Btrfs: introduce btrfs_{start, end}_nocow_write() for each subvolume

[firefly-linux-kernel-4.4.55.git] / fs / btrfs / file.c

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index d88f2dc4d045d757e39befe387f8d9a07095ad83..006cf9f0e8520b5ee935387a97aa956b44dd2311 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1410,6 +1410,10 @@ static noinline int check_can_nocow(struct inode *inode, loff_t pos,
        u64 num_bytes;
        int ret;
 
+       ret = btrfs_start_nocow_write(root);
+       if (!ret)
+               return -ENOSPC;
+
        lockstart = round_down(pos, root->sectorsize);
        lockend = round_up(pos + *write_bytes, root->sectorsize) - 1;
 
@@ -1427,11 +1431,13 @@ static noinline int check_can_nocow(struct inode *inode, loff_t pos,
 
        num_bytes = lockend - lockstart + 1;
        ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, NULL, NULL);
-       if (ret <= 0)
+       if (ret <= 0) {
                ret = 0;
-       else
+               btrfs_end_nocow_write(root);
+       } else {
                *write_bytes = min_t(size_t, *write_bytes ,
                                     num_bytes - pos + lockstart);
+       }
 
        unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
 
@@ -1520,6 +1526,8 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
                        if (!only_release_metadata)
                                btrfs_free_reserved_data_space(inode,
                                                               reserve_bytes);
+                       else
+                               btrfs_end_nocow_write(root);
                        break;
                }
 
@@ -1608,6 +1616,9 @@ again:
                }
 
                release_bytes = 0;
+               if (only_release_metadata)
+                       btrfs_end_nocow_write(root);
+
                if (only_release_metadata && copied > 0) {
                        u64 lockstart = round_down(pos, root->sectorsize);
                        u64 lockend = lockstart +
@@ -1634,10 +1645,12 @@ again:
        kfree(pages);
 
        if (release_bytes) {
-               if (only_release_metadata)
+               if (only_release_metadata) {
+                       btrfs_end_nocow_write(root);
                        btrfs_delalloc_release_metadata(inode, release_bytes);
-               else
+               } else {
                        btrfs_delalloc_release_space(inode, release_bytes);
+               }
        }
 
        return num_written ? num_written : ret;