1 files changed, 100 insertions, 7 deletions

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index 6b6b39416ad3..57adf2d60dfc 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -95,7 +95,8 @@ xfs_inode_ag_walk(
                                            struct xfs_perag *pag, int flags),
         int                     flags,
         int                     tag,
-        int                     exclusive)
+        int                     exclusive,
+        int                     *nr_to_scan)
 {
         struct xfs_perag        *pag = &mp->m_perag[ag];
         uint32_t                first_index;
@@ -135,7 +136,7 @@ restart:
                 if (error == EFSCORRUPTED)
                         break;
 
-        } while (1);
+        } while ((*nr_to_scan)--);
 
         if (skipped) {
                 delay(1);
@@ -153,23 +154,30 @@ xfs_inode_ag_iterator(
                                            struct xfs_perag *pag, int flags),
         int                     flags,
         int                     tag,
-        int                     exclusive)
+        int                     exclusive,
+        int                     *nr_to_scan)
 {
         int                     error = 0;
         int                     last_error = 0;
         xfs_agnumber_t          ag;
+        int                     nr;
 
+        nr = nr_to_scan ? *nr_to_scan : INT_MAX;
         for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
                 if (!mp->m_perag[ag].pag_ici_init)
                         continue;
                 error = xfs_inode_ag_walk(mp, ag, execute, flags, tag,
-                                                exclusive);
+                                                exclusive, &nr);
                 if (error) {
                         last_error = error;
                         if (error == EFSCORRUPTED)
                                 break;
                 }
+                if (nr <= 0)
+                        break;
         }
+        if (nr_to_scan)
+                *nr_to_scan = nr;
         return XFS_ERROR(last_error);
 }
 
@@ -289,7 +297,7 @@ xfs_sync_data(
         ASSERT((flags & ~(SYNC_TRYLOCK|SYNC_WAIT)) == 0);
 
         error = xfs_inode_ag_iterator(mp, xfs_sync_inode_data, flags,
-                                      XFS_ICI_NO_TAG, 0);
+                                      XFS_ICI_NO_TAG, 0, NULL);
         if (error)
                 return XFS_ERROR(error);
 
@@ -311,7 +319,7 @@ xfs_sync_attr(
         ASSERT((flags & ~SYNC_WAIT) == 0);
 
         return xfs_inode_ag_iterator(mp, xfs_sync_inode_attr, flags,
-                                     XFS_ICI_NO_TAG, 0);
+                                     XFS_ICI_NO_TAG, 0, NULL);
 }
 
 STATIC int
@@ -679,6 +687,7 @@ __xfs_inode_set_reclaim_tag(
         radix_tree_tag_set(&pag->pag_ici_root,
                            XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino),
                            XFS_ICI_RECLAIM_TAG);
+        pag->pag_ici_reclaimable++;
 }
 
 /*
@@ -710,6 +719,7 @@ __xfs_inode_clear_reclaim_tag(
 {
         radix_tree_tag_clear(&pag->pag_ici_root,
                         XFS_INO_TO_AGINO(mp, ip->i_ino), XFS_ICI_RECLAIM_TAG);
+        pag->pag_ici_reclaimable--;
 }
 
 STATIC int
@@ -770,5 +780,88 @@ xfs_reclaim_inodes(
         int             mode)
 {
         return xfs_inode_ag_iterator(mp, xfs_reclaim_inode, mode,
-                                        XFS_ICI_RECLAIM_TAG, 1);
+                                        XFS_ICI_RECLAIM_TAG, 1, NULL);
+}
+
+/*
+ * Shrinker infrastructure.
+ *
+ * This is all far more complex than it needs to be. It adds a global list of
+ * mounts because the shrinkers can only call a global context. We need to make
+ * the shrinkers pass a context to avoid the need for global state.
+ */
+static LIST_HEAD(xfs_mount_list);
+static struct rw_semaphore xfs_mount_list_lock;
+
+static int
+xfs_reclaim_inode_shrink(
+        int             nr_to_scan,
+        gfp_t           gfp_mask)
+{
+        struct xfs_mount *mp;
+        xfs_agnumber_t  ag;
+        int             reclaimable = 0;
+
+        if (nr_to_scan) {
+                if (!(gfp_mask & __GFP_FS))
+                        return -1;
+
+                down_read(&xfs_mount_list_lock);
+                list_for_each_entry(mp, &xfs_mount_list, m_mplist) {
+                        xfs_inode_ag_iterator(mp, xfs_reclaim_inode, 0,
+                                        XFS_ICI_RECLAIM_TAG, 1, &nr_to_scan);
+                        if (nr_to_scan <= 0)
+                                break;
+                }
+                up_read(&xfs_mount_list_lock);
+        }
+
+        down_read(&xfs_mount_list_lock);
+        list_for_each_entry(mp, &xfs_mount_list, m_mplist) {
+                for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
+
+                        if (!mp->m_perag[ag].pag_ici_init)
+                                continue;
+                        reclaimable += mp->m_perag[ag].pag_ici_reclaimable;
+                }
+        }
+        up_read(&xfs_mount_list_lock);
+        return reclaimable;
+}
+
+static struct shrinker xfs_inode_shrinker = {
+        .shrink = xfs_reclaim_inode_shrink,
+        .seeks = DEFAULT_SEEKS,
+};
+
+void __init
+xfs_inode_shrinker_init(void)
+{
+        init_rwsem(&xfs_mount_list_lock);
+        register_shrinker(&xfs_inode_shrinker);
+}
+
+void
+xfs_inode_shrinker_destroy(void)
+{
+        ASSERT(list_empty(&xfs_mount_list));
+        unregister_shrinker(&xfs_inode_shrinker);
+}
+
+void
+xfs_inode_shrinker_register(
+        struct xfs_mount        *mp)
+{
+        down_write(&xfs_mount_list_lock);
+        list_add_tail(&mp->m_mplist, &xfs_mount_list);
+        up_write(&xfs_mount_list_lock);
+}
+
+void
+xfs_inode_shrinker_unregister(
+        struct xfs_mount        *mp)
+{
+        down_write(&xfs_mount_list_lock);
+        list_del(&mp->m_mplist);
+        up_write(&xfs_mount_list_lock);
 }