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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
commit 13e6d5cdde
10 changed files with 23 additions and 112 deletions
Download patch file Download diff file Expand all files Collapse all files

1
fs/xfs/linux-2.6/xfs_aops.c
View file

@ -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);
}

19
fs/xfs/linux-2.6/xfs_file.c
View file

@ -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

7
fs/xfs/linux-2.6/xfs_lrw.c
View file

@ -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;
}

1
fs/xfs/xfs_iget.c
View file

@ -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;

1
fs/xfs/xfs_inode.h
View file

@ -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 */

8
fs/xfs/xfs_inode_item.c
View file

@ -262,14 +262,6 @@ xfs_inode_item_format(
SYNCHRONIZE();
}
/*
* We don't have to worry about re-ordering here because
* the update_size field is protected by the inode lock
* and we have that held in exclusive mode.
*/
if (ip->i_update_size)
ip->i_update_size = 0;
/*
* Make sure to get the latest atime from the Linux inode.
*/

84
fs/xfs/xfs_rw.c
View file

@ -87,90 +87,6 @@ xfs_write_clear_setuid(
return 0;
}
/*
* Handle logging requirements of various synchronous types of write.
*/
int
xfs_write_sync_logforce(
xfs_mount_t *mp,
xfs_inode_t *ip)
{
int error = 0;
/*
* If we're treating this as O_DSYNC and we have not updated the
* size, force the log.
*/
if (!(mp->m_flags & XFS_MOUNT_OSYNCISOSYNC) &&
!(ip->i_update_size)) {
xfs_inode_log_item_t *iip = ip->i_itemp;
/*
* If an allocation transaction occurred
* without extending the size, then we have to force
* the log up the proper point to ensure that the
* allocation is permanent. We can't count on
* the fact that buffered writes lock out direct I/O
* writes - the direct I/O write could have extended
* the size nontransactionally, then finished before
* we started. xfs_write_file will think that the file
* didn't grow but the update isn't safe unless the
* size change is logged.
*
* Force the log if we've committed a transaction
* against the inode or if someone else has and
* the commit record hasn't gone to disk (e.g.
* the inode is pinned). This guarantees that
* all changes affecting the inode are permanent
* when we return.
*/
if (iip && iip->ili_last_lsn) {
error = _xfs_log_force(mp, iip->ili_last_lsn,
XFS_LOG_FORCE | XFS_LOG_SYNC, NULL);
} else if (xfs_ipincount(ip) > 0) {
error = _xfs_log_force(mp, (xfs_lsn_t)0,
XFS_LOG_FORCE | XFS_LOG_SYNC, NULL);
}
} else {
xfs_trans_t *tp;
/*
* O_SYNC or O_DSYNC _with_ a size update are handled
* the same way.
*
* If the write was synchronous then we need to make
* sure that the inode modification time is permanent.
* We'll have updated the timestamp above, so here
* we use a synchronous transaction to log the inode.
* It's not fast, but it's necessary.
*
* If this a dsync write and the size got changed
* non-transactionally, then we need to ensure that
* the size change gets logged in a synchronous
* transaction.
*/
tp = xfs_trans_alloc(mp, XFS_TRANS_WRITE_SYNC);
if ((error = xfs_trans_reserve(tp, 0,
XFS_SWRITE_LOG_RES(mp),
0, 0, 0))) {
/* Transaction reserve failed */
xfs_trans_cancel(tp, 0);
} else {
/* Transaction reserve successful */
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
xfs_trans_ihold(tp, ip);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
xfs_trans_set_sync(tp);
error = xfs_trans_commit(tp, 0);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
}
}
return error;
}
/*
* Force a shutdown of the filesystem instantly while keeping
* the filesystem consistent. We don't do an unmount here; just shutdown

1
fs/xfs/xfs_rw.h
View file

@ -68,7 +68,6 @@ xfs_get_extsz_hint(
* Prototypes for functions in xfs_rw.c.
*/
extern int xfs_write_clear_setuid(struct xfs_inode *ip);
extern int xfs_write_sync_logforce(struct xfs_mount *mp, struct xfs_inode *ip);
extern int xfs_bwrite(struct xfs_mount *mp, struct xfs_buf *bp);
extern int xfs_bioerror(struct xfs_buf *bp);
extern int xfs_bioerror_relse(struct xfs_buf *bp);

2
fs/xfs/xfs_trans.h
View file

@ -68,7 +68,7 @@ typedef struct xfs_trans_header {
#define XFS_TRANS_GROWFS 14
#define XFS_TRANS_STRAT_WRITE 15
#define XFS_TRANS_DIOSTRAT 16
#define XFS_TRANS_WRITE_SYNC 17
/* 17 was XFS_TRANS_WRITE_SYNC */
#define XFS_TRANS_WRITEID 18
#define XFS_TRANS_ADDAFORK 19
#define XFS_TRANS_ATTRINVAL 20

11
fs/xfs/xfs_vnodeops.c
View file

@ -611,7 +611,7 @@ xfs_fsync(
xfs_inode_t *ip)
{
xfs_trans_t *tp;
int error;
int error = 0;
int log_flushed = 0, changed = 1;
xfs_itrace_entry(ip);
@ -619,14 +619,9 @@ xfs_fsync(
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
return XFS_ERROR(EIO);
/* capture size updates in I/O completion before writing the inode. */
error = xfs_wait_on_pages(ip, 0, -1);
if (error)
return XFS_ERROR(error);
/*
* We always need to make sure that the required inode state is safe on
* disk. The vnode might be clean but we still might need to force the
* disk. The inode might be clean but we still might need to force the
* log because of committed transactions that haven't hit the disk yet.
* Likewise, there could be unflushed non-transactional changes to the
* inode core that have to go to disk and this requires us to issue
@ -638,7 +633,7 @@ xfs_fsync(
*/
xfs_ilock(ip, XFS_ILOCK_SHARED);
if (!(ip->i_update_size || ip->i_update_core)) {
if (!ip->i_update_core) {
/*
* Timestamps/size haven't changed since last inode flush or
* inode transaction commit. That means either nothing got