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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 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
Show Stats 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