linux/fs/xfs
Darrick J. Wong 27fb5a72f5 xfs: prohibit fs freezing when using empty transactions
I noticed that fsfreeze can take a very long time to freeze an XFS if
there happens to be a GETFSMAP caller running in the background.  I also
happened to notice the following in dmesg:

------------[ cut here ]------------
WARNING: CPU: 2 PID: 43492 at fs/xfs/xfs_super.c:853 xfs_quiesce_attr+0x83/0x90 [xfs]
Modules linked in: xfs libcrc32c ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 ip_set_hash_ip ip_set_hash_net xt_tcpudp xt_set ip_set_hash_mac ip_set nfnetlink ip6table_filter ip6_tables bfq iptable_filter sch_fq_codel ip_tables x_tables nfsv4 af_packet [last unloaded: xfs]
CPU: 2 PID: 43492 Comm: xfs_io Not tainted 5.6.0-rc4-djw #rc4
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.10.2-1ubuntu1 04/01/2014
RIP: 0010:xfs_quiesce_attr+0x83/0x90 [xfs]
Code: 7c 07 00 00 85 c0 75 22 48 89 df 5b e9 96 c1 00 00 48 c7 c6 b0 2d 38 a0 48 89 df e8 57 64 ff ff 8b 83 7c 07 00 00 85 c0 74 de <0f> 0b 48 89 df 5b e9 72 c1 00 00 66 90 0f 1f 44 00 00 41 55 41 54
RSP: 0018:ffffc900030f3e28 EFLAGS: 00010202
RAX: 0000000000000001 RBX: ffff88802ac54000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81e4a6f0 RDI: 00000000ffffffff
RBP: ffff88807859f070 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000010 R12: 0000000000000000
R13: ffff88807859f388 R14: ffff88807859f4b8 R15: ffff88807859f5e8
FS:  00007fad1c6c0fc0(0000) GS:ffff88807e000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0c7d237000 CR3: 0000000077f01003 CR4: 00000000001606a0
Call Trace:
 xfs_fs_freeze+0x25/0x40 [xfs]
 freeze_super+0xc8/0x180
 do_vfs_ioctl+0x70b/0x750
 ? __fget_files+0x135/0x210
 ksys_ioctl+0x3a/0xb0
 __x64_sys_ioctl+0x16/0x20
 do_syscall_64+0x50/0x1a0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

These two things appear to be related.  The assertion trips when another
thread initiates a fsmap request (which uses an empty transaction) after
the freezer waited for m_active_trans to hit zero but before the the
freezer executes the WARN_ON just prior to calling xfs_log_quiesce.

The lengthy delays in freezing happen because the freezer calls
xfs_wait_buftarg to clean out the buffer lru list.  Meanwhile, the
GETFSMAP caller is continuing to grab and release buffers, which means
that it can take a very long time for the buffer lru list to empty out.

We fix both of these races by calling sb_start_write to obtain freeze
protection while using empty transactions for GETFSMAP and for metadata
scrubbing.  The other two users occur during mount, during which time we
cannot fs freeze.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-03-26 08:19:24 -07:00
..
libxfs xfs: remove the di_version field from struct icdinode 2020-03-19 08:48:47 -07:00
scrub xfs: prohibit fs freezing when using empty transactions 2020-03-26 08:19:24 -07:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
kmem.c xfs: Correct comment tyops -> typos 2019-11-10 10:21:57 -08:00
kmem.h xfs: Remove kmem_zone_free() wrapper 2019-11-18 08:40:44 -08:00
Makefile xfs: introduce fake roots for ag-rooted btrees 2020-03-18 08:12:23 -07:00
mrlock.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_acl.c xfs: only allocate the buffer size actually needed in __xfs_set_acl 2020-03-02 20:55:55 -08:00
xfs_acl.h xfs: improve xfs_forget_acl 2020-03-02 20:55:55 -08:00
xfs_aops.c xfs: ratelimit xfs_discard_page messages 2020-03-02 20:55:51 -08:00
xfs_aops.h xfs: add a xfs_inode_buftarg helper 2019-10-28 08:37:54 -07:00
xfs_attr_inactive.c xfs: add a function to deal with corrupt buffers post-verifiers 2020-03-12 07:58:12 -07:00
xfs_attr_list.c xfs: add a function to deal with corrupt buffers post-verifiers 2020-03-12 07:58:12 -07:00
xfs_bio_io.c xfs: chain bios the right way around in xfs_rw_bdev 2019-07-10 10:04:16 -07:00
xfs_bmap_item.c xfs: Remove kmem_zone_free() wrapper 2019-11-18 08:40:44 -08:00
xfs_bmap_item.h xfs: merge xfs_bud_init into xfs_trans_get_bud 2019-06-28 19:27:36 -07:00
xfs_bmap_util.c xfs: remove the di_version field from struct icdinode 2020-03-19 08:48:47 -07:00
xfs_bmap_util.h xfs: simplify xfs_iomap_eof_align_last_fsb 2019-11-03 10:22:30 -08:00
xfs_buf_item.c xfs: add a new xfs_sb_version_has_v3inode helper 2020-03-19 08:47:34 -07:00
xfs_buf_item.h xfs: check log iovec size to make sure it's plausibly a buffer log format 2020-01-16 08:07:24 -08:00
xfs_buf.c xfs: xfs_buf_corruption_error should take __this_address 2020-03-12 07:58:12 -07:00
xfs_buf.h xfs: add a function to deal with corrupt buffers post-verifiers 2020-03-12 07:58:12 -07:00
xfs_dir2_readdir.c xfs: fix regression in "cleanup xfs_dir2_block_getdents" 2020-03-13 10:37:13 -07:00
xfs_discard.c xfs: remove XFS_BUF_TO_AGF 2020-03-11 09:11:39 -07:00
xfs_discard.h
xfs_dquot_item.c xfs: fix unmount hang and memory leak on shutdown during quotaoff 2020-03-18 08:12:23 -07:00
xfs_dquot_item.h xfs: factor out quotaoff intent AIL removal and memory free 2020-03-18 08:12:23 -07:00
xfs_dquot.c xfs: remove the kuid/kgid conversion wrappers 2020-03-02 20:55:50 -08:00
xfs_dquot.h xfs: remove the xfs_dq_logitem_t typedef 2019-11-13 18:22:26 -08:00
xfs_error.c xfs: xfs_buf_corruption_error should take __this_address 2020-03-12 07:58:12 -07:00
xfs_error.h xfs: xfs_buf_corruption_error should take __this_address 2020-03-12 07:58:12 -07:00
xfs_export.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_export.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extent_busy.c xfs: cleanup use of the XFS_ALLOC_ flags 2019-11-03 10:22:31 -08:00
xfs_extent_busy.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extfree_item.c xfs: Remove kmem_zone_free() wrapper 2019-11-18 08:40:44 -08:00
xfs_extfree_item.h xfs: merge xfs_efd_init into xfs_trans_get_efd 2019-06-28 19:27:35 -07:00
xfs_file.c xfs: fix IOCB_NOWAIT handling in xfs_file_dio_aio_read 2020-01-15 22:13:11 -08:00
xfs_filestream.c xfs: make xfs_*read_agf return EAGAIN to ALLOC_FLAG_TRYLOCK callers 2020-01-26 14:32:26 -08:00
xfs_filestream.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_fsmap.c xfs: prohibit fs freezing when using empty transactions 2020-03-26 08:19:24 -07:00
xfs_fsmap.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_fsops.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_fsops.h xfs: change some error-less functions to void types 2019-05-01 20:26:30 -07:00
xfs_globals.c xfs: multithreaded iwalk implementation 2019-07-03 07:33:26 -07:00
xfs_health.c xfs: introduce new v5 bulkstat structure 2019-07-03 20:36:26 -07:00
xfs_icache.c xfs: ensure that the inode uid/gid match values match the icdinode ones 2020-03-02 20:55:50 -08:00
xfs_icache.h xfs: rename the speculative block allocation reclaim toggle functions 2019-04-26 12:28:55 -07:00
xfs_icreate_item.c xfs: Remove kmem_zone_free() wrapper 2019-11-18 08:40:44 -08:00
xfs_icreate_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_inode_item.c xfs: remove the di_version field from struct icdinode 2020-03-19 08:48:47 -07:00
xfs_inode_item.h xfs: remove the xfs_log_item_t typedef 2019-06-28 19:27:33 -07:00
xfs_inode.c xfs: remove the di_version field from struct icdinode 2020-03-19 08:48:47 -07:00
xfs_inode.h xfs: merge the projid fields in struct xfs_icdinode 2019-11-13 11:13:45 -08:00
xfs_ioctl32.c xfs: lift cursor copy in/out into xfs_ioc_attr_list 2020-03-02 20:55:54 -08:00
xfs_ioctl32.h xfs: rename compat_time_t to old_time32_t 2020-01-06 08:57:36 -08:00
xfs_ioctl.c xfs: remove the di_version field from struct icdinode 2020-03-19 08:48:47 -07:00
xfs_ioctl.h xfs: embedded the attrlist cursor into struct xfs_attr_list_context 2020-03-02 20:55:55 -08:00
xfs_iomap.c xfs: change return value of xfs_inode_need_cow to int 2020-01-20 14:34:47 -08:00
xfs_iomap.h xfs: simplify the xfs_iomap_write_direct calling 2019-11-03 10:22:30 -08:00
xfs_iops.c xfs: remove the di_version field from struct icdinode 2020-03-19 08:48:47 -07:00
xfs_iops.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_itable.c xfs: remove the di_version field from struct icdinode 2020-03-19 08:48:47 -07:00
xfs_itable.h xfs: remove all *_ITER_ABORT values 2019-08-29 21:22:41 -07:00
xfs_iwalk.c xfs: kill the XFS_WANT_CORRUPT_* macros 2019-11-12 17:19:02 -08:00
xfs_iwalk.h xfs: remove all *_ITER_CONTINUE values 2019-08-30 22:43:56 -07:00
xfs_linux.h xfs: clean up the attr flag confusion 2020-03-02 20:55:55 -08:00
xfs_log_cil.c xfs: remove the aborted parameter to xlog_state_done_syncing 2020-03-23 08:27:59 -07:00
xfs_log_priv.h xfs: remove the unused XLOG_UNMOUNT_REC_TYPE define 2020-03-13 10:37:15 -07:00
xfs_log_recover.c xfs: remove the di_version field from struct icdinode 2020-03-19 08:48:47 -07:00
xfs_log.c xfs: shutdown on failure to add page to log bio 2020-03-26 08:19:24 -07:00
xfs_log.h xfs: remove the aborted parameter to xlog_state_done_syncing 2020-03-23 08:27:59 -07:00
xfs_message.c xfs: make the assertion message functions take a mount parameter 2019-11-05 08:28:27 -08:00
xfs_message.h xfs: make the assertion message functions take a mount parameter 2019-11-05 08:28:27 -08:00
xfs_mount.c xfs: remove XFS_BUF_TO_SBP 2020-03-11 09:11:39 -07:00
xfs_mount.h xfs: remove unused structure members & simple typedefs 2019-11-13 18:22:41 -08:00
xfs_mru_cache.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_mru_cache.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_ondisk.h xfs: make struct xfs_buf_log_format have a consistent size 2020-01-16 08:07:23 -08:00
xfs_pnfs.c xfs: use super s_id instead of struct xfs_mount m_fsname 2019-11-05 08:28:25 -08:00
xfs_pnfs.h
xfs_pwork.c xfs: poll waiting for quotacheck 2019-07-03 08:21:58 -07:00
xfs_pwork.h xfs: poll waiting for quotacheck 2019-07-03 08:21:58 -07:00
xfs_qm_bhv.c xfs: remove the xfs_disk_dquot_t and xfs_dquot_t 2019-11-13 11:13:45 -08:00
xfs_qm_syscalls.c xfs: fix unmount hang and memory leak on shutdown during quotaoff 2020-03-18 08:12:23 -07:00
xfs_qm.c xfs: preserve default grace interval during quotacheck 2020-03-26 08:19:24 -07:00
xfs_qm.h xfs: quota: move to time64_t interfaces 2020-01-06 08:57:37 -08:00
xfs_quota.h xfs: remove the icdinode di_uid/di_gid members 2020-03-02 20:55:50 -08:00
xfs_quotaops.c xfs: quota: move to time64_t interfaces 2020-01-06 08:57:37 -08:00
xfs_refcount_item.c xfs: Remove kmem_zone_free() wrapper 2019-11-18 08:40:44 -08:00
xfs_refcount_item.h xfs: merge xfs_cud_init into xfs_trans_get_cud 2019-06-28 19:27:35 -07:00
xfs_reflink.c xfs: remove unnecessary null pointer checks from _read_agf callers 2020-01-26 14:32:27 -08:00
xfs_reflink.h xfs: change return value of xfs_inode_need_cow to int 2020-01-20 14:34:47 -08:00
xfs_rmap_item.c xfs: Remove kmem_zone_free() wrapper 2019-11-18 08:40:44 -08:00
xfs_rmap_item.h xfs: merge xfs_rud_init into xfs_trans_get_rud 2019-06-28 19:27:36 -07:00
xfs_rtalloc.c xfs: make xfs_trans_get_buf return an error code 2020-01-26 14:32:26 -08:00
xfs_rtalloc.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_stats.c xfs: Use scnprintf() for avoiding potential buffer overflow 2020-03-12 07:58:13 -07:00
xfs_stats.h xfs: use offsetof() in place of offset macros for __xfsstats 2018-10-18 17:21:39 +11:00
xfs_super.c Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-02-08 13:26:41 -08:00
xfs_super.h xfs: include QUOTA, FATAL ASSERT build options in XFS_BUILD_OPTIONS 2019-10-21 09:04:57 -07:00
xfs_symlink.c xfs: only check the superblock version for dinode size calculation 2020-03-19 08:48:47 -07:00
xfs_symlink.h xfs: Correct comment tyops -> typos 2019-11-10 10:21:57 -08:00
xfs_sysctl.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_sysctl.h xfs: multithreaded iwalk implementation 2019-07-03 07:33:26 -07:00
xfs_sysfs.c xfs: avoid unused to_mp() function warning 2019-09-24 09:40:19 -07:00
xfs_sysfs.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trace.c xfs: support bulk loading of staged btrees 2020-03-18 08:12:23 -07:00
xfs_trace.h xfs: support bulk loading of staged btrees 2020-03-18 08:12:23 -07:00
xfs_trans_ail.c xfs: clear PF_MEMALLOC before exiting xfsaild thread 2020-03-11 09:11:38 -07:00
xfs_trans_buf.c xfs: fix xfs_buf_ioerror_alert location reporting 2020-01-26 14:32:27 -08:00
xfs_trans_dquot.c xfs: quota: move to time64_t interfaces 2020-01-06 08:57:37 -08:00
xfs_trans_priv.h xfs: don't use xfs_trans_free_items in the commit path 2019-06-28 19:27:31 -07:00
xfs_trans.c xfs: prohibit fs freezing when using empty transactions 2020-03-26 08:19:24 -07:00
xfs_trans.h xfs: make xfs_trans_get_buf return an error code 2020-01-26 14:32:26 -08:00
xfs_xattr.c xfs: embedded the attrlist cursor into struct xfs_attr_list_context 2020-03-02 20:55:55 -08:00
xfs.h xfs: remove b_last_holder & associated macros 2018-08-12 08:37:31 -07:00