xfs: fix internal error from AGFL exhaustion

0002-xfs-fix-internal-error-from-AGFL-exhaustion.patch

@@ -0,0 +1,107 @@
+From 8fdde9dd48edc32a2f5e5a061a12e8dad54c3c7e Mon Sep 17 00:00:00 2001
+From: Omar Sandoval <osandov@fb.com>
+Date: Thu, 15 Feb 2024 09:27:54 +0100
+Subject: xfs: fix internal error from AGFL exhaustion
+
+Source kernel commit: f63a5b3769ad7659da4c0420751d78958ab97675
+
+We've been seeing XFS errors like the following:
+
+XFS: Internal error i != 1 at line 3526 of file fs/xfs/libxfs/xfs_btree.c.  Caller xfs_btree_insert+0x1ec/0x280
+...
+Call Trace:
+xfs_corruption_error+0x94/0xa0
+xfs_btree_insert+0x221/0x280
+xfs_alloc_fixup_trees+0x104/0x3e0
+xfs_alloc_ag_vextent_size+0x667/0x820
+xfs_alloc_fix_freelist+0x5d9/0x750
+xfs_free_extent_fix_freelist+0x65/0xa0
+__xfs_free_extent+0x57/0x180
+...
+
+This is the XFS_IS_CORRUPT() check in xfs_btree_insert() when
+xfs_btree_insrec() fails.
+
+After converting this into a panic and dissecting the core dump, I found
+that xfs_btree_insrec() is failing because it's trying to split a leaf
+node in the cntbt when the AG free list is empty. In particular, it's
+failing to get a block from the AGFL _while trying to refill the AGFL_.
+
+If a single operation splits every level of the bnobt and the cntbt (and
+the rmapbt if it is enabled) at once, the free list will be empty. Then,
+when the next operation tries to refill the free list, it allocates
+space. If the allocation does not use a full extent, it will need to
+insert records for the remaining space in the bnobt and cntbt. And if
+those new records go in full leaves, the leaves (and potentially more
+nodes up to the old root) need to be split.
+
+Fix it by accounting for the additional splits that may be required to
+refill the free list in the calculation for the minimum free list size.
+
+P.S. As far as I can tell, this bug has existed for a long time -- maybe
+back to xfs-history commit afdf80ae7405 ("Add XFS_AG_MAXLEVELS macros
+...") in April 1994! It requires a very unlucky sequence of events, and
+in fact we didn't hit it until a particular sparse mmap workload updated
+from 5.12 to 5.19. But this bug existed in 5.12, so it must've been
+exposed by some other change in allocation or writeback patterns. It's
+also much less likely to be hit with the rmapbt enabled, since that
+increases the minimum free list size and is unlikely to split at the
+same time as the bnobt and cntbt.
+
+Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
+Reviewed-by: Dave Chinner <dchinner@redhat.com>
+Signed-off-by: Omar Sandoval <osandov@fb.com>
+Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
+Signed-off-by: Carlos Maiolino <cem@kernel.org>
+---
+ libxfs/xfs_alloc.c | 27 ++++++++++++++++++++++++---
+ 1 file changed, 24 insertions(+), 3 deletions(-)
+
+diff --git a/libxfs/xfs_alloc.c b/libxfs/xfs_alloc.c
+index 4519a05551..7ac7c2f6cc 100644
+--- a/libxfs/xfs_alloc.c
++++ b/libxfs/xfs_alloc.c
+@@ -2271,16 +2271,37 @@ xfs_alloc_min_freelist(
+ 
+ 	ASSERT(mp->m_alloc_maxlevels > 0);
+ 
++	/*
++	 * For a btree shorter than the maximum height, the worst case is that
++	 * every level gets split and a new level is added, then while inserting
++	 * another entry to refill the AGFL, every level under the old root gets
++	 * split again. This is:
++	 *
++	 *   (full height split reservation) + (AGFL refill split height)
++	 * = (current height + 1) + (current height - 1)
++	 * = (new height) + (new height - 2)
++	 * = 2 * new height - 2
++	 *
++	 * For a btree of maximum height, the worst case is that every level
++	 * under the root gets split, then while inserting another entry to
++	 * refill the AGFL, every level under the root gets split again. This is
++	 * also:
++	 *
++	 *   2 * (current height - 1)
++	 * = 2 * (new height - 1)
++	 * = 2 * new height - 2
++	 */
++
+ 	/* space needed by-bno freespace btree */
+ 	min_free = min_t(unsigned int, levels[XFS_BTNUM_BNOi] + 1,
+-				       mp->m_alloc_maxlevels);
++				       mp->m_alloc_maxlevels) * 2 - 2;
+ 	/* space needed by-size freespace btree */
+ 	min_free += min_t(unsigned int, levels[XFS_BTNUM_CNTi] + 1,
+-				       mp->m_alloc_maxlevels);
++				       mp->m_alloc_maxlevels) * 2 - 2;
+ 	/* space needed reverse mapping used space btree */
+ 	if (xfs_has_rmapbt(mp))
+ 		min_free += min_t(unsigned int, levels[XFS_BTNUM_RMAPi] + 1,
+-						mp->m_rmap_maxlevels);
++						mp->m_rmap_maxlevels) * 2 - 2;
+ 
+ 	return min_free;
+ }
+-- 
+cgit 1.2.3-korg
+

xfsprogs.spec

@@ -1,6 +1,6 @@
 Name:           xfsprogs
 Version:        6.6.0
-Release:        1
+Release:        2
 Summary:        Administration and debugging tools for the XFS file system
 License:        GPL+ and LGPLv2+
 URL:            https://xfs.wiki.kernel.org
@@ -20,6 +20,7 @@ Conflicts:      xfsdump < 3.0.1
 
 Patch0:		xfsprogs-5.12.0-default-bigtime-inobtcnt-on.patch
 Patch1:		0001-xfsprogs-Add-sw64-architecture.patch
+Patch2:		0002-xfs-fix-internal-error-from-AGFL-exhaustion.patch
 
 %description
 xfsprogs are the userspace utilities that manage XFS filesystems.
@@ -101,6 +102,9 @@ rm -rf %{buildroot}%{_datadir}/doc/xfsprogs/
 
 
 %changelog
+* Fri Mar 29 2024 liuh <liuhuan01@kylinos.cn> - 6.6.0-2
+- sync patch from community
+
 * Tue Feb 27 2024 wuguanghao <wuguanghao3@huawei.com> - 6.6.0-1
 - upgrade version to 6.6.0