Patch "xfs: don't rely on ->total in xfs_alloc_space_available" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

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

    xfs: don't rely on ->total in xfs_alloc_space_available

to the 4.9-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:
     xfs-don-t-rely-on-total-in-xfs_alloc_space_available.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From hch@lst.de  Thu Feb  2 11:13:10 2017
From: Christoph Hellwig <hch@lst.de>
Date: Thu,  2 Feb 2017 08:55:56 +0100
Subject: xfs: don't rely on ->total in xfs_alloc_space_available
To: stable@vger.kernel.org
Cc: linux-xfs@vger.kernel.org, "Darrick J. Wong" <darrick.wong@oracle.com>
Message-ID: <1486022171-8076-5-git-send-email-hch@lst.de>

From: Christoph Hellwig <hch@lst.de>

commit 12ef830198b0d71668eb9b59f9ba69d32951a48a upstream.

->total is a bit of an odd parameter passed down to the low-level
allocator all the way from the high-level callers.  It's supposed to
contain the maximum number of blocks to be allocated for the whole
transaction [1].

But in xfs_iomap_write_allocate we only convert existing delayed
allocations and thus only have a minimal block reservation for the
current transaction, so xfs_alloc_space_available can't use it for
the allocation decisions.  Use the maximum of args->total and the
calculated block requirement to make a decision.  We probably should
get rid of args->total eventually and instead apply ->minleft more
broadly, but that will require some extensive changes all over.

[1] which creates lots of confusion as most callers don't decrement it
once doing a first allocation.  But that's for a separate series.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/xfs/libxfs/xfs_alloc.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -1995,7 +1995,7 @@ xfs_alloc_space_available(
 	int			flags)
 {
 	struct xfs_perag	*pag = args->pag;
-	xfs_extlen_t		longest;
+	xfs_extlen_t		alloc_len, longest;
 	xfs_extlen_t		reservation; /* blocks that are still reserved */
 	int			available;
 
@@ -2005,15 +2005,16 @@ xfs_alloc_space_available(
 	reservation = xfs_ag_resv_needed(pag, args->resv);
 
 	/* do we have enough contiguous free space for the allocation? */
+	alloc_len = args->minlen + (args->alignment - 1) + args->minalignslop;
 	longest = xfs_alloc_longest_free_extent(args->mp, pag, min_free,
 			reservation);
-	if ((args->minlen + args->alignment + args->minalignslop - 1) > longest)
+	if (longest < alloc_len)
 		return false;
 
 	/* do we have enough free space remaining for the allocation? */
 	available = (int)(pag->pagf_freeblks + pag->pagf_flcount -
 			  reservation - min_free - args->minleft);
-	if (available < (int)args->total)
+	if (available < (int)max(args->total, alloc_len))
 		return false;
 
 	/*


Patches currently in stable-queue which might be from hch@lst.de are

queue-4.9/xfs-don-t-rely-on-total-in-xfs_alloc_space_available.patch
queue-4.9/xfs-replace-xfs_mode_to_ftype-table-with-switch-statement.patch
queue-4.9/xfs-fix-bogus-minleft-manipulations.patch
queue-4.9/xfs-fix-cow-writeback-race.patch
queue-4.9/xfs-sanity-check-inode-mode-when-creating-new-dentry.patch
queue-4.9/xfs-extsize-hints-are-not-unlikely-in-xfs_bmap_btalloc.patch
queue-4.9/xfs-bump-up-reserved-blocks-in-xfs_alloc_set_aside.patch
queue-4.9/xfs-add-missing-include-dependencies-to-xfs_dir2.h.patch
queue-4.9/xfs-fix-bmv_count-confusion-w-shared-extents.patch
queue-4.9/xfs-adjust-allocation-length-in-xfs_alloc_space_available.patch
queue-4.9/xfs-verify-dirblocklog-correctly.patch
queue-4.9/xfs-fix-xfs_mode_to_ftype-prototype.patch
queue-4.9/xfs-clear-_xbf_pages-from-buffers-when-readahead-page.patch
queue-4.9/xfs-remove-racy-hasattr-check-from-attr-ops.patch
queue-4.9/xfs-make-the-assert-condition-likely.patch
queue-4.9/xfs-sanity-check-directory-inode-di_size.patch
queue-4.9/xfs-don-t-print-warnings-when-xfs_log_force-fails.patch
queue-4.9/xfs-don-t-wrap-id-in-xfs_dq_get_next_id.patch
queue-4.9/xfs-sanity-check-inode-di_mode.patch