ext4: fix online resizing for bigalloc file systems with a 1k block size

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>
Cc: stable@vger.kernel.org

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 33655a6eff4ddf03876641bb8c7d3df2079daa56..ebbc663d07985038ef17520fb41c5fae0e5d3637 100644 (file)
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -19,6 +19,7 @@
 
 int ext4_resize_begin(struct super_block *sb)
 {
+       struct ext4_sb_info *sbi = EXT4_SB(sb);
        int ret = 0;
 
        if (!capable(CAP_SYS_RESOURCE))
@@ -29,7 +30,7 @@ int ext4_resize_begin(struct super_block *sb)
          * 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);