From 3c46f72697d06f219222314b4372562973975995 Mon Sep 17 00:00:00 2001 From: Jie Liu Date: Wed, 11 Sep 2013 14:20:05 -0700 Subject: ocfs2: fix the end cluster offset of FIEMAP commit 28e8be31803b19d0d8f76216cb11b480b8a98bec upstream. Call fiemap ioctl(2) with given start offset as well as an desired mapping range should show extents if possible. However, we somehow figure out the end offset of mapping via 'mapping_end -= cpos' before iterating the extent records which would cause problems if the given fiemap length is too small to a cluster size, e.g, Cluster size 4096: debugfs.ocfs2 1.6.3 Block Size Bits: 12 Cluster Size Bits: 12 The extended fiemap test utility From David: https://gist.github.com/anonymous/6172331 # dd if=/dev/urandom of=/ocfs2/test_file bs=1M count=1000 # ./fiemap /ocfs2/test_file 4096 10 start: 4096, length: 10 File /ocfs2/test_file has 0 extents: # Logical Physical Length Flags ^^^^^ <-- No extent is shown In this case, at ocfs2_fiemap(): cpos == mapping_end == 1. Hence the loop of searching extent records was not executed at all. This patch remove the in question 'mapping_end -= cpos', and loops until the cpos is larger than the mapping_end as usual. # ./fiemap /ocfs2/test_file 4096 10 start: 4096, length: 10 File /ocfs2/test_file has 1 extents: # Logical Physical Length Flags 0: 0000000000000000 0000000056a01000 0000000006a00000 0000 Signed-off-by: Jie Liu Reported-by: David Weber Tested-by: David Weber Cc: Sunil Mushran Cc: Mark Fashen Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/extent_map.c | 1 - 1 file changed, 1 deletion(-) (limited to 'fs/ocfs2') diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c index 2487116d0d33..846064726682 100644 --- a/fs/ocfs2/extent_map.c +++ b/fs/ocfs2/extent_map.c @@ -781,7 +781,6 @@ int ocfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, cpos = map_start >> osb->s_clustersize_bits; mapping_end = ocfs2_clusters_for_bytes(inode->i_sb, map_start + map_len); - mapping_end -= cpos; is_last = 0; while (cpos < mapping_end && !is_last) { u32 fe_flags; -- cgit v1.2.3