From 2d324f59f343967a03eeb2690f0ff178304d0687 Mon Sep 17 00:00:00 2001 From: Liu Bo Date: Tue, 17 May 2016 17:21:48 -0700 Subject: [PATCH] Btrfs: fix unexpected return value of fiemap btrfs's fiemap is supposed to return 0 on success and return < 0 on error. however, ret becomes 1 after looking up the last file extent: btrfs_lookup_file_extent -> btrfs_search_slot(..., ins_len=0, cow=0) and if the offset is beyond EOF, we'll get 'path' pointed to the place of potentail insertion, and ret == 1. This may confuse applications using ioctl(FIEL_IOC_FIEMAP). Signed-off-by: Liu Bo Signed-off-by: David Sterba --- fs/btrfs/extent_io.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 2f83448d34fe..f661688c2102 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -4389,8 +4389,12 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, if (ret < 0) { btrfs_free_path(path); return ret; + } else { + WARN_ON(!ret); + if (ret == 1) + ret = 0; } - WARN_ON(!ret); + path->slots[0]--; btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]); found_type = found_key.type; -- 2.20.1