kernel/linux.git/fs/ext4/mmp.c, branch v6.4

ext4: fix lockdep warning when enabling MMP

2023-05-08T01:11:18+00:00

When we enable MMP in ext4_multi_mount_protect() during mount or remount, we end up calling sb_start_write() from write_mmp_block(). This triggers lockdep warning because freeze protection ranks above s_umount semaphore we are holding during mount / remount. The problem is harmless because we are guaranteed the filesystem is not frozen during mount / remount but still let's fix the warning by not grabbing freeze protection from ext4_multi_mount_protect(). Cc: stable@kernel.org Reported-by: syzbot+6b7df7d5506b32467149@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=ab7e5b6f400b7778d46f01841422e5718fb81843 Signed-off-by: Jan Kara Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20230411121019.21940-1-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: reflect error codes from ext4_multi_mount_protect() to its callers

2023-04-28T16:56:40+00:00

This will allow more fine-grained errno codes to be returned by the mount system call. Cc: Andreas Dilger Signed-off-by: Theodore Ts'o

treewide: use get_random_u32_{above,below}() instead of manual loop

2022-11-18T01:15:22+00:00

These cases were done with this Coccinelle: @@ expression E; identifier I; @@ - do { ... when != I - I = get_random_u32(); ... when != I - } while (I > E); + I = get_random_u32_below(E + 1); @@ expression E; identifier I; @@ - do { ... when != I - I = get_random_u32(); ... when != I - } while (I >= E); + I = get_random_u32_below(E); @@ expression E; identifier I; @@ - do { ... when != I - I = get_random_u32(); ... when != I - } while (I < E); + I = get_random_u32_above(E - 1); @@ expression E; identifier I; @@ - do { ... when != I - I = get_random_u32(); ... when != I - } while (I <= E); + I = get_random_u32_above(E); @@ identifier I; @@ - do { ... when != I - I = get_random_u32(); ... when != I - } while (!I); + I = get_random_u32_above(0); @@ identifier I; @@ - do { ... when != I - I = get_random_u32(); ... when != I - } while (I == 0); + I = get_random_u32_above(0); @@ expression E; @@ - E + 1 + get_random_u32_below(U32_MAX - E) + get_random_u32_above(E) Reviewed-by: Kees Cook Reviewed-by: Greg Kroah-Hartman Signed-off-by: Jason A. Donenfeld

treewide: use get_random_u32() when possible

2022-10-11T23:42:58+00:00

The prandom_u32() function has been a deprecated inline wrapper around get_random_u32() for several releases now, and compiles down to the exact same code. Replace the deprecated wrapper with a direct call to the real function. The same also applies to get_random_int(), which is just a wrapper around get_random_u32(). This was done as a basic find and replace. Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kees Cook Reviewed-by: Yury Norov Reviewed-by: Jan Kara # for ext4 Acked-by: Toke Høiland-Jørgensen # for sch_cake Acked-by: Chuck Lever # for nfsd Acked-by: Jakub Kicinski Acked-by: Mika Westerberg # for thunderbolt Acked-by: Darrick J. Wong # for xfs Acked-by: Helge Deller # for parisc Acked-by: Heiko Carstens # for s390 Signed-off-by: Jason A. Donenfeld

fs/buffer: Combine two submit_bh() and ll_rw_block() arguments

2022-07-14T18:14:32+00:00

Both submit_bh() and ll_rw_block() accept a request operation type and request flags as their first two arguments. Micro-optimize these two functions by combining these first two arguments into a single argument. This patch does not change the behavior of any of the modified code. Cc: Alexander Viro Cc: Jan Kara Acked-by: Song Liu (for the md changes) Signed-off-by: Bart Van Assche Link: https://lore.kernel.org/r/20220714180729.1065367-48-bvanassche@acm.org Signed-off-by: Jens Axboe

block: remove bdevname

2022-07-14T16:27:56+00:00

Replace the remaining calls of bdevname with snprintf using the %pg format specifier. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Reviewed-by: Chaitanya Kulkarni Reviewed-by: Johannes Thumshirn Link: https://lore.kernel.org/r/20220713055317.1888500-10-hch@lst.de Signed-off-by: Jens Axboe

ext4: only initialize mmp_bdevname once

2022-07-14T16:27:56+00:00

mmp_bdevname is currently both initialized nested inside the kthread_run call in ext4_multi_mount_protect and in the kmmpd thread started by it. Lift the initiaization out of the kthread_run call in ext4_multi_mount_protect, move the BUILD_BUG_ON next to it and remove the duplicate assignment inside of kmmpd. Signed-off-by: Christoph Hellwig Acked-by: Theodore Ts'o Reviewed-by: Jan Kara Reviewed-by: Chaitanya Kulkarni Reviewed-by: Johannes Thumshirn Link: https://lore.kernel.org/r/20220713055317.1888500-9-hch@lst.de Signed-off-by: Jens Axboe

ext4: remove unnecessary type castings

2022-05-11T19:19:06+00:00

remove unnecessary void* type castings. Signed-off-by: Yu Zhe Link: https://lore.kernel.org/r/20220401081321.73735-1-yuzhe@nfschina.com Signed-off-by: Theodore Ts'o

ext4: fix potential uninitialized access to retval in kmmpd

2021-07-23T11:31:29+00:00

if (!ext4_has_feature_mmp(sb)) then retval can be unitialized before we jump to the wait_to_exit label. Fixes: 61bb4a1c417e ("ext4: fix possible UAF when remounting r/o a mmp-protected file system") Signed-off-by: Ye Bin Link: https://lore.kernel.org/r/20210713022728.2533770-1-yebin10@huawei.com Signed-off-by: Theodore Ts'o

ext4: fix possible UAF when remounting r/o a mmp-protected file system

2021-07-08T12:36:09+00:00

After commit 618f003199c6 ("ext4: fix memory leak in ext4_fill_super"), after the file system is remounted read-only, there is a race where the kmmpd thread can exit, causing sbi->s_mmp_tsk to point at freed memory, which the call to ext4_stop_mmpd() can trip over. Fix this by only allowing kmmpd() to exit when it is stopped via ext4_stop_mmpd(). Link: https://lore.kernel.org/r/20210707002433.3719773-1-tytso@mit.edu Reported-by: Ye Bin Bug-Report-Link: <20210629143603.2166962-1-yebin10@huawei.com> Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara