btrfs: make lock_and_cleanup_extent_if_need nowait compatible

Add the nowait parameter to lock_and_cleanup_extent_if_need(). If the
nowait parameter is specified we try to lock the extent in nowait mode.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Stefan Roesch <shr@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 2181b549df4eda69b3773aed62258825f6c04860..5113e3d60f78668140a26e07c4dc7f24d824a291 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1439,7 +1439,7 @@ static noinline int
 lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
                                size_t num_pages, loff_t pos,
                                size_t write_bytes,
-                               u64 *lockstart, u64 *lockend,
+                               u64 *lockstart, u64 *lockend, bool nowait,
                                struct extent_state **cached_state)
 {
        struct btrfs_fs_info *fs_info = inode->root->fs_info;
@@ -1454,7 +1454,20 @@ lock_and_cleanup_extent_if_need(struct btrfs_inode *inode, struct page **pages,
        if (start_pos < inode->vfs_inode.i_size) {
                struct btrfs_ordered_extent *ordered;
 
-               lock_extent(&inode->io_tree, start_pos, last_pos, cached_state);
+               if (nowait) {
+                       if (!try_lock_extent(&inode->io_tree, start_pos, last_pos)) {
+                               for (i = 0; i < num_pages; i++) {
+                                       unlock_page(pages[i]);
+                                       put_page(pages[i]);
+                                       pages[i] = NULL;
+                               }
+
+                               return -EAGAIN;
+                       }
+               } else {
+                       lock_extent(&inode->io_tree, start_pos, last_pos, cached_state);
+               }
+
                ordered = btrfs_lookup_ordered_range(inode, start_pos,
                                                     last_pos - start_pos + 1);
                if (ordered &&
@@ -1752,7 +1765,7 @@ again:
                extents_locked = lock_and_cleanup_extent_if_need(
                                BTRFS_I(inode), pages,
                                num_pages, pos, write_bytes, &lockstart,
-                               &lockend, &cached_state);
+                               &lockend, false, &cached_state);
                if (extents_locked < 0) {
                        if (extents_locked == -EAGAIN)
                                goto again;