kernel/git/stable/linux.git/fs/ext4, branch linux-5.16.y

ext4: don't BUG if someone dirty pages without asking ext4 first

2022-04-08T12:06:35+00:00

[ Upstream commit cc5095747edfb054ca2068d01af20be3fcc3634f ] [un]pin_user_pages_remote is dirtying pages without properly warning the file system in advance. A related race was noted by Jan Kara in 2018[1]; however, more recently instead of it being a very hard-to-hit race, it could be reliably triggered by process_vm_writev(2) which was discovered by Syzbot[2]. This is technically a bug in mm/gup.c, but arguably ext4 is fragile in that if some other kernel subsystem dirty pages without properly notifying the file system using page_mkwrite(), ext4 will BUG, while other file systems will not BUG (although data will still be lost). So instead of crashing with a BUG, issue a warning (since there may be potential data loss) and just mark the page as clean to avoid unprivileged denial of service attacks until the problem can be properly fixed. More discussion and background can be found in the thread starting at [2]. [1] https://lore.kernel.org/linux-mm/20180103100430.GE4911@quack2.suse.cz [2] https://lore.kernel.org/r/Yg0m6IjcNmfaSokM@google.com Reported-by: syzbot+d59332e2db681cf18f0318a06e994ebbb529a8db@syzkaller.appspotmail.com Reported-by: Lee Jones Signed-off-by: Theodore Ts'o Link: https://lore.kernel.org/r/YiDS9wVfq4mM2jGK@mit.edu Signed-off-by: Sasha Levin

ext4: fix ext4_mb_mark_bb() with flex_bg with fast_commit

2022-04-08T12:06:35+00:00

[ Upstream commit bfdc502a4a4c058bf4cbb1df0c297761d528f54d ] In case of flex_bg feature (which is by default enabled), extents for any given inode might span across blocks from two different block group. ext4_mb_mark_bb() only reads the buffer_head of block bitmap once for the starting block group, but it fails to read it again when the extent length boundary overflows to another block group. Then in this below loop it accesses memory beyond the block group bitmap buffer_head and results into a data abort. for (i = 0; i < clen; i++) if (!mb_test_bit(blkoff + i, bitmap_bh->b_data) == !state) already++; This patch adds this functionality for checking block group boundary in ext4_mb_mark_bb() and update the buffer_head(bitmap_bh) for every different block group. w/o this patch, I was easily able to hit a data access abort using Power platform. <...> [ 74.327662] EXT4-fs error (device loop3): ext4_mb_generate_buddy:1141: group 11, block bitmap and bg descriptor inconsistent: 21248 vs 23294 free clusters [ 74.533214] EXT4-fs (loop3): shut down requested (2) [ 74.536705] Aborting journal on device loop3-8. [ 74.702705] BUG: Unable to handle kernel data access on read at 0xc00000005e980000 [ 74.703727] Faulting instruction address: 0xc0000000007bffb8 cpu 0xd: Vector: 300 (Data Access) at [c000000015db7060] pc: c0000000007bffb8: ext4_mb_mark_bb+0x198/0x5a0 lr: c0000000007bfeec: ext4_mb_mark_bb+0xcc/0x5a0 sp: c000000015db7300 msr: 800000000280b033 dar: c00000005e980000 dsisr: 40000000 current = 0xc000000027af6880 paca = 0xc00000003ffd5200 irqmask: 0x03 irq_happened: 0x01 pid = 5167, comm = mount <...> enter ? for help [c000000015db7380] c000000000782708 ext4_ext_clear_bb+0x378/0x410 [c000000015db7400] c000000000813f14 ext4_fc_replay+0x1794/0x2000 [c000000015db7580] c000000000833f7c do_one_pass+0xe9c/0x12a0 [c000000015db7710] c000000000834504 jbd2_journal_recover+0x184/0x2d0 [c000000015db77c0] c000000000841398 jbd2_journal_load+0x188/0x4a0 [c000000015db7880] c000000000804de8 ext4_fill_super+0x2638/0x3e10 [c000000015db7a40] c0000000005f8404 get_tree_bdev+0x2b4/0x350 [c000000015db7ae0] c0000000007ef058 ext4_get_tree+0x28/0x40 [c000000015db7b00] c0000000005f6344 vfs_get_tree+0x44/0x100 [c000000015db7b70] c00000000063c408 path_mount+0xdd8/0xe70 [c000000015db7c40] c00000000063c8f0 sys_mount+0x450/0x550 [c000000015db7d50] c000000000035770 system_call_exception+0x4a0/0x4e0 [c000000015db7e10] c00000000000c74c system_call_common+0xec/0x250 Signed-off-by: Ritesh Harjani Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/2609bc8f66fc15870616ee416a18a3d392a209c4.1644992609.git.riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: correct cluster len and clusters changed accounting in ext4_mb_mark_bb

2022-04-08T12:06:35+00:00

[ Upstream commit a5c0e2fdf7cea535ba03259894dc184e5a4c2800 ] ext4_mb_mark_bb() currently wrongly calculates cluster len (clen) and flex_group->free_clusters. This patch fixes that. Identified based on code review of ext4_mb_mark_bb() function. Signed-off-by: Ritesh Harjani Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/a0b035d536bafa88110b74456853774b64c8ac40.1644992609.git.riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: make mb_optimize_scan performance mount option work with extents

2022-04-08T12:05:30+00:00

commit 077d0c2c78df6f7260cdd015a991327efa44d8ad upstream. Currently mb_optimize_scan scan feature which improves filesystem performance heavily (when FS is fragmented), seems to be not working with files with extents (ext4 by default has files with extents). This patch fixes that and makes mb_optimize_scan feature work for files with extents. Below are some performance numbers obtained when allocating a 10M and 100M file with and w/o this patch on a filesytem with no 1M contiguous block. =============== Workload: dd if=/dev/urandom of=test conv=fsync bs=1M count=10/100 Time taken ===================================================== no. Size without-patch with-patch Diff(%) 1 10M 0m8.401s 0m5.623s 33.06% 2 100M 1m40.465s 1m14.737s 25.6% ============= w/o patch: mballoc: reqs: 17056 success: 11407 groups_scanned: 13643 cr0_stats: hits: 37 groups_considered: 9472 useless_loops: 36 bad_suggestions: 0 cr1_stats: hits: 11418 groups_considered: 908560 useless_loops: 1894 bad_suggestions: 0 cr2_stats: hits: 1873 groups_considered: 6913 useless_loops: 21 cr3_stats: hits: 21 groups_considered: 5040 useless_loops: 21 extents_scanned: 417364 goal_hits: 3707 2^n_hits: 37 breaks: 1873 lost: 0 buddies_generated: 239/240 buddies_time_used: 651080 preallocated: 705 discarded: 478 with patch: mballoc: reqs: 12768 success: 11305 groups_scanned: 12768 cr0_stats: hits: 1 groups_considered: 18 useless_loops: 0 bad_suggestions: 0 cr1_stats: hits: 5829 groups_considered: 50626 useless_loops: 0 bad_suggestions: 0 cr2_stats: hits: 6938 groups_considered: 580363 useless_loops: 0 cr3_stats: hits: 0 groups_considered: 0 useless_loops: 0 extents_scanned: 309059 goal_hits: 0 2^n_hits: 1 breaks: 1463 lost: 0 buddies_generated: 239/240 buddies_time_used: 791392 preallocated: 673 discarded: 446 Fixes: 196e402 (ext4: improve cr 0 / cr 1 group scanning) Cc: stable@kernel.org Reported-by: Geetika Moolchandani Reported-by: Nageswara R Sastry Suggested-by: Ritesh Harjani Signed-off-by: Ojaswin Mujoo Link: https://lore.kernel.org/r/fc9a48f7f8dcfc83891a8b21f6dd8cdf056ed810.1646732698.git.ojaswin@linux.ibm.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: fix fs corruption when tring to remove a non-empty directory with IO error

2022-04-08T12:05:30+00:00

commit 7aab5c84a0f6ec2290e2ba4a6b245178b1bf949a upstream. We inject IO error when rmdir non empty direcory, then got issue as follows: step1: mkfs.ext4 -F /dev/sda step2: mount /dev/sda test step3: cd test step4: mkdir -p 1/2 step5: rmdir 1 [ 110.920551] ext4_empty_dir: inject fault [ 110.921926] EXT4-fs warning (device sda): ext4_rmdir:3113: inode #12: comm rmdir: empty directory '1' has too many links (3) step6: cd .. step7: umount test step8: fsck.ext4 -f /dev/sda e2fsck 1.42.9 (28-Dec-2013) Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Entry '..' in .../??? (13) has deleted/unused inode 12. Clear? yes Pass 3: Checking directory connectivity Unconnected directory inode 13 (...) Connect to /lost+found? yes Pass 4: Checking reference counts Inode 13 ref count is 3, should be 2. Fix? yes Pass 5: Checking group summary information /dev/sda: ***** FILE SYSTEM WAS MODIFIED ***** /dev/sda: 12/131072 files (0.0% non-contiguous), 26157/524288 blocks ext4_rmdir if (!ext4_empty_dir(inode)) goto end_rmdir; ext4_empty_dir bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE); if (IS_ERR(bh)) return true; Now if read directory block failed, 'ext4_empty_dir' will return true, assume directory is empty. Obviously, it will lead to above issue. To solve this issue, if read directory block failed 'ext4_empty_dir' just return false. To avoid making things worse when file system is already corrupted, 'ext4_empty_dir' also return false. Signed-off-by: Ye Bin Cc: stable@kernel.org Link: https://lore.kernel.org/r/20220228024815.3952506-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman

ext4: fast commit may miss file actions

2022-03-08T18:14:05+00:00

[ Upstream commit bdc8a53a6f2f0b1cb5f991440f2100732299eb93 ] in the follow scenario: 1. jbd start transaction n 2. task A get new handle for transaction n+1 3. task A do some actions and add inode to FC_Q_MAIN fc_q 4. jbd complete transaction n and clear FC_Q_MAIN fc_q 5. task A call fsync Fast commit will lost the file actions during a full commit. we should also add updates to staging queue during a full commit. and in ext4_fc_cleanup(), when reset a inode's fc track range, check it's i_sync_tid, if it bigger than current transaction tid, do not rest it, or we will lost the track range. And EXT4_MF_FC_COMMITTING is not needed anymore, so drop it. Signed-off-by: Xin Yin Link: https://lore.kernel.org/r/20220117093655.35160-3-yinxin.x@bytedance.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Sasha Levin

ext4: fast commit may not fallback for ineligible commit

2022-03-08T18:14:05+00:00

[ Upstream commit e85c81ba8859a4c839bcd69c5d83b32954133a5b ] For the follow scenario: 1. jbd start commit transaction n 2. task A get new handle for transaction n+1 3. task A do some ineligible actions and mark FC_INELIGIBLE 4. jbd complete transaction n and clean FC_INELIGIBLE 5. task A call fsync In this case fast commit will not fallback to full commit and transaction n+1 also not handled by jbd. Make ext4_fc_mark_ineligible() also record transaction tid for latest ineligible case, when call ext4_fc_cleanup() check current transaction tid, if small than latest ineligible tid do not clear the EXT4_MF_FC_INELIGIBLE. Reported-by: kernel test robot Reported-by: Dan Carpenter Reported-by: Ritesh Harjani Suggested-by: Harshad Shirwadkar Signed-off-by: Xin Yin Link: https://lore.kernel.org/r/20220117093655.35160-2-yinxin.x@bytedance.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Sasha Levin

ext4: simplify updating of fast commit stats

2022-03-08T18:14:04+00:00

[ Upstream commit 0915e464cb274648e1ef1663e1356e53ff400983 ] Move fast commit stats updating logic to a separate function from ext4_fc_commit(). This significantly improves readability of ext4_fc_commit(). Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20211223202140.2061101-4-harshads@google.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: drop ineligible txn start stop APIs

2022-03-08T18:14:04+00:00

[ Upstream commit 7bbbe241ec7ce0def9f71464c878fdbd2b0dcf37 ] This patch drops ext4_fc_start_ineligible() and ext4_fc_stop_ineligible() APIs. Fast commit ineligible transactions should simply call ext4_fc_mark_ineligible() after starting the trasaction. Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20211223202140.2061101-3-harshads@google.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

ext4: fix incorrect type issue during replay_del_range

2022-02-08T17:35:19+00:00

commit 8fca8a2b0a822f7936130af7299d2fd7f0a66714 upstream. should not use fast commit log data directly, add le32_to_cpu(). Reported-by: kernel test robot Fixes: 0b5b5a62b945 ("ext4: use ext4_ext_remove_space() for fast commit replay delete range") Cc: stable@kernel.org Signed-off-by: Xin Yin Reviewed-by: Ritesh Harjani Link: https://lore.kernel.org/r/20220126063146.2302-1-yinxin.x@bytedance.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman