1 files changed, 25 insertions, 8 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 9ed17dbe5c6e..f19e1259a971 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -123,7 +123,10 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 
         end_of_last_block = start_pos + num_bytes - 1;
-        btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
+        err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
+        if (err)
+                return err;
+
         for (i = 0; i < num_pages; i++) {
                 struct page *p = pages[i];
                 SetPageUptodate(p);
@@ -917,21 +920,35 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
         start_pos = pos;
 
         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+
+        /* do the reserve before the mutex lock in case we have to do some
+         * flushing.  We wouldn't deadlock, but this is more polite.
+         */
+        err = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
+        if (err)
+                goto out_nolock;
+
+        mutex_lock(&inode->i_mutex);
+
         current->backing_dev_info = inode->i_mapping->backing_dev_info;
         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
         if (err)
-                goto out_nolock;
+                goto out;
+
         if (count == 0)
-                goto out_nolock;
+                goto out;
 
         err = file_remove_suid(file);
         if (err)
-                goto out_nolock;
+                goto out;
+
         file_update_time(file);
 
         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
 
-        mutex_lock(&inode->i_mutex);
+        /* generic_write_checks can change our pos */
+        start_pos = pos;
+
         BTRFS_I(inode)->sequence++;
         first_index = pos >> PAGE_CACHE_SHIFT;
         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
@@ -1005,9 +1022,8 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                 }
 
                 if (will_write) {
-                        btrfs_fdatawrite_range(inode->i_mapping, pos,
-                                               pos + write_bytes - 1,
-                                               WB_SYNC_ALL);
+                        filemap_fdatawrite_range(inode->i_mapping, pos,
+                                                 pos + write_bytes - 1);
                 } else {
                         balance_dirty_pages_ratelimited_nr(inode->i_mapping,
                                                            num_pages);
@@ -1028,6 +1044,7 @@ out:
         mutex_unlock(&inode->i_mutex);
         if (ret)
                 err = ret;
+        btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
 
 out_nolock:
         kfree(pages);