debugfs: properly set up extent header in do_write do_write doesn't fully set up the first extent header on a new inode, so if we write a 0-length file, and don't write any data to the new file, we end up creating something that looks corrupt to kernelspace: EXT4-fs error (device loop0): ext4_ext_check_inode:464: inode #12: comm ls: bad header/extent: invalid magic - magic 0, entries 0, max 0(0), depth 0(0) Do something similar to ext4_ext_tree_init() here, and fill out the first extent header upon creation to avoid this. Upstream-Status: Backport Reported-by: Robert Yang Signed-off-by: Eric Sandeen --- debugfs/debugfs.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c --- a/debugfs/debugfs.c +++ b/debugfs/debugfs.c @@ -1726,8 +1726,19 @@ void do_write(int argc, char *argv[]) inode.i_links_count = 1; inode.i_size = statbuf.st_size; if (current_fs->super->s_feature_incompat & - EXT3_FEATURE_INCOMPAT_EXTENTS) + EXT3_FEATURE_INCOMPAT_EXTENTS) { + int i; + struct ext3_extent_header *eh; + + eh = (struct ext3_extent_header *) &inode.i_block[0]; + eh->eh_depth = 0; + eh->eh_entries = 0; + eh->eh_magic = EXT3_EXT_MAGIC; + i = (sizeof(inode.i_block) - sizeof(*eh)) / + sizeof(struct ext3_extent); + eh->eh_max = ext2fs_cpu_to_le16(i); inode.i_flags |= EXT4_EXTENTS_FL; + } if (debugfs_write_new_inode(newfile, &inode, argv[0])) { close(fd); return; -- 1.8.1.2