Btrfs: Fix disk_i_size update corner case

There are some cases file extents are inserted without involving
ordered struct. In these cases, we update disk_i_size directly,
without checking pending ordered extent and DELALLOC bit. This
patch extends btrfs_ordered_update_i_size() to handle these cases.

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

1 files changed, 44 insertions, 27 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index ef250be49cdb..fa57247887e3 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -188,8 +188,18 @@ static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
         btrfs_mark_buffer_dirty(leaf);
         btrfs_free_path(path);
 
+        /*
+         * we're an inline extent, so nobody can
+         * extend the file past i_size without locking
+         * a page we already have locked.
+         *
+         * We must do any isize and inode updates
+         * before we unlock the pages.  Otherwise we
+         * could end up racing with unlink.
+         */
         BTRFS_I(inode)->disk_i_size = inode->i_size;
         btrfs_update_inode(trans, root, inode);
+
         return 0;
 fail:
         btrfs_free_path(path);
@@ -415,7 +425,6 @@ again:
                                                     start, end,
                                                     total_compressed, pages);
                 }
-                btrfs_end_transaction(trans, root);
                 if (ret == 0) {
                         /*
                          * inline extent creation worked, we don't need
@@ -429,9 +438,11 @@ again:
                              EXTENT_CLEAR_DELALLOC |
                              EXTENT_CLEAR_ACCOUNTING |
                              EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
-                        ret = 0;
+
+                        btrfs_end_transaction(trans, root);
                         goto free_pages_out;
                 }
+                btrfs_end_transaction(trans, root);
         }
 
         if (will_compress) {
@@ -542,7 +553,6 @@ static noinline int submit_compressed_extents(struct inode *inode,
         if (list_empty(&async_cow->extents))
                 return 0;
 
-        trans = btrfs_join_transaction(root, 1);
 
         while (!list_empty(&async_cow->extents)) {
                 async_extent = list_entry(async_cow->extents.next,
@@ -589,19 +599,15 @@ retry:
                 lock_extent(io_tree, async_extent->start,
                             async_extent->start + async_extent->ram_size - 1,
                             GFP_NOFS);
-                /*
-                 * here we're doing allocation and writeback of the
-                 * compressed pages
-                 */
-                btrfs_drop_extent_cache(inode, async_extent->start,
-                                        async_extent->start +
-                                        async_extent->ram_size - 1, 0);
 
+                trans = btrfs_join_transaction(root, 1);
                 ret = btrfs_reserve_extent(trans, root,
                                            async_extent->compressed_size,
                                            async_extent->compressed_size,
                                            0, alloc_hint,
                                            (u64)-1, &ins, 1);
+                btrfs_end_transaction(trans, root);
+
                 if (ret) {
                         int i;
                         for (i = 0; i < async_extent->nr_pages; i++) {
@@ -617,6 +623,14 @@ retry:
                         goto retry;
                 }
 
+                /*
+                 * here we're doing allocation and writeback of the
+                 * compressed pages
+                 */
+                btrfs_drop_extent_cache(inode, async_extent->start,
+                                        async_extent->start +
+                                        async_extent->ram_size - 1, 0);
+
                 em = alloc_extent_map(GFP_NOFS);
                 em->start = async_extent->start;
                 em->len = async_extent->ram_size;
@@ -648,8 +662,6 @@ retry:
                                                BTRFS_ORDERED_COMPRESSED);
                 BUG_ON(ret);
 
-                btrfs_end_transaction(trans, root);
-
                 /*
                  * clear dirty, set writeback and unlock the pages.
                  */
@@ -671,13 +683,11 @@ retry:
                                     async_extent->nr_pages);
 
                 BUG_ON(ret);
-                trans = btrfs_join_transaction(root, 1);
                 alloc_hint = ins.objectid + ins.offset;
                 kfree(async_extent);
                 cond_resched();
         }
 
-        btrfs_end_transaction(trans, root);
         return 0;
 }
 
@@ -741,6 +751,7 @@ static noinline int cow_file_range(struct inode *inode,
                                      EXTENT_CLEAR_DIRTY |
                                      EXTENT_SET_WRITEBACK |
                                      EXTENT_END_WRITEBACK);
+
                         *nr_written = *nr_written +
                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
                         *page_started = 1;
@@ -1727,18 +1738,27 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
                 }
         }
 
-        trans = btrfs_join_transaction(root, 1);
-
         if (!ordered_extent)
                 ordered_extent = btrfs_lookup_ordered_extent(inode, start);
         BUG_ON(!ordered_extent);
-        if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags))
-                goto nocow;
+        if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
+                BUG_ON(!list_empty(&ordered_extent->list));
+                ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
+                if (!ret) {
+                        trans = btrfs_join_transaction(root, 1);
+                        ret = btrfs_update_inode(trans, root, inode);
+                        BUG_ON(ret);
+                        btrfs_end_transaction(trans, root);
+                }
+                goto out;
+        }
 
         lock_extent(io_tree, ordered_extent->file_offset,
                     ordered_extent->file_offset + ordered_extent->len - 1,
                     GFP_NOFS);
 
+        trans = btrfs_join_transaction(root, 1);
+
         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
                 compressed = 1;
         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
@@ -1765,22 +1785,20 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
         unlock_extent(io_tree, ordered_extent->file_offset,
                     ordered_extent->file_offset + ordered_extent->len - 1,
                     GFP_NOFS);
-nocow:
         add_pending_csums(trans, inode, ordered_extent->file_offset,
                           &ordered_extent->list);
 
-        mutex_lock(&BTRFS_I(inode)->extent_mutex);
-        btrfs_ordered_update_i_size(inode, ordered_extent);
-        btrfs_update_inode(trans, root, inode);
-        btrfs_remove_ordered_extent(inode, ordered_extent);
-        mutex_unlock(&BTRFS_I(inode)->extent_mutex);
-
+        /* this also removes the ordered extent from the tree */
+        btrfs_ordered_update_i_size(inode, 0, ordered_extent);
+        ret = btrfs_update_inode(trans, root, inode);
+        BUG_ON(ret);
+        btrfs_end_transaction(trans, root);
+out:
         /* once for us */
         btrfs_put_ordered_extent(ordered_extent);
         /* once for the tree */
         btrfs_put_ordered_extent(ordered_extent);
 
-        btrfs_end_transaction(trans, root);
         return 0;
 }
 
@@ -3562,7 +3580,6 @@ static noinline void init_btrfs_i(struct inode *inode)
         INIT_LIST_HEAD(&BTRFS_I(inode)->ordered_operations);
         RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
         btrfs_ordered_inode_tree_init(&BTRFS_I(inode)->ordered_tree);
-        mutex_init(&BTRFS_I(inode)->extent_mutex);
         mutex_init(&BTRFS_I(inode)->log_mutex);
 }