Commit 12f2930f authored by Darrick J. Wong's avatar Darrick J. Wong
Browse files

xfs: port xfs_ioc_start_commit to multigrain timestamps 



Take advantage of the multigrain timestamp APIs to ensure that nobody
can sneak in and write things to a file between starting a file update
operation and committing the results.  This should have been part of the
multigrain timestamp merge, but I forgot to fling it at jlayton when he
resubmitted the patchset due to developer bandwidth problems.

Cc: <stable@vger.kernel.org> # v6.13-rc1
Fixes: 4e40eff0 ("fs: add infrastructure for multigrain timestamps")
Signed-off-by: default avatarDarrick J. Wong <djwong@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
parent 7f8b718c

fs/xfs/xfs_exchrange.c

+7 −7
Original line number Diff line number Diff line
@@ -854,7 +854,7 @@ xfs_ioc_start_commit( 
	struct xfs_commit_range __user	*argp)

{

	struct xfs_commit_range		args = { };

	struct timespec64		ts;

	struct kstat			kstat = { };

	struct xfs_commit_range_fresh	*kern_f;

	struct xfs_commit_range_fresh	__user *user_f;

	struct inode			*inode2 = file_inode(file);
@@ -871,12 +871,12 @@ xfs_ioc_start_commit( 
	memcpy(&kern_f->fsid, ip2->i_mount->m_fixedfsid, sizeof(xfs_fsid_t));



	xfs_ilock(ip2, lockflags);

	ts = inode_get_ctime(inode2);

	kern_f->file2_ctime		= ts.tv_sec;

	kern_f->file2_ctime_nsec	= ts.tv_nsec;

	ts = inode_get_mtime(inode2);

	kern_f->file2_mtime		= ts.tv_sec;

	kern_f->file2_mtime_nsec	= ts.tv_nsec;

	/* Force writing of a distinct ctime if any writes happen. */

	fill_mg_cmtime(&kstat, STATX_CTIME | STATX_MTIME, inode2);

	kern_f->file2_ctime		= kstat.ctime.tv_sec;

	kern_f->file2_ctime_nsec	= kstat.ctime.tv_nsec;

	kern_f->file2_mtime		= kstat.mtime.tv_sec;

	kern_f->file2_mtime_nsec	= kstat.mtime.tv_nsec;

	kern_f->file2_ino		= ip2->i_ino;

	kern_f->file2_gen		= inode2->i_generation;

	kern_f->magic			= XCR_FRESH_MAGIC;