[PATCH 05/28] XFS: Use the inode tree for finding dirty inodes V3

Dave Chinner
2008-08-19T13:17:04Z

Update xfs_sync_inodes to walk the inode radix tree cache to find
dirty inodes. This removes a huge bunch of nasty, messy code for
traversing the mount inode list safely and removes another user of
the mount inode list.

Version 3
o rediff against new linux-2.6/xfs_sync.c code

Version 2
o add comment explaining use of gang lookups for a single inode
o use IRELE, not VN_RELE
o move check for ag initialisation to caller.

Signed-off-by: Dave Chinner <david@fromorbit.com>
---
fs/xfs/linux-2.6/xfs_sync.c | 361 ++++++++++++-------------------------------
1 files changed, 101 insertions(+), 260 deletions(-)

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index cd82ba5..53d85ec 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -121,356 +121,197 @@ xfs_sync(
}

/*
- * xfs sync routine for internal use
- *
- * This routine supports all of the flags defined for the generic vfs_sync
- * interface as explained above under xfs_sync.
- *
+ * Sync all the inodes in the given AG according to the
+ * direction given by the flags.
*/
-int
-xfs_sync_inodes(
+STATIC int
+xfs_sync_inodes_ag(
xfs_mount_t *mp,
+ int ag,
int flags,
- int *bypassed)
+ int *bypassed)
{
xfs_inode_t *ip = NULL;
struct inode *vp = NULL;
- int error;
- int last_error;
- uint64_t fflag;
- uint lock_flags;
- uint base_lock_flags;
- boolean_t mount_locked;
- boolean_t vnode_refed;
- int preempt;
- xfs_iptr_t *ipointer;
-#ifdef DEBUG
- boolean_t ipointer_in = B_FALSE;
-
-#define IPOINTER_SET ipointer_in = B_TRUE
-#define IPOINTER_CLR ipointer_in = B_FALSE
-#else
-#define IPOINTER_SET
-#define IPOINTER_CLR
-#endif
-
-
-/* Insert a marker record into the inode list after inode ip. The list
- * must be locked when this is called. After the call the list will no
- * longer be locked.
- */
-#define IPOINTER_INSERT(ip, mp) { \
- ASSERT(ipointer_in == B_FALSE); \
- ipointer->ip_mnext = ip->i_mnext; \
- ipointer->ip_mprev = ip; \
- ip->i_mnext = (xfs_inode_t *)ipointer; \
- ipointer->ip_mnext->i_mprev = (xfs_inode_t *)ipointer; \
- preempt = 0; \
- XFS_MOUNT_IUNLOCK(mp); \
- mount_locked = B_FALSE; \
- IPOINTER_SET; \
- }
-
-/* Remove the marker from the inode list. If the marker was the only item
- * in the list then there are no remaining inodes and we should zero out
- * the whole list. If we are the current head of the list then move the head
- * past us.
- */
-#define IPOINTER_REMOVE(ip, mp) { \
- ASSERT(ipointer_in == B_TRUE); \
- if (ipointer->ip_mnext != (xfs_inode_t *)ipointer) { \
- ip = ipointer->ip_mnext; \
- ip->i_mprev = ipointer->ip_mprev; \
- ipointer->ip_mprev->i_mnext = ip; \
- if (mp->m_inodes == (xfs_inode_t *)ipointer) { \
- mp->m_inodes = ip; \
- } \
- } else { \
- ASSERT(mp->m_inodes == (xfs_inode_t *)ipointer); \
- mp->m_inodes = NULL; \
- ip = NULL; \
- } \
- IPOINTER_CLR; \
- }
-
-#define XFS_PREEMPT_MASK 0x7f
-
- ASSERT(!(flags & SYNC_BDFLUSH));
-
- if (bypassed)
- *bypassed = 0;
- if (mp->m_flags & XFS_MOUNT_RDONLY)
- return 0;
- error = 0;
- last_error = 0;
- preempt = 0;
-
- /* Allocate a reference marker */
- ipointer = (xfs_iptr_t *)kmem_zalloc(sizeof(xfs_iptr_t), KM_SLEEP);
+ xfs_perag_t *pag = &mp->m_perag[ag];
+ boolean_t vnode_refed = B_FALSE;
+ int nr_found;
+ int first_index = 0;
+ int error = 0;
+ int last_error = 0;
+ int fflag = XFS_B_ASYNC;
+ int lock_flags = XFS_ILOCK_SHARED;

- fflag = XFS_B_ASYNC; /* default is don't wait */
if (flags & SYNC_DELWRI)
fflag = XFS_B_DELWRI;
if (flags & SYNC_WAIT)
fflag = 0; /* synchronous overrides all */

- base_lock_flags = XFS_ILOCK_SHARED;
if (flags & (SYNC_DELWRI | SYNC_CLOSE)) {
/*
* We need the I/O lock if we're going to call any of
* the flush/inval routines.
*/
- base_lock_flags |= XFS_IOLOCK_SHARED;
+ lock_flags |= XFS_IOLOCK_SHARED;
}

- XFS_MOUNT_ILOCK(mp);
-
- ip = mp->m_inodes;
-
- mount_locked = B_TRUE;
- vnode_refed = B_FALSE;
-
- IPOINTER_CLR;
-
do {
- ASSERT(ipointer_in == B_FALSE);
- ASSERT(vnode_refed == B_FALSE);
-
- lock_flags = base_lock_flags;
-
/*
- * There were no inodes in the list, just break out
- * of the loop.
+ * use a gang lookup to find the next inode in the tree
+ * as the tree is sparse and a gang lookup walks to find
+ * the number of objects requested.
*/
- if (ip == NULL) {
- break;
- }
+ read_lock(&pag->pag_ici_lock);
+ nr_found = radix_tree_gang_lookup(&pag->pag_ici_root,
+ (void**)&ip, first_index, 1);

- /*
- * We found another sync thread marker - skip it
- */
- if (ip->i_mount == NULL) {
- ip = ip->i_mnext;
- continue;
+ if (!nr_found) {
+ read_unlock(&pag->pag_ici_lock);
+ break;
}

- vp = VFS_I(ip);
+ /* update the index for the next lookup */
+ first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);

/*
- * If the vnode is gone then this is being torn down,
- * call reclaim if it is flushed, else let regular flush
- * code deal with it later in the loop.
+ * skip inodes in reclaim. Let xfs_syncsub do that for
+ * us so we don't need to worry.
*/
-
- if (vp == NULL) {
- /* Skip ones already in reclaim */
- if (ip->i_flags & XFS_IRECLAIM) {
- ip = ip->i_mnext;
- continue;
- }
- if (xfs_ilock_nowait(ip, XFS_ILOCK_EXCL) == 0) {
- ip = ip->i_mnext;
- } else if ((xfs_ipincount(ip) == 0) &&
- xfs_iflock_nowait(ip)) {
- IPOINTER_INSERT(ip, mp);
-
- xfs_finish_reclaim(ip, 1,
- XFS_IFLUSH_DELWRI_ELSE_ASYNC);
-
- XFS_MOUNT_ILOCK(mp);
- mount_locked = B_TRUE;
- IPOINTER_REMOVE(ip, mp);
- } else {
- xfs_iunlock(ip, XFS_ILOCK_EXCL);
- ip = ip->i_mnext;
- }
+ vp = VFS_I(ip);
+ if (!vp) {
+ read_unlock(&pag->pag_ici_lock);
continue;
}

+ /* bad inodes are dealt with elsewhere */
if (VN_BAD(vp)) {
- ip = ip->i_mnext;
+ read_unlock(&pag->pag_ici_lock);
continue;
}

+ /* nothing to sync during shutdown */
if (XFS_FORCED_SHUTDOWN(mp) && !(flags & SYNC_CLOSE)) {
- XFS_MOUNT_IUNLOCK(mp);
- kmem_free(ipointer);
+ read_unlock(&pag->pag_ici_lock);
return 0;
}

/*
- * 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
- * bdflush() here, then don't bother.
- *
- * The inode lock here actually coordinates with the
- * almost spurious inode lock in xfs_ireclaim() to prevent
- * the vnode we handle here without a reference from
- * being freed while we reference it. If we lock the inode
- * while it's on the mount list here, then the spurious inode
- * lock in xfs_ireclaim() after the inode is pulled from
- * the mount list will sleep until we release it here.
- * This keeps the vnode from being freed while we reference
- * it.
+ * The inode lock here actually coordinates with the almost
+ * spurious inode lock in xfs_ireclaim() to prevent the vnode
+ * we handle here without a reference from being freed while we
+ * reference it. If we lock the inode while it's on the mount
+ * list here, then the spurious inode lock in xfs_ireclaim()
+ * after the inode is pulled from the mount list will sleep
+ * until we release it here. This keeps the vnode from being
+ * freed while we reference it.
*/
if (xfs_ilock_nowait(ip, lock_flags) == 0) {
- if (vp == NULL) {
- ip = ip->i_mnext;
- continue;
- }
-
vp = vn_grab(vp);
- if (vp == NULL) {
- ip = ip->i_mnext;
+ read_unlock(&pag->pag_ici_lock);
+ if (!vp)
continue;
- }
-
- IPOINTER_INSERT(ip, mp);
xfs_ilock(ip, lock_flags);

ASSERT(vp == VFS_I(ip));
ASSERT(ip->i_mount == mp);

vnode_refed = B_TRUE;
+ } else {
+ /* safe to unlock here as we have a reference */
+ read_unlock(&pag->pag_ici_lock);
}
-
- /* From here on in the loop we may have a marker record
- * in the inode list.
- */
-
/*
* If we have to flush data or wait for I/O completion
* we need to drop the ilock that we currently hold.
* If we need to drop the lock, insert a marker if we
* have not already done so.
*/
- if ((flags & (SYNC_CLOSE|SYNC_IOWAIT)) ||
- ((flags & SYNC_DELWRI) && VN_DIRTY(vp))) {
- if (mount_locked) {
- IPOINTER_INSERT(ip, mp);
- }
+ if (flags & SYNC_CLOSE) {
xfs_iunlock(ip, XFS_ILOCK_SHARED);
-
- if (flags & SYNC_CLOSE) {
- /* Shutdown case. Flush and invalidate. */
- if (XFS_FORCED_SHUTDOWN(mp))
- xfs_tosspages(ip, 0, -1,
- FI_REMAPF);
- else
- error = xfs_flushinval_pages(ip,
- 0, -1, FI_REMAPF);
- } else if ((flags & SYNC_DELWRI) && VN_DIRTY(vp)) {
- error = xfs_flush_pages(ip, 0,
- -1, fflag, FI_NONE);
- }
-
- /*
- * When freezing, we need to wait ensure all I/O (including direct
- * I/O) is complete to ensure no further data modification can take
- * place after this point
- */
+ if (XFS_FORCED_SHUTDOWN(mp))
+ xfs_tosspages(ip, 0, -1, FI_REMAPF);
+ else
+ error = xfs_flushinval_pages(ip, 0, -1,
+ FI_REMAPF);
+ /* wait for I/O on freeze */
if (flags & SYNC_IOWAIT)
vn_iowait(ip);

xfs_ilock(ip, XFS_ILOCK_SHARED);
}

- 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);
+ if ((flags & SYNC_DELWRI) && VN_DIRTY(vp)) {
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+ error = xfs_flush_pages(ip, 0, -1, fflag, FI_NONE);
+ if (flags & SYNC_IOWAIT)
+ vn_iowait(ip);
+ xfs_ilock(ip, XFS_ILOCK_SHARED);
+ }

+ if ((flags & SYNC_ATTR) && !xfs_inode_clean(ip)) {
if (flags & SYNC_WAIT) {
xfs_iflock(ip);
- error = xfs_iflush(ip, XFS_IFLUSH_SYNC);
-
- /*
- * 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_inode_clean(ip))
+ error = xfs_iflush(ip, XFS_IFLUSH_SYNC);
+ else
+ xfs_ifunlock(ip);
} else if (xfs_iflock_nowait(ip)) {
- error = xfs_iflush(ip, XFS_IFLUSH_DELWRI);
+ if (!xfs_inode_clean(ip))
+ error = xfs_iflush(ip, XFS_IFLUSH_DELWRI);
+ else
+ xfs_ifunlock(ip);
} else if (bypassed) {
(*bypassed)++;
}
}

- if (lock_flags != 0) {
+ if (lock_flags)
xfs_iunlock(ip, lock_flags);
- }

if (vnode_refed) {
- /*
- * If we had to take a reference on the vnode
- * above, then wait until after we've unlocked
- * the inode to release the reference. This is
- * because we can be already holding the inode
- * lock when IRELE() calls xfs_inactive().
- *
- * Make sure to drop the mount lock before calling
- * IRELE() so that we don't trip over ourselves if
- * we have to go for the mount lock again in the
- * inactive code.
- */
- if (mount_locked) {
- IPOINTER_INSERT(ip, mp);
- }
-
IRELE(ip);
-
vnode_refed = B_FALSE;
}

- if (error) {
+ if (error)
last_error = error;
- }
-
/*
* bail out if the filesystem is corrupted.
*/
- if (error == EFSCORRUPTED) {
- if (!mount_locked) {
- XFS_MOUNT_ILOCK(mp);
- IPOINTER_REMOVE(ip, mp);
- }
- XFS_MOUNT_IUNLOCK(mp);
- ASSERT(ipointer_in == B_FALSE);
- kmem_free(ipointer);
+ if (error == EFSCORRUPTED)
return XFS_ERROR(error);
- }
-
- /* Let other threads have a chance at the mount lock
- * if we have looped many times without dropping the
- * lock.
- */
- if ((++preempt & XFS_PREEMPT_MASK) == 0) {
- if (mount_locked) {
- IPOINTER_INSERT(ip, mp);
- }
- }
-
- if (mount_locked == B_FALSE) {
- XFS_MOUNT_ILOCK(mp);
- mount_locked = B_TRUE;
- IPOINTER_REMOVE(ip, mp);
- continue;
- }

- ASSERT(ipointer_in == B_FALSE);
- ip = ip->i_mnext;
+ } while (nr_found);

- } while (ip != mp->m_inodes);
+ return last_error;
+}

- XFS_MOUNT_IUNLOCK(mp);
+int
+xfs_sync_inodes(
+ xfs_mount_t *mp,
+ int flags,
+ int *bypassed)
+{
+ int error;
+ int last_error;
+ int i;

- ASSERT(ipointer_in == B_FALSE);
+ if (bypassed)
+ *bypassed = 0;
+ if (mp->m_flags & XFS_MOUNT_RDONLY)
+ return 0;
+ error = 0;
+ last_error = 0;

- kmem_free(ipointer);
+ for (i = 0; i < mp->m_sb.sb_agcount; i++) {
+ if (!mp->m_perag[i].pag_ici_init)
+ continue;
+ error = xfs_sync_inodes_ag(mp, i, flags, bypassed);
+ if (error)
+ last_error = error;
+ if (error == EFSCORRUPTED)
+ break;
+ }
return XFS_ERROR(last_error);
}

--
1.5.6