrp = blocknr;
+ else if (ret == -ENOENT) {
+ /*
+ * If there was no valid entry in DAT for the block
+ * address obtained by b_ops->bop_lookup, then pass
+ * internal code -EINVAL to nilfs_bmap_convert_error
+ * to treat it as metadata corruption.
+ */
+ ret = -EINVAL;
+ }
}
out:
up_read(&bmap->b_sem);
- return ret;
+ return nilfs_bmap_convert_error(bmap, __func__, ret);
}
int nilfs_bmap_lookup_contig(struct nilfs_bmap *bmap, __u64 key, __u64 *ptrp,
_
Patches currently in -mm which might be from konishi.ryusuke@xxxxxxxxx are
nilfs2-fix-infinite-loop-in-nilfs_mdt_get_block.patch
