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Commit 0f0ff9a9 authored by Theodore Ts'o's avatar Theodore Ts'o
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ext4: fix fencepost error in lazytime optimization 



Commit 8f4d8558: "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.

Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
parent a2fd66d0

fs/ext4/inode.c

+6 −1
Original line number Diff line number Diff line
@@ -4348,7 +4348,12 @@ static void ext4_update_other_inodes_time(struct super_block *sb, 
	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;