[BUG]
Since e2fsprog 1.47, even with a newly created empty ext4 filesystem,
btrfs-convert would result an fs that btrfs-check would complain:
# mkfs.ext4 -F test.img
# btrfs-convert test.img
# btrfs-check test.img
Opening filesystem to check...
Checking filesystem on test.img
UUID: e45da158-8967-4e4d-9c9f-66b0d127dbce
[1/7] checking root items
[2/7] checking extents
[3/7] checking free space cache
[4/7] checking fs roots
root 5 inode 266 errors 2000, link count wrong
ERROR: errors found in fs roots
found 26333184 bytes used, error(s) found <<<
total csum bytes: 25540
total tree bytes: 180224
total fs tree bytes: 49152
total extent tree bytes: 16384
btree space waste bytes: 145423
file data blocks allocated: 33947648
referenced 26284032
[CAUSE]
Ext4 has a new compat feature, COMPAT_ORPHAN_FILE, as a better way to
track all the orphan inodes.
This new feature would create a new special inode for this purpose, and
such orphan file inode would not be reachable from any other inode, but
only from super block.
Unfortunately btrfs-convert only skip ext2 known special inodes, not the
newer one.
[FIX]
According to the kernel document, we can locate the orphan file inode
using ext2 super block s_orphan_file_inum, and skip it for
btrfs-convert.
And such skip would only happen if we have the definition of
EXT4_FEATURE_COMPAT_ORPHAN_FILE, to be compatible with older e2fsprogs.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
f3353a5e85