3.16.62-rc1 review patch. If anyone has any objections, please let me know.
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From: Theodore Ts'o tytso@mit.edu
commit f0a459dec5495a3580f8d784555e6f8f3bf7f263 upstream.
Avoid growing the file system to an extent so that the last block group is too small to hold all of the metadata that must be stored in the block group.
This problem can be triggered with the following reproducer:
umount /mnt mke2fs -F -m0 -b 4096 -t ext4 -O resize_inode,^has_journal \ -E resize=1073741824 /tmp/foo.img 128M mount /tmp/foo.img /mnt truncate --size 1708M /tmp/foo.img resize2fs /dev/loop0 295400 umount /mnt e2fsck -fy /tmp/foo.img
Reported-by: Torsten Hilbrich torsten.hilbrich@secunet.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Ben Hutchings ben@decadent.org.uk --- fs/ext4/resize.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
--- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -1957,6 +1957,26 @@ retry: } }
+ /* + * Make sure the last group has enough space so that it's + * guaranteed to have enough space for all metadata blocks + * that it might need to hold. (We might not need to store + * the inode table blocks in the last block group, but there + * will be cases where this might be needed.) + */ + if ((ext4_group_first_block_no(sb, n_group) + + ext4_group_overhead_blocks(sb, n_group) + 2 + + sbi->s_itb_per_group + sbi->s_cluster_ratio) >= n_blocks_count) { + n_blocks_count = ext4_group_first_block_no(sb, n_group); + n_group--; + n_blocks_count_retry = 0; + if (resize_inode) { + iput(resize_inode); + resize_inode = NULL; + } + goto retry; + } + /* extend the last group */ if (n_group == o_group) add = n_blocks_count - o_blocks_count;