Commit 0bf11106 authored by John Garry's avatar John Garry Committed by Long Li
Browse files

fs: Add FS_XFLAG_ATOMICWRITES flag 

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I9VTE3
CVE: NA

Reference: https://lore.kernel.org/all/20240326133813.3224593-1-john.g.garry@oracle.com/



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Add a flag indicating that a regular file is enabled for atomic writes.

This is a file attribute that mirrors an ondisk inode flag.  Actual support
for untorn file writes (for now) depends on both the iflag and the
underlying storage devices, which we can only really check at statx and
pwritev2() time.  This is the same story as FS_XFLAG_DAX, which signals to
the fs that we should try to enable the fsdax IO path on the file (instead
of the regular page cache), but applications have to query STAT_ATTR_DAX
to find out if they really got that IO path.

Signed-off-by: default avatarJohn Garry <john.g.garry@oracle.com>
Signed-off-by: default avatarLong Li <leo.lilong@huawei.com>
parent 6b7349ec

include/uapi/linux/fs.h

+1 −0
Original line number Diff line number Diff line
@@ -142,6 +142,7 @@ struct fsxattr { 
#define FS_XFLAG_COWEXTSIZE	0x00010000	/* CoW extent size allocator hint */

/* data extent mappings for regular files must be aligned to extent size hint */

#define FS_XFLAG_FORCEALIGN	0x00020000

#define FS_XFLAG_ATOMICWRITES	0x00040000	/* atomic writes enabled */

#define FS_XFLAG_HASATTR	0x80000000	/* no DIFLAG for this	*/



/* the read-only stuff doesn't really belong here, but any other place is