linux/fs/ext4
Lukas Czerner a0ade1deb8 ext4: fix resize when resizing within single group
When resizing file system in the way that the new size of the file
system is still in the same group (no new groups are added), then we can
hit a BUG_ON in ext4_alloc_group_tables()

BUG_ON(flex_gd->count == 0 || group_data == NULL);

because flex_gd->count is zero. The reason is the missing check for such
case, so the code always extend the last group fully and then attempt to
add more groups, but at that time n_blocks_count is actually smaller
than o_blocks_count.

It can be easily reproduced like this:

mkfs.ext4 -b 4096 /dev/sda 30M
mount /dev/sda /mnt/test
resize2fs /dev/sda 50M

Fix this by checking whether the resize happens within the singe group
and only add that many blocks into the last group to satisfy user
request. Then o_blocks_count == n_blocks_count and the resize will exit
successfully without and attempt to add more groups into the fs.

Also fix mixing together block number and blocks count which might be
confusing and can easily lead to off-by-one errors (but it is actually
not the case here since the two occurrence of this mix-up will cancel
each other).

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reported-by: Milan Broz <mbroz@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-02-20 23:02:06 -05:00
..
acl.c switch posix_acl_equiv_mode() to umode_t * 2011-08-01 02:10:06 -04:00
acl.h fs: take the ACL checks to common code 2011-07-25 14:30:23 -04:00
balloc.c ext4: fix balloc.c printk-format-warning 2012-02-20 17:57:24 -05:00
bitmap.c ext4: Change unsigned long to unsigned int 2008-11-05 00:14:04 -05:00
block_validity.c ext2/3/4: delete unneeded includes of module.h 2012-01-09 13:52:10 +01:00
dir.c ext4: remove an unneeded NULL check in __ext4_check_dir_entry() 2012-02-20 17:53:05 -05:00
ext4_extents.h ext4: Fix bigalloc quota accounting and i_blocks value 2011-09-09 19:04:51 -04:00
ext4_jbd2.c jbd2: add debugging information to jbd2_journal_dirty_metadata() 2011-09-04 10:18:14 -04:00
ext4_jbd2.h ext4: expand commit callback and 2012-02-20 17:53:02 -05:00
ext4.h ext4: fix race between unwritten extent conversion and truncate 2012-02-20 17:59:24 -05:00
extents.c Merge branch 'for_linus' into for_linus_merged 2012-01-10 11:54:07 -05:00
file.c Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 2011-11-02 10:06:20 -07:00
fsync.c ext4: optimize locking for end_io extent conversion 2011-10-31 10:56:32 -04:00
hash.c ext4: Add support for non-native signed/unsigned htree hash algorithms 2008-10-28 13:21:44 -04:00
ialloc.c ext4: fix race when setting bitmap_uptodate flag 2012-02-20 17:52:46 -05:00
indirect.c ext2/3/4: delete unneeded includes of module.h 2012-01-09 13:52:10 +01:00
inode.c ext4: fix race between unwritten extent conversion and truncate 2012-02-20 17:59:24 -05:00
ioctl.c Merge branch 'for_linus' into for_linus_merged 2012-01-10 11:54:07 -05:00
Kconfig ext4: Don't ask about supporting ext2/3 in ext4 if ext4 is not configured 2009-12-21 10:54:09 -05:00
Makefile ext4: move ext4_ind_* functions from inode.c to indirect.c 2011-06-27 19:40:50 -04:00
mballoc.c ext4: remove EXT4_MB_{BITMAP,BUDDY} macros 2012-02-20 17:54:06 -05:00
mballoc.h ext4: remove EXT4_MB_{BITMAP,BUDDY} macros 2012-02-20 17:54:06 -05:00
migrate.c ext4: using PTR_ERR() on the wrong variable in ext4_ext_migrate() 2012-02-20 17:53:06 -05:00
mmp.c ext4: Fix comparison endianness problem in MMP initialization 2011-10-18 10:53:51 -04:00
move_extent.c ext4: add some tracepoints in ext4/extents.c 2011-09-09 19:18:51 -04:00
namei.c ext[34]: avoid i_nlink warnings triggered by drop_nlink/inc_nlink kludge in symlink() 2012-01-08 20:19:30 -05:00
page-io.c ext4: fix race between unwritten extent conversion and truncate 2012-02-20 17:59:24 -05:00
resize.c ext4: fix resize when resizing within single group 2012-02-20 23:02:06 -05:00
super.c ext4: remove the resize mount option 2012-02-20 17:53:04 -05:00
symlink.c ext4: symlink must be handled via filesystem specific operation 2010-05-16 02:00:00 -04:00
truncate.h ext4: move common truncate functions to header file 2011-06-27 19:16:04 -04:00
xattr_security.c Merge branch 'for_linus' into for_linus_merged 2012-01-10 11:54:07 -05:00
xattr_trusted.c ext2/3/4: delete unneeded includes of module.h 2012-01-09 13:52:10 +01:00
xattr_user.c ext2/3/4: delete unneeded includes of module.h 2012-01-09 13:52:10 +01:00
xattr.c ext4: remove unneeded variable in ext4_xattr_check_block() 2012-02-20 17:53:05 -05:00
xattr.h fs/vfs/security: pass last path component to LSM on inode creation 2011-02-01 11:12:29 -05:00