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Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/extent_io.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index e1939a6..97efc2f 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3077,8 +3077,15 @@ static int lock_extent_buffer_for_io(struct extent_buffer *eb,
}
}
+ /*
+ * We need to do this to prevent races in people who check if the eb is
+ * under IO since we can end up having no IO bits set for a short period
+ * of time.
+ */
+ spin_lock(&eb->refs_lock);
if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags);
+ spin_unlock(&eb->refs_lock);
btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
spin_lock(&fs_info->delalloc_lock);
if (fs_info->dirty_metadata_bytes >= eb->len)
@@ -3087,6 +3094,8 @@ static int lock_extent_buffer_for_io(struct extent_buffer *eb,
WARN_ON(1);
spin_unlock(&fs_info->delalloc_lock);
ret = 1;
+ } else {
+ spin_unlock(&eb->refs_lock);
}
btrfs_tree_unlock(eb);