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.
Reported-by: Robert Yang <liezhi.yang@xxxxxxxxxxxxx>
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
---
diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c
index dcf16e2..2660218 100644
--- a/debugfs/debugfs.c
+++ b/debugfs/debugfs.c
@@ -1677,8 +1677,19 @@ 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;
--
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