1 files changed, 346 insertions, 102 deletions

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: