Re: [PATCH 3.16 102/305] xfs: xfs_iflush_cluster fails to abort on error
From: Dave Chinner <david@fromorbit.com>
Date: 2016-08-14 10:16:17
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On Sat, Aug 13, 2016 at 06:42:51PM +0100, Ben Hutchings wrote:
3.16.37-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Dave Chinner <redacted> commit b1438f477934f5a4d5a44df26f3079a7575d5946 upstream. When a failure due to an inode buffer occurs, the error handling fails to abort the inode writeback correctly. This can result in the inode being reclaimed whilst still in the AIL, leading to use-after-free situations as well as filesystems that cannot be unmounted as the inode log items left in the AIL never get removed. Fix this by ensuring fatal errors from xfs_imap_to_bp() result in the inode flush being aborted correctly.
....
/*
- * Get the buffer containing the on-disk inode.
+ * Get the buffer containing the on-disk inode. We are doing a try-lock
+ * operation here, so we may get an EAGAIN error. In that case, we
+ * simply want to return with the inode still dirty.
+ *
+ * If we get any other error, we effectively have a corruption situation
+ * and we cannot flush the inode, so we treat it the same as failing
+ * xfs_iflush_int().
*/
error = xfs_imap_to_bp(mp, NULL, &ip->i_imap, &dip, &bp, XBF_TRYLOCK,
0);
- if (error || !bp) {
+ if (error == -EAGAIN) {Wrong. As was pointed out for other -stable trees after users reported regressions, the error signs in XFS changed from positive to negative in 3.17-rc1. -Dave. -- Dave Chinner david@fromorbit.com