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| author |   Amir Goldstein <amir73il@gmail.com> | 2019-05-13 17:22:30 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-14 09:47:50 -0700 |
| commit | c553ea4fdf2701d64b9e9cca4497a8a2512bb025 (patch) | |
| tree | 545b8034a6e27d2fa63eac9704c41165cc4bdf1d /include/uapi/linux/fs.h | |
| parent | xen/privcmd-buf.c: convert to use vm_map_pages_zero() (diff) | |
| download | linux-dev-c553ea4fdf2701d64b9e9cca4497a8a2512bb025.tar.xz linux-dev-c553ea4fdf2701d64b9e9cca4497a8a2512bb025.zip | |
fs/sync.c: sync_file_range(2) may use WB_SYNC_ALL writeback
23d0127096cb ("fs/sync.c: make sync_file_range(2) use WB_SYNC_NONE
writeback") claims that sync_file_range(2) syscall was "created for
userspace to be able to issue background writeout and so waiting for
in-flight IO is undesirable there" and changes the writeback (back) to
WB_SYNC_NONE.
This claim is only partially true. It is true for users that use the flag
SYNC_FILE_RANGE_WRITE by itself, as does PostgreSQL, the user that was the
reason for changing to WB_SYNC_NONE writeback.
However, that claim is not true for users that use that flag combination
SYNC_FILE_RANGE_{WAIT_BEFORE|WRITE|_WAIT_AFTER}. Those users explicitly
requested to wait for in-flight IO as well as to writeback of dirty pages.
Re-brand that flag combination as SYNC_FILE_RANGE_WRITE_AND_WAIT and use
WB_SYNC_ALL writeback to perform the full range sync request.
Link: http://lkml.kernel.org/r/20190409114922.30095-1-amir73il@gmail.com
Link: http://lkml.kernel.org/r/20190419072938.31320-1-amir73il@gmail.com
Fixes: 23d0127096cb ("fs/sync.c: make sync_file_range(2) use WB_SYNC_NONE")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Jan Kara <jack@suse.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/uapi/linux/fs.h')
| -rw-r--r-- | include/uapi/linux/fs.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 121e82ce296b..59c71fa8c553 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -320,6 +320,9 @@ struct fscrypt_key { #define SYNC_FILE_RANGE_WAIT_BEFORE 1 #define SYNC_FILE_RANGE_WRITE 2 #define SYNC_FILE_RANGE_WAIT_AFTER 4 +#define SYNC_FILE_RANGE_WRITE_AND_WAIT (SYNC_FILE_RANGE_WRITE | \ + SYNC_FILE_RANGE_WAIT_BEFORE | \ + SYNC_FILE_RANGE_WAIT_AFTER) /* * Flags for preadv2/pwritev2: |