btrfs: plumb NOWAIT through the write path

We have everywhere setup for nowait, plumb NOWAIT through the write path.

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

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 5113e3d60f78668140a26e07c4dc7f24d824a291..805dd86d8527bed9de1d85aeb0c4460c9f58e1a8 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1652,8 +1652,9 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
        bool force_page_uptodate = false;
        loff_t old_isize = i_size_read(inode);
        unsigned int ilock_flags = 0;
+       const bool nowait = (iocb->ki_flags & IOCB_NOWAIT);
 
-       if (iocb->ki_flags & IOCB_NOWAIT)
+       if (nowait)
                ilock_flags |= BTRFS_ILOCK_TRY;
 
        ret = btrfs_inode_lock(inode, ilock_flags);
@@ -1709,17 +1710,22 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
                extent_changeset_release(data_reserved);
                ret = btrfs_check_data_free_space(BTRFS_I(inode),
                                                  &data_reserved, pos,
-                                                 write_bytes, false);
+                                                 write_bytes, nowait);
                if (ret < 0) {
                        int can_nocow;
 
+                       if (nowait && (ret == -ENOSPC || ret == -EAGAIN)) {
+                               ret = -EAGAIN;
+                               break;
+                       }
+
                        /*
                         * If we don't have to COW at the offset, reserve
                         * metadata only. write_bytes may get smaller than
                         * requested here.
                         */
                        can_nocow = btrfs_check_nocow_lock(BTRFS_I(inode), pos,
-                                                          &write_bytes, false);
+                                                          &write_bytes, nowait);
                        if (can_nocow < 0)
                                ret = can_nocow;
                        if (can_nocow > 0)
@@ -1736,7 +1742,7 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
                WARN_ON(reserve_bytes == 0);
                ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
                                                      reserve_bytes,
-                                                     reserve_bytes, false);
+                                                     reserve_bytes, nowait);
                if (ret) {
                        if (!only_release_metadata)
                                btrfs_free_reserved_data_space(BTRFS_I(inode),
@@ -1765,10 +1771,11 @@ again:
                extents_locked = lock_and_cleanup_extent_if_need(
                                BTRFS_I(inode), pages,
                                num_pages, pos, write_bytes, &lockstart,
-                               &lockend, false, &cached_state);
+                               &lockend, nowait, &cached_state);
                if (extents_locked < 0) {
-                       if (extents_locked == -EAGAIN)
+                       if (!nowait && extents_locked == -EAGAIN)
                                goto again;
+
                        btrfs_delalloc_release_extents(BTRFS_I(inode),
                                                       reserve_bytes);
                        ret = extents_locked;