[PATCH 3.16 189/328] ext4: fix online resizing for bigalloc file systems with a 1k block size

Ben Hutchings
2018-12-09T22:10:27Z

From: Theodore Ts'o <tytso@mit.edu>

commit 5f8c10936fab2b69a487400f2872902e597dd320 upstream.

An online resize of a file system with the bigalloc feature enabled
and a 1k block size would be refused since ext4_resize_begin() did not
understand s_first_data_block is 0 for all bigalloc file systems, even
when the block size is 1k.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/ext4/resize.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -18,6 +18,7 @@

int ext4_resize_begin(struct super_block *sb)
{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
int ret = 0;

if (!capable(CAP_SYS_RESOURCE))
@@ -28,7 +29,7 @@ int ext4_resize_begin(struct super_block
* because the user tools have no way of handling this. Probably a
* bad time to do it anyways.
*/
- if (EXT4_SB(sb)->s_sbh->b_blocknr !=
+ if (EXT4_B2C(sbi, sbi->s_sbh->b_blocknr) !=
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
ext4_warning(sb, "won't resize using backup superblock at %llu",
(unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr);