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| author | OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> | 2019-09-24 01:32:53 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-09-25 01:54:06 +0300 |
| commit | 07bfa4415ab607e459b69bd86aa7e7602ce10b4f (patch) | |
| tree | 62a7bc60deca51a1a795c8a22293e658d88efc07 /fs/overlayfs/readdir.c | |
| parent | 619e17cf75dd58905aa67ccd494a6ba5f19d6cc6 (diff) | |
| download | linux-07bfa4415ab607e459b69bd86aa7e7602ce10b4f.tar.xz | |
fat: work around race with userspace's read via blockdev while mounting
If userspace reads the buffer via blockdev while mounting,
sb_getblk()+modify can race with buffer read via blockdev.
For example,
FS userspace
bh = sb_getblk()
modify bh->b_data
read
ll_rw_block(bh)
fill bh->b_data by on-disk data
/* lost modified data by FS */
set_buffer_uptodate(bh)
set_buffer_uptodate(bh)
Userspace should not use the blockdev while mounting though, the udev
seems to be already doing this. Although I think the udev should try to
avoid this, workaround the race by small overhead.
Link: http://lkml.kernel.org/r/87pnk7l3sw.fsf_-_@mail.parknet.co.jp
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reported-by: Jan Stancek <jstancek@redhat.com>
Tested-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/overlayfs/readdir.c')
0 files changed, 0 insertions, 0 deletions