6 files changed, 230 insertions, 31 deletions

diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
index b05ce6642919..f71658adddb5 100644
--- a/fs/ocfs2/localalloc.c
+++ b/fs/ocfs2/localalloc.c
@@ -73,16 +73,51 @@ static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
 static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
                                           struct inode *local_alloc_inode);
 
+static inline int ocfs2_la_state_enabled(struct ocfs2_super *osb)
+{
+        return (osb->local_alloc_state == OCFS2_LA_THROTTLED ||
+                osb->local_alloc_state == OCFS2_LA_ENABLED);
+}
+
+void ocfs2_local_alloc_seen_free_bits(struct ocfs2_super *osb,
+                                      unsigned int num_clusters)
+{
+        spin_lock(&osb->osb_lock);
+        if (osb->local_alloc_state == OCFS2_LA_DISABLED ||
+            osb->local_alloc_state == OCFS2_LA_THROTTLED)
+                if (num_clusters >= osb->local_alloc_default_bits) {
+                        cancel_delayed_work(&osb->la_enable_wq);
+                        osb->local_alloc_state = OCFS2_LA_ENABLED;
+                }
+        spin_unlock(&osb->osb_lock);
+}
+
+void ocfs2_la_enable_worker(struct work_struct *work)
+{
+        struct ocfs2_super *osb =
+                container_of(work, struct ocfs2_super,
+                             la_enable_wq.work);
+        spin_lock(&osb->osb_lock);
+        osb->local_alloc_state = OCFS2_LA_ENABLED;
+        spin_unlock(&osb->osb_lock);
+}
+
 /*
  * Tell us whether a given allocation should use the local alloc
  * file. Otherwise, it has to go to the main bitmap.
+ *
+ * This function does semi-dirty reads of local alloc size and state!
+ * This is ok however, as the values are re-checked once under mutex.
  */
 int ocfs2_alloc_should_use_local(struct ocfs2_super *osb, u64 bits)
 {
-        int la_bits = osb->local_alloc_bits;
         int ret = 0;
+        int la_bits;
+
+        spin_lock(&osb->osb_lock);
+        la_bits = osb->local_alloc_bits;
 
-        if (osb->local_alloc_state != OCFS2_LA_ENABLED)
+        if (!ocfs2_la_state_enabled(osb))
                 goto bail;
 
         /* la_bits should be at least twice the size (in clusters) of
@@ -96,6 +131,7 @@ int ocfs2_alloc_should_use_local(struct ocfs2_super *osb, u64 bits)
 bail:
         mlog(0, "state=%d, bits=%llu, la_bits=%d, ret=%d\n",
              osb->local_alloc_state, (unsigned long long)bits, la_bits, ret);
+        spin_unlock(&osb->osb_lock);
         return ret;
 }
 
@@ -208,6 +244,9 @@ void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb)
 
         mlog_entry_void();
 
+        cancel_delayed_work(&osb->la_enable_wq);
+        flush_workqueue(ocfs2_wq);
+
         if (osb->local_alloc_state == OCFS2_LA_UNUSED)
                 goto out;
 
@@ -445,7 +484,7 @@ out:
 }
 
 /*
- * make sure we've got at least bitswanted contiguous bits in the
+ * make sure we've got at least bits_wanted contiguous bits in the
  * local alloc. You lose them when you drop i_mutex.
  *
  * We will add ourselves to the transaction passed in, but may start
@@ -476,16 +515,18 @@ int ocfs2_reserve_local_alloc_bits(struct ocfs2_super *osb,
 
         mutex_lock(&local_alloc_inode->i_mutex);
 
-        if (osb->local_alloc_state != OCFS2_LA_ENABLED) {
-                status = -ENOSPC;
-                goto bail;
-        }
-
-        if (bits_wanted > osb->local_alloc_bits) {
-                mlog(0, "Asking for more than my max window size!\n");
+        /*
+         * We must double check state and allocator bits because
+         * another process may have changed them while holding i_mutex.
+         */
+        spin_lock(&osb->osb_lock);
+        if (!ocfs2_la_state_enabled(osb) ||
+            (bits_wanted > osb->local_alloc_bits)) {
+                spin_unlock(&osb->osb_lock);
                 status = -ENOSPC;
                 goto bail;
         }
+        spin_unlock(&osb->osb_lock);
 
         alloc = (struct ocfs2_dinode *) osb->local_alloc_bh->b_data;
 
@@ -513,6 +554,21 @@ int ocfs2_reserve_local_alloc_bits(struct ocfs2_super *osb,
                                 mlog_errno(status);
                         goto bail;
                 }
+
+                /*
+                 * Under certain conditions, the window slide code
+                 * might have reduced the number of bits available or
+                 * disabled the the local alloc entirely. Re-check
+                 * here and return -ENOSPC if necessary.
+                 */
+                status = -ENOSPC;
+                if (!ocfs2_la_state_enabled(osb))
+                        goto bail;
+
+                free_bits = le32_to_cpu(alloc->id1.bitmap1.i_total) -
+                        le32_to_cpu(alloc->id1.bitmap1.i_used);
+                if (bits_wanted > free_bits)
+                        goto bail;
         }
 
         ac->ac_inode = local_alloc_inode;
@@ -780,6 +836,85 @@ bail:
         return status;
 }
 
+enum ocfs2_la_event {
+        OCFS2_LA_EVENT_SLIDE,           /* Normal window slide. */
+        OCFS2_LA_EVENT_FRAGMENTED,      /* The global bitmap has
+                                         * enough bits theoretically
+                                         * free, but a contiguous
+                                         * allocation could not be
+                                         * found. */
+        OCFS2_LA_EVENT_ENOSPC,          /* Global bitmap doesn't have
+                                         * enough bits free to satisfy
+                                         * our request. */
+};
+#define OCFS2_LA_ENABLE_INTERVAL (30 * HZ)
+/*
+ * Given an event, calculate the size of our next local alloc window.
+ *
+ * This should always be called under i_mutex of the local alloc inode
+ * so that local alloc disabling doesn't race with processes trying to
+ * use the allocator.
+ *
+ * Returns the state which the local alloc was left in. This value can
+ * be ignored by some paths.
+ */
+static int ocfs2_recalc_la_window(struct ocfs2_super *osb,
+                                  enum ocfs2_la_event event)
+{
+        unsigned int bits;
+        int state;
+
+        spin_lock(&osb->osb_lock);
+        if (osb->local_alloc_state == OCFS2_LA_DISABLED) {
+                WARN_ON_ONCE(osb->local_alloc_state == OCFS2_LA_DISABLED);
+                goto out_unlock;
+        }
+
+        /*
+         * ENOSPC and fragmentation are treated similarly for now.
+         */
+        if (event == OCFS2_LA_EVENT_ENOSPC ||
+            event == OCFS2_LA_EVENT_FRAGMENTED) {
+                /*
+                 * We ran out of contiguous space in the primary
+                 * bitmap. Drastically reduce the number of bits used
+                 * by local alloc until we have to disable it.
+                 */
+                bits = osb->local_alloc_bits >> 1;
+                if (bits > ocfs2_megabytes_to_clusters(osb->sb, 1)) {
+                        /*
+                         * By setting state to THROTTLED, we'll keep
+                         * the number of local alloc bits used down
+                         * until an event occurs which would give us
+                         * reason to assume the bitmap situation might
+                         * have changed.
+                         */
+                        osb->local_alloc_state = OCFS2_LA_THROTTLED;
+                        osb->local_alloc_bits = bits;
+                } else {
+                        osb->local_alloc_state = OCFS2_LA_DISABLED;
+                }
+                queue_delayed_work(ocfs2_wq, &osb->la_enable_wq,
+                                   OCFS2_LA_ENABLE_INTERVAL);
+                goto out_unlock;
+        }
+
+        /*
+         * Don't increase the size of the local alloc window until we
+         * know we might be able to fulfill the request. Otherwise, we
+         * risk bouncing around the global bitmap during periods of
+         * low space.
+         */
+        if (osb->local_alloc_state != OCFS2_LA_THROTTLED)
+                osb->local_alloc_bits = osb->local_alloc_default_bits;
+
+out_unlock:
+        state = osb->local_alloc_state;
+        spin_unlock(&osb->osb_lock);
+
+        return state;
+}
+
 static int ocfs2_local_alloc_reserve_for_window(struct ocfs2_super *osb,
                                                 struct ocfs2_alloc_context **ac,
                                                 struct inode **bitmap_inode,
@@ -794,12 +929,21 @@ static int ocfs2_local_alloc_reserve_for_window(struct ocfs2_super *osb,
                 goto bail;
         }
 
+retry_enospc:
         (*ac)->ac_bits_wanted = osb->local_alloc_bits;
 
         status = ocfs2_reserve_cluster_bitmap_bits(osb, *ac);
+        if (status == -ENOSPC) {
+                if (ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_ENOSPC) ==
+                    OCFS2_LA_DISABLED)
+                        goto bail;
+
+                ocfs2_free_ac_resource(*ac);
+                memset(*ac, 0, sizeof(struct ocfs2_alloc_context));
+                goto retry_enospc;
+        }
         if (status < 0) {
-                if (status != -ENOSPC)
-                        mlog_errno(status);
+                mlog_errno(status);
                 goto bail;
         }
 
@@ -852,6 +996,34 @@ static int ocfs2_local_alloc_new_window(struct ocfs2_super *osb,
          * the more specific cluster api to claim bits. */
         status = ocfs2_claim_clusters(osb, handle, ac, osb->local_alloc_bits,
                                       &cluster_off, &cluster_count);
+        if (status == -ENOSPC) {
+retry_enospc:
+                /*
+                 * Note: We could also try syncing the journal here to
+                 * allow use of any free bits which the current
+                 * transaction can't give us access to. --Mark
+                 */
+                if (ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_FRAGMENTED) ==
+                    OCFS2_LA_DISABLED)
+                        goto bail;
+
+                status = ocfs2_claim_clusters(osb, handle, ac,
+                                              osb->local_alloc_bits,
+                                              &cluster_off,
+                                              &cluster_count);
+                if (status == -ENOSPC)
+                        goto retry_enospc;
+                /*
+                 * We only shrunk the *minimum* number of in our
+                 * request - it's entirely possible that the allocator
+                 * might give us more than we asked for.
+                 */
+                if (status == 0) {
+                        spin_lock(&osb->osb_lock);
+                        osb->local_alloc_bits = cluster_count;
+                        spin_unlock(&osb->osb_lock);
+                }
+        }
         if (status < 0) {
                 if (status != -ENOSPC)
                         mlog_errno(status);
@@ -895,6 +1067,8 @@ static int ocfs2_local_alloc_slide_window(struct ocfs2_super *osb,
 
         mlog_entry_void();
 
+        ocfs2_recalc_la_window(osb, OCFS2_LA_EVENT_SLIDE);
+
         /* This will lock the main bitmap for us. */
         status = ocfs2_local_alloc_reserve_for_window(osb,
                                                       &ac,
diff --git a/fs/ocfs2/localalloc.h b/fs/ocfs2/localalloc.h
index 3f76631e110c..ac5ea9f86653 100644
--- a/fs/ocfs2/localalloc.h
+++ b/fs/ocfs2/localalloc.h
@@ -52,4 +52,8 @@ int ocfs2_claim_local_alloc_bits(struct ocfs2_super *osb,
                                  u32 *bit_off,
                                  u32 *num_bits);
 
+void ocfs2_local_alloc_seen_free_bits(struct ocfs2_super *osb,
+                                      unsigned int num_clusters);
+void ocfs2_la_enable_worker(struct work_struct *work);
+
 #endif /* OCFS2_LOCALALLOC_H */
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 43dd42e313a1..4d6e200a4843 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -171,9 +171,13 @@ struct ocfs2_alloc_stats
 
 enum ocfs2_local_alloc_state
 {
-        OCFS2_LA_UNUSED = 0,
-        OCFS2_LA_ENABLED,
-        OCFS2_LA_DISABLED
+        OCFS2_LA_UNUSED = 0,    /* Local alloc will never be used for
+                                 * this mountpoint. */
+        OCFS2_LA_ENABLED,       /* Local alloc is in use. */
+        OCFS2_LA_THROTTLED,     /* Local alloc is in use, but number
+                                 * of bits has been reduced. */
+        OCFS2_LA_DISABLED       /* Local alloc has temporarily been
+                                 * disabled. */
 };
 
 enum ocfs2_mount_options
@@ -252,9 +256,20 @@ struct ocfs2_super
         struct ocfs2_journal *journal;
         unsigned long osb_commit_interval;
 
+        struct delayed_work             la_enable_wq;
+
+        /*
+         * Must hold local alloc i_mutex and osb->osb_lock to change
+         * local_alloc_bits. Reads can be done under either lock.
+         */
         unsigned int local_alloc_bits;
-        enum ocfs2_local_alloc_state local_alloc_state;
+        unsigned int local_alloc_default_bits;
+
+        enum ocfs2_local_alloc_state local_alloc_state; /* protected
+                                                         * by osb_lock */
+
         struct buffer_head *local_alloc_bh;
+
         u64 la_last_gd;
 
         /* Next two fields are for local node slot recovery during
diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index d2d278fb9819..de7b93d76d12 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -111,7 +111,7 @@ static inline void ocfs2_block_to_cluster_group(struct inode *inode,
                                                 u64 *bg_blkno,
                                                 u16 *bg_bit_off);
 
-static void ocfs2_free_ac_resource(struct ocfs2_alloc_context *ac)
+void ocfs2_free_ac_resource(struct ocfs2_alloc_context *ac)
 {
         struct inode *inode = ac->ac_inode;
 
@@ -686,15 +686,6 @@ int ocfs2_reserve_clusters(struct ocfs2_super *osb,
                 if ((status < 0) && (status != -ENOSPC)) {
                         mlog_errno(status);
                         goto bail;
-                } else if (status == -ENOSPC) {
-                        /* reserve_local_bits will return enospc with
-                         * the local alloc inode still locked, so we
-                         * can change this safely here. */
-                        mlog(0, "Disabling local alloc\n");
-                        /* We set to OCFS2_LA_DISABLED so that umount
-                         * can clean up what's left of the local
-                         * allocation */
-                        osb->local_alloc_state = OCFS2_LA_DISABLED;
                 }
         }
 
@@ -1005,6 +996,7 @@ static int ocfs2_cluster_group_search(struct inode *inode,
         int search = -ENOSPC;
         int ret;
         struct ocfs2_group_desc *gd = (struct ocfs2_group_desc *) group_bh->b_data;
+        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
         u16 tmp_off, tmp_found;
         unsigned int max_bits, gd_cluster_off;
 
@@ -1045,6 +1037,12 @@ static int ocfs2_cluster_group_search(struct inode *inode,
                         *bit_off = tmp_off;
                         *bits_found = tmp_found;
                         search = 0; /* success */
+                } else if (tmp_found) {
+                        /*
+                         * Don't show bits which we'll be returning
+                         * for allocation to the local alloc bitmap.
+                         */
+                        ocfs2_local_alloc_seen_free_bits(osb, tmp_found);
                 }
         }
 
@@ -1203,9 +1201,8 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac,
         status = -ENOSPC;
         /* for now, the chain search is a bit simplistic. We just use
          * the 1st group with any empty bits. */
-        while ((status = ac->ac_group_search(alloc_inode, group_bh,
-                                             bits_wanted, min_bits, bit_off,
-                                             &tmp_bits)) == -ENOSPC) {
+        while ((status = ac->ac_group_search(alloc_inode, group_bh, bits_wanted,
+                                             min_bits, bit_off, &tmp_bits)) == -ENOSPC) {
                 if (!bg->bg_next_group)
                         break;
 
@@ -1838,9 +1835,15 @@ int ocfs2_free_clusters(handle_t *handle,
         status = ocfs2_free_suballoc_bits(handle, bitmap_inode, bitmap_bh,
                                           bg_start_bit, bg_blkno,
                                           num_clusters);
-        if (status < 0)
+        if (status < 0) {
                 mlog_errno(status);
+                goto out;
+        }
+
+        ocfs2_local_alloc_seen_free_bits(OCFS2_SB(bitmap_inode->i_sb),
+                                         num_clusters);
 
+out:
         mlog_exit(status);
         return status;
 }
diff --git a/fs/ocfs2/suballoc.h b/fs/ocfs2/suballoc.h
index 544c600662bd..40d51daf5fbc 100644
--- a/fs/ocfs2/suballoc.h
+++ b/fs/ocfs2/suballoc.h
@@ -147,6 +147,7 @@ static inline int ocfs2_is_cluster_bitmap(struct inode *inode)
  * apis above. */
 int ocfs2_reserve_cluster_bitmap_bits(struct ocfs2_super *osb,
                                       struct ocfs2_alloc_context *ac);
+void ocfs2_free_ac_resource(struct ocfs2_alloc_context *ac);
 
 /* given a cluster offset, calculate which block group it belongs to
  * and return that block offset. */
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 3dee61ebd69a..a2d3dcf70252 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -637,7 +637,8 @@ static int ocfs2_fill_super(struct super_block *sb, void *data, int silent)
         osb->s_atime_quantum = parsed_options.atime_quantum;
         osb->preferred_slot = parsed_options.slot;
         osb->osb_commit_interval = parsed_options.commit_interval;
-        osb->local_alloc_bits = ocfs2_megabytes_to_clusters(sb, parsed_options.localalloc_opt);
+        osb->local_alloc_default_bits = ocfs2_megabytes_to_clusters(sb, parsed_options.localalloc_opt);
+        osb->local_alloc_bits = osb->local_alloc_default_bits;
 
         status = ocfs2_verify_userspace_stack(osb, &parsed_options);
         if (status)
@@ -1425,6 +1426,7 @@ static int ocfs2_initialize_super(struct super_block *sb,
 
         osb->local_alloc_state = OCFS2_LA_UNUSED;
         osb->local_alloc_bh = NULL;
+        INIT_DELAYED_WORK(&osb->la_enable_wq, ocfs2_la_enable_worker);
 
         init_waitqueue_head(&osb->osb_mount_event);