Patch "ext4: fix fencepost error in lazytime optimization" has been added to the 4.1-stable tree

This is a note to let you know that I've just added the patch titled

ext4: fix fencepost error in lazytime optimization

to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
ext4-fix-fencepost-error-in-lazytime-optimization.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Theodore Ts'o <[email protected]>
Date: Wed, 1 Jul 2015 23:37:46 -0400
Subject: ext4: fix fencepost error in lazytime optimization

From: Theodore Ts'o <[email protected]>

commit 0f0ff9a9f3fa2ec6f427603fd521d5f3a0b076d1 upstream.

Commit 8f4d8558391: "ext4: fix lazytime optimization" was not a complete fix. In the case where the inode number is a multiple of 16, and we could still end up updating an inode with dirty timestamps written to the wrong inode on disk. Oops.

This can be easily reproduced by using generic/005 with a file system with metadata_csum and lazytime enabled.

---
 fs/ext4/inode.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

@@ -4360,7 +4360,12 @@ static void ext4_update_other_inodes_tim
 	int inode_size = EXT4_INODE_SIZE(sb);
 
 	oi.orig_ino = orig_ino;
-	ino = (orig_ino & ~(inodes_per_block - 1)) + 1;
+	/*
+	 * Calculate the first inode in the inode table block.  Inode
+	 * numbers are one-based.  That is, the first inode in a block
+	 * (assuming 4k blocks and 256 byte inodes) is (n*16 + 1).
+	 */
+	ino = ((orig_ino - 1) & ~(inodes_per_block - 1)) + 1;
 	for (i = 0; i < inodes_per_block; i++, ino++, buf += inode_size) {
 		if (ino == orig_ino)
 			continue;

Patches currently in stable-queue which might be from [email protected] are

queue-4.1/ext4-correctly-migrate-a-file-with-a-hole-at-the-beginning.patch queue-4.1/ext4-set-lazytime-on-remount-if-ms_lazytime-is-set-by-mount.patch queue-4.1/jbd2-fix-ocfs2-corrupt-when-updating-journal-superblock-fails.patch queue-4.1/ext4-be-more-strict-when-migrating-to-non-extent-based-file.patch queue-4.1/jbd2-use-gfp_nofs-in-jbd2_cleanup_journal_tail.patch queue-4.1/ext4-fix-fencepost-error-in-lazytime-optimization.patch queue-4.1/ext4-replace-open-coded-nofail-allocation-in-ext4_free_blocks.patch queue-4.1/ext4-don-t-retry-file-block-mapping-on-bigalloc-fs-with-non-extent-file.patch queue-4.1/bufferhead-add-_gfp-version-for-sb_getblk.patch queue-4.1/ext4-avoid-deadlocks-in-the-writeback-path-by-using-sb_getblk_gfp.patch queue-4.1/ext4-call-sync_blockdev-before-invalidate_bdev-in-put_super.patch queue-4.1/ext4-fix-race-between-truncate-and-__ext4_journalled_writepage.patch queue-4.1/ext4-fix-reservation-release-on-invalidatepage-for-delalloc-fs.patch