xfs: create function to scan and clear EOFBLOCKS inodes

xfs_inodes_free_eofblocks() implements scanning functionality for
EOFBLOCKS inodes. It uses the AG iterator to walk the tagged inodes
and free post-EOF blocks via the xfs_inode_free_eofblocks() execute
function. The scan can be invoked in best-effort mode or wait
(force) mode.

A best-effort scan (default) handles all inodes that do not have a
dirty cache and we successfully acquire the io lock via trylock. In
wait mode, we continue to cycle through an AG until all inodes are
handled.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

3 files changed, 45 insertions, 0 deletions

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 2a96dc48ebe6..d115cb44b103 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -1170,6 +1170,49 @@ xfs_reclaim_inodes_count(
         return reclaimable;
 }
 
+STATIC int
+xfs_inode_free_eofblocks(
+        struct xfs_inode        *ip,
+        struct xfs_perag        *pag,
+        int                     flags,
+        void                    *args)
+{
+        int ret;
+
+        if (!xfs_can_free_eofblocks(ip, false)) {
+                /* inode could be preallocated or append-only */
+                trace_xfs_inode_free_eofblocks_invalid(ip);
+                xfs_inode_clear_eofblocks_tag(ip);
+                return 0;
+        }
+
+        /*
+         * If the mapping is dirty the operation can block and wait for some
+         * time. Unless we are waiting, skip it.
+         */
+        if (!(flags & SYNC_WAIT) &&
+            mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY))
+                return 0;
+
+        ret = xfs_free_eofblocks(ip->i_mount, ip, true);
+
+        /* don't revisit the inode if we're not waiting */
+        if (ret == EAGAIN && !(flags & SYNC_WAIT))
+                ret = 0;
+
+        return ret;
+}
+
+int
+xfs_icache_free_eofblocks(
+        struct xfs_mount        *mp,
+        int                     flags)
+{
+        ASSERT((flags & ~(SYNC_TRYLOCK|SYNC_WAIT)) == 0);
+        return xfs_inode_ag_iterator_tag(mp, xfs_inode_free_eofblocks, flags,
+                                         NULL, XFS_ICI_EOFBLOCKS_TAG);
+}
+
 void
 xfs_inode_set_eofblocks_tag(
         xfs_inode_t     *ip)
diff --git a/fs/xfs/xfs_icache.h b/fs/xfs/xfs_icache.h
index 54c113478dfc..cb6b8d0eee61 100644
--- a/fs/xfs/xfs_icache.h
+++ b/fs/xfs/xfs_icache.h
@@ -37,6 +37,7 @@ void xfs_inode_set_reclaim_tag(struct xfs_inode *ip);
 
 void xfs_inode_set_eofblocks_tag(struct xfs_inode *ip);
 void xfs_inode_clear_eofblocks_tag(struct xfs_inode *ip);
+int xfs_icache_free_eofblocks(struct xfs_mount *, int);
 
 int xfs_sync_inode_grab(struct xfs_inode *ip);
 int xfs_inode_ag_iterator(struct xfs_mount *mp,
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 6f46e034b766..cb5234632072 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -589,6 +589,7 @@ DEFINE_INODE_EVENT(xfs_dquot_dqdetach);
 
 DEFINE_INODE_EVENT(xfs_inode_set_eofblocks_tag);
 DEFINE_INODE_EVENT(xfs_inode_clear_eofblocks_tag);
+DEFINE_INODE_EVENT(xfs_inode_free_eofblocks_invalid);
 
 DECLARE_EVENT_CLASS(xfs_iref_class,
         TP_PROTO(struct xfs_inode *ip, unsigned long caller_ip),