From: Goldwyn Rodrigues <rgoldwyn@suse.de>
Date: Thu, 8 Apr 2021 12:40:25 +0000 (-0500)
Subject: btrfs: correct try_lock_extent() usage in read_extent_buffer_subpage()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=dc56219fe22e9d2f395f5c58ba3277f8df4cff84;p=linux.git

btrfs: correct try_lock_extent() usage in read_extent_buffer_subpage()

try_lock_extent() returns 1 on success or 0 for failure and not an error
code. If try_lock_extent() fails, read_extent_buffer_subpage() returns
zero indicating subpage extent read success.

Return EAGAIN/EWOULDBLOCK if try_lock_extent() fails in locking the
extent.

Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
---

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index dee2dafbc872f..74ba2e1a39277 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -6184,10 +6184,8 @@ static int read_extent_buffer_subpage(struct extent_buffer *eb, int wait,
 	io_tree = &BTRFS_I(fs_info->btree_inode)->io_tree;
 
 	if (wait == WAIT_NONE) {
-		ret = try_lock_extent(io_tree, eb->start,
-				      eb->start + eb->len - 1);
-		if (ret <= 0)
-			return ret;
+		if (!try_lock_extent(io_tree, eb->start, eb->start + eb->len - 1))
+			return -EAGAIN;
 	} else {
 		ret = lock_extent(io_tree, eb->start, eb->start + eb->len - 1);
 		if (ret < 0)