Commit 13e6d5cd authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Felix Blyakher
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xfs: merge fsync and O_SYNC handling 



The guarantees for O_SYNC are exactly the same as the ones we need to
make for an fsync call (and given that Linux O_SYNC is O_DSYNC the
equivalent is fdadatasync, but we treat both the same in XFS), except
with a range data writeout.  Jan Kara has started unifying these two
path for filesystems using the generic helpers, and I've started to
look at XFS.

The actual transaction commited by xfs_fsync and xfs_write_sync_logforce
has a different transaction number, but actually is exactly the same.
We'll only use the fsync transaction going forward.  One major difference
is that xfs_write_sync_logforce never issues a cache flush unless we
commit a transaction causing that as a side-effect, which is an obvious
bug in the O_SYNC handling.  Second all the locking and i_update_size
vs i_update_core changes from 978b7237
never made it to xfs_write_sync_logforce, so we add them back.

To make xfs_fsync easily usable from the O_SYNC path, the filemap_fdatawait
call is moved up to xfs_file_fsync, so that we don't wait on the whole
file after we already waited for our portion in xfs_write.

We'll also use a plain call to filemap_write_and_wait_range instead
of the previous sync_page_rang which did it in two steps including
an half-hearted inode write out that doesn't help us.

Once we're done with this also remove the now useless i_update_size
tracking.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarFelix Blyakher <felixb@sgi.com>
Signed-off-by: default avatarFelix Blyakher <felixb@sgi.com>
parent bd169565

fs/xfs/linux-2.6/xfs_aops.c

+0 −1
Original line number Diff line number Diff line
@@ -216,7 +216,6 @@ xfs_setfilesize( 
	if (ip->i_d.di_size < isize) {

		ip->i_d.di_size = isize;

		ip->i_update_core = 1;

		ip->i_update_size = 1;

		xfs_mark_inode_dirty_sync(ip);

	}

fs/xfs/linux-2.6/xfs_file.c

+14 −5
Original line number Diff line number Diff line
@@ -172,12 +172,21 @@ xfs_file_release( 
 */

STATIC int

xfs_file_fsync(

	struct file	*filp,

	struct file		*file,

	struct dentry		*dentry,

	int			datasync)

{

	xfs_iflags_clear(XFS_I(dentry->d_inode), XFS_ITRUNCATED);

	return -xfs_fsync(XFS_I(dentry->d_inode));

	struct inode		*inode = dentry->d_inode;

	struct xfs_inode	*ip = XFS_I(inode);

	int			error;



	/* capture size updates in I/O completion before writing the inode. */

	error = filemap_fdatawait(inode->i_mapping);

	if (error)

		return error;



	xfs_iflags_clear(ip, XFS_ITRUNCATED);

	return -xfs_fsync(ip);

}



STATIC int

fs/xfs/linux-2.6/xfs_lrw.c

+5 −2
Original line number Diff line number Diff line
@@ -812,18 +812,21 @@ write_retry: 


	/* Handle various SYNC-type writes */

	if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {

		loff_t end = pos + ret - 1;

		int error2;



		xfs_iunlock(xip, iolock);

		if (need_i_mutex)

			mutex_unlock(&inode->i_mutex);

		error2 = sync_page_range(inode, mapping, pos, ret);



		error2 = filemap_write_and_wait_range(mapping, pos, end);

		if (!error)

			error = error2;

		if (need_i_mutex)

			mutex_lock(&inode->i_mutex);

		xfs_ilock(xip, iolock);

		error2 = xfs_write_sync_logforce(mp, xip);



		error2 = xfs_fsync(xip);

		if (!error)

			error = error2;

	}

fs/xfs/xfs_iget.c

+0 −1
Original line number Diff line number Diff line
@@ -82,7 +82,6 @@ xfs_inode_alloc( 
	memset(&ip->i_df, 0, sizeof(xfs_ifork_t));

	ip->i_flags = 0;

	ip->i_update_core = 0;

	ip->i_update_size = 0;

	ip->i_delayed_blks = 0;

	memset(&ip->i_d, 0, sizeof(xfs_icdinode_t));

	ip->i_size = 0;

fs/xfs/xfs_inode.h

+0 −1
Original line number Diff line number Diff line
@@ -261,7 +261,6 @@ typedef struct xfs_inode { 
	/* Miscellaneous state. */

	unsigned short		i_flags;	/* see defined flags below */

	unsigned char		i_update_core;	/* timestamps/size is dirty */

	unsigned char		i_update_size;	/* di_size field is dirty */

	unsigned int		i_delayed_blks;	/* count of delay alloc blks */



	xfs_icdinode_t		i_d;		/* most of ondisk inode */

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