| Message ID | 20221103094639.39984-1-hsiangkao@linux.alibaba.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xfs: extend the freelist before available space check | expand |
Hi Gao,
I love your patch! Perhaps something to improve:
[auto build test WARNING on xfs-linux/for-next]
[also build test WARNING on linus/master v6.1-rc3 next-20221103]
[cannot apply to djwong-xfs/djwong-devel]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Gao-Xiang/xfs-extend-the-freelist-before-available-space-check/20221103-174840
base: https://git.kernel.org/pub/scm/fs/xfs/xfs-linux.git for-next
patch link: https://lore.kernel.org/r/20221103094639.39984-1-hsiangkao%40linux.alibaba.com
patch subject: [PATCH] xfs: extend the freelist before available space check
config: hexagon-randconfig-r004-20221102
compiler: clang version 15.0.4 (https://github.com/llvm/llvm-project 5c68a1cb123161b54b72ce90e7975d95a8eaf2a4)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/427b4db33a93f832a6da62b2838bd5a558d024d9
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Gao-Xiang/xfs-extend-the-freelist-before-available-space-check/20221103-174840
git checkout 427b4db33a93f832a6da62b2838bd5a558d024d9
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash fs/xfs/
If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
In file included from fs/xfs/libxfs/xfs_alloc.c:6:
In file included from fs/xfs/xfs.h:22:
In file included from fs/xfs/xfs_linux.h:31:
In file included from include/linux/blkdev.h:9:
In file included from include/linux/blk_types.h:10:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/hexagon/include/asm/io.h:334:
include/asm-generic/io.h:547:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __raw_readb(PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:560:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:37:51: note: expanded from macro '__le16_to_cpu'
#define __le16_to_cpu(x) ((__force __u16)(__le16)(x))
^
In file included from fs/xfs/libxfs/xfs_alloc.c:6:
In file included from fs/xfs/xfs.h:22:
In file included from fs/xfs/xfs_linux.h:31:
In file included from include/linux/blkdev.h:9:
In file included from include/linux/blk_types.h:10:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/hexagon/include/asm/io.h:334:
include/asm-generic/io.h:573:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/little_endian.h:35:51: note: expanded from macro '__le32_to_cpu'
#define __le32_to_cpu(x) ((__force __u32)(__le32)(x))
^
In file included from fs/xfs/libxfs/xfs_alloc.c:6:
In file included from fs/xfs/xfs.h:22:
In file included from fs/xfs/xfs_linux.h:31:
In file included from include/linux/blkdev.h:9:
In file included from include/linux/blk_types.h:10:
In file included from include/linux/bvec.h:10:
In file included from include/linux/highmem.h:12:
In file included from include/linux/hardirq.h:11:
In file included from ./arch/hexagon/include/generated/asm/hardirq.h:1:
In file included from include/asm-generic/hardirq.h:17:
In file included from include/linux/irq.h:20:
In file included from include/linux/io.h:13:
In file included from arch/hexagon/include/asm/io.h:334:
include/asm-generic/io.h:584:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writeb(value, PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:594:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:604:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
>> fs/xfs/libxfs/xfs_alloc.c:2597:1: warning: no previous prototype for function 'xfs_fill_agfl' [-Wmissing-prototypes]
xfs_fill_agfl(
^
fs/xfs/libxfs/xfs_alloc.c:2596:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
int
^
static
7 warnings generated.
vim +/xfs_fill_agfl +2597 fs/xfs/libxfs/xfs_alloc.c
2585
2586 /*
2587 * The freelist has to be in a good state before the available space check
2588 * since multiple allocations could be performed from a single AG and
2589 * transaction under certain conditions. For example, A bmbt allocation
2590 * request made for inode extent to bmap format conversion after an extent
2591 * allocation is expected to be satisfied by the same AG. Such bmap conversion
2592 * allocation can fail due to the available space check if allocbt required an
2593 * extra btree block from the freelist in the previous allocation but without
2594 * make the freelist longer.
2595 */
2596 int
> 2597 xfs_fill_agfl(
2598 struct xfs_alloc_arg *args,
2599 int flags,
2600 xfs_extlen_t need,
2601 struct xfs_buf *agbp)
2602 {
2603 struct xfs_trans *tp = args->tp;
2604 struct xfs_perag *pag = agbp->b_pag;
2605 struct xfs_alloc_arg targs = {
2606 .tp = tp,
2607 .mp = tp->t_mountp,
2608 .agbp = agbp,
2609 .agno = args->agno,
2610 .alignment = 1,
2611 .minlen = 1,
2612 .prod = 1,
2613 .type = XFS_ALLOCTYPE_THIS_AG,
2614 .pag = pag,
2615 };
2616 struct xfs_buf *agflbp = NULL;
2617 xfs_agblock_t bno;
2618 int error;
2619
2620 if (flags & XFS_ALLOC_FLAG_NORMAP)
2621 targs.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE;
2622 else
2623 targs.oinfo = XFS_RMAP_OINFO_AG;
2624
2625 error = xfs_alloc_read_agfl(pag, tp, &agflbp);
2626 if (error)
2627 return error;
2628
2629 /* Make the freelist longer if it's too short. */
2630 while (pag->pagf_flcount < need) {
2631 targs.agbno = 0;
2632 targs.maxlen = need - pag->pagf_flcount;
2633 targs.resv = XFS_AG_RESV_AGFL;
2634
2635 /* Allocate as many blocks as possible at once. */
2636 error = xfs_alloc_ag_vextent(&targs);
2637 if (error)
2638 goto out_agflbp_relse;
2639
2640 /*
2641 * Stop if we run out. Won't happen if callers are obeying
2642 * the restrictions correctly. Can happen for free calls
2643 * on a completely full ag.
2644 */
2645 if (targs.agbno == NULLAGBLOCK) {
2646 if (flags & XFS_ALLOC_FLAG_FREEING)
2647 break;
2648 error = -ENOSPC;
2649 goto out_agflbp_relse;
2650 }
2651 /*
2652 * Put each allocated block on the list.
2653 */
2654 for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) {
2655 error = xfs_alloc_put_freelist(pag, tp, agbp,
2656 agflbp, bno, 0);
2657 if (error)
2658 goto out_agflbp_relse;
2659 }
2660 }
2661 out_agflbp_relse:
2662 xfs_trans_brelse(tp, agflbp);
2663 return error;
2664 }
2665
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c index 6261599bb389..5d5e0e0e5227 100644 --- a/fs/xfs/libxfs/xfs_alloc.c +++ b/fs/xfs/libxfs/xfs_alloc.c @@ -2587,6 +2587,86 @@ xfs_exact_minlen_extent_available( } #endif +/* + * The freelist has to be in a good state before the available space check + * since multiple allocations could be performed from a single AG and + * transaction under certain conditions. For example, A bmbt allocation + * request made for inode extent to bmap format conversion after an extent + * allocation is expected to be satisfied by the same AG. Such bmap conversion + * allocation can fail due to the available space check if allocbt required an + * extra btree block from the freelist in the previous allocation but without + * make the freelist longer. + */ +int +xfs_fill_agfl( + struct xfs_alloc_arg *args, + int flags, + xfs_extlen_t need, + struct xfs_buf *agbp) +{ + struct xfs_trans *tp = args->tp; + struct xfs_perag *pag = agbp->b_pag; + struct xfs_alloc_arg targs = { + .tp = tp, + .mp = tp->t_mountp, + .agbp = agbp, + .agno = args->agno, + .alignment = 1, + .minlen = 1, + .prod = 1, + .type = XFS_ALLOCTYPE_THIS_AG, + .pag = pag, + }; + struct xfs_buf *agflbp = NULL; + xfs_agblock_t bno; + int error; + + if (flags & XFS_ALLOC_FLAG_NORMAP) + targs.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE; + else + targs.oinfo = XFS_RMAP_OINFO_AG; + + error = xfs_alloc_read_agfl(pag, tp, &agflbp); + if (error) + return error; + + /* Make the freelist longer if it's too short. */ + while (pag->pagf_flcount < need) { + targs.agbno = 0; + targs.maxlen = need - pag->pagf_flcount; + targs.resv = XFS_AG_RESV_AGFL; + + /* Allocate as many blocks as possible at once. */ + error = xfs_alloc_ag_vextent(&targs); + if (error) + goto out_agflbp_relse; + + /* + * Stop if we run out. Won't happen if callers are obeying + * the restrictions correctly. Can happen for free calls + * on a completely full ag. + */ + if (targs.agbno == NULLAGBLOCK) { + if (flags & XFS_ALLOC_FLAG_FREEING) + break; + error = -ENOSPC; + goto out_agflbp_relse; + } + /* + * Put each allocated block on the list. + */ + for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) { + error = xfs_alloc_put_freelist(pag, tp, agbp, + agflbp, bno, 0); + if (error) + goto out_agflbp_relse; + } + } +out_agflbp_relse: + xfs_trans_brelse(tp, agflbp); + return error; +} + /* * Decide whether to use this allocation group for this allocation. * If so, fix up the btree freelist's size. @@ -2600,8 +2680,7 @@ xfs_alloc_fix_freelist( struct xfs_perag *pag = args->pag; struct xfs_trans *tp = args->tp; struct xfs_buf *agbp = NULL; - struct xfs_buf *agflbp = NULL; - struct xfs_alloc_arg targs; /* local allocation arguments */ + struct xfs_owner_info oinfo; xfs_agblock_t bno; /* freelist block */ xfs_extlen_t need; /* total blocks needed in freelist */ int error = 0; @@ -2630,22 +2709,45 @@ xfs_alloc_fix_freelist( goto out_agbp_relse; } - need = xfs_alloc_min_freelist(mp, pag); - if (!xfs_alloc_space_available(args, need, flags | - XFS_ALLOC_FLAG_CHECK)) - goto out_agbp_relse; - /* - * Get the a.g. freespace buffer. - * Can fail if we're not blocking on locks, and it's held. + * See the comment above xfs_fill_agfl() for the reason why we need to + * make freelist longer here. Assumed that such case is quite rare, so + * in order to simplify the code, let's take agbp unconditionally. */ - if (!agbp) { - error = xfs_alloc_read_agf(pag, tp, flags, &agbp); - if (error) { - /* Couldn't lock the AGF so skip this AG. */ - if (error == -EAGAIN) - error = 0; - goto out_no_agbp; + need = xfs_alloc_min_freelist(mp, pag); + if (pag->pagf_flcount < need) { + /* + * Get the a.g. freespace buffer. + * Can fail if we're not blocking on locks, and it's held. + */ + if (!agbp) { + error = xfs_alloc_read_agf(pag, tp, flags, &agbp); + if (error) { + /* Couldn't lock the AGF so skip this AG. */ + if (error == -EAGAIN) + error = 0; + goto out_no_agbp; + } + } + + need = xfs_alloc_min_freelist(mp, pag); + error = xfs_fill_agfl(args, flags, need, agbp); + if (error) + goto out_agbp_relse; + } else { + if (!xfs_alloc_space_available(args, need, flags | + XFS_ALLOC_FLAG_CHECK)) + goto out_agbp_relse; + + /* Get the a.g. freespace buffer. */ + if (!agbp) { + error = xfs_alloc_read_agf(pag, tp, flags, &agbp); + if (error) { + /* Couldn't lock the AGF so skip this AG. */ + if (error == -EAGAIN) + error = 0; + goto out_no_agbp; + } } } @@ -2691,69 +2793,22 @@ xfs_alloc_fix_freelist( * regenerated AGFL, bnobt, and cntbt. See repair/phase5.c and * repair/rmap.c in xfsprogs for details. */ - memset(&targs, 0, sizeof(targs)); - /* struct copy below */ if (flags & XFS_ALLOC_FLAG_NORMAP) - targs.oinfo = XFS_RMAP_OINFO_SKIP_UPDATE; + oinfo = XFS_RMAP_OINFO_SKIP_UPDATE; else - targs.oinfo = XFS_RMAP_OINFO_AG; + oinfo = XFS_RMAP_OINFO_AG; while (!(flags & XFS_ALLOC_FLAG_NOSHRINK) && pag->pagf_flcount > need) { error = xfs_alloc_get_freelist(pag, tp, agbp, &bno, 0); if (error) goto out_agbp_relse; /* defer agfl frees */ - xfs_defer_agfl_block(tp, args->agno, bno, &targs.oinfo); + xfs_defer_agfl_block(tp, args->agno, bno, &oinfo); } - targs.tp = tp; - targs.mp = mp; - targs.agbp = agbp; - targs.agno = args->agno; - targs.alignment = targs.minlen = targs.prod = 1; - targs.type = XFS_ALLOCTYPE_THIS_AG; - targs.pag = pag; - error = xfs_alloc_read_agfl(pag, tp, &agflbp); - if (error) - goto out_agbp_relse; - - /* Make the freelist longer if it's too short. */ - while (pag->pagf_flcount < need) { - targs.agbno = 0; - targs.maxlen = need - pag->pagf_flcount; - targs.resv = XFS_AG_RESV_AGFL; - - /* Allocate as many blocks as possible at once. */ - error = xfs_alloc_ag_vextent(&targs); - if (error) - goto out_agflbp_relse; - - /* - * Stop if we run out. Won't happen if callers are obeying - * the restrictions correctly. Can happen for free calls - * on a completely full ag. - */ - if (targs.agbno == NULLAGBLOCK) { - if (flags & XFS_ALLOC_FLAG_FREEING) - break; - goto out_agflbp_relse; - } - /* - * Put each allocated block on the list. - */ - for (bno = targs.agbno; bno < targs.agbno + targs.len; bno++) { - error = xfs_alloc_put_freelist(pag, tp, agbp, - agflbp, bno, 0); - if (error) - goto out_agflbp_relse; - } - } - xfs_trans_brelse(tp, agflbp); args->agbp = agbp; return 0; -out_agflbp_relse: - xfs_trans_brelse(tp, agflbp); out_agbp_relse: if (agbp) xfs_trans_brelse(tp, agbp);
There is a long standing issue which could cause fs shutdown due to inode extent to btree conversion failure right after an extent allocation in the same AG, which is absolutely unexpected due to the proper minleft reservation in the previous allocation. Brian once addressed one of the root cause [1], however, such symptom can still occur after the commit is merged as reported [2], and our cloud environment is also suffering from this issue. From the description of the commit [1], I found that Zirong has an in-house stress test reproducer for this issue, therefore I asked him to reproduce again and he confirmed that such issue can still be reproducable on RHEL 9. Thanks to him, after dumping the transaction log items, I think the root cause is as below: 1. BUF: ... start blkno:0x3bffe81 len:1 bmap size:1 flags:0x2800 AGF Buffer: (XAGF) ver:1 seq#:3 len:2621424 root BNO:9 CNT:7 level BNO:2 CNT:2 1st:64 last:69 cnt:6 freeblks:18277 longest:6395 2. agfl (flfirst = 64, fllast = 69, flcount = 6) 64:547 65:167 66:1651 67:2040807 68:783 69:604 3. The log records a new AGF blkno 62914177, len 1, map_size 1 00000000: 58 41 47 46 00 00 00 01 00 00 00 03 00 27 ff f0 XAGF.........'.. 00000010: 00 00 00 09 00 00 00 07 00 00 00 00 00 00 00 02 ................ 00000020: 00 00 00 02 00 00 00 00 00 00 00 41 00 00 00 45 ...........A...E 00000030: 00 00 00 05 00 00 47 65 00 00 18 fb 00 00 00 09 ......Ge........ 00000040: 75 dc c1 b5 1a 45 40 2a 80 50 72 f0 59 6e 62 66 u....E@*.Pr.Ynbf agf 3 flfirst: 65 (0x41) fllast: 69 (0x45) cnt: 5 4. agfl 64 (daddr 62918552) was then written as a cntbt block log item: type#011= 0x123c flags#011= 0x8 blkno 62918552, len 8, map_size 1 00000000: 41 42 33 43 00 00 00 fd 00 1f 23 e4 ff ff ff ff AB3C......#..... 00000010: 00 00 00 00 03 c0 0f 98 00 00 00 00 00 00 00 00 ................ 00000020: 75 dc c1 b5 1a 45 40 2a 80 50 72 f0 59 6e 62 66 u....E@*.Pr.Ynbf 5. Finally, kaboom. Nov 1 07:56:09 dell-per750-08 kernel: ------------[ cut here ]------------ Nov 1 07:56:09 dell-per750-08 kernel: WARNING: CPU: 15 PID: 49290 at fs/xfs/libxfs/xfs_bmap.c:717 xfs_bmap_extents_to_btree+0xc51/0x1050 [xfs] ... Nov 1 07:56:10 dell-per750-08 kernel: XFS (sda2): agno 3 agflcount 5 freeblks 18277 reservation 18276 6 In order to fix the issue above, freelist needs to be filled with the minimal blocks at least before available space check, and then we also know the freelist has enough blocks for the following emergency btree allocations. [1] commit 1ca89fbc48e1 ("xfs: don't account extra agfl blocks as available") https://lore.kernel.org/r/20190327145000.10756-1-bfoster@redhat.com [2] https://lore.kernel.org/r/20220105071052.GD20464@templeofstupid.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com> --- fs/xfs/libxfs/xfs_alloc.c | 187 ++++++++++++++++++++++++-------------- 1 file changed, 121 insertions(+), 66 deletions(-)