Commit 9d311e11fc ("Btrfs: fiemap: pass correct bytenr when
fm_extent_count is zero") introduced a regression where we no longer
report 0 as the physical offset for inline extents (and other extents
with a special block_start value). This is because it always sets the
variable used to report the physical offset ("disko") as em->block_start
plus some offset, and em->block_start has the value 18446744073709551614
((u64) -2) for inline extents.
This made the btrfs test 004 (from fstests) often fail, for example, for
a file with an inline extent we have the following items in the subvolume
tree:
item 101 key (418 INODE_ITEM 0) itemoff 11029 itemsize 160
generation 25 transid 38 size 1525 nbytes 1525
block group 0 mode 100666 links 1 uid 0 gid 0 rdev 0
sequence 0 flags 0x2(none)
atime 1529342058.461891730 (2018-06-18 18:14:18)
ctime 1529342058.461891730 (2018-06-18 18:14:18)
mtime 1529342058.461891730 (2018-06-18 18:14:18)
otime 1529342055.869892885 (2018-06-18 18:14:15)
item 102 key (418 INODE_REF 264) itemoff 11016 itemsize 13
index 25 namelen 3 name: fc7
item 103 key (418 EXTENT_DATA 0) itemoff 9470 itemsize 1546
generation 38 type 0 (inline)
inline extent data size 1525 ram_bytes 1525 compression 0 (none)
Then when test 004 invoked fiemap against the file it got a non-zero
physical offset:
$ filefrag -v /mnt/p0/d4/d7/fc7
Filesystem type is: 9123683e
File size of /mnt/p0/d4/d7/fc7 is 1525 (1 block of 4096 bytes)
ext: logical_offset: physical_offset: length: expected: flags:
0: 0.. 4095: 18446744073709551614.. 4093: 4096: last,not_aligned,inline,eof
/mnt/p0/d4/d7/fc7: 1 extent found
This resulted in the test failing like this:
btrfs/004 49s ... [failed, exit status 1]- output mismatch (see /home/fdmanana/git/hub/xfstests/results//btrfs/004.out.bad)
--- tests/btrfs/004.out 2016-08-23 10:17:35.027012095 +0100
+++ /home/fdmanana/git/hub/xfstests/results//btrfs/004.out.bad 2018-06-18 18:15:02.385872155 +0100
@@ -1,3 +1,10 @@
QA output created by 004
*** test backref walking
-*** done
+./tests/btrfs/004: line 227: [: 7.55578637259143e+22: integer expression expected
+ERROR: 7.55578637259143e+22 is not a valid numeric value.
+unexpected output from
+ /home/fdmanana/git/hub/btrfs-progs/btrfs inspect-internal logical-resolve -s 65536 -P 7.55578637259143e+22 /home/fdmanana/btrfs-tests/scratch_1
...
(Run 'diff -u tests/btrfs/004.out /home/fdmanana/git/hub/xfstests/results//btrfs/004.out.bad' to see the entire diff)
Ran: btrfs/004
The large number in scientific notation reported as an invalid numeric
value is the result from the filter passed to perl which multiplies the
physical offset by the block size reported by fiemap.
So fix this by ensuring the physical offset is always set to 0 when we
are processing an extent with a special block_start value.
Fixes: 9d311e11fc ("Btrfs: fiemap: pass correct bytenr when fm_extent_count is zero")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
f098631848