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authorAmir Goldstein <amir73il@gmail.com>2019-05-13 17:22:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-14 09:47:50 -0700
commitc553ea4fdf2701d64b9e9cca4497a8a2512bb025 (patch)
tree545b8034a6e27d2fa63eac9704c41165cc4bdf1d /include
parent5326905798dee047bc6216da63ecf2c93c15968e (diff)
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')
-rw-r--r--include/uapi/linux/fs.h3
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: