8 files changed, 678 insertions, 135 deletions

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index d0b0e43a6a8b..93b1aa932014 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -153,6 +153,7 @@ struct btrfs_inode {
         unsigned ordered_data_close:1;
         unsigned orphan_meta_reserved:1;
         unsigned dummy_inode:1;
+        unsigned in_defrag:1;
 
         /*
          * always compress this one file
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 026fc47b42cf..332323e19dd1 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1074,6 +1074,11 @@ struct btrfs_fs_info {
         /* all metadata allocations go through this cluster */
         struct btrfs_free_cluster meta_alloc_cluster;
 
+        /* auto defrag inodes go here */
+        spinlock_t defrag_inodes_lock;
+        struct rb_root defrag_inodes;
+        atomic_t defrag_running;
+
         spinlock_t ref_cache_lock;
         u64 total_ref_cache_size;
 
@@ -1205,6 +1210,38 @@ struct btrfs_root {
         struct super_block anon_super;
 };
 
+struct btrfs_ioctl_defrag_range_args {
+        /* start of the defrag operation */
+        __u64 start;
+
+        /* number of bytes to defrag, use (u64)-1 to say all */
+        __u64 len;
+
+        /*
+         * flags for the operation, which can include turning
+         * on compression for this one defrag
+         */
+        __u64 flags;
+
+        /*
+         * any extent bigger than this will be considered
+         * already defragged.  Use 0 to take the kernel default
+         * Use 1 to say every single extent must be rewritten
+         */
+        __u32 extent_thresh;
+
+        /*
+         * which compression method to use if turning on compression
+         * for this defrag operation.  If unspecified, zlib will
+         * be used
+         */
+        __u32 compress_type;
+
+        /* spare for later */
+        __u32 unused[4];
+};
+
+
 /*
  * inode items have the data typically returned from stat and store other
  * info about object characteristics.  There is one for every file and dir in
@@ -1302,6 +1339,7 @@ struct btrfs_root {
 #define BTRFS_MOUNT_CLEAR_CACHE         (1 << 13)
 #define BTRFS_MOUNT_USER_SUBVOL_RM_ALLOWED (1 << 14)
 #define BTRFS_MOUNT_ENOSPC_DEBUG         (1 << 15)
+#define BTRFS_MOUNT_AUTO_DEFRAG         (1 << 16)
 
 #define btrfs_clear_opt(o, opt)         ((o) &= ~BTRFS_MOUNT_##opt)
 #define btrfs_set_opt(o, opt)           ((o) |= BTRFS_MOUNT_##opt)
@@ -2528,8 +2566,13 @@ extern const struct dentry_operations btrfs_dentry_operations;
 long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 void btrfs_update_iflags(struct inode *inode);
 void btrfs_inherit_iflags(struct inode *inode, struct inode *dir);
-
+int btrfs_defrag_file(struct inode *inode, struct file *file,
+                      struct btrfs_ioctl_defrag_range_args *range,
+                      u64 newer_than, unsigned long max_pages);
 /* file.c */
+int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
+                           struct inode *inode);
+int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info);
 int btrfs_sync_file(struct file *file, int datasync);
 int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                             int skip_pinned);
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 16d335b342a2..b2588a552658 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1475,6 +1475,7 @@ static int cleaner_kthread(void *arg)
                         btrfs_run_delayed_iputs(root);
                         btrfs_clean_old_snapshots(root);
                         mutex_unlock(&root->fs_info->cleaner_mutex);
+                        btrfs_run_defrag_inodes(root->fs_info);
                 }
 
                 if (freezing(current)) {
@@ -1616,6 +1617,7 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         spin_lock_init(&fs_info->ref_cache_lock);
         spin_lock_init(&fs_info->fs_roots_radix_lock);
         spin_lock_init(&fs_info->delayed_iput_lock);
+        spin_lock_init(&fs_info->defrag_inodes_lock);
 
         init_completion(&fs_info->kobj_unregister);
         fs_info->tree_root = tree_root;
@@ -1638,9 +1640,11 @@ struct btrfs_root *open_ctree(struct super_block *sb,
         atomic_set(&fs_info->async_delalloc_pages, 0);
         atomic_set(&fs_info->async_submit_draining, 0);
         atomic_set(&fs_info->nr_async_bios, 0);
+        atomic_set(&fs_info->defrag_running, 0);
         fs_info->sb = sb;
         fs_info->max_inline = 8192 * 1024;
         fs_info->metadata_ratio = 0;
+        fs_info->defrag_inodes = RB_ROOT;
 
         fs_info->thread_pool_size = min_t(unsigned long,
                                           num_online_cpus() + 2, 8);
@@ -2501,6 +2505,14 @@ int close_ctree(struct btrfs_root *root)
         smp_mb();
 
         btrfs_scrub_cancel(root);
+
+        /* wait for any defraggers to finish */
+        wait_event(fs_info->transaction_wait,
+                   (atomic_read(&fs_info->defrag_running) == 0));
+
+        /* clear out the rbtree of defraggable inodes */
+        btrfs_run_defrag_inodes(root->fs_info);
+
         btrfs_put_block_group_cache(fs_info);
 
         /*
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 58ddc4442159..c6a22d783c35 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -40,6 +40,263 @@
 #include "locking.h"
 #include "compat.h"
 
+/*
+ * when auto defrag is enabled we
+ * queue up these defrag structs to remember which
+ * inodes need defragging passes
+ */
+struct inode_defrag {
+        struct rb_node rb_node;
+        /* objectid */
+        u64 ino;
+        /*
+         * transid where the defrag was added, we search for
+         * extents newer than this
+         */
+        u64 transid;
+
+        /* root objectid */
+        u64 root;
+
+        /* last offset we were able to defrag */
+        u64 last_offset;
+
+        /* if we've wrapped around back to zero once already */
+        int cycled;
+};
+
+/* pop a record for an inode into the defrag tree.  The lock
+ * must be held already
+ *
+ * If you're inserting a record for an older transid than an
+ * existing record, the transid already in the tree is lowered
+ *
+ * If an existing record is found the defrag item you
+ * pass in is freed
+ */
+static int __btrfs_add_inode_defrag(struct inode *inode,
+                                    struct inode_defrag *defrag)
+{
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct inode_defrag *entry;
+        struct rb_node **p;
+        struct rb_node *parent = NULL;
+
+        p = &root->fs_info->defrag_inodes.rb_node;
+        while (*p) {
+                parent = *p;
+                entry = rb_entry(parent, struct inode_defrag, rb_node);
+
+                if (defrag->ino < entry->ino)
+                        p = &parent->rb_left;
+                else if (defrag->ino > entry->ino)
+                        p = &parent->rb_right;
+                else {
+                        /* if we're reinserting an entry for
+                         * an old defrag run, make sure to
+                         * lower the transid of our existing record
+                         */
+                        if (defrag->transid < entry->transid)
+                                entry->transid = defrag->transid;
+                        if (defrag->last_offset > entry->last_offset)
+                                entry->last_offset = defrag->last_offset;
+                        goto exists;
+                }
+        }
+        BTRFS_I(inode)->in_defrag = 1;
+        rb_link_node(&defrag->rb_node, parent, p);
+        rb_insert_color(&defrag->rb_node, &root->fs_info->defrag_inodes);
+        return 0;
+
+exists:
+        kfree(defrag);
+        return 0;
+
+}
+
+/*
+ * insert a defrag record for this inode if auto defrag is
+ * enabled
+ */
+int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
+                           struct inode *inode)
+{
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct inode_defrag *defrag;
+        int ret = 0;
+        u64 transid;
+
+        if (!btrfs_test_opt(root, AUTO_DEFRAG))
+                return 0;
+
+        if (root->fs_info->closing)
+                return 0;
+
+        if (BTRFS_I(inode)->in_defrag)
+                return 0;
+
+        if (trans)
+                transid = trans->transid;
+        else
+                transid = BTRFS_I(inode)->root->last_trans;
+
+        defrag = kzalloc(sizeof(*defrag), GFP_NOFS);
+        if (!defrag)
+                return -ENOMEM;
+
+        defrag->ino = inode->i_ino;
+        defrag->transid = transid;
+        defrag->root = root->root_key.objectid;
+
+        spin_lock(&root->fs_info->defrag_inodes_lock);
+        if (!BTRFS_I(inode)->in_defrag)
+                ret = __btrfs_add_inode_defrag(inode, defrag);
+        spin_unlock(&root->fs_info->defrag_inodes_lock);
+        return ret;
+}
+
+/*
+ * must be called with the defrag_inodes lock held
+ */
+struct inode_defrag *btrfs_find_defrag_inode(struct btrfs_fs_info *info, u64 ino,
+                                             struct rb_node **next)
+{
+        struct inode_defrag *entry = NULL;
+        struct rb_node *p;
+        struct rb_node *parent = NULL;
+
+        p = info->defrag_inodes.rb_node;
+        while (p) {
+                parent = p;
+                entry = rb_entry(parent, struct inode_defrag, rb_node);
+
+                if (ino < entry->ino)
+                        p = parent->rb_left;
+                else if (ino > entry->ino)
+                        p = parent->rb_right;
+                else
+                        return entry;
+        }
+
+        if (next) {
+                while (parent && ino > entry->ino) {
+                        parent = rb_next(parent);
+                        entry = rb_entry(parent, struct inode_defrag, rb_node);
+                }
+                *next = parent;
+        }
+        return NULL;
+}
+
+/*
+ * run through the list of inodes in the FS that need
+ * defragging
+ */
+int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
+{
+        struct inode_defrag *defrag;
+        struct btrfs_root *inode_root;
+        struct inode *inode;
+        struct rb_node *n;
+        struct btrfs_key key;
+        struct btrfs_ioctl_defrag_range_args range;
+        u64 first_ino = 0;
+        int num_defrag;
+        int defrag_batch = 1024;
+
+        memset(&range, 0, sizeof(range));
+        range.len = (u64)-1;
+
+        atomic_inc(&fs_info->defrag_running);
+        spin_lock(&fs_info->defrag_inodes_lock);
+        while(1) {
+                n = NULL;
+
+                /* find an inode to defrag */
+                defrag = btrfs_find_defrag_inode(fs_info, first_ino, &n);
+                if (!defrag) {
+                        if (n)
+                                defrag = rb_entry(n, struct inode_defrag, rb_node);
+                        else if (first_ino) {
+                                first_ino = 0;
+                                continue;
+                        } else {
+                                break;
+                        }
+                }
+
+                /* remove it from the rbtree */
+                first_ino = defrag->ino + 1;
+                rb_erase(&defrag->rb_node, &fs_info->defrag_inodes);
+
+                if (fs_info->closing)
+                        goto next_free;
+
+                spin_unlock(&fs_info->defrag_inodes_lock);
+
+                /* get the inode */
+                key.objectid = defrag->root;
+                btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
+                key.offset = (u64)-1;
+                inode_root = btrfs_read_fs_root_no_name(fs_info, &key);
+                if (IS_ERR(inode_root))
+                        goto next;
+
+                key.objectid = defrag->ino;
+                btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
+                key.offset = 0;
+
+                inode = btrfs_iget(fs_info->sb, &key, inode_root, NULL);
+                if (IS_ERR(inode))
+                        goto next;
+
+                /* do a chunk of defrag */
+                BTRFS_I(inode)->in_defrag = 0;
+                range.start = defrag->last_offset;
+                num_defrag = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
+                                               defrag_batch);
+                /*
+                 * if we filled the whole defrag batch, there
+                 * must be more work to do.  Queue this defrag
+                 * again
+                 */
+                if (num_defrag == defrag_batch) {
+                        defrag->last_offset = range.start;
+                        __btrfs_add_inode_defrag(inode, defrag);
+                        /*
+                         * we don't want to kfree defrag, we added it back to
+                         * the rbtree
+                         */
+                        defrag = NULL;
+                } else if (defrag->last_offset && !defrag->cycled) {
+                        /*
+                         * we didn't fill our defrag batch, but
+                         * we didn't start at zero.  Make sure we loop
+                         * around to the start of the file.
+                         */
+                        defrag->last_offset = 0;
+                        defrag->cycled = 1;
+                        __btrfs_add_inode_defrag(inode, defrag);
+                        defrag = NULL;
+                }
+
+                iput(inode);
+next:
+                spin_lock(&fs_info->defrag_inodes_lock);
+next_free:
+                kfree(defrag);
+        }
+        spin_unlock(&fs_info->defrag_inodes_lock);
+
+        atomic_dec(&fs_info->defrag_running);
+
+        /*
+         * during unmount, we use the transaction_wait queue to
+         * wait for the defragger to stop
+         */
+        wake_up(&fs_info->transaction_wait);
+        return 0;
+}
 
 /* simple helper to fault in pages and copy.  This should go away
  * and be replaced with calls into generic code.
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d378f8b70ef7..bb51bb1fa44f 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -342,6 +342,10 @@ static noinline int compress_file_range(struct inode *inode,
         int will_compress;
         int compress_type = root->fs_info->compress_type;
 
+        /* if this is a small write inside eof, kick off a defragbot */
+        if (end <= BTRFS_I(inode)->disk_i_size && (end - start + 1) < 16 * 1024)
+                btrfs_add_inode_defrag(NULL, inode);
+
         actual_end = min_t(u64, isize, end + 1);
 again:
         will_compress = 0;
@@ -799,6 +803,10 @@ static noinline int cow_file_range(struct inode *inode,
         disk_num_bytes = num_bytes;
         ret = 0;
 
+        /* if this is a small write inside eof, kick off defrag */
+        if (end <= BTRFS_I(inode)->disk_i_size && num_bytes < 64 * 1024)
+                btrfs_add_inode_defrag(trans, inode);
+
         if (start == 0) {
                 /* lets try to make an inline extent */
                 ret = cow_file_range_inline(trans, root, inode,
@@ -5371,6 +5379,9 @@ static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
         if (IS_ERR(trans))
                 return ERR_CAST(trans);
 
+        if (start <= BTRFS_I(inode)->disk_i_size && len < 64 * 1024)
+                btrfs_add_inode_defrag(trans, inode);
+
         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
 
         alloc_hint = get_extent_allocation_hint(inode, start, len);
@@ -6682,6 +6693,7 @@ struct inode *btrfs_alloc_inode(struct super_block *sb)
         ei->ordered_data_close = 0;
         ei->orphan_meta_reserved = 0;
         ei->dummy_inode = 0;
+        ei->in_defrag = 0;
         ei->force_compress = BTRFS_COMPRESS_NONE;
 
         ei->delayed_node = NULL;
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index c4f17e4e2c9c..85e818ce00c5 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -656,6 +656,106 @@ out_unlock:
         return error;
 }
 
+/*
+ * When we're defragging a range, we don't want to kick it off again
+ * if it is really just waiting for delalloc to send it down.
+ * If we find a nice big extent or delalloc range for the bytes in the
+ * file you want to defrag, we return 0 to let you know to skip this
+ * part of the file
+ */
+static int check_defrag_in_cache(struct inode *inode, u64 offset, int thresh)
+{
+        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+        struct extent_map *em = NULL;
+        struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+        u64 end;
+
+        read_lock(&em_tree->lock);
+        em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
+        read_unlock(&em_tree->lock);
+
+        if (em) {
+                end = extent_map_end(em);
+                free_extent_map(em);
+                if (end - offset > thresh)
+                        return 0;
+        }
+        /* if we already have a nice delalloc here, just stop */
+        thresh /= 2;
+        end = count_range_bits(io_tree, &offset, offset + thresh,
+                               thresh, EXTENT_DELALLOC, 1);
+        if (end >= thresh)
+                return 0;
+        return 1;
+}
+
+/*
+ * helper function to walk through a file and find extents
+ * newer than a specific transid, and smaller than thresh.
+ *
+ * This is used by the defragging code to find new and small
+ * extents
+ */
+static int find_new_extents(struct btrfs_root *root,
+                            struct inode *inode, u64 newer_than,
+                            u64 *off, int thresh)
+{
+        struct btrfs_path *path;
+        struct btrfs_key min_key;
+        struct btrfs_key max_key;
+        struct extent_buffer *leaf;
+        struct btrfs_file_extent_item *extent;
+        int type;
+        int ret;
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+
+        min_key.objectid = inode->i_ino;
+        min_key.type = BTRFS_EXTENT_DATA_KEY;
+        min_key.offset = *off;
+
+        max_key.objectid = inode->i_ino;
+        max_key.type = (u8)-1;
+        max_key.offset = (u64)-1;
+
+        path->keep_locks = 1;
+
+        while(1) {
+                ret = btrfs_search_forward(root, &min_key, &max_key,
+                                           path, 0, newer_than);
+                if (ret != 0)
+                        goto none;
+                if (min_key.objectid != inode->i_ino)
+                        goto none;
+                if (min_key.type != BTRFS_EXTENT_DATA_KEY)
+                        goto none;
+
+                leaf = path->nodes[0];
+                extent = btrfs_item_ptr(leaf, path->slots[0],
+                                        struct btrfs_file_extent_item);
+
+                type = btrfs_file_extent_type(leaf, extent);
+                if (type == BTRFS_FILE_EXTENT_REG &&
+                    btrfs_file_extent_num_bytes(leaf, extent) < thresh &&
+                    check_defrag_in_cache(inode, min_key.offset, thresh)) {
+                        *off = min_key.offset;
+                        btrfs_free_path(path);
+                        return 0;
+                }
+
+                if (min_key.offset == (u64)-1)
+                        goto none;
+
+                min_key.offset++;
+                btrfs_release_path(path);
+        }
+none:
+        btrfs_free_path(path);
+        return -ENOENT;
+}
+
 static int should_defrag_range(struct inode *inode, u64 start, u64 len,
                                int thresh, u64 *last_len, u64 *skip,
                                u64 *defrag_end)
@@ -665,10 +765,6 @@ static int should_defrag_range(struct inode *inode, u64 start, u64 len,
         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
         int ret = 1;
 
-
-        if (thresh == 0)
-                thresh = 256 * 1024;
-
         /*
          * make sure that once we start defragging and extent, we keep on
          * defragging it
@@ -727,27 +823,176 @@ static int should_defrag_range(struct inode *inode, u64 start, u64 len,
         return ret;
 }
 
-static int btrfs_defrag_file(struct file *file,
-                             struct btrfs_ioctl_defrag_range_args *range)
+/*
+ * it doesn't do much good to defrag one or two pages
+ * at a time.  This pulls in a nice chunk of pages
+ * to COW and defrag.
+ *
+ * It also makes sure the delalloc code has enough
+ * dirty data to avoid making new small extents as part
+ * of the defrag
+ *
+ * It's a good idea to start RA on this range
+ * before calling this.
+ */
+static int cluster_pages_for_defrag(struct inode *inode,
+                                    struct page **pages,
+                                    unsigned long start_index,
+                                    int num_pages)
 {
-        struct inode *inode = fdentry(file)->d_inode;
-        struct btrfs_root *root = BTRFS_I(inode)->root;
-        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+        unsigned long file_end;
+        u64 isize = i_size_read(inode);
+        u64 page_start;
+        u64 page_end;
+        int ret;
+        int i;
+        int i_done;
         struct btrfs_ordered_extent *ordered;
-        struct page *page;
+        struct extent_state *cached_state = NULL;
+
+        if (isize == 0)
+                return 0;
+        file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
+
+        ret = btrfs_delalloc_reserve_space(inode,
+                                           num_pages << PAGE_CACHE_SHIFT);
+        if (ret)
+                return ret;
+again:
+        ret = 0;
+        i_done = 0;
+
+        /* step one, lock all the pages */
+        for (i = 0; i < num_pages; i++) {
+                struct page *page;
+                page = grab_cache_page(inode->i_mapping,
+                                            start_index + i);
+                if (!page)
+                        break;
+
+                if (!PageUptodate(page)) {
+                        btrfs_readpage(NULL, page);
+                        lock_page(page);
+                        if (!PageUptodate(page)) {
+                                unlock_page(page);
+                                page_cache_release(page);
+                                ret = -EIO;
+                                break;
+                        }
+                }
+                isize = i_size_read(inode);
+                file_end = (isize - 1) >> PAGE_CACHE_SHIFT;
+                if (!isize || page->index > file_end ||
+                    page->mapping != inode->i_mapping) {
+                        /* whoops, we blew past eof, skip this page */
+                        unlock_page(page);
+                        page_cache_release(page);
+                        break;
+                }
+                pages[i] = page;
+                i_done++;
+        }
+        if (!i_done || ret)
+                goto out;
+
+        if (!(inode->i_sb->s_flags & MS_ACTIVE))
+                goto out;
+
+        /*
+         * so now we have a nice long stream of locked
+         * and up to date pages, lets wait on them
+         */
+        for (i = 0; i < i_done; i++)
+                wait_on_page_writeback(pages[i]);
+
+        page_start = page_offset(pages[0]);
+        page_end = page_offset(pages[i_done - 1]) + PAGE_CACHE_SIZE;
+
+        lock_extent_bits(&BTRFS_I(inode)->io_tree,
+                         page_start, page_end - 1, 0, &cached_state,
+                         GFP_NOFS);
+        ordered = btrfs_lookup_first_ordered_extent(inode, page_end - 1);
+        if (ordered &&
+            ordered->file_offset + ordered->len > page_start &&
+            ordered->file_offset < page_end) {
+                btrfs_put_ordered_extent(ordered);
+                unlock_extent_cached(&BTRFS_I(inode)->io_tree,
+                                     page_start, page_end - 1,
+                                     &cached_state, GFP_NOFS);
+                for (i = 0; i < i_done; i++) {
+                        unlock_page(pages[i]);
+                        page_cache_release(pages[i]);
+                }
+                btrfs_wait_ordered_range(inode, page_start,
+                                         page_end - page_start);
+                goto again;
+        }
+        if (ordered)
+                btrfs_put_ordered_extent(ordered);
+
+        clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start,
+                          page_end - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
+                          EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
+                          GFP_NOFS);
+
+        if (i_done != num_pages) {
+                atomic_inc(&BTRFS_I(inode)->outstanding_extents);
+                btrfs_delalloc_release_space(inode,
+                                     (num_pages - i_done) << PAGE_CACHE_SHIFT);
+        }
+
+
+        btrfs_set_extent_delalloc(inode, page_start, page_end - 1,
+                                  &cached_state);
+
+        unlock_extent_cached(&BTRFS_I(inode)->io_tree,
+                             page_start, page_end - 1, &cached_state,
+                             GFP_NOFS);
+
+        for (i = 0; i < i_done; i++) {
+                clear_page_dirty_for_io(pages[i]);
+                ClearPageChecked(pages[i]);
+                set_page_extent_mapped(pages[i]);
+                set_page_dirty(pages[i]);
+                unlock_page(pages[i]);
+                page_cache_release(pages[i]);
+        }
+        return i_done;
+out:
+        for (i = 0; i < i_done; i++) {
+                unlock_page(pages[i]);
+                page_cache_release(pages[i]);
+        }
+        btrfs_delalloc_release_space(inode, num_pages << PAGE_CACHE_SHIFT);
+        return ret;
+
+}
+
+int btrfs_defrag_file(struct inode *inode, struct file *file,
+                      struct btrfs_ioctl_defrag_range_args *range,
+                      u64 newer_than, unsigned long max_to_defrag)
+{
+        struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_super_block *disk_super;
+        struct file_ra_state *ra = NULL;
         unsigned long last_index;
-        unsigned long ra_pages = root->fs_info->bdi.ra_pages;
-        unsigned long total_read = 0;
         u64 features;
-        u64 page_start;
-        u64 page_end;
         u64 last_len = 0;
         u64 skip = 0;
         u64 defrag_end = 0;
+        u64 newer_off = range->start;
+        int newer_left = 0;
         unsigned long i;
         int ret;
+        int defrag_count = 0;
         int compress_type = BTRFS_COMPRESS_ZLIB;
+        int extent_thresh = range->extent_thresh;
+        int newer_cluster = (256 * 1024) >> PAGE_CACHE_SHIFT;
+        u64 new_align = ~((u64)128 * 1024 - 1);
+        struct page **pages = NULL;
+
+        if (extent_thresh == 0)
+                extent_thresh = 256 * 1024;
 
         if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS) {
                 if (range->compress_type > BTRFS_COMPRESS_TYPES)
@@ -759,6 +1004,27 @@ static int btrfs_defrag_file(struct file *file,
         if (inode->i_size == 0)
                 return 0;
 
+        /*
+         * if we were not given a file, allocate a readahead
+         * context
+         */
+        if (!file) {
+                ra = kzalloc(sizeof(*ra), GFP_NOFS);
+                if (!ra)
+                        return -ENOMEM;
+                file_ra_state_init(ra, inode->i_mapping);
+        } else {
+                ra = &file->f_ra;
+        }
+
+        pages = kmalloc(sizeof(struct page *) * newer_cluster,
+                        GFP_NOFS);
+        if (!pages) {
+                ret = -ENOMEM;
+                goto out_ra;
+        }
+
+        /* find the last page to defrag */
         if (range->start + range->len > range->start) {
                 last_index = min_t(u64, inode->i_size - 1,
                          range->start + range->len - 1) >> PAGE_CACHE_SHIFT;
@@ -766,11 +1032,37 @@ static int btrfs_defrag_file(struct file *file,
                 last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT;
         }
 
-        i = range->start >> PAGE_CACHE_SHIFT;
-        while (i <= last_index) {
-                if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
+        if (newer_than) {
+                ret = find_new_extents(root, inode, newer_than,
+                                       &newer_off, 64 * 1024);
+                if (!ret) {
+                        range->start = newer_off;
+                        /*
+                         * we always align our defrag to help keep
+                         * the extents in the file evenly spaced
+                         */
+                        i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
+                        newer_left = newer_cluster;
+                } else
+                        goto out_ra;
+        } else {
+                i = range->start >> PAGE_CACHE_SHIFT;
+        }
+        if (!max_to_defrag)
+                max_to_defrag = last_index - 1;
+
+        while (i <= last_index && defrag_count < max_to_defrag) {
+                /*
+                 * make sure we stop running if someone unmounts
+                 * the FS
+                 */
+                if (!(inode->i_sb->s_flags & MS_ACTIVE))
+                        break;
+
+                if (!newer_than &&
+                    !should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
                                         PAGE_CACHE_SIZE,
-                                        range->extent_thresh,
+                                        extent_thresh,
                                         &last_len, &skip,
                                         &defrag_end)) {
                         unsigned long next;
@@ -782,92 +1074,39 @@ static int btrfs_defrag_file(struct file *file,
                         i = max(i + 1, next);
                         continue;
                 }
-
-                if (total_read % ra_pages == 0) {
-                        btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
-                                       min(last_index, i + ra_pages - 1));
-                }
-                total_read++;
-                mutex_lock(&inode->i_mutex);
                 if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
                         BTRFS_I(inode)->force_compress = compress_type;
 
-                ret  = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
-                if (ret)
-                        goto err_unlock;
-again:
-                if (inode->i_size == 0 ||
-                    i > ((inode->i_size - 1) >> PAGE_CACHE_SHIFT)) {
-                        ret = 0;
-                        goto err_reservations;
-                }
+                btrfs_force_ra(inode->i_mapping, ra, file, i, newer_cluster);
 
-                page = grab_cache_page(inode->i_mapping, i);
-                if (!page) {
-                        ret = -ENOMEM;
-                        goto err_reservations;
-                }
-
-                if (!PageUptodate(page)) {
-                        btrfs_readpage(NULL, page);
-                        lock_page(page);
-                        if (!PageUptodate(page)) {
-                                unlock_page(page);
-                                page_cache_release(page);
-                                ret = -EIO;
-                                goto err_reservations;
-                        }
-                }
-
-                if (page->mapping != inode->i_mapping) {
-                        unlock_page(page);
-                        page_cache_release(page);
-                        goto again;
-                }
-
-                wait_on_page_writeback(page);
+                ret = cluster_pages_for_defrag(inode, pages, i, newer_cluster);
+                if (ret < 0)
+                        goto out_ra;
 
-                if (PageDirty(page)) {
-                        btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
-                        goto loop_unlock;
-                }
+                defrag_count += ret;
+                balance_dirty_pages_ratelimited_nr(inode->i_mapping, ret);
+                i += ret;
 
-                page_start = (u64)page->index << PAGE_CACHE_SHIFT;
-                page_end = page_start + PAGE_CACHE_SIZE - 1;
-                lock_extent(io_tree, page_start, page_end, GFP_NOFS);
+                if (newer_than) {
+                        if (newer_off == (u64)-1)
+                                break;
 
-                ordered = btrfs_lookup_ordered_extent(inode, page_start);
-                if (ordered) {
-                        unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
-                        unlock_page(page);
-                        page_cache_release(page);
-                        btrfs_start_ordered_extent(inode, ordered, 1);
-                        btrfs_put_ordered_extent(ordered);
-                        goto again;
+                        newer_off = max(newer_off + 1,
+                                        (u64)i << PAGE_CACHE_SHIFT);
+
+                        ret = find_new_extents(root, inode,
+                                               newer_than, &newer_off,
+                                               64 * 1024);
+                        if (!ret) {
+                                range->start = newer_off;
+                                i = (newer_off & new_align) >> PAGE_CACHE_SHIFT;
+                                newer_left = newer_cluster;
+                        } else {
+                                break;
+                        }
+                } else {
+                        i++;
                 }
-                set_page_extent_mapped(page);
-
-                /*
-                 * this makes sure page_mkwrite is called on the
-                 * page if it is dirtied again later
-                 */
-                clear_page_dirty_for_io(page);
-                clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start,
-                                  page_end, EXTENT_DIRTY | EXTENT_DELALLOC |
-                                  EXTENT_DO_ACCOUNTING, GFP_NOFS);
-
-                btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
-                ClearPageChecked(page);
-                set_page_dirty(page);
-                unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
-
-loop_unlock:
-                unlock_page(page);
-                page_cache_release(page);
-                mutex_unlock(&inode->i_mutex);
-
-                balance_dirty_pages_ratelimited_nr(inode->i_mapping, 1);
-                i++;
         }
 
         if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO))
@@ -899,12 +1138,14 @@ loop_unlock:
                 btrfs_set_super_incompat_flags(disk_super, features);
         }
 
-        return 0;
+        if (!file)
+                kfree(ra);
+        return defrag_count;
 
-err_reservations:
-        btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
-err_unlock:
-        mutex_unlock(&inode->i_mutex);
+out_ra:
+        if (!file)
+                kfree(ra);
+        kfree(pages);
         return ret;
 }
 
@@ -1756,7 +1997,10 @@ static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
                         /* the rest are all set to zero by kzalloc */
                         range->len = (u64)-1;
                 }
-                ret = btrfs_defrag_file(file, range);
+                ret = btrfs_defrag_file(fdentry(file)->d_inode, file,
+                                        range, 0, 0);
+                if (ret > 0)
+                        ret = 0;
                 kfree(range);
                 break;
         default:
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index e5e0ee2cad4e..ad1ea789fcb4 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -181,37 +181,6 @@ struct btrfs_ioctl_clone_range_args {
 #define BTRFS_DEFRAG_RANGE_COMPRESS 1
 #define BTRFS_DEFRAG_RANGE_START_IO 2
 
-struct btrfs_ioctl_defrag_range_args {
-        /* start of the defrag operation */
-        __u64 start;
-
-        /* number of bytes to defrag, use (u64)-1 to say all */
-        __u64 len;
-
-        /*
-         * flags for the operation, which can include turning
-         * on compression for this one defrag
-         */
-        __u64 flags;
-
-        /*
-         * any extent bigger than this will be considered
-         * already defragged.  Use 0 to take the kernel default
-         * Use 1 to say every single extent must be rewritten
-         */
-        __u32 extent_thresh;
-
-        /*
-         * which compression method to use if turning on compression
-         * for this defrag operation.  If unspecified, zlib will
-         * be used
-         */
-        __u32 compress_type;
-
-        /* spare for later */
-        __u32 unused[4];
-};
-
 struct btrfs_ioctl_space_info {
         __u64 flags;
         __u64 total_bytes;
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index cd0c7cd2c8fb..28e3cb2607ff 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -160,7 +160,7 @@ enum {
         Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
         Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
         Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
-        Opt_enospc_debug, Opt_subvolrootid, Opt_err,
+        Opt_enospc_debug, Opt_subvolrootid, Opt_defrag, Opt_err,
 };
 
 static match_table_t tokens = {
@@ -191,6 +191,7 @@ static match_table_t tokens = {
         {Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
         {Opt_enospc_debug, "enospc_debug"},
         {Opt_subvolrootid, "subvolrootid=%d"},
+        {Opt_defrag, "autodefrag"},
         {Opt_err, NULL},
 };
 
@@ -369,6 +370,10 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                 case Opt_enospc_debug:
                         btrfs_set_opt(info->mount_opt, ENOSPC_DEBUG);
                         break;
+                case Opt_defrag:
+                        printk(KERN_INFO "btrfs: enabling auto defrag");
+                        btrfs_set_opt(info->mount_opt, AUTO_DEFRAG);
+                        break;
                 case Opt_err:
                         printk(KERN_INFO "btrfs: unrecognized mount option "
                                "'%s'\n", p);