[PATCH] remove dead SYNC_BDFLUSH case in xfs_sync_inodes

Christoph Hellwig
2007-09-09T15:42:24Z

A large part of xfs_sync_inodes is conditional on the SYNC_BDFLUSH which
is never passed to it. This patch removes it and adds an assert that
triggers in case some new code tries to pass SYNC_BDFLUSH to it.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6-xfs/fs/xfs/xfs_vfsops.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_vfsops.c 2007-09-08 17:43:39.000000000 +0200
+++ linux-2.6-xfs/fs/xfs/xfs_vfsops.c 2007-09-08 19:06:31.000000000 +0200
@@ -981,8 +981,6 @@ xfs_sync_inodes(
int *bypassed)
{
xfs_inode_t *ip = NULL;
- xfs_inode_t *ip_next;
- xfs_buf_t *bp;
bhv_vnode_t *vp = NULL;
int error;
int last_error;
@@ -992,7 +990,6 @@ xfs_sync_inodes(
boolean_t mount_locked;
boolean_t vnode_refed;
int preempt;
- xfs_dinode_t *dip;
xfs_iptr_t *ipointer;
#ifdef DEBUG
boolean_t ipointer_in = B_FALSE;
@@ -1045,6 +1042,8 @@ xfs_sync_inodes(

#define XFS_PREEMPT_MASK 0x7f

+ ASSERT(!(flags & SYNC_BDFLUSH));
+
if (bypassed)
*bypassed = 0;
if (mp->m_flags & XFS_MOUNT_RDONLY)
@@ -1057,7 +1056,7 @@ xfs_sync_inodes(
ipointer = (xfs_iptr_t *)kmem_zalloc(sizeof(xfs_iptr_t), KM_SLEEP);

fflag = XFS_B_ASYNC; /* default is don't wait */
- if (flags & (SYNC_BDFLUSH | SYNC_DELWRI))
+ if (flags & SYNC_DELWRI)
fflag = XFS_B_DELWRI;
if (flags & SYNC_WAIT)
fflag = 0; /* synchronous overrides all */
@@ -1147,24 +1146,6 @@ xfs_sync_inodes(
}

/*
- * If this is just vfs_sync() or pflushd() calling
- * then we can skip inodes for which it looks like
- * there is nothing to do. Since we don't have the
- * inode locked this is racy, but these are periodic
- * calls so it doesn't matter. For the others we want
- * to know for sure, so we at least try to lock them.
- */
- if (flags & SYNC_BDFLUSH) {
- if (((ip->i_itemp == NULL) ||
- !(ip->i_itemp->ili_format.ilf_fields &
- XFS_ILOG_ALL)) &&
- (ip->i_update_core == 0)) {
- ip = ip->i_mnext;
- continue;
- }
- }
-
- /*
* Try to lock without sleeping. We're out of order with
* the inode list lock here, so if we fail we need to drop
* the mount lock and try again. If we're called from
@@ -1181,7 +1162,7 @@ xfs_sync_inodes(
* it.
*/
if (xfs_ilock_nowait(ip, lock_flags) == 0) {
- if ((flags & SYNC_BDFLUSH) || (vp == NULL)) {
+ if (vp == NULL) {
ip = ip->i_mnext;
continue;
}
@@ -1242,160 +1223,27 @@ xfs_sync_inodes(
xfs_ilock(ip, XFS_ILOCK_SHARED);
}

- if (flags & SYNC_BDFLUSH) {
- if ((flags & SYNC_ATTR) &&
- ((ip->i_update_core) ||
- ((ip->i_itemp != NULL) &&
- (ip->i_itemp->ili_format.ilf_fields != 0)))) {
-
- /* Insert marker and drop lock if not already
- * done.
- */
- if (mount_locked) {
- IPOINTER_INSERT(ip, mp);
- }
-
- /*
- * We don't want the periodic flushing of the
- * inodes by vfs_sync() to interfere with
- * I/O to the file, especially read I/O
- * where it is only the access time stamp
- * that is being flushed out. To prevent
- * long periods where we have both inode
- * locks held shared here while reading the
- * inode's buffer in from disk, we drop the
- * inode lock while reading in the inode
- * buffer. We have to release the buffer
- * and reacquire the inode lock so that they
- * are acquired in the proper order (inode
- * locks first). The buffer will go at the
- * end of the lru chain, though, so we can
- * expect it to still be there when we go
- * for it again in xfs_iflush().
- */
- if ((xfs_ipincount(ip) == 0) &&
- xfs_iflock_nowait(ip)) {
-
- xfs_ifunlock(ip);
- xfs_iunlock(ip, XFS_ILOCK_SHARED);
-
- error = xfs_itobp(mp, NULL, ip,
- &dip, &bp, 0, 0);
- if (!error) {
- xfs_buf_relse(bp);
- } else {
- /* Bailing out, remove the
- * marker and free it.
- */
- XFS_MOUNT_ILOCK(mp);
- IPOINTER_REMOVE(ip, mp);
- XFS_MOUNT_IUNLOCK(mp);
-
- ASSERT(!(lock_flags &
- XFS_IOLOCK_SHARED));
-
- kmem_free(ipointer,
- sizeof(xfs_iptr_t));
- return (0);
- }
-
- /*
- * Since we dropped the inode lock,
- * the inode may have been reclaimed.
- * Therefore, we reacquire the mount
- * lock and check to see if we were the
- * inode reclaimed. If this happened
- * then the ipointer marker will no
- * longer point back at us. In this
- * case, move ip along to the inode
- * after the marker, remove the marker
- * and continue.
- */
- XFS_MOUNT_ILOCK(mp);
- mount_locked = B_TRUE;
-
- if (ip != ipointer->ip_mprev) {
- IPOINTER_REMOVE(ip, mp);
-
- ASSERT(!vnode_refed);
- ASSERT(!(lock_flags &
- XFS_IOLOCK_SHARED));
- continue;
- }
-
- ASSERT(ip->i_mount == mp);
-
- if (xfs_ilock_nowait(ip,
- XFS_ILOCK_SHARED) == 0) {
- ASSERT(ip->i_mount == mp);
- /*
- * We failed to reacquire
- * the inode lock without
- * sleeping, so just skip
- * the inode for now. We
- * clear the ILOCK bit from
- * the lock_flags so that we
- * won't try to drop a lock
- * we don't hold below.
- */
- lock_flags &= ~XFS_ILOCK_SHARED;
- IPOINTER_REMOVE(ip_next, mp);
- } else if ((xfs_ipincount(ip) == 0) &&
- xfs_iflock_nowait(ip)) {
- ASSERT(ip->i_mount == mp);
- /*
- * Since this is vfs_sync()
- * calling we only flush the
- * inode out if we can lock
- * it without sleeping and
- * it is not pinned. Drop
- * the mount lock here so
- * that we don't hold it for
- * too long. We already have
- * a marker in the list here.
- */
- XFS_MOUNT_IUNLOCK(mp);
- mount_locked = B_FALSE;
- error = xfs_iflush(ip,
- XFS_IFLUSH_DELWRI);
- } else {
- ASSERT(ip->i_mount == mp);
- IPOINTER_REMOVE(ip_next, mp);
- }
- }
-
- }
+ if ((flags & SYNC_ATTR) &&
+ (ip->i_update_core ||
+ (ip->i_itemp && ip->i_itemp->ili_format.ilf_fields))) {
+ if (mount_locked)
+ IPOINTER_INSERT(ip, mp);

- } else {
- if ((flags & SYNC_ATTR) &&
- ((ip->i_update_core) ||
- ((ip->i_itemp != NULL) &&
- (ip->i_itemp->ili_format.ilf_fields != 0)))) {
- if (mount_locked) {
- IPOINTER_INSERT(ip, mp);
- }
+ if (flags & SYNC_WAIT) {
+ xfs_iflock(ip);
+ error = xfs_iflush(ip, XFS_IFLUSH_SYNC);

- if (flags & SYNC_WAIT) {
- xfs_iflock(ip);
- error = xfs_iflush(ip,
- XFS_IFLUSH_SYNC);
- } else {
- /*
- * If we can't acquire the flush
- * lock, then the inode is already
- * being flushed so don't bother
- * waiting. If we can lock it then
- * do a delwri flush so we can
- * combine multiple inode flushes
- * in each disk write.
- */
- if (xfs_iflock_nowait(ip)) {
- error = xfs_iflush(ip,
- XFS_IFLUSH_DELWRI);
- }
- else if (bypassed)
- (*bypassed)++;
- }
+ /*
+ * If we can't acquire the flush lock, then the inode
+ * is already being flushed so don't bother waiting.
+ *
+ * If we can lock it then do a delwri flush so we can
+ * combine multiple inode flushes in each disk write.
+ */
+ } else if (xfs_iflock_nowait(ip)) {
+ error = xfs_iflush(ip, XFS_IFLUSH_DELWRI);
+ } else if (bypassed) {
+ (*bypassed)++;
}
}