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32546a9586
linux/fs/cifs
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Ronnie Sahlberg 32546a9586 cifs: move cifsFileInfo_put logic into a work-queue 
This patch moves the final part of the cifsFileInfo_put() logic where we
need a write lock on lock_sem to be processed in a separate thread that
holds no other locks.
This is to prevent deadlocks like the one below:

> there are 6 processes looping to while trying to down_write
> cinode->lock_sem, 5 of them from _cifsFileInfo_put, and one from
> cifs_new_fileinfo
>
> and there are 5 other processes which are blocked, several of them
> waiting on either PG_writeback or PG_locked (which are both set), all
> for the same page of the file
>
> 2 inode_lock() (inode->i_rwsem) for the file
> 1 wait_on_page_writeback() for the page
> 1 down_read(inode->i_rwsem) for the inode of the directory
> 1 inode_lock()(inode->i_rwsem) for the inode of the directory
> 1 __lock_page
>
>
> so processes are blocked waiting on:
>   page flags PG_locked and PG_writeback for one specific page
>   inode->i_rwsem for the directory
>   inode->i_rwsem for the file
>   cifsInodeInflock_sem
>
>
>
> here are the more gory details (let me know if I need to provide
> anything more/better):
>
> [0 00:48:22.765] [UN]  PID: 8863   TASK: ffff8c691547c5c0  CPU: 3
> COMMAND: "reopen_file"
>  #0 [ffff9965007e3ba8] __schedule at ffffffff9b6e6095
>  #1 [ffff9965007e3c38] schedule at ffffffff9b6e64df
>  #2 [ffff9965007e3c48] rwsem_down_write_slowpath at ffffffff9af283d7
>  #3 [ffff9965007e3cb8] legitimize_path at ffffffff9b0f975d
>  #4 [ffff9965007e3d08] path_openat at ffffffff9b0fe55d
>  #5 [ffff9965007e3dd8] do_filp_open at ffffffff9b100a33
>  #6 [ffff9965007e3ee0] do_sys_open at ffffffff9b0eb2d6
>  #7 [ffff9965007e3f38] do_syscall_64 at ffffffff9ae04315
> * (I think legitimize_path is bogus)
>
> in path_openat
>         } else {
>                 const char *s = path_init(nd, flags);
>                 while (!(error = link_path_walk(s, nd)) &&
>                         (error = do_last(nd, file, op)) > 0) {  <<<<
>
> do_last:
>         if (open_flag & O_CREAT)
>                 inode_lock(dir->d_inode);  <<<<
>         else
> so it's trying to take inode->i_rwsem for the directory
>
>      DENTRY           INODE           SUPERBLK     TYPE PATH
> ffff8c68bb8e79c0 ffff8c691158ef20 ffff8c6915bf9000 DIR  /mnt/vm1_smb/
> inode.i_rwsem is ffff8c691158efc0
>
> <struct rw_semaphore 0xffff8c691158efc0>:
>         owner: <struct task_struct 0xffff8c6914275d00> (UN -   8856 -
> reopen_file), counter: 0x0000000000000003
>         waitlist: 2
>         0xffff9965007e3c90     8863   reopen_file      UN 0  1:29:22.926
>   RWSEM_WAITING_FOR_WRITE
>         0xffff996500393e00     9802   ls               UN 0  1:17:26.700
>   RWSEM_WAITING_FOR_READ
>
>
> the owner of the inode.i_rwsem of the directory is:
>
> [0 00:00:00.109] [UN]  PID: 8856   TASK: ffff8c6914275d00  CPU: 3
> COMMAND: "reopen_file"
>  #0 [ffff99650065b828] __schedule at ffffffff9b6e6095
>  #1 [ffff99650065b8b8] schedule at ffffffff9b6e64df
>  #2 [ffff99650065b8c8] schedule_timeout at ffffffff9b6e9f89
>  #3 [ffff99650065b940] msleep at ffffffff9af573a9
>  #4 [ffff99650065b948] _cifsFileInfo_put.cold.63 at ffffffffc0a42dd6 [cifs]
>  #5 [ffff99650065ba38] cifs_writepage_locked at ffffffffc0a0b8f3 [cifs]
>  #6 [ffff99650065bab0] cifs_launder_page at ffffffffc0a0bb72 [cifs]
>  #7 [ffff99650065bb30] invalidate_inode_pages2_range at ffffffff9b04d4bd
>  #8 [ffff99650065bcb8] cifs_invalidate_mapping at ffffffffc0a11339 [cifs]
>  #9 [ffff99650065bcd0] cifs_revalidate_mapping at ffffffffc0a1139a [cifs]
> #10 [ffff99650065bcf0] cifs_d_revalidate at ffffffffc0a014f6 [cifs]
> #11 [ffff99650065bd08] path_openat at ffffffff9b0fe7f7
> #12 [ffff99650065bdd8] do_filp_open at ffffffff9b100a33
> #13 [ffff99650065bee0] do_sys_open at ffffffff9b0eb2d6
> #14 [ffff99650065bf38] do_syscall_64 at ffffffff9ae04315
>
> cifs_launder_page is for page 0xffffd1e2c07d2480
>
> crash> page.index,mapping,flags 0xffffd1e2c07d2480
>       index = 0x8
>       mapping = 0xffff8c68f3cd0db0
>   flags = 0xfffffc0008095
>
>   PAGE-FLAG       BIT  VALUE
>   PG_locked         0  0000001
>   PG_uptodate       2  0000004
>   PG_lru            4  0000010
>   PG_waiters        7  0000080
>   PG_writeback     15  0008000
>
>
> inode is ffff8c68f3cd0c40
> inode.i_rwsem is ffff8c68f3cd0ce0
>      DENTRY           INODE           SUPERBLK     TYPE PATH
> ffff8c68a1f1b480 ffff8c68f3cd0c40 ffff8c6915bf9000 REG
> /mnt/vm1_smb/testfile.8853
>
>
> this process holds the inode->i_rwsem for the parent directory, is
> laundering a page attached to the inode of the file it's opening, and in
> _cifsFileInfo_put is trying to down_write the cifsInodeInflock_sem
> for the file itself.
>
>
> <struct rw_semaphore 0xffff8c68f3cd0ce0>:
>         owner: <struct task_struct 0xffff8c6914272e80> (UN -   8854 -
> reopen_file), counter: 0x0000000000000003
>         waitlist: 1
>         0xffff9965005dfd80     8855   reopen_file      UN 0  1:29:22.912
>   RWSEM_WAITING_FOR_WRITE
>
> this is the inode.i_rwsem for the file
>
> the owner:
>
> [0 00:48:22.739] [UN]  PID: 8854   TASK: ffff8c6914272e80  CPU: 2
> COMMAND: "reopen_file"
>  #0 [ffff99650054fb38] __schedule at ffffffff9b6e6095
>  #1 [ffff99650054fbc8] schedule at ffffffff9b6e64df
>  #2 [ffff99650054fbd8] io_schedule at ffffffff9b6e68e2
>  #3 [ffff99650054fbe8] __lock_page at ffffffff9b03c56f
>  #4 [ffff99650054fc80] pagecache_get_page at ffffffff9b03dcdf
>  #5 [ffff99650054fcc0] grab_cache_page_write_begin at ffffffff9b03ef4c
>  #6 [ffff99650054fcd0] cifs_write_begin at ffffffffc0a064ec [cifs]
>  #7 [ffff99650054fd30] generic_perform_write at ffffffff9b03bba4
>  #8 [ffff99650054fda8] __generic_file_write_iter at ffffffff9b04060a
>  #9 [ffff99650054fdf0] cifs_strict_writev.cold.70 at ffffffffc0a4469b [cifs]
> #10 [ffff99650054fe48] new_sync_write at ffffffff9b0ec1dd
> #11 [ffff99650054fed0] vfs_write at ffffffff9b0eed35
> #12 [ffff99650054ff00] ksys_write at ffffffff9b0eefd9
> #13 [ffff99650054ff38] do_syscall_64 at ffffffff9ae04315
>
> the process holds the inode->i_rwsem for the file to which it's writing,
> and is trying to __lock_page for the same page as in the other processes
>
>
> the other tasks:
> [0 00:00:00.028] [UN]  PID: 8859   TASK: ffff8c6915479740  CPU: 2
> COMMAND: "reopen_file"
>  #0 [ffff9965007b39d8] __schedule at ffffffff9b6e6095
>  #1 [ffff9965007b3a68] schedule at ffffffff9b6e64df
>  #2 [ffff9965007b3a78] schedule_timeout at ffffffff9b6e9f89
>  #3 [ffff9965007b3af0] msleep at ffffffff9af573a9
>  #4 [ffff9965007b3af8] cifs_new_fileinfo.cold.61 at ffffffffc0a42a07 [cifs]
>  #5 [ffff9965007b3b78] cifs_open at ffffffffc0a0709d [cifs]
>  #6 [ffff9965007b3cd8] do_dentry_open at ffffffff9b0e9b7a
>  #7 [ffff9965007b3d08] path_openat at ffffffff9b0fe34f
>  #8 [ffff9965007b3dd8] do_filp_open at ffffffff9b100a33
>  #9 [ffff9965007b3ee0] do_sys_open at ffffffff9b0eb2d6
> #10 [ffff9965007b3f38] do_syscall_64 at ffffffff9ae04315
>
> this is opening the file, and is trying to down_write cinode->lock_sem
>
>
> [0 00:00:00.041] [UN]  PID: 8860   TASK: ffff8c691547ae80  CPU: 2
> COMMAND: "reopen_file"
> [0 00:00:00.057] [UN]  PID: 8861   TASK: ffff8c6915478000  CPU: 3
> COMMAND: "reopen_file"
> [0 00:00:00.059] [UN]  PID: 8858   TASK: ffff8c6914271740  CPU: 2
> COMMAND: "reopen_file"
> [0 00:00:00.109] [UN]  PID: 8862   TASK: ffff8c691547dd00  CPU: 6
> COMMAND: "reopen_file"
>  #0 [ffff9965007c3c78] __schedule at ffffffff9b6e6095
>  #1 [ffff9965007c3d08] schedule at ffffffff9b6e64df
>  #2 [ffff9965007c3d18] schedule_timeout at ffffffff9b6e9f89
>  #3 [ffff9965007c3d90] msleep at ffffffff9af573a9
>  #4 [ffff9965007c3d98] _cifsFileInfo_put.cold.63 at ffffffffc0a42dd6 [cifs]
>  #5 [ffff9965007c3e88] cifs_close at ffffffffc0a07aaf [cifs]
>  #6 [ffff9965007c3ea0] __fput at ffffffff9b0efa6e
>  #7 [ffff9965007c3ee8] task_work_run at ffffffff9aef1614
>  #8 [ffff9965007c3f20] exit_to_usermode_loop at ffffffff9ae03d6f
>  #9 [ffff9965007c3f38] do_syscall_64 at ffffffff9ae0444c
>
> closing the file, and trying to down_write cifsi->lock_sem
>
>
> [0 00:48:22.839] [UN]  PID: 8857   TASK: ffff8c6914270000  CPU: 7
> COMMAND: "reopen_file"
>  #0 [ffff9965006a7cc8] __schedule at ffffffff9b6e6095
>  #1 [ffff9965006a7d58] schedule at ffffffff9b6e64df
>  #2 [ffff9965006a7d68] io_schedule at ffffffff9b6e68e2
>  #3 [ffff9965006a7d78] wait_on_page_bit at ffffffff9b03cac6
>  #4 [ffff9965006a7e10] __filemap_fdatawait_range at ffffffff9b03b028
>  #5 [ffff9965006a7ed8] filemap_write_and_wait at ffffffff9b040165
>  #6 [ffff9965006a7ef0] cifs_flush at ffffffffc0a0c2fa [cifs]
>  #7 [ffff9965006a7f10] filp_close at ffffffff9b0e93f1
>  #8 [ffff9965006a7f30] __x64_sys_close at ffffffff9b0e9a0e
>  #9 [ffff9965006a7f38] do_syscall_64 at ffffffff9ae04315
>
> in __filemap_fdatawait_range
>                         wait_on_page_writeback(page);
> for the same page of the file
>
>
>
> [0 00:48:22.718] [UN]  PID: 8855   TASK: ffff8c69142745c0  CPU: 7
> COMMAND: "reopen_file"
>  #0 [ffff9965005dfc98] __schedule at ffffffff9b6e6095
>  #1 [ffff9965005dfd28] schedule at ffffffff9b6e64df
>  #2 [ffff9965005dfd38] rwsem_down_write_slowpath at ffffffff9af283d7
>  #3 [ffff9965005dfdf0] cifs_strict_writev at ffffffffc0a0c40a [cifs]
>  #4 [ffff9965005dfe48] new_sync_write at ffffffff9b0ec1dd
>  #5 [ffff9965005dfed0] vfs_write at ffffffff9b0eed35
>  #6 [ffff9965005dff00] ksys_write at ffffffff9b0eefd9
>  #7 [ffff9965005dff38] do_syscall_64 at ffffffff9ae04315
>
>         inode_lock(inode);
>
>
> and one 'ls' later on, to see whether the rest of the mount is available
> (the test file is in the root, so we get blocked up on the directory
> ->i_rwsem), so the entire mount is unavailable
>
> [0 00:36:26.473] [UN]  PID: 9802   TASK: ffff8c691436ae80  CPU: 4
> COMMAND: "ls"
>  #0 [ffff996500393d28] __schedule at ffffffff9b6e6095
>  #1 [ffff996500393db8] schedule at ffffffff9b6e64df
>  #2 [ffff996500393dc8] rwsem_down_read_slowpath at ffffffff9b6e9421
>  #3 [ffff996500393e78] down_read_killable at ffffffff9b6e95e2
>  #4 [ffff996500393e88] iterate_dir at ffffffff9b103c56
>  #5 [ffff996500393ec8] ksys_getdents64 at ffffffff9b104b0c
>  #6 [ffff996500393f30] __x64_sys_getdents64 at ffffffff9b104bb6
>  #7 [ffff996500393f38] do_syscall_64 at ffffffff9ae04315
>
> in iterate_dir:
>         if (shared)
>                 res = down_read_killable(&inode->i_rwsem);  <<<<
>         else
>                 res = down_write_killable(&inode->i_rwsem);
>

Reported-by: Frank Sorenson <sorenson@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 01:17:12 -06:00
..
asn1.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
cache.c cifs: use 64-bit timestamps for fscache 2018-08-07 14:15:41 -05:00
cifs_debug.c cifs: Don't display RDMA transport on reconnect 2019-11-25 01:14:14 -06:00
cifs_debug.h cifs: add a debug macro that prints \\server\share for errors 2019-09-16 11:43:38 -05:00
cifs_dfs_ref.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
cifs_fs_sb.h smb3: add mount option to allow RW caching of share accessed by only 1 client 2019-09-16 11:43:38 -05:00
cifs_ioctl.h smb3: allow decryption keys to be dumped by admin for debugging 2019-09-21 06:02:26 -05:00
cifs_spnego.c cifs: switch servers depending on binding state 2019-11-25 01:16:30 -06:00
cifs_spnego.h [CIFS] Rename three structures to avoid camel case 2011-05-27 04:34:02 +00:00
cifs_unicode.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
cifs_unicode.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
cifs_uniupr.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
cifsacl.c cifs: remove unused variable 'sid_user' 2019-11-25 01:14:14 -06:00
cifsacl.h smb3: missing ACL related flags 2019-09-26 16:37:43 -05:00
cifsencrypt.c fs: cifs: switch to RC4 library interface 2019-06-20 14:19:55 +08:00
cifsfs.c cifs: move cifsFileInfo_put logic into a work-queue 2019-11-25 01:17:12 -06:00
cifsfs.h cifs: add support for flock 2019-11-25 01:14:14 -06:00
cifsglob.h cifs: move cifsFileInfo_put logic into a work-queue 2019-11-25 01:17:12 -06:00
cifspdu.h smb3: missing defines and structs for reparse point handling 2018-11-02 14:09:41 -05:00
cifsproto.h cifs: try opening channels after mounting 2019-11-25 01:16:30 -06:00
cifsroot.c cifs: cifsroot: add more err checking 2019-09-16 11:43:39 -05:00
cifssmb.c smb3: pass mode bits into create calls 2019-09-26 02:06:42 -05:00
connect.c cifs: try opening channels after mounting 2019-11-25 01:16:30 -06:00
dfs_cache.c fs: cifs: Drop unlikely before IS_ERR(_OR_NULL) 2019-07-07 22:37:42 -05:00
dfs_cache.h cifs: Fix DFS cache refresher for DFS links 2019-05-07 23:24:54 -05:00
dir.c CIFS: Return directly after a failed build_path_from_dentry() in cifs_do_create() 2019-11-25 01:14:53 -06:00
dns_resolve.c keys: Pass the network namespace into request_key mechanism 2019-06-27 23:02:12 +01:00
dns_resolve.h DNS: Separate out CIFS DNS Resolver code 2010-08-05 17:17:51 +00:00
export.c docs: fs: convert docs without extension to ReST 2019-07-31 13:31:05 -06:00
file.c cifs: move cifsFileInfo_put logic into a work-queue 2019-11-25 01:17:12 -06:00
fscache.c cifs: use 64-bit timestamps for fscache 2018-08-07 14:15:41 -05:00
fscache.h cifs: use 64-bit timestamps for fscache 2018-08-07 14:15:41 -05:00
inode.c CIFS: refactor cifs_get_inode_info() 2019-11-25 01:16:30 -06:00
ioctl.c smb3: allow decryption keys to be dumped by admin for debugging 2019-09-21 06:02:26 -05:00
Kconfig various cifs/smb3 fixes (including for share deleted cases) and features including improved encrypted read performance, and various debugging improvements 2019-09-19 10:32:16 -07:00
link.c SMB3: Clean up query symlink when reparse point 2019-05-07 23:24:55 -05:00
Makefile cifs: Add support for root file systems 2019-09-16 11:43:38 -05:00
misc.c cifs: replace various strncpy with strscpy and similar 2019-08-27 17:25:12 -05:00
netmisc.c fs: cifs: mute -Wunused-const-variable message 2019-10-06 22:04:35 -05:00
nterr.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 2019-05-24 17:36:45 +02:00
nterr.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61 2019-05-24 17:36:45 +02:00
ntlmssp.h cifs: dynamic allocation of ntlmssp blob 2016-06-23 23:45:07 -05:00
readdir.c cifs: check ntwrk_buf_start for NULL before dereferencing it 2018-12-23 22:41:31 -06:00
rfc1002pdu.h
sess.c cifs: try opening channels after mounting 2019-11-25 01:16:30 -06:00
smb1ops.c CIFS: avoid using MID 0xFFFF 2019-10-20 19:19:49 -05:00
smb2file.c cifs: Fix cifsInodeInfo lock_sem deadlock when reconnect occurs 2019-10-24 21:35:04 -05:00
smb2glob.h cifs: change SMB2_OP_RENAME and SMB2_OP_HARDLINK to use compounding 2018-10-23 21:16:04 -05:00
smb2inode.c smb3: pass mode bits into create calls 2019-09-26 02:06:42 -05:00
smb2maperror.c smb3: improve handling of share deleted (and share recreated) 2019-09-16 11:43:38 -05:00
smb2misc.c cifs: try opening channels after mounting 2019-11-25 01:16:30 -06:00
smb2ops.c cifs: try opening channels after mounting 2019-11-25 01:16:30 -06:00
smb2pdu.c cifs: try opening channels after mounting 2019-11-25 01:16:30 -06:00
smb2pdu.h SMB3: Fix persistent handles reconnect 2019-11-06 21:32:18 -06:00
smb2proto.h cifs: add server param 2019-11-25 01:16:30 -06:00
smb2status.h cifs: don't use __constant_cpu_to_le32() 2019-05-07 23:24:54 -05:00
smb2transport.c cifs: try opening channels after mounting 2019-11-25 01:16:30 -06:00
smbdirect.c cifs: smbd: Only queue work for error recovery on memory registration 2019-11-25 01:16:30 -06:00
smbdirect.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 2019-05-30 11:26:37 -07:00
smbencrypt.c fs: cifs: move from the crypto cipher API to the new DES library interface 2019-08-22 14:57:34 +10:00
smberr.h cifs: map NT_STATUS_ERROR_WRITE_PROTECTED to -EROFS 2010-08-02 12:40:40 +00:00
smbfsctl.h smb3: Add missing reparse tags 2019-09-24 23:31:32 -05:00
trace.c smb3: Cleanup license mess 2019-01-24 09:37:33 -06:00
trace.h smb3: add missing worker function for SMB3 change notify 2019-09-16 11:43:39 -05:00
transport.c cifs: try opening channels after mounting 2019-11-25 01:16:30 -06:00
winucase.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
xattr.c CIFS: fix max ea value size 2019-09-23 23:28:59 -05:00