| Message ID | 1367856367-15924-1-git-send-email-maarten@treewalker.org |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Mon 06-05-13 18:06:07, Maarten ter Huurne wrote: > Subtracting the number of the first data block places the superblock > backups one block too early, corrupting the file system. When the block > size is larger than 1K, the first data block is 0, so the subtraction > has no effect and no corruption occurs. Looking where mke2fs places backup super blocks you are right. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > > Signed-off-by: Maarten ter Huurne <maarten@treewalker.org> > --- > fs/ext4/resize.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c > index c169477..116c80d 100644 > --- a/fs/ext4/resize.c > +++ b/fs/ext4/resize.c > @@ -1654,12 +1654,10 @@ errout: > err = err2; > > if (!err) { > - ext4_fsblk_t first_block; > - first_block = ext4_group_first_block_no(sb, 0); > if (test_opt(sb, DEBUG)) > printk(KERN_DEBUG "EXT4-fs: extended group to %llu " > "blocks\n", ext4_blocks_count(es)); > - update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr - first_block, > + update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, > (char *)es, sizeof(struct ext4_super_block), 0); > } > return err; > -- > 1.7.10.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, May 08, 2013 at 03:58:25PM +0200, Jan Kara wrote: > On Mon 06-05-13 18:06:07, Maarten ter Huurne wrote: > > Subtracting the number of the first data block places the superblock > > backups one block too early, corrupting the file system. When the block > > size is larger than 1K, the first data block is 0, so the subtraction > > has no effect and no corruption occurs. > Looking where mke2fs places backup super blocks you are right. You can > add: > Reviewed-by: Jan Kara <jack@suse.cz> Applied, thanks. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index c169477..116c80d 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1654,12 +1654,10 @@ errout: err = err2; if (!err) { - ext4_fsblk_t first_block; - first_block = ext4_group_first_block_no(sb, 0); if (test_opt(sb, DEBUG)) printk(KERN_DEBUG "EXT4-fs: extended group to %llu " "blocks\n", ext4_blocks_count(es)); - update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr - first_block, + update_backups(sb, EXT4_SB(sb)->s_sbh->b_blocknr, (char *)es, sizeof(struct ext4_super_block), 0); } return err;
Subtracting the number of the first data block places the superblock backups one block too early, corrupting the file system. When the block size is larger than 1K, the first data block is 0, so the subtraction has no effect and no corruption occurs. Signed-off-by: Maarten ter Huurne <maarten@treewalker.org> --- fs/ext4/resize.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)