Btrfs: Pre-allocate space for data relocation

Pre-allocate space for data relocation. This can detect ENOPSC
condition caused by fragmentation of free space.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

3 files changed, 92 insertions, 45 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index fc324f9fcb42..65530837d04b 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2420,6 +2420,9 @@ int btrfs_cont_expand(struct inode *inode, loff_t size);
 int btrfs_invalidate_inodes(struct btrfs_root *root);
 void btrfs_add_delayed_iput(struct inode *inode);
 void btrfs_run_delayed_iputs(struct btrfs_root *root);
+int btrfs_prealloc_file_range(struct inode *inode, int mode,
+                              u64 start, u64 num_bytes, u64 min_size,
+                              loff_t actual_len, u64 *alloc_hint);
 extern const struct dentry_operations btrfs_dentry_operations;
 
 /* ioctl.c */
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index bef69bedf3cf..460dd512eebd 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1175,6 +1175,13 @@ out_check:
                                                num_bytes, num_bytes, type);
                 BUG_ON(ret);
 
+                if (root->root_key.objectid ==
+                    BTRFS_DATA_RELOC_TREE_OBJECTID) {
+                        ret = btrfs_reloc_clone_csums(inode, cur_offset,
+                                                      num_bytes);
+                        BUG_ON(ret);
+                }
+
                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
                                 cur_offset, cur_offset + num_bytes - 1,
                                 locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
@@ -6080,16 +6087,15 @@ out_unlock:
         return err;
 }
 
-static int prealloc_file_range(struct inode *inode, u64 start, u64 end,
-                        u64 alloc_hint, int mode, loff_t actual_len)
+int btrfs_prealloc_file_range(struct inode *inode, int mode,
+                              u64 start, u64 num_bytes, u64 min_size,
+                              loff_t actual_len, u64 *alloc_hint)
 {
         struct btrfs_trans_handle *trans;
         struct btrfs_root *root = BTRFS_I(inode)->root;
         struct btrfs_key ins;
         u64 cur_offset = start;
-        u64 num_bytes = end - start;
         int ret = 0;
-        u64 i_size;
 
         while (num_bytes > 0) {
                 trans = btrfs_start_transaction(root, 3);
@@ -6098,9 +6104,8 @@ static int prealloc_file_range(struct inode *inode, u64 start, u64 end,
                         break;
                 }
 
-                ret = btrfs_reserve_extent(trans, root, num_bytes,
-                                           root->sectorsize, 0, alloc_hint,
-                                           (u64)-1, &ins, 1);
+                ret = btrfs_reserve_extent(trans, root, num_bytes, min_size,
+                                           0, *alloc_hint, (u64)-1, &ins, 1);
                 if (ret) {
                         btrfs_end_transaction(trans, root);
                         break;
@@ -6117,20 +6122,19 @@ static int prealloc_file_range(struct inode *inode, u64 start, u64 end,
 
                 num_bytes -= ins.offset;
                 cur_offset += ins.offset;
-                alloc_hint = ins.objectid + ins.offset;
+                *alloc_hint = ins.objectid + ins.offset;
 
                 inode->i_ctime = CURRENT_TIME;
                 BTRFS_I(inode)->flags |= BTRFS_INODE_PREALLOC;
                 if (!(mode & FALLOC_FL_KEEP_SIZE) &&
-                        (actual_len > inode->i_size) &&
-                        (cur_offset > inode->i_size)) {
-
+                    (actual_len > inode->i_size) &&
+                    (cur_offset > inode->i_size)) {
                         if (cur_offset > actual_len)
-                                i_size  = actual_len;
+                                i_size_write(inode, actual_len);
                         else
-                                i_size = cur_offset;
-                        i_size_write(inode, i_size);
-                        btrfs_ordered_update_i_size(inode, i_size, NULL);
+                                i_size_write(inode, cur_offset);
+                        i_size_write(inode, cur_offset);
+                        btrfs_ordered_update_i_size(inode, cur_offset, NULL);
                 }
 
                 ret = btrfs_update_inode(trans, root, inode);
@@ -6216,16 +6220,16 @@ static long btrfs_fallocate(struct inode *inode, int mode,
                 if (em->block_start == EXTENT_MAP_HOLE ||
                     (cur_offset >= inode->i_size &&
                      !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
-                        ret = prealloc_file_range(inode,
-                                                  cur_offset, last_byte,
-                                                alloc_hint, mode, offset+len);
+                        ret = btrfs_prealloc_file_range(inode, 0, cur_offset,
+                                                        last_byte - cur_offset,
+                                                        1 << inode->i_blkbits,
+                                                        offset + len,
+                                                        &alloc_hint);
                         if (ret < 0) {
                                 free_extent_map(em);
                                 break;
                         }
                 }
-                if (em->block_start <= EXTENT_MAP_LAST_BYTE)
-                        alloc_hint = em->block_start;
                 free_extent_map(em);
 
                 cur_offset = last_byte;
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c
index 145a468c300d..3943526b7348 100644
--- a/fs/btrfs/relocation.c
+++ b/fs/btrfs/relocation.c
@@ -2546,6 +2546,50 @@ out:
 }
 
 static noinline_for_stack
+int prealloc_file_extent_cluster(struct inode *inode,
+                                 struct file_extent_cluster *cluster)
+{
+        u64 alloc_hint = 0;
+        u64 start;
+        u64 end;
+        u64 offset = BTRFS_I(inode)->index_cnt;
+        u64 num_bytes;
+        int nr = 0;
+        int ret = 0;
+
+        BUG_ON(cluster->start != cluster->boundary[0]);
+        mutex_lock(&inode->i_mutex);
+
+        ret = btrfs_check_data_free_space(inode, cluster->end +
+                                          1 - cluster->start);
+        if (ret)
+                goto out;
+
+        while (nr < cluster->nr) {
+                start = cluster->boundary[nr] - offset;
+                if (nr + 1 < cluster->nr)
+                        end = cluster->boundary[nr + 1] - 1 - offset;
+                else
+                        end = cluster->end - offset;
+
+                lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
+                num_bytes = end + 1 - start;
+                ret = btrfs_prealloc_file_range(inode, 0, start,
+                                                num_bytes, num_bytes,
+                                                end + 1, &alloc_hint);
+                unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
+                if (ret)
+                        break;
+                nr++;
+        }
+        btrfs_free_reserved_data_space(inode, cluster->end +
+                                       1 - cluster->start);
+out:
+        mutex_unlock(&inode->i_mutex);
+        return ret;
+}
+
+static noinline_for_stack
 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
                          u64 block_start)
 {
@@ -2588,7 +2632,6 @@ static int relocate_file_extent_cluster(struct inode *inode,
         u64 offset = BTRFS_I(inode)->index_cnt;
         unsigned long index;
         unsigned long last_index;
-        unsigned int dirty_page = 0;
         struct page *page;
         struct file_ra_state *ra;
         int nr = 0;
@@ -2601,21 +2644,24 @@ static int relocate_file_extent_cluster(struct inode *inode,
         if (!ra)
                 return -ENOMEM;
 
-        index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
-        last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
+        ret = prealloc_file_extent_cluster(inode, cluster);
+        if (ret)
+                goto out;
 
-        mutex_lock(&inode->i_mutex);
+        file_ra_state_init(ra, inode->i_mapping);
 
-        i_size_write(inode, cluster->end + 1 - offset);
         ret = setup_extent_mapping(inode, cluster->start - offset,
                                    cluster->end - offset, cluster->start);
         if (ret)
-                goto out_unlock;
-
-        file_ra_state_init(ra, inode->i_mapping);
+                goto out;
 
-        WARN_ON(cluster->start != cluster->boundary[0]);
+        index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
+        last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
         while (index <= last_index) {
+                ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
+                if (ret)
+                        goto out;
+
                 page = find_lock_page(inode->i_mapping, index);
                 if (!page) {
                         page_cache_sync_readahead(inode->i_mapping,
@@ -2623,8 +2669,10 @@ static int relocate_file_extent_cluster(struct inode *inode,
                                                   last_index + 1 - index);
                         page = grab_cache_page(inode->i_mapping, index);
                         if (!page) {
+                                btrfs_delalloc_release_metadata(inode,
+                                                        PAGE_CACHE_SIZE);
                                 ret = -ENOMEM;
-                                goto out_unlock;
+                                goto out;
                         }
                 }
 
@@ -2640,8 +2688,10 @@ static int relocate_file_extent_cluster(struct inode *inode,
                         if (!PageUptodate(page)) {
                                 unlock_page(page);
                                 page_cache_release(page);
+                                btrfs_delalloc_release_metadata(inode,
+                                                        PAGE_CACHE_SIZE);
                                 ret = -EIO;
-                                goto out_unlock;
+                                goto out;
                         }
                 }
 
@@ -2660,10 +2710,9 @@ static int relocate_file_extent_cluster(struct inode *inode,
                                         EXTENT_BOUNDARY, GFP_NOFS);
                         nr++;
                 }
-                btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
 
+                btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
                 set_page_dirty(page);
-                dirty_page++;
 
                 unlock_extent(&BTRFS_I(inode)->io_tree,
                               page_start, page_end, GFP_NOFS);
@@ -2671,20 +2720,11 @@ static int relocate_file_extent_cluster(struct inode *inode,
                 page_cache_release(page);
 
                 index++;
-                if (nr < cluster->nr &&
-                    page_end + 1 + offset == cluster->boundary[nr]) {
-                        balance_dirty_pages_ratelimited_nr(inode->i_mapping,
-                                                           dirty_page);
-                        dirty_page = 0;
-                }
-        }
-        if (dirty_page) {
-                balance_dirty_pages_ratelimited_nr(inode->i_mapping,
-                                                   dirty_page);
+                balance_dirty_pages_ratelimited(inode->i_mapping);
+                btrfs_throttle(BTRFS_I(inode)->root);
         }
         WARN_ON(nr != cluster->nr);
-out_unlock:
-        mutex_unlock(&inode->i_mutex);
+out:
         kfree(ra);
         return ret;
 }