| Message ID | 20220425070620.19986-1-jianchao.wan9@gmail.com (mailing list archive) |
|---|---|
| State | Deferred, archived |
| Headers | show |
| Series | xfs: fix the ABBA deadlock around agf and inode | expand |
The deadlock context is as following,
hold inode, try to require agf
inode buf xfs_buf.b_log_item ffff9ca7491eb2c0
PID: 82240 TASK: ffff9ca4cd633d80 CPU: 88 COMMAND: ""
#0 [ffffb696ad7f7410] __schedule at ffffffffa0067073
#1 [ffffb696ad7f74b0] schedule at ffffffffa0067678
#2 [ffffb696ad7f74b8] schedule_timeout at ffffffffa006b88d
#3 [ffffb696ad7f7558] __down at ffffffffa0069dcb
#4 [ffffb696ad7f75b8] down at ffffffff9f90890b
#5 [ffffb696ad7f75d0] xfs_buf_lock at ffffffffc6cb1133 [xfs]
#6 [ffffb696ad7f75f0] xfs_buf_find at ffffffffc6cb15fa [xfs]
#7 [ffffb696ad7f7688] xfs_buf_get_map at ffffffffc6cb18e0 [xfs]
#8 [ffffb696ad7f76d0] xfs_buf_read_map at ffffffffc6cb20e8 [xfs]
#9 [ffffb696ad7f7710] xfs_trans_read_buf_map at ffffffffc6ce6796 [xfs]
#10 [ffffb696ad7f7750] xfs_read_agf at ffffffffc6c66fde [xfs]
#11 [ffffb696ad7f77b8] xfs_alloc_read_agf at ffffffffc6c670ae [xfs]
#12 [ffffb696ad7f77f0] xfs_alloc_fix_freelist at ffffffffc6c675dc [xfs]
#13 [ffffb696ad7f7900] xfs_alloc_vextent at ffffffffc6c6796b [xfs]
#14 [ffffb696ad7f7940] __xfs_inobt_alloc_block at ffffffffc6c972f0 [xfs]
#15 [ffffb696ad7f79f8] __xfs_btree_split at ffffffffc6c7ee5d [xfs]
#16 [ffffb696ad7f7ab8] xfs_btree_split at ffffffffc6c7f34b [xfs]
#17 [ffffb696ad7f7b68] xfs_btree_make_block_unfull at ffffffffc6c80882 [xfs]
#18 [ffffb696ad7f7bc8] xfs_btree_insrec at ffffffffc6c80ccd [xfs]
#19 [ffffb696ad7f7ca0] xfs_btree_insert at ffffffffc6c80e3b [xfs]
#20 [ffffb696ad7f7d60] xfs_difree_finobt at ffffffffc6c94859 [xfs]
#21 [ffffb696ad7f7db8] xfs_difree at ffffffffc6c9634e [xfs]
#22 [ffffb696ad7f7e08] xfs_ifree at ffffffffc6cc63d2 [xfs]
#23 [ffffb696ad7f7e58] xfs_inactive_ifree at ffffffffc6cc6551 [xfs]
#24 [ffffb696ad7f7e88] xfs_inactive at ffffffffc6cc66fe [xfs]
#25 [ffffb696ad7f7ea0] xfs_fs_destroy_inode at ffffffffc6ccfdb8 [xfs]
#26 [ffffb696ad7f7ec0] do_unlinkat at ffffffff9face066
#27 [ffffb696ad7f7f38] do_syscall_64 at ffffffff9f8041cb
#28 [ffffb696ad7f7f50] entry_SYSCALL_64_after_hwframe at ffffffffa02000ad
RIP: 00007f5e27b64e57 RSP: 00007f5e0d1f9a98 RFLAGS: 00000202
RAX: ffffffffffffffda RBX: 00007f578b4011a0 RCX: 00007f5e27b64e57
RDX: 00007f5b1684e680 RSI: 0000000000000070 RDI: 00007f5b1684e680
RBP: 00007f578b4011c0 R8: 00000000000002e8 R9: 0000000000000007
R10: 00007f5e0d1fae20 R11: 0000000000000202 R12: 00007f5e0d1f9c00
R13: 00007f5d191e2118 R14: 00007f5d191e22d0 R15: 00007f5e0d1f9b50
ORIG_RAX: 0000000000000057 CS: 0033 SS: 002b
The task hold agf, try to require inode
PID: 1653499 TASK: ffff9c9f5490bd80 CPU: 66 COMMAND: "kworker/u209:2"
#0 [ffffb696ccdff270] __schedule at ffffffffa0067073
#1 [ffffb696ccdff310] schedule at ffffffffa0067678
#2 [ffffb696ccdff318] schedule_timeout at ffffffffa006b88d
#3 [ffffb696ccdff3b8] __down at ffffffffa0069dcb
#4 [ffffb696ccdff410] down at ffffffff9f90890b
#5 [ffffb696ccdff428] xfs_buf_lock at ffffffffc6cb1133 [xfs]
#6 [ffffb696ccdff448] xfs_buf_find at ffffffffc6cb15fa [xfs]
#7 [ffffb696ccdff4e0] xfs_buf_get_map at ffffffffc6cb18e0 [xfs]
#8 [ffffb696ccdff528] xfs_buf_read_map at ffffffffc6cb20e8 [xfs]
#9 [ffffb696ccdff568] xfs_trans_read_buf_map at ffffffffc6ce6796 [xfs]
#10 [ffffb696ccdff5a8] xfs_imap_to_bp at ffffffffc6c9a3e7 [xfs]
#11 [ffffb696ccdff608] xfs_trans_log_inode at ffffffffc6ce757e [xfs]
#12 [ffffb696ccdff658] xfs_bmap_btalloc at ffffffffc6c75ccc [xfs]
#13 [ffffb696ccdff750] xfs_bmapi_write at ffffffffc6c77ca0 [xfs]
#14 [ffffb696ccdff8a8] xfs_bmapi_convert_delalloc at ffffffffc6c782a4 [xfs]
#15 [ffffb696ccdff8d0] xfs_iomap_write_allocate at ffffffffc6cc11a7 [xfs]
#16 [ffffb696ccdff940] xfs_map_blocks at ffffffffc6ca9f97 [xfs]
#17 [ffffb696ccdff9d0] xfs_do_writepage at ffffffffc6caa911 [xfs]
#18 [ffffb696ccdffa48] write_cache_pages at ffffffff9fa20675
#19 [ffffb696ccdffb40] xfs_vm_writepages at ffffffffc6caa3e4 [xfs]
#20 [ffffb696ccdffba8] do_writepages at ffffffff9fa217c1
#21 [ffffb696ccdffc10] __writeback_single_inode at ffffffff9faec1bd
#22 [ffffb696ccdffc58] writeback_sb_inodes at ffffffff9faec953
#23 [ffffb696ccdffd38] __writeback_inodes_wb at ffffffff9faecc1d
#24 [ffffb696ccdffd78] wb_writeback at ffffffff9faecf9f
#25 [ffffb696ccdffe08] wb_workfn at ffffffff9faed8a2
#26 [ffffb696ccdffe98] process_one_work at ffffffff9f8cd9f7
#27 [ffffb696ccdffed8] worker_thread at ffffffff9f8ce0fa
#28 [ffffb696ccdfff10] kthread at ffffffff9f8d3802
#29 [ffffb696ccdfff50] ret_from_fork at ffffffffa020023f
Thanks
Jianchao
On 2022/4/25 3:06 下午, Wang Jianchao (Kuaishou) wrote:
> Recently, we encounter a deadlock case where there are many tasks
> hung on agi and agf xfs_buf. It end up with a deadlock between
> agf and inode xfs_buf as following,
>
> xfs_ifree() xfs_bmap_btalloc()
> xfs_iunlink_remove() xfs_alloc_vextent()
> hold inode bp hold agf
> xfs_difree() xfs_trans_log_inode()
> require agf require inode bp
>
> The task requires inode bp with agf held block other tasks which
> want to require agf with agi held. Then the whole filesystem
> looks like a agi/agf deadlock. To fix this issue, get agf in
> xfs_iunlink_remove() after it get agi and before get indoe bp.
>
> Signed-off-by: Wang Jianchao (Kuaishou) <jianchao.wan9@gmail.com>
> ---
> fs/xfs/xfs_inode.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> index 9de6205fe134..c0a29fd00b0e 100644
> --- a/fs/xfs/xfs_inode.c
> +++ b/fs/xfs/xfs_inode.c
> @@ -36,6 +36,7 @@
> #include "xfs_reflink.h"
> #include "xfs_ag.h"
> #include "xfs_log_priv.h"
> +#include "xfs_alloc.h"
>
> struct kmem_cache *xfs_inode_cache;
>
> @@ -2337,6 +2338,7 @@ xfs_iunlink_remove(
> {
> struct xfs_mount *mp = tp->t_mountp;
> struct xfs_agi *agi;
> + struct xfs_buf *agfbp;
> struct xfs_buf *agibp;
> struct xfs_buf *last_ibp;
> struct xfs_dinode *last_dip = NULL;
> @@ -2352,6 +2354,14 @@ xfs_iunlink_remove(
> error = xfs_read_agi(mp, tp, pag->pag_agno, &agibp);
> if (error)
> return error;
> +
> + /*
> + * Get the agf buffer first to ensure the lock ordering against inode bp
> + */
> + error = xfs_read_agf(mp, tp, pag->pag_agno, 0, &agfbp);
> + if (error)
> + return error;
> +
> agi = agibp->b_addr;
>
> /*
On Mon, Apr 25, 2022 at 03:10:02PM +0800, Wang Jianchao wrote: > The deadlock context is as following, > hold inode, try to require agf > > inode buf xfs_buf.b_log_item ffff9ca7491eb2c0 > > PID: 82240 TASK: ffff9ca4cd633d80 CPU: 88 COMMAND: "" > #0 [ffffb696ad7f7410] __schedule at ffffffffa0067073 > #1 [ffffb696ad7f74b0] schedule at ffffffffa0067678 > #2 [ffffb696ad7f74b8] schedule_timeout at ffffffffa006b88d > #3 [ffffb696ad7f7558] __down at ffffffffa0069dcb > #4 [ffffb696ad7f75b8] down at ffffffff9f90890b > #5 [ffffb696ad7f75d0] xfs_buf_lock at ffffffffc6cb1133 [xfs] > #6 [ffffb696ad7f75f0] xfs_buf_find at ffffffffc6cb15fa [xfs] > #7 [ffffb696ad7f7688] xfs_buf_get_map at ffffffffc6cb18e0 [xfs] > #8 [ffffb696ad7f76d0] xfs_buf_read_map at ffffffffc6cb20e8 [xfs] > #9 [ffffb696ad7f7710] xfs_trans_read_buf_map at ffffffffc6ce6796 [xfs] > #10 [ffffb696ad7f7750] xfs_read_agf at ffffffffc6c66fde [xfs] > #11 [ffffb696ad7f77b8] xfs_alloc_read_agf at ffffffffc6c670ae [xfs] > #12 [ffffb696ad7f77f0] xfs_alloc_fix_freelist at ffffffffc6c675dc [xfs] > #13 [ffffb696ad7f7900] xfs_alloc_vextent at ffffffffc6c6796b [xfs] > #14 [ffffb696ad7f7940] __xfs_inobt_alloc_block at ffffffffc6c972f0 [xfs] > #15 [ffffb696ad7f79f8] __xfs_btree_split at ffffffffc6c7ee5d [xfs] > #16 [ffffb696ad7f7ab8] xfs_btree_split at ffffffffc6c7f34b [xfs] > #17 [ffffb696ad7f7b68] xfs_btree_make_block_unfull at ffffffffc6c80882 [xfs] > #18 [ffffb696ad7f7bc8] xfs_btree_insrec at ffffffffc6c80ccd [xfs] > #19 [ffffb696ad7f7ca0] xfs_btree_insert at ffffffffc6c80e3b [xfs] > #20 [ffffb696ad7f7d60] xfs_difree_finobt at ffffffffc6c94859 [xfs] > #21 [ffffb696ad7f7db8] xfs_difree at ffffffffc6c9634e [xfs] > #22 [ffffb696ad7f7e08] xfs_ifree at ffffffffc6cc63d2 [xfs] > #23 [ffffb696ad7f7e58] xfs_inactive_ifree at ffffffffc6cc6551 [xfs] > #24 [ffffb696ad7f7e88] xfs_inactive at ffffffffc6cc66fe [xfs] > #25 [ffffb696ad7f7ea0] xfs_fs_destroy_inode at ffffffffc6ccfdb8 [xfs] > #26 [ffffb696ad7f7ec0] do_unlinkat at ffffffff9face066 > #27 [ffffb696ad7f7f38] do_syscall_64 at ffffffff9f8041cb > #28 [ffffb696ad7f7f50] entry_SYSCALL_64_after_hwframe at ffffffffa02000ad > RIP: 00007f5e27b64e57 RSP: 00007f5e0d1f9a98 RFLAGS: 00000202 > RAX: ffffffffffffffda RBX: 00007f578b4011a0 RCX: 00007f5e27b64e57 > RDX: 00007f5b1684e680 RSI: 0000000000000070 RDI: 00007f5b1684e680 > RBP: 00007f578b4011c0 R8: 00000000000002e8 R9: 0000000000000007 > R10: 00007f5e0d1fae20 R11: 0000000000000202 R12: 00007f5e0d1f9c00 > R13: 00007f5d191e2118 R14: 00007f5d191e22d0 R15: 00007f5e0d1f9b50 > ORIG_RAX: 0000000000000057 CS: 0033 SS: 002b > > > The task hold agf, try to require inode > > > PID: 1653499 TASK: ffff9c9f5490bd80 CPU: 66 COMMAND: "kworker/u209:2" > #0 [ffffb696ccdff270] __schedule at ffffffffa0067073 > #1 [ffffb696ccdff310] schedule at ffffffffa0067678 > #2 [ffffb696ccdff318] schedule_timeout at ffffffffa006b88d > #3 [ffffb696ccdff3b8] __down at ffffffffa0069dcb > #4 [ffffb696ccdff410] down at ffffffff9f90890b > #5 [ffffb696ccdff428] xfs_buf_lock at ffffffffc6cb1133 [xfs] > #6 [ffffb696ccdff448] xfs_buf_find at ffffffffc6cb15fa [xfs] > #7 [ffffb696ccdff4e0] xfs_buf_get_map at ffffffffc6cb18e0 [xfs] > #8 [ffffb696ccdff528] xfs_buf_read_map at ffffffffc6cb20e8 [xfs] > #9 [ffffb696ccdff568] xfs_trans_read_buf_map at ffffffffc6ce6796 [xfs] > #10 [ffffb696ccdff5a8] xfs_imap_to_bp at ffffffffc6c9a3e7 [xfs] > #11 [ffffb696ccdff608] xfs_trans_log_inode at ffffffffc6ce757e [xfs] > #12 [ffffb696ccdff658] xfs_bmap_btalloc at ffffffffc6c75ccc [xfs] > #13 [ffffb696ccdff750] xfs_bmapi_write at ffffffffc6c77ca0 [xfs] > #14 [ffffb696ccdff8a8] xfs_bmapi_convert_delalloc at ffffffffc6c782a4 [xfs] > #15 [ffffb696ccdff8d0] xfs_iomap_write_allocate at ffffffffc6cc11a7 [xfs] > #16 [ffffb696ccdff940] xfs_map_blocks at ffffffffc6ca9f97 [xfs] > #17 [ffffb696ccdff9d0] xfs_do_writepage at ffffffffc6caa911 [xfs] > #18 [ffffb696ccdffa48] write_cache_pages at ffffffff9fa20675 > #19 [ffffb696ccdffb40] xfs_vm_writepages at ffffffffc6caa3e4 [xfs] > #20 [ffffb696ccdffba8] do_writepages at ffffffff9fa217c1 > #21 [ffffb696ccdffc10] __writeback_single_inode at ffffffff9faec1bd > #22 [ffffb696ccdffc58] writeback_sb_inodes at ffffffff9faec953 > #23 [ffffb696ccdffd38] __writeback_inodes_wb at ffffffff9faecc1d > #24 [ffffb696ccdffd78] wb_writeback at ffffffff9faecf9f > #25 [ffffb696ccdffe08] wb_workfn at ffffffff9faed8a2 > #26 [ffffb696ccdffe98] process_one_work at ffffffff9f8cd9f7 > #27 [ffffb696ccdffed8] worker_thread at ffffffff9f8ce0fa > #28 [ffffb696ccdfff10] kthread at ffffffff9f8d3802 > #29 [ffffb696ccdfff50] ret_from_fork at ffffffffa020023f Does this solve the same problem as[1]? [1] https://lore.kernel.org/linux-xfs/20220404232204.GT1544202@dread.disaster.area/ --D > > > Thanks > Jianchao > > On 2022/4/25 3:06 下午, Wang Jianchao (Kuaishou) wrote: > > Recently, we encounter a deadlock case where there are many tasks > > hung on agi and agf xfs_buf. It end up with a deadlock between > > agf and inode xfs_buf as following, > > > > xfs_ifree() xfs_bmap_btalloc() > > xfs_iunlink_remove() xfs_alloc_vextent() > > hold inode bp hold agf > > xfs_difree() xfs_trans_log_inode() > > require agf require inode bp > > > > The task requires inode bp with agf held block other tasks which > > want to require agf with agi held. Then the whole filesystem > > looks like a agi/agf deadlock. To fix this issue, get agf in > > xfs_iunlink_remove() after it get agi and before get indoe bp. > > > > Signed-off-by: Wang Jianchao (Kuaishou) <jianchao.wan9@gmail.com> > > --- > > fs/xfs/xfs_inode.c | 10 ++++++++++ > > 1 file changed, 10 insertions(+) > > > > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c > > index 9de6205fe134..c0a29fd00b0e 100644 > > --- a/fs/xfs/xfs_inode.c > > +++ b/fs/xfs/xfs_inode.c > > @@ -36,6 +36,7 @@ > > #include "xfs_reflink.h" > > #include "xfs_ag.h" > > #include "xfs_log_priv.h" > > +#include "xfs_alloc.h" > > > > struct kmem_cache *xfs_inode_cache; > > > > @@ -2337,6 +2338,7 @@ xfs_iunlink_remove( > > { > > struct xfs_mount *mp = tp->t_mountp; > > struct xfs_agi *agi; > > + struct xfs_buf *agfbp; > > struct xfs_buf *agibp; > > struct xfs_buf *last_ibp; > > struct xfs_dinode *last_dip = NULL; > > @@ -2352,6 +2354,14 @@ xfs_iunlink_remove( > > error = xfs_read_agi(mp, tp, pag->pag_agno, &agibp); > > if (error) > > return error; > > + > > + /* > > + * Get the agf buffer first to ensure the lock ordering against inode bp > > + */ > > + error = xfs_read_agf(mp, tp, pag->pag_agno, 0, &agfbp); > > + if (error) > > + return error; > > + > > agi = agibp->b_addr; > > > > /*
On 2022/4/26 12:16 上午, Darrick J. Wong wrote: > On Mon, Apr 25, 2022 at 03:10:02PM +0800, Wang Jianchao wrote: >> The deadlock context is as following, >> hold inode, try to require agf >> >> inode buf xfs_buf.b_log_item ffff9ca7491eb2c0 >> >> PID: 82240 TASK: ffff9ca4cd633d80 CPU: 88 COMMAND: "" >> #0 [ffffb696ad7f7410] __schedule at ffffffffa0067073 >> #1 [ffffb696ad7f74b0] schedule at ffffffffa0067678 >> #2 [ffffb696ad7f74b8] schedule_timeout at ffffffffa006b88d >> #3 [ffffb696ad7f7558] __down at ffffffffa0069dcb >> #4 [ffffb696ad7f75b8] down at ffffffff9f90890b >> #5 [ffffb696ad7f75d0] xfs_buf_lock at ffffffffc6cb1133 [xfs] >> #6 [ffffb696ad7f75f0] xfs_buf_find at ffffffffc6cb15fa [xfs] >> #7 [ffffb696ad7f7688] xfs_buf_get_map at ffffffffc6cb18e0 [xfs] >> #8 [ffffb696ad7f76d0] xfs_buf_read_map at ffffffffc6cb20e8 [xfs] >> #9 [ffffb696ad7f7710] xfs_trans_read_buf_map at ffffffffc6ce6796 [xfs] >> #10 [ffffb696ad7f7750] xfs_read_agf at ffffffffc6c66fde [xfs] >> #11 [ffffb696ad7f77b8] xfs_alloc_read_agf at ffffffffc6c670ae [xfs] >> #12 [ffffb696ad7f77f0] xfs_alloc_fix_freelist at ffffffffc6c675dc [xfs] >> #13 [ffffb696ad7f7900] xfs_alloc_vextent at ffffffffc6c6796b [xfs] >> #14 [ffffb696ad7f7940] __xfs_inobt_alloc_block at ffffffffc6c972f0 [xfs] >> #15 [ffffb696ad7f79f8] __xfs_btree_split at ffffffffc6c7ee5d [xfs] >> #16 [ffffb696ad7f7ab8] xfs_btree_split at ffffffffc6c7f34b [xfs] >> #17 [ffffb696ad7f7b68] xfs_btree_make_block_unfull at ffffffffc6c80882 [xfs] >> #18 [ffffb696ad7f7bc8] xfs_btree_insrec at ffffffffc6c80ccd [xfs] >> #19 [ffffb696ad7f7ca0] xfs_btree_insert at ffffffffc6c80e3b [xfs] >> #20 [ffffb696ad7f7d60] xfs_difree_finobt at ffffffffc6c94859 [xfs] >> #21 [ffffb696ad7f7db8] xfs_difree at ffffffffc6c9634e [xfs] >> #22 [ffffb696ad7f7e08] xfs_ifree at ffffffffc6cc63d2 [xfs] >> #23 [ffffb696ad7f7e58] xfs_inactive_ifree at ffffffffc6cc6551 [xfs] >> #24 [ffffb696ad7f7e88] xfs_inactive at ffffffffc6cc66fe [xfs] >> #25 [ffffb696ad7f7ea0] xfs_fs_destroy_inode at ffffffffc6ccfdb8 [xfs] >> #26 [ffffb696ad7f7ec0] do_unlinkat at ffffffff9face066 >> #27 [ffffb696ad7f7f38] do_syscall_64 at ffffffff9f8041cb >> #28 [ffffb696ad7f7f50] entry_SYSCALL_64_after_hwframe at ffffffffa02000ad >> RIP: 00007f5e27b64e57 RSP: 00007f5e0d1f9a98 RFLAGS: 00000202 >> RAX: ffffffffffffffda RBX: 00007f578b4011a0 RCX: 00007f5e27b64e57 >> RDX: 00007f5b1684e680 RSI: 0000000000000070 RDI: 00007f5b1684e680 >> RBP: 00007f578b4011c0 R8: 00000000000002e8 R9: 0000000000000007 >> R10: 00007f5e0d1fae20 R11: 0000000000000202 R12: 00007f5e0d1f9c00 >> R13: 00007f5d191e2118 R14: 00007f5d191e22d0 R15: 00007f5e0d1f9b50 >> ORIG_RAX: 0000000000000057 CS: 0033 SS: 002b >> >> >> The task hold agf, try to require inode >> >> >> PID: 1653499 TASK: ffff9c9f5490bd80 CPU: 66 COMMAND: "kworker/u209:2" >> #0 [ffffb696ccdff270] __schedule at ffffffffa0067073 >> #1 [ffffb696ccdff310] schedule at ffffffffa0067678 >> #2 [ffffb696ccdff318] schedule_timeout at ffffffffa006b88d >> #3 [ffffb696ccdff3b8] __down at ffffffffa0069dcb >> #4 [ffffb696ccdff410] down at ffffffff9f90890b >> #5 [ffffb696ccdff428] xfs_buf_lock at ffffffffc6cb1133 [xfs] >> #6 [ffffb696ccdff448] xfs_buf_find at ffffffffc6cb15fa [xfs] >> #7 [ffffb696ccdff4e0] xfs_buf_get_map at ffffffffc6cb18e0 [xfs] >> #8 [ffffb696ccdff528] xfs_buf_read_map at ffffffffc6cb20e8 [xfs] >> #9 [ffffb696ccdff568] xfs_trans_read_buf_map at ffffffffc6ce6796 [xfs] >> #10 [ffffb696ccdff5a8] xfs_imap_to_bp at ffffffffc6c9a3e7 [xfs] >> #11 [ffffb696ccdff608] xfs_trans_log_inode at ffffffffc6ce757e [xfs] >> #12 [ffffb696ccdff658] xfs_bmap_btalloc at ffffffffc6c75ccc [xfs] >> #13 [ffffb696ccdff750] xfs_bmapi_write at ffffffffc6c77ca0 [xfs] >> #14 [ffffb696ccdff8a8] xfs_bmapi_convert_delalloc at ffffffffc6c782a4 [xfs] >> #15 [ffffb696ccdff8d0] xfs_iomap_write_allocate at ffffffffc6cc11a7 [xfs] >> #16 [ffffb696ccdff940] xfs_map_blocks at ffffffffc6ca9f97 [xfs] >> #17 [ffffb696ccdff9d0] xfs_do_writepage at ffffffffc6caa911 [xfs] >> #18 [ffffb696ccdffa48] write_cache_pages at ffffffff9fa20675 >> #19 [ffffb696ccdffb40] xfs_vm_writepages at ffffffffc6caa3e4 [xfs] >> #20 [ffffb696ccdffba8] do_writepages at ffffffff9fa217c1 >> #21 [ffffb696ccdffc10] __writeback_single_inode at ffffffff9faec1bd >> #22 [ffffb696ccdffc58] writeback_sb_inodes at ffffffff9faec953 >> #23 [ffffb696ccdffd38] __writeback_inodes_wb at ffffffff9faecc1d >> #24 [ffffb696ccdffd78] wb_writeback at ffffffff9faecf9f >> #25 [ffffb696ccdffe08] wb_workfn at ffffffff9faed8a2 >> #26 [ffffb696ccdffe98] process_one_work at ffffffff9f8cd9f7 >> #27 [ffffb696ccdffed8] worker_thread at ffffffff9f8ce0fa >> #28 [ffffb696ccdfff10] kthread at ffffffff9f8d3802 >> #29 [ffffb696ccdfff50] ret_from_fork at ffffffffa020023f > > Does this solve the same problem as[1]? > > [1] > https://lore.kernel.org/linux-xfs/20220404232204.GT1544202@dread.disaster.area/ Yes, it is ! Thanks so much Jianchao > > --D > >> >> >> Thanks >> Jianchao >> >> On 2022/4/25 3:06 下午, Wang Jianchao (Kuaishou) wrote: >>> Recently, we encounter a deadlock case where there are many tasks >>> hung on agi and agf xfs_buf. It end up with a deadlock between >>> agf and inode xfs_buf as following, >>> >>> xfs_ifree() xfs_bmap_btalloc() >>> xfs_iunlink_remove() xfs_alloc_vextent() >>> hold inode bp hold agf >>> xfs_difree() xfs_trans_log_inode() >>> require agf require inode bp >>> >>> The task requires inode bp with agf held block other tasks which >>> want to require agf with agi held. Then the whole filesystem >>> looks like a agi/agf deadlock. To fix this issue, get agf in >>> xfs_iunlink_remove() after it get agi and before get indoe bp. >>> >>> Signed-off-by: Wang Jianchao (Kuaishou) <jianchao.wan9@gmail.com> >>> --- >>> fs/xfs/xfs_inode.c | 10 ++++++++++ >>> 1 file changed, 10 insertions(+) >>> >>> diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c >>> index 9de6205fe134..c0a29fd00b0e 100644 >>> --- a/fs/xfs/xfs_inode.c >>> +++ b/fs/xfs/xfs_inode.c >>> @@ -36,6 +36,7 @@ >>> #include "xfs_reflink.h" >>> #include "xfs_ag.h" >>> #include "xfs_log_priv.h" >>> +#include "xfs_alloc.h" >>> >>> struct kmem_cache *xfs_inode_cache; >>> >>> @@ -2337,6 +2338,7 @@ xfs_iunlink_remove( >>> { >>> struct xfs_mount *mp = tp->t_mountp; >>> struct xfs_agi *agi; >>> + struct xfs_buf *agfbp; >>> struct xfs_buf *agibp; >>> struct xfs_buf *last_ibp; >>> struct xfs_dinode *last_dip = NULL; >>> @@ -2352,6 +2354,14 @@ xfs_iunlink_remove( >>> error = xfs_read_agi(mp, tp, pag->pag_agno, &agibp); >>> if (error) >>> return error; >>> + >>> + /* >>> + * Get the agf buffer first to ensure the lock ordering against inode bp >>> + */ >>> + error = xfs_read_agf(mp, tp, pag->pag_agno, 0, &agfbp); >>> + if (error) >>> + return error; >>> + >>> agi = agibp->b_addr; >>> >>> /*
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 9de6205fe134..c0a29fd00b0e 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -36,6 +36,7 @@ #include "xfs_reflink.h" #include "xfs_ag.h" #include "xfs_log_priv.h" +#include "xfs_alloc.h" struct kmem_cache *xfs_inode_cache; @@ -2337,6 +2338,7 @@ xfs_iunlink_remove( { struct xfs_mount *mp = tp->t_mountp; struct xfs_agi *agi; + struct xfs_buf *agfbp; struct xfs_buf *agibp; struct xfs_buf *last_ibp; struct xfs_dinode *last_dip = NULL; @@ -2352,6 +2354,14 @@ xfs_iunlink_remove( error = xfs_read_agi(mp, tp, pag->pag_agno, &agibp); if (error) return error; + + /* + * Get the agf buffer first to ensure the lock ordering against inode bp + */ + error = xfs_read_agf(mp, tp, pag->pag_agno, 0, &agfbp); + if (error) + return error; + agi = agibp->b_addr; /*
Recently, we encounter a deadlock case where there are many tasks hung on agi and agf xfs_buf. It end up with a deadlock between agf and inode xfs_buf as following, xfs_ifree() xfs_bmap_btalloc() xfs_iunlink_remove() xfs_alloc_vextent() hold inode bp hold agf xfs_difree() xfs_trans_log_inode() require agf require inode bp The task requires inode bp with agf held block other tasks which want to require agf with agi held. Then the whole filesystem looks like a agi/agf deadlock. To fix this issue, get agf in xfs_iunlink_remove() after it get agi and before get indoe bp. Signed-off-by: Wang Jianchao (Kuaishou) <jianchao.wan9@gmail.com> --- fs/xfs/xfs_inode.c | 10 ++++++++++ 1 file changed, 10 insertions(+)