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author | Ryusuke Konishi <konishi.ryusuke@gmail.com> | 2024-03-13 13:58:26 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-04-03 16:32:22 +0300 |
commit | 82827ca21e7c8a91384c5baa656f78a5adfa4ab4 (patch) | |
tree | 9bd9e17732e2c1f90009e2c8d41f97592aab3e50 /fs/nilfs2 | |
parent | 0a0f63c9e61dc55c067b1f1a4996d7f79a561125 (diff) | |
download | linux-82827ca21e7c8a91384c5baa656f78a5adfa4ab4.tar.xz |
nilfs2: fix failure to detect DAT corruption in btree and direct mappings
[ Upstream commit f2f26b4a84a0ef41791bd2d70861c8eac748f4ba ]
Patch series "nilfs2: fix kernel bug at submit_bh_wbc()".
This resolves a kernel BUG reported by syzbot. Since there are two
flaws involved, I've made each one a separate patch.
The first patch alone resolves the syzbot-reported bug, but I think
both fixes should be sent to stable, so I've tagged them as such.
This patch (of 2):
Syzbot has reported a kernel bug in submit_bh_wbc() when writing file data
to a nilfs2 file system whose metadata is corrupted.
There are two flaws involved in this issue.
The first flaw is that when nilfs_get_block() locates a data block using
btree or direct mapping, if the disk address translation routine
nilfs_dat_translate() fails with internal code -ENOENT due to DAT metadata
corruption, it can be passed back to nilfs_get_block(). This causes
nilfs_get_block() to misidentify an existing block as non-existent,
causing both data block lookup and insertion to fail inconsistently.
The second flaw is that nilfs_get_block() returns a successful status in
this inconsistent state. This causes the caller __block_write_begin_int()
or others to request a read even though the buffer is not mapped,
resulting in a BUG_ON check for the BH_Mapped flag in submit_bh_wbc()
failing.
This fixes the first issue by changing the return value to code -EINVAL
when a conversion using DAT fails with code -ENOENT, avoiding the
conflicting condition that leads to the kernel bug described above. Here,
code -EINVAL indicates that metadata corruption was detected during the
block lookup, which will be properly handled as a file system error and
converted to -EIO when passing through the nilfs2 bmap layer.
Link: https://lkml.kernel.org/r/20240313105827.5296-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20240313105827.5296-2-konishi.ryusuke@gmail.com
Fixes: c3a7abf06ce7 ("nilfs2: support contiguous lookup of blocks")
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+cfed5b56649bddf80d6e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=cfed5b56649bddf80d6e
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/nilfs2')
-rw-r--r-- | fs/nilfs2/btree.c | 9 | ||||
-rw-r--r-- | fs/nilfs2/direct.c | 9 |
2 files changed, 14 insertions, 4 deletions
diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c index 13592e82eaf6..65659fa0372e 100644 --- a/fs/nilfs2/btree.c +++ b/fs/nilfs2/btree.c @@ -724,7 +724,7 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree, dat = nilfs_bmap_get_dat(btree); ret = nilfs_dat_translate(dat, ptr, &blocknr); if (ret < 0) - goto out; + goto dat_error; ptr = blocknr; } cnt = 1; @@ -743,7 +743,7 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree, if (dat) { ret = nilfs_dat_translate(dat, ptr2, &blocknr); if (ret < 0) - goto out; + goto dat_error; ptr2 = blocknr; } if (ptr2 != ptr + cnt || ++cnt == maxblocks) @@ -781,6 +781,11 @@ static int nilfs_btree_lookup_contig(const struct nilfs_bmap *btree, out: nilfs_btree_free_path(path); return ret; + + dat_error: + if (ret == -ENOENT) + ret = -EINVAL; /* Notify bmap layer of metadata corruption */ + goto out; } static void nilfs_btree_promote_key(struct nilfs_bmap *btree, diff --git a/fs/nilfs2/direct.c b/fs/nilfs2/direct.c index 4c85914f2abc..893ab36824cc 100644 --- a/fs/nilfs2/direct.c +++ b/fs/nilfs2/direct.c @@ -66,7 +66,7 @@ static int nilfs_direct_lookup_contig(const struct nilfs_bmap *direct, dat = nilfs_bmap_get_dat(direct); ret = nilfs_dat_translate(dat, ptr, &blocknr); if (ret < 0) - return ret; + goto dat_error; ptr = blocknr; } @@ -79,7 +79,7 @@ static int nilfs_direct_lookup_contig(const struct nilfs_bmap *direct, if (dat) { ret = nilfs_dat_translate(dat, ptr2, &blocknr); if (ret < 0) - return ret; + goto dat_error; ptr2 = blocknr; } if (ptr2 != ptr + cnt) @@ -87,6 +87,11 @@ static int nilfs_direct_lookup_contig(const struct nilfs_bmap *direct, } *ptrp = ptr; return cnt; + + dat_error: + if (ret == -ENOENT) + ret = -EINVAL; /* Notify bmap layer of metadata corruption */ + return ret; } static __u64 |