xfs: use xfs_sync_inodes() for device flushing

Currently xfs_device_flush calls sync_blockdev() which is
a no-op for XFS as all it's metadata is held in a different
address to the one sync_blockdev() works on.

Call xfs_sync_inodes() instead to flush all the delayed
allocation blocks out. To do this as efficiently as possible,
do it via two passes - one to do an async flush of all the
dirty blocks and a second to wait for all the IO to complete.
This requires some modification to the xfs-sync_inodes_ag()
flush code to do efficiently.

Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

5 files changed, 38 insertions, 30 deletions

diff --git a/fs/xfs/linux-2.6/xfs_fs_subr.c b/fs/xfs/linux-2.6/xfs_fs_subr.c
index 5aeb77776961..08be36d7326c 100644
--- a/fs/xfs/linux-2.6/xfs_fs_subr.c
+++ b/fs/xfs/linux-2.6/xfs_fs_subr.c
@@ -74,14 +74,14 @@ xfs_flush_pages(
 
         if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
                 xfs_iflags_clear(ip, XFS_ITRUNCATED);
-                ret = filemap_fdatawrite(mapping);
-                if (flags & XFS_B_ASYNC)
-                        return -ret;
-                ret2 = filemap_fdatawait(mapping);
-                if (!ret)
-                        ret = ret2;
+                ret = -filemap_fdatawrite(mapping);
         }
-        return -ret;
+        if (flags & XFS_B_ASYNC)
+                return ret;
+        ret2 = xfs_wait_on_pages(ip, first, last);
+        if (!ret)
+                ret = ret2;
+        return ret;
 }
 
 int
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index a608e72fa405..88caafc8ef1b 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -62,12 +62,6 @@ xfs_sync_inodes_ag(
         uint32_t        first_index = 0;
         int             error = 0;
         int             last_error = 0;
-        int             fflag = XFS_B_ASYNC;
-
-        if (flags & SYNC_DELWRI)
-                fflag = XFS_B_DELWRI;
-        if (flags & SYNC_WAIT)
-                fflag = 0;              /* synchronous overrides all */
 
         do {
                 struct inode    *inode;
@@ -128,11 +122,23 @@ xfs_sync_inodes_ag(
                  * If we have to flush data or wait for I/O completion
                  * we need to hold the iolock.
                  */
-                if ((flags & SYNC_DELWRI) && VN_DIRTY(inode)) {
-                        xfs_ilock(ip, XFS_IOLOCK_SHARED);
-                        lock_flags |= XFS_IOLOCK_SHARED;
-                        error = xfs_flush_pages(ip, 0, -1, fflag, FI_NONE);
-                        if (flags & SYNC_IOWAIT)
+                if (flags & SYNC_DELWRI) {
+                        if (VN_DIRTY(inode)) {
+                                if (flags & SYNC_TRYLOCK) {
+                                        if (xfs_ilock_nowait(ip, XFS_IOLOCK_SHARED))
+                                                lock_flags |= XFS_IOLOCK_SHARED;
+                                } else {
+                                        xfs_ilock(ip, XFS_IOLOCK_SHARED);
+                                        lock_flags |= XFS_IOLOCK_SHARED;
+                                }
+                                if (lock_flags & XFS_IOLOCK_SHARED) {
+                                        error = xfs_flush_pages(ip, 0, -1,
+                                                        (flags & SYNC_WAIT) ? 0
+                                                                : XFS_B_ASYNC,
+                                                        FI_NONE);
+                                }
+                        }
+                        if (VN_CACHED(inode) && (flags & SYNC_IOWAIT))
                                 xfs_ioend_wait(ip);
                 }
                 xfs_ilock(ip, XFS_ILOCK_SHARED);
@@ -400,9 +406,9 @@ xfs_syncd_queue_work(
         void            *data,
         void            (*syncer)(struct xfs_mount *, void *))
 {
-        struct bhv_vfs_sync_work *work;
+        struct xfs_sync_work *work;
 
-        work = kmem_alloc(sizeof(struct bhv_vfs_sync_work), KM_SLEEP);
+        work = kmem_alloc(sizeof(struct xfs_sync_work), KM_SLEEP);
         INIT_LIST_HEAD(&work->w_list);
         work->w_syncer = syncer;
         work->w_data = data;
@@ -445,23 +451,24 @@ xfs_flush_inode(
  * (IOW, "If at first you don't succeed, use a Bigger Hammer").
  */
 STATIC void
-xfs_flush_device_work(
+xfs_flush_inodes_work(
         struct xfs_mount *mp,
         void            *arg)
 {
         struct inode    *inode = arg;
-        sync_blockdev(mp->m_super->s_bdev);
+        xfs_sync_inodes(mp, SYNC_DELWRI | SYNC_TRYLOCK);
+        xfs_sync_inodes(mp, SYNC_DELWRI | SYNC_TRYLOCK | SYNC_IOWAIT);
         iput(inode);
 }
 
 void
-xfs_flush_device(
+xfs_flush_inodes(
         xfs_inode_t     *ip)
 {
         struct inode    *inode = VFS_I(ip);
 
         igrab(inode);
-        xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_device_work);
+        xfs_syncd_queue_work(ip->i_mount, inode, xfs_flush_inodes_work);
         delay(msecs_to_jiffies(500));
         xfs_log_force(ip->i_mount, (xfs_lsn_t)0, XFS_LOG_FORCE|XFS_LOG_SYNC);
 }
@@ -497,7 +504,7 @@ xfssyncd(
 {
         struct xfs_mount        *mp = arg;
         long                    timeleft;
-        bhv_vfs_sync_work_t     *work, *n;
+        xfs_sync_work_t         *work, *n;
         LIST_HEAD               (tmp);
 
         set_freezable();
diff --git a/fs/xfs/linux-2.6/xfs_sync.h b/fs/xfs/linux-2.6/xfs_sync.h
index 04f058c848ae..ec95e264805b 100644
--- a/fs/xfs/linux-2.6/xfs_sync.h
+++ b/fs/xfs/linux-2.6/xfs_sync.h
@@ -21,18 +21,19 @@
 struct xfs_mount;
 struct xfs_perag;
 
-typedef struct bhv_vfs_sync_work {
+typedef struct xfs_sync_work {
         struct list_head        w_list;
         struct xfs_mount        *w_mount;
         void                    *w_data;        /* syncer routine argument */
         void                    (*w_syncer)(struct xfs_mount *, void *);
-} bhv_vfs_sync_work_t;
+} xfs_sync_work_t;
 
 #define SYNC_ATTR               0x0001  /* sync attributes */
 #define SYNC_DELWRI             0x0002  /* look at delayed writes */
 #define SYNC_WAIT               0x0004  /* wait for i/o to complete */
 #define SYNC_BDFLUSH            0x0008  /* BDFLUSH is calling -- don't block */
 #define SYNC_IOWAIT             0x0010  /* wait for all I/O to complete */
+#define SYNC_TRYLOCK            0x0020  /* only try to lock inodes */
 
 int xfs_syncd_init(struct xfs_mount *mp);
 void xfs_syncd_stop(struct xfs_mount *mp);
@@ -44,7 +45,7 @@ int xfs_quiesce_data(struct xfs_mount *mp);
 void xfs_quiesce_attr(struct xfs_mount *mp);
 
 void xfs_flush_inode(struct xfs_inode *ip);
-void xfs_flush_device(struct xfs_inode *ip);
+void xfs_flush_inodes(struct xfs_inode *ip);
 
 int xfs_reclaim_inode(struct xfs_inode *ip, int locked, int sync_mode);
 int xfs_reclaim_inodes(struct xfs_mount *mp, int noblock, int mode);
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 08ce72316bfe..8b97d82d7a88 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -361,7 +361,7 @@ xfs_flush_space(
                 return 0;
         case 2:
                 xfs_iunlock(ip, XFS_ILOCK_EXCL);
-                xfs_flush_device(ip);
+                xfs_flush_inodes(ip);
                 xfs_ilock(ip, XFS_ILOCK_EXCL);
                 *fsynced = 3;
                 return 0;
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 7af44adffc8f..d6a64392f983 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -313,7 +313,7 @@ typedef struct xfs_mount {
 #endif
         struct xfs_mru_cache    *m_filestream;  /* per-mount filestream data */
         struct task_struct      *m_sync_task;   /* generalised sync thread */
-        bhv_vfs_sync_work_t     m_sync_work;    /* work item for VFS_SYNC */
+        xfs_sync_work_t         m_sync_work;    /* work item for VFS_SYNC */
         struct list_head        m_sync_list;    /* sync thread work item list */
         spinlock_t              m_sync_lock;    /* work item list lock */
         int                     m_sync_seq;     /* sync thread generation no. */