4 files changed, 171 insertions, 88 deletions

diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index 95af6f878501..83b20fcf9400 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -104,6 +104,78 @@
 #define EXT4_MAXQUOTAS_INIT_BLOCKS(sb) (MAXQUOTAS*EXT4_QUOTA_INIT_BLOCKS(sb))
 #define EXT4_MAXQUOTAS_DEL_BLOCKS(sb) (MAXQUOTAS*EXT4_QUOTA_DEL_BLOCKS(sb))
 
+/**
+ *   struct ext4_journal_cb_entry - Base structure for callback information.
+ *
+ *   This struct is a 'seed' structure for a using with your own callback
+ *   structs. If you are using callbacks you must allocate one of these
+ *   or another struct of your own definition which has this struct
+ *   as it's first element and pass it to ext4_journal_callback_add().
+ */
+struct ext4_journal_cb_entry {
+        /* list information for other callbacks attached to the same handle */
+        struct list_head jce_list;
+
+        /*  Function to call with this callback structure */
+        void (*jce_func)(struct super_block *sb,
+                         struct ext4_journal_cb_entry *jce, int error);
+
+        /* user data goes here */
+};
+
+/**
+ * ext4_journal_callback_add: add a function to call after transaction commit
+ * @handle: active journal transaction handle to register callback on
+ * @func: callback function to call after the transaction has committed:
+ *        @sb: superblock of current filesystem for transaction
+ *        @jce: returned journal callback data
+ *        @rc: journal state at commit (0 = transaction committed properly)
+ * @jce: journal callback data (internal and function private data struct)
+ *
+ * The registered function will be called in the context of the journal thread
+ * after the transaction for which the handle was created has completed.
+ *
+ * No locks are held when the callback function is called, so it is safe to
+ * call blocking functions from within the callback, but the callback should
+ * not block or run for too long, or the filesystem will be blocked waiting for
+ * the next transaction to commit. No journaling functions can be used, or
+ * there is a risk of deadlock.
+ *
+ * There is no guaranteed calling order of multiple registered callbacks on
+ * the same transaction.
+ */
+static inline void ext4_journal_callback_add(handle_t *handle,
+                        void (*func)(struct super_block *sb,
+                                     struct ext4_journal_cb_entry *jce,
+                                     int rc),
+                        struct ext4_journal_cb_entry *jce)
+{
+        struct ext4_sb_info *sbi =
+                        EXT4_SB(handle->h_transaction->t_journal->j_private);
+
+        /* Add the jce to transaction's private list */
+        jce->jce_func = func;
+        spin_lock(&sbi->s_md_lock);
+        list_add_tail(&jce->jce_list, &handle->h_transaction->t_private_list);
+        spin_unlock(&sbi->s_md_lock);
+}
+
+/**
+ * ext4_journal_callback_del: delete a registered callback
+ * @handle: active journal transaction handle on which callback was registered
+ * @jce: registered journal callback entry to unregister
+ */
+static inline void ext4_journal_callback_del(handle_t *handle,
+                                             struct ext4_journal_cb_entry *jce)
+{
+        struct ext4_sb_info *sbi =
+                        EXT4_SB(handle->h_transaction->t_journal->j_private);
+
+        spin_lock(&sbi->s_md_lock);
+        list_del_init(&jce->jce_list);
+        spin_unlock(&sbi->s_md_lock);
+}
+
 int
 ext4_mark_iloc_dirty(handle_t *handle,
                      struct inode *inode,
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 545fa0256606..2e467718d413 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -21,6 +21,7 @@
  * mballoc.c contains the multiblocks allocation routines
  */
 
+#include "ext4_jbd2.h"
 #include "mballoc.h"
 #include <linux/debugfs.h>
 #include <linux/slab.h>
@@ -339,7 +340,7 @@
  */
 static struct kmem_cache *ext4_pspace_cachep;
 static struct kmem_cache *ext4_ac_cachep;
-static struct kmem_cache *ext4_free_ext_cachep;
+static struct kmem_cache *ext4_free_data_cachep;
 
 /* We create slab caches for groupinfo data structures based on the
  * superblock block size.  There will be one per mounted filesystem for
@@ -357,7 +358,8 @@ static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
                                         ext4_group_t group);
 static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
                                                 ext4_group_t group);
-static void release_blocks_on_commit(journal_t *journal, transaction_t *txn);
+static void ext4_free_data_callback(struct super_block *sb,
+                                struct ext4_journal_cb_entry *jce, int rc);
 
 static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
 {
@@ -2473,9 +2475,6 @@ int ext4_mb_init(struct super_block *sb, int needs_recovery)
                 proc_create_data("mb_groups", S_IRUGO, sbi->s_proc,
                                  &ext4_mb_seq_groups_fops, sb);
 
-        if (sbi->s_journal)
-                sbi->s_journal->j_commit_callback = release_blocks_on_commit;
-
         return 0;
 
 out_free_locality_groups:
@@ -2588,58 +2587,55 @@ static inline int ext4_issue_discard(struct super_block *sb,
  * This function is called by the jbd2 layer once the commit has finished,
  * so we know we can free the blocks that were released with that commit.
  */
-static void release_blocks_on_commit(journal_t *journal, transaction_t *txn)
+static void ext4_free_data_callback(struct super_block *sb,
+                                    struct ext4_journal_cb_entry *jce,
+                                    int rc)
 {
-        struct super_block *sb = journal->j_private;
+        struct ext4_free_data *entry = (struct ext4_free_data *)jce;
         struct ext4_buddy e4b;
         struct ext4_group_info *db;
         int err, count = 0, count2 = 0;
-        struct ext4_free_data *entry;
-        struct list_head *l, *ltmp;
 
-        list_for_each_safe(l, ltmp, &txn->t_private_list) {
-                entry = list_entry(l, struct ext4_free_data, list);
+        mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
+                 entry->efd_count, entry->efd_group, entry);
 
-                mb_debug(1, "gonna free %u blocks in group %u (0x%p):",
-                         entry->count, entry->group, entry);
+        if (test_opt(sb, DISCARD))
+                ext4_issue_discard(sb, entry->efd_group,
+                                   entry->efd_start_cluster, entry->efd_count);
 
-                if (test_opt(sb, DISCARD))
-                        ext4_issue_discard(sb, entry->group,
-                                           entry->start_cluster, entry->count);
+        err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
+        /* we expect to find existing buddy because it's pinned */
+        BUG_ON(err != 0);
 
-                err = ext4_mb_load_buddy(sb, entry->group, &e4b);
-                /* we expect to find existing buddy because it's pinned */
-                BUG_ON(err != 0);
 
-                db = e4b.bd_info;
-                /* there are blocks to put in buddy to make them really free */
-                count += entry->count;
-                count2++;
-                ext4_lock_group(sb, entry->group);
-                /* Take it out of per group rb tree */
-                rb_erase(&entry->node, &(db->bb_free_root));
-                mb_free_blocks(NULL, &e4b, entry->start_cluster, entry->count);
+        db = e4b.bd_info;
+        /* there are blocks to put in buddy to make them really free */
+        count += entry->efd_count;
+        count2++;
+        ext4_lock_group(sb, entry->efd_group);
+        /* Take it out of per group rb tree */
+        rb_erase(&entry->efd_node, &(db->bb_free_root));
+        mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
 
-                /*
-                 * Clear the trimmed flag for the group so that the next
-                 * ext4_trim_fs can trim it.
-                 * If the volume is mounted with -o discard, online discard
-                 * is supported and the free blocks will be trimmed online.
-                 */
-                if (!test_opt(sb, DISCARD))
-                        EXT4_MB_GRP_CLEAR_TRIMMED(db);
+        /*
+         * Clear the trimmed flag for the group so that the next
+         * ext4_trim_fs can trim it.
+         * If the volume is mounted with -o discard, online discard
+         * is supported and the free blocks will be trimmed online.
+         */
+        if (!test_opt(sb, DISCARD))
+                EXT4_MB_GRP_CLEAR_TRIMMED(db);
 
-                if (!db->bb_free_root.rb_node) {
-                        /* No more items in the per group rb tree
-                         * balance refcounts from ext4_mb_free_metadata()
-                         */
-                        page_cache_release(e4b.bd_buddy_page);
-                        page_cache_release(e4b.bd_bitmap_page);
-                }
-                ext4_unlock_group(sb, entry->group);
-                kmem_cache_free(ext4_free_ext_cachep, entry);
-                ext4_mb_unload_buddy(&e4b);
+        if (!db->bb_free_root.rb_node) {
+                /* No more items in the per group rb tree
+                 * balance refcounts from ext4_mb_free_metadata()
+                 */
+                page_cache_release(e4b.bd_buddy_page);
+                page_cache_release(e4b.bd_bitmap_page);
         }
+        ext4_unlock_group(sb, entry->efd_group);
+        kmem_cache_free(ext4_free_data_cachep, entry);
+        ext4_mb_unload_buddy(&e4b);
 
         mb_debug(1, "freed %u blocks in %u structures\n", count, count2);
 }
@@ -2692,9 +2688,9 @@ int __init ext4_init_mballoc(void)
                 return -ENOMEM;
         }
 
-        ext4_free_ext_cachep = KMEM_CACHE(ext4_free_data,
-                                          SLAB_RECLAIM_ACCOUNT);
-        if (ext4_free_ext_cachep == NULL) {
+        ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
+                                           SLAB_RECLAIM_ACCOUNT);
+        if (ext4_free_data_cachep == NULL) {
                 kmem_cache_destroy(ext4_pspace_cachep);
                 kmem_cache_destroy(ext4_ac_cachep);
                 return -ENOMEM;
@@ -2712,7 +2708,7 @@ void ext4_exit_mballoc(void)
         rcu_barrier();
         kmem_cache_destroy(ext4_pspace_cachep);
         kmem_cache_destroy(ext4_ac_cachep);
-        kmem_cache_destroy(ext4_free_ext_cachep);
+        kmem_cache_destroy(ext4_free_data_cachep);
         ext4_groupinfo_destroy_slabs();
         ext4_remove_debugfs_entry();
 }
@@ -3272,8 +3268,8 @@ static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
         n = rb_first(&(grp->bb_free_root));
 
         while (n) {
-                entry = rb_entry(n, struct ext4_free_data, node);
-                ext4_set_bits(bitmap, entry->start_cluster, entry->count);
+                entry = rb_entry(n, struct ext4_free_data, efd_node);
+                ext4_set_bits(bitmap, entry->efd_start_cluster, entry->efd_count);
                 n = rb_next(n);
         }
         return;
@@ -4379,9 +4375,9 @@ out:
 static int can_merge(struct ext4_free_data *entry1,
                         struct ext4_free_data *entry2)
 {
-        if ((entry1->t_tid == entry2->t_tid) &&
-            (entry1->group == entry2->group) &&
-            ((entry1->start_cluster + entry1->count) == entry2->start_cluster))
+        if ((entry1->efd_tid == entry2->efd_tid) &&
+            (entry1->efd_group == entry2->efd_group) &&
+            ((entry1->efd_start_cluster + entry1->efd_count) == entry2->efd_start_cluster))
                 return 1;
         return 0;
 }
@@ -4403,8 +4399,8 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
         BUG_ON(e4b->bd_bitmap_page == NULL);
         BUG_ON(e4b->bd_buddy_page == NULL);
 
-        new_node = &new_entry->node;
-        cluster = new_entry->start_cluster;
+        new_node = &new_entry->efd_node;
+        cluster = new_entry->efd_start_cluster;
 
         if (!*n) {
                 /* first free block exent. We need to
@@ -4417,10 +4413,10 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
         }
         while (*n) {
                 parent = *n;
-                entry = rb_entry(parent, struct ext4_free_data, node);
-                if (cluster < entry->start_cluster)
+                entry = rb_entry(parent, struct ext4_free_data, efd_node);
+                if (cluster < entry->efd_start_cluster)
                         n = &(*n)->rb_left;
-                else if (cluster >= (entry->start_cluster + entry->count))
+                else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
                         n = &(*n)->rb_right;
                 else {
                         ext4_grp_locked_error(sb, group, 0,
@@ -4437,34 +4433,29 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
         /* Now try to see the extent can be merged to left and right */
         node = rb_prev(new_node);
         if (node) {
-                entry = rb_entry(node, struct ext4_free_data, node);
+                entry = rb_entry(node, struct ext4_free_data, efd_node);
                 if (can_merge(entry, new_entry)) {
-                        new_entry->start_cluster = entry->start_cluster;
-                        new_entry->count += entry->count;
+                        new_entry->efd_start_cluster = entry->efd_start_cluster;
+                        new_entry->efd_count += entry->efd_count;
                         rb_erase(node, &(db->bb_free_root));
-                        spin_lock(&sbi->s_md_lock);
-                        list_del(&entry->list);
-                        spin_unlock(&sbi->s_md_lock);
-                        kmem_cache_free(ext4_free_ext_cachep, entry);
+                        ext4_journal_callback_del(handle, &entry->efd_jce);
+                        kmem_cache_free(ext4_free_data_cachep, entry);
                 }
         }
 
         node = rb_next(new_node);
         if (node) {
-                entry = rb_entry(node, struct ext4_free_data, node);
+                entry = rb_entry(node, struct ext4_free_data, efd_node);
                 if (can_merge(new_entry, entry)) {
-                        new_entry->count += entry->count;
+                        new_entry->efd_count += entry->efd_count;
                         rb_erase(node, &(db->bb_free_root));
-                        spin_lock(&sbi->s_md_lock);
-                        list_del(&entry->list);
-                        spin_unlock(&sbi->s_md_lock);
-                        kmem_cache_free(ext4_free_ext_cachep, entry);
+                        ext4_journal_callback_del(handle, &entry->efd_jce);
+                        kmem_cache_free(ext4_free_data_cachep, entry);
                 }
         }
         /* Add the extent to transaction's private list */
-        spin_lock(&sbi->s_md_lock);
-        list_add(&new_entry->list, &handle->h_transaction->t_private_list);
-        spin_unlock(&sbi->s_md_lock);
+        ext4_journal_callback_add(handle, ext4_free_data_callback,
+                                  &new_entry->efd_jce);
         return 0;
 }
 
@@ -4642,15 +4633,15 @@ do_more:
                  * blocks being freed are metadata. these blocks shouldn't
                  * be used until this transaction is committed
                  */
-                new_entry = kmem_cache_alloc(ext4_free_ext_cachep, GFP_NOFS);
+                new_entry = kmem_cache_alloc(ext4_free_data_cachep, GFP_NOFS);
                 if (!new_entry) {
                         err = -ENOMEM;
                         goto error_return;
                 }
-                new_entry->start_cluster = bit;
-                new_entry->group  = block_group;
-                new_entry->count = count_clusters;
-                new_entry->t_tid = handle->h_transaction->t_tid;
+                new_entry->efd_start_cluster = bit;
+                new_entry->efd_group = block_group;
+                new_entry->efd_count = count_clusters;
+                new_entry->efd_tid = handle->h_transaction->t_tid;
 
                 ext4_lock_group(sb, block_group);
                 mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index 47705f3285e3..7128f46d8501 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -96,21 +96,23 @@ extern u8 mb_enable_debug;
 
 
 struct ext4_free_data {
-        /* this links the free block information from group_info */
-        struct rb_node node;
+        /* MUST be the first member */
+        struct ext4_journal_cb_entry    efd_jce;
+
+        /* ext4_free_data private data starts from here */
 
-        /* this links the free block information from ext4_sb_info */
-        struct list_head list;
+        /* this links the free block information from group_info */
+        struct rb_node                  efd_node;
 
         /* group which free block extent belongs */
-        ext4_group_t group;
+        ext4_group_t                    efd_group;
 
         /* free block extent */
-        ext4_grpblk_t start_cluster;
-        ext4_grpblk_t count;
+        ext4_grpblk_t                   efd_start_cluster;
+        ext4_grpblk_t                   efd_count;
 
         /* transaction which freed this extent */
-        tid_t   t_tid;
+        tid_t                           efd_tid;
 };
 
 struct ext4_prealloc_space {
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 502c61fd7392..3e697ec7feca 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -431,6 +431,22 @@ static int block_device_ejected(struct super_block *sb)
         return bdi->dev == NULL;
 }
 
+static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
+{
+        struct super_block              *sb = journal->j_private;
+        struct ext4_sb_info             *sbi = EXT4_SB(sb);
+        int                             error = is_journal_aborted(journal);
+        struct ext4_journal_cb_entry    *jce, *tmp;
+
+        spin_lock(&sbi->s_md_lock);
+        list_for_each_entry_safe(jce, tmp, &txn->t_private_list, jce_list) {
+                list_del_init(&jce->jce_list);
+                spin_unlock(&sbi->s_md_lock);
+                jce->jce_func(sb, jce, error);
+                spin_lock(&sbi->s_md_lock);
+        }
+        spin_unlock(&sbi->s_md_lock);
+}
 
 /* Deal with the reporting of failure conditions on a filesystem such as
  * inconsistencies detected or read IO failures.
@@ -3694,6 +3710,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
         }
         set_task_ioprio(sbi->s_journal->j_task, journal_ioprio);
 
+        sbi->s_journal->j_commit_callback = ext4_journal_commit_callback;
+
         /*
          * The journal may have updated the bg summary counts, so we
          * need to update the global counters.