linux-stable.git/fs/ext4, branch linux-5.7.y

ext4: check journal inode extents more carefully

2020-08-26T09:42:14+00:00

[ Upstream commit ce9f24cccdc019229b70a5c15e2b09ad9c0ab5d1 ]

Currently, system zones just track ranges of block, that are "important"
fs metadata (bitmaps, group descriptors, journal blocks, etc.). This
however complicates how extent tree (or indirect blocks) can be checked
for inodes that actually track such metadata - currently the journal
inode but arguably we should be treating quota files or resize inode
similarly. We cannot run __ext4_ext_check() on such metadata inodes when
loading their extents as that would immediately trigger the validity
checks and so we just hack around that and special-case the journal
inode. This however leads to a situation that a journal inode which has
extent tree of depth at least one can have invalid extent tree that gets
unnoticed until ext4_cache_extents() crashes.

To overcome this limitation, track inode number each system zone belongs
to (0 is used for zones not belonging to any inode). We can then verify
inode number matches the expected one when verifying extent tree and
thus avoid the false errors. With this there's no need to to
special-case journal inode during extent tree checking anymore so remove
it.

Fixes: 0a944e8a6c66 ("ext4: don't perform block validity checks on the journal inode")
Reported-by: Wolfgang Frisch 
Reviewed-by: Lukas Czerner 
Signed-off-by: Jan Kara 
Link: https://lore.kernel.org/r/20200728130437.7804-4-jack@suse.cz
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: don't allow overlapping system zones

2020-08-26T09:42:14+00:00

[ Upstream commit bf9a379d0980e7413d94cb18dac73db2bfc5f470 ]

Currently, add_system_zone() just silently merges two added system zones
that overlap. However the overlap should not happen and it generally
suggests that some unrelated metadata overlap which indicates the fs is
corrupted. We should have caught such problems earlier (e.g. in
ext4_check_descriptors()) but add this check as another line of defense.
In later patch we also use this for stricter checking of journal inode
extent tree.

Reviewed-by: Lukas Czerner 
Signed-off-by: Jan Kara 
Link: https://lore.kernel.org/r/20200728130437.7804-3-jack@suse.cz
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: fix potential negative array index in do_split()

2020-08-26T09:42:14+00:00

[ Upstream commit 5872331b3d91820e14716632ebb56b1399b34fe1 ]

If for any reason a directory passed to do_split() does not have enough
active entries to exceed half the size of the block, we can end up
iterating over all "count" entries without finding a split point.

In this case, count == move, and split will be zero, and we will
attempt a negative index into map[].

Guard against this by detecting this case, and falling back to
split-to-half-of-count instead; in this case we will still have
plenty of space (> half blocksize) in each split block.

Fixes: ef2b02d3e617 ("ext34: ensure do_split leaves enough free space in both blocks")
Signed-off-by: Eric Sandeen 
Reviewed-by: Andreas Dilger 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/f53e246b-647c-64bb-16ec-135383c70ad7@redhat.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: fix checking of directory entry validity for inline directories

2020-08-26T09:42:06+00:00

commit 7303cb5bfe845f7d43cd9b2dbd37dbb266efda9b upstream.

ext4_search_dir() and ext4_generic_delete_entry() can be called both for
standard director blocks and for inline directories stored inside inode
or inline xattr space. For the second case we didn't call
ext4_check_dir_entry() with proper constraints that could result in
accepting corrupted directory entry as well as false positive filesystem
errors like:

EXT4-fs error (device dm-0): ext4_search_dir:1395: inode #28320400:
block 113246792: comm dockerd: bad entry in directory: directory entry too
close to block end - offset=0, inode=28320403, rec_len=32, name_len=8,
size=4096

Fix the arguments passed to ext4_check_dir_entry().

Fixes: 109ba779d6cc ("ext4: check for directory entries too close to block end")
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara 
Link: https://lore.kernel.org/r/20200731162135.8080-1-jack@suse.cz
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: do not block RWF_NOWAIT dio write on unallocated space

2020-08-26T09:42:06+00:00

commit 0b3171b6d195637f84ddf8b59bae818ea20bc8ac upstream.

Since commit 378f32bab371 ("ext4: introduce direct I/O write using iomap
infrastructure") we don't properly bail out of RWF_NOWAIT direct IO
write if underlying blocks are not allocated. Also
ext4_dio_write_checks() does not honor RWF_NOWAIT when re-acquiring
i_rwsem. Fix both issues.

Fixes: 378f32bab371 ("ext4: introduce direct I/O write using iomap infrastructure")
Cc: stable@kernel.org
Reported-by: Filipe Manana 
Signed-off-by: Jan Kara 
Reviewed-by: Ritesh Harjani 
Link: https://lore.kernel.org/r/20200708153516.9507-1-jack@suse.cz
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: avoid race conditions when remounting with options that change dax

2020-06-24T15:49:20+00:00

[ Upstream commit 829b37b8cddb1db75c1b7905505b90e593b15db1 ]

Trying to change dax mount options when remounting could allow mount
options to be enabled for a small amount of time, and then the mount
option change would be reverted.

In the case of "mount -o remount,dax", this can cause a race where
files would temporarily treated as DAX --- and then not.

Cc: stable@kernel.org
Reported-by: syzbot+bca9799bf129256190da@syzkaller.appspotmail.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4, jbd2: ensure panic by fix a race between jbd2 abort and ext4 error handlers

2020-06-24T15:49:17+00:00

commit 7b97d868b7ab2448859668de9222b8af43f76e78 upstream.

In the ext4 filesystem with errors=panic, if one process is recording
errno in the superblock when invoking jbd2_journal_abort() due to some
error cases, it could be raced by another __ext4_abort() which is
setting the SB_RDONLY flag but missing panic because errno has not been
recorded.

jbd2_journal_commit_transaction()
 jbd2_journal_abort()
  journal->j_flags |= JBD2_ABORT;
  jbd2_journal_update_sb_errno()
                                    | ext4_journal_check_start()
                                    |  __ext4_abort()
                                    |   sb->s_flags |= SB_RDONLY;
                                    |   if (!JBD2_REC_ERR)
                                    |        return;
  journal->j_flags |= JBD2_REC_ERR;

Finally, it will no longer trigger panic because the filesystem has
already been set read-only. Fix this by introduce j_abort_mutex to make
sure journal abort is completed before panic, and remove JBD2_REC_ERR
flag.

Fixes: 4327ba52afd03 ("ext4, jbd2: ensure entering into panic after recording an error in superblock")
Signed-off-by: zhangyi (F) 
Reviewed-by: Jan Kara 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20200609073540.3810702-1-yi.zhang@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: avoid utf8_strncasecmp() with unstable name

2020-06-24T15:49:17+00:00

commit 2ce3ee931a097e9720310db3f09c01c825a4580c upstream.

If the dentry name passed to ->d_compare() fits in dentry::d_iname, then
it may be concurrently modified by a rename.  This can cause undefined
behavior (possibly out-of-bounds memory accesses or crashes) in
utf8_strncasecmp(), since fs/unicode/ isn't written to handle strings
that may be concurrently modified.

Fix this by first copying the filename to a stack buffer if needed.
This way we get a stable snapshot of the filename.

Fixes: b886ee3e778e ("ext4: Support case-insensitive file name lookups")
Cc:  # v5.2+
Cc: Al Viro 
Cc: Daniel Rosenberg 
Cc: Gabriel Krisman Bertazi 
Signed-off-by: Eric Biggers 
Reviewed-by: Andreas Dilger 
Link: https://lore.kernel.org/r/20200601200543.59417-1-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: fix partial cluster initialization when splitting extent

2020-06-24T15:49:17+00:00

commit cfb3c85a600c6aa25a2581b3c1c4db3460f14e46 upstream.

Fix the bug when calculating the physical block number of the first
block in the split extent.

This bug will cause xfstests shared/298 failure on ext4 with bigalloc
enabled occasionally. Ext4 error messages indicate that previously freed
blocks are being freed again, and the following fsck will fail due to
the inconsistency of block bitmap and bg descriptor.

The following is an example case:

1. First, Initialize a ext4 filesystem with cluster size '16K', block size
'4K', in which case, one cluster contains four blocks.

2. Create one file (e.g., xxx.img) on this ext4 filesystem. Now the extent
tree of this file is like:

...
36864:[0]4:220160
36868:[0]14332:145408
51200:[0]2:231424
...

3. Then execute PUNCH_HOLE fallocate on this file. The hole range is
like:

..
ext4_ext_remove_space: dev 254,16 ino 12 since 49506 end 49506 depth 1
ext4_ext_remove_space: dev 254,16 ino 12 since 49544 end 49546 depth 1
ext4_ext_remove_space: dev 254,16 ino 12 since 49605 end 49607 depth 1
...

4. Then the extent tree of this file after punching is like

...
49507:[0]37:158047
49547:[0]58:158087
...

5. Detailed procedure of punching hole [49544, 49546]

5.1. The block address space:
```
lblk        ~49505  49506   49507~49543     49544~49546    49547~
	  ---------+------+-------------+----------------+--------
	    extent | hole |   extent	|	hole	 | extent
	  ---------+------+-------------+----------------+--------
pblk       ~158045  158046  158047~158083  158084~158086   158087~
```

5.2. The detailed layout of cluster 39521:
```
		cluster 39521
	<------------------------------->

		hole		  extent
	<----------------------><--------

lblk      49544   49545   49546   49547
	+-------+-------+-------+-------+
	|	|	|	|	|
	+-------+-------+-------+-------+
pblk     158084  1580845  158086  158087
```

5.3. The ftrace output when punching hole [49544, 49546]:
- ext4_ext_remove_space (start 49544, end 49546)
  - ext4_ext_rm_leaf (start 49544, end 49546, last_extent [49507(158047), 40], partial [pclu 39522 lblk 0 state 2])
    - ext4_remove_blocks (extent [49507(158047), 40], from 49544 to 49546, partial [pclu 39522 lblk 0 state 2]
      - ext4_free_blocks: (block 158084 count 4)
        - ext4_mballoc_free (extent 1/6753/1)

5.4. Ext4 error message in dmesg:
EXT4-fs error (device vdb): mb_free_blocks:1457: group 1, block 158084:freeing already freed block (bit 6753); block bitmap corrupt.
EXT4-fs error (device vdb): ext4_mb_generate_buddy:747: group 1, block bitmap and bg descriptor inconsistent: 19550 vs 19551 free clusters

In this case, the whole cluster 39521 is freed mistakenly when freeing
pblock 158084~158086 (i.e., the first three blocks of this cluster),
although pblock 158087 (the last remaining block of this cluster) has
not been freed yet.

The root cause of this isuue is that, the pclu of the partial cluster is
calculated mistakenly in ext4_ext_remove_space(). The correct
partial_cluster.pclu (i.e., the cluster number of the first block in the
next extent, that is, lblock 49597 (pblock 158086)) should be 39521 rather
than 39522.

Fixes: f4226d9ea400 ("ext4: fix partial cluster initialization")
Signed-off-by: Jeffle Xu 
Reviewed-by: Eric Whitney 
Cc: stable@kernel.org # v3.19+
Link: https://lore.kernel.org/r/1590121124-37096-1-git-send-email-jefflexu@linux.alibaba.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman

ext4: stop overwrite the errcode in ext4_setup_super

2020-06-24T15:49:13+00:00

[ Upstream commit 5adaccac46ea79008d7b75f47913f1a00f91d0ce ]

Now the errcode from ext4_commit_super will overwrite EROFS exists in
ext4_setup_super. Actually, no need to call ext4_commit_super since we
will return EROFS. Fix it by goto done directly.

Fixes: c89128a00838 ("ext4: handle errors on ext4_commit_super")
Signed-off-by: yangerkun 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20200601073404.3712492-1-yangerkun@huawei.com
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin