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xfs: merge fsync and O_SYNC handling

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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 978b723712
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: Christoph Hellwig <hch@lst.de>
Reviewed-by: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Felix Blyakher <felixb@sgi.com>
This commit is contained in:
Christoph Hellwig
2009-08-31 21:00:31 -03:00
committed by Felix Blyakher
parent bd16956599
commit 13e6d5cdde
10 changed files with 23 additions and 112 deletions
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19
fs/xfs/linux-2.6/xfs_file.c
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@ -172,12 +172,21 @@ xfs_file_release(
*/
STATIC int
xfs_file_fsync(
struct file *filp,
struct dentry *dentry,
int datasync)
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