4.9-stable review patch. If anyone has any objections, please let me know.
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From: Theodore Ts'o tytso@mit.edu
commit 4274f516d4bc50648a4d97e4f67ecbd7b65cde4a upstream.
When mounting the superblock, ext4_fill_super() calculates the free blocks and free inodes and stores them in the superblock. It's not strictly necessary, since we don't use them any more, but it's nice to keep them roughly aligned to reality.
Since it's not critical for file system correctness, the code doesn't call ext4_commit_super(). The problem is that it's in ext4_commit_super() that we recalculate the superblock checksum. So if we're not going to call ext4_commit_super(), we need to call ext4_superblock_csum_set() to make sure the superblock checksum is consistent.
Most of the time, this doesn't matter, since we end up calling ext4_commit_super() very soon thereafter, and definitely by the time the file system is unmounted. However, it doesn't work in this sequence:
mke2fs -Fq -t ext4 /dev/vdc 128M mount /dev/vdc /vdc cp xfstests/git-versions /vdc godown /vdc umount /vdc mount /dev/vdc tune2fs -l /dev/vdc
With this commit, the "tune2fs -l" no longer fails.
Reported-by: Chengguang Xu cgxu519@gmx.com Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/ext4/super.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4187,11 +4187,13 @@ no_journal: block = ext4_count_free_clusters(sb); ext4_free_blocks_count_set(sbi->s_es, EXT4_C2B(sbi, block)); + ext4_superblock_csum_set(sb); err = percpu_counter_init(&sbi->s_freeclusters_counter, block, GFP_KERNEL); if (!err) { unsigned long freei = ext4_count_free_inodes(sb); sbi->s_es->s_free_inodes_count = cpu_to_le32(freei); + ext4_superblock_csum_set(sb); err = percpu_counter_init(&sbi->s_freeinodes_counter, freei, GFP_KERNEL); }