The caller of cifs_posix_lock_set will do retry(like
fcntl_setlk64->do_lock_file_wait) if we will wait for any file_lock.
So the retry in cifs_poxis_lock_set seems duplicated, remove it to
make a cleanup.
Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Adds calls to the newer info level for query info using SMB3.1.1 posix extensions.
The remaining two places that call the older query info (non-SMB3.1.1 POSIX)
require passing in the fid and can be updated in a later patch.
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
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Merge tag '5.8-rc-smb3-fixes-part-1' of git://git.samba.org/sfrench/cifs-2.6
Pull cifs updates from Steve French:
"22 changesets, 2 for stable.
Includes big performance improvement for large i/o when using
multichannel, also includes DFS fixes"
* tag '5.8-rc-smb3-fixes-part-1' of git://git.samba.org/sfrench/cifs-2.6: (22 commits)
cifs: update internal module version number
cifs: multichannel: try to rebind when reconnecting a channel
cifs: multichannel: use pointer for binding channel
smb3: remove static checker warning
cifs: multichannel: move channel selection above transport layer
cifs: multichannel: always zero struct cifs_io_parms
cifs: dump Security Type info in DebugData
smb3: fix incorrect number of credits when ioctl MaxOutputResponse > 64K
smb3: default to minimum of two channels when multichannel specified
cifs: multichannel: move channel selection in function
cifs: fix minor typos in comments and log messages
smb3: minor update to compression header definitions
cifs: minor fix to two debug messages
cifs: Standardize logging output
smb3: Add new parm "nodelete"
cifs: move some variables off the stack in smb2_ioctl_query_info
cifs: reduce stack use in smb2_compound_op
cifs: get rid of unused parameter in reconn_setup_dfs_targets()
cifs: handle hostnames that resolve to same ip in failover
cifs: set up next DFS target before generic_ip_connect()
...
Move the channel (TCP_Server_Info*) selection from the tranport
layer to higher in the call stack so that:
- credit handling is done with the server that will actually be used
to send.
* ->wait_mtu_credit
* ->set_credits / set_credits
* ->add_credits / add_credits
* add_credits_and_wake_if
- potential reconnection (smb2_reconnect) done when initializing a
request is checked and done with the server that will actually be
used to send.
To do this:
- remove the cifs_pick_channel() call out of compound_send_recv()
- select channel and pass it down by adding a cifs_pick_channel(ses)
call in:
- smb311_posix_mkdir
- SMB2_open
- SMB2_ioctl
- __SMB2_close
- query_info
- SMB2_change_notify
- SMB2_flush
- smb2_async_readv (if none provided in context param)
- SMB2_read (if none provided in context param)
- smb2_async_writev (if none provided in context param)
- SMB2_write (if none provided in context param)
- SMB2_query_directory
- send_set_info
- SMB2_oplock_break
- SMB311_posix_qfs_info
- SMB2_QFS_info
- SMB2_QFS_attr
- smb2_lockv
- SMB2_lease_break
- smb2_compound_op
- smb2_set_ea
- smb2_ioctl_query_info
- smb2_query_dir_first
- smb2_query_info_comound
- smb2_query_symlink
- cifs_writepages
- cifs_write_from_iter
- cifs_send_async_read
- cifs_read
- cifs_readpages
- add TCP_Server_Info *server param argument to:
- cifs_send_recv
- compound_send_recv
- SMB2_open_init
- SMB2_query_info_init
- SMB2_set_info_init
- SMB2_close_init
- SMB2_ioctl_init
- smb2_iotcl_req_init
- SMB2_query_directory_init
- SMB2_notify_init
- SMB2_flush_init
- build_qfs_info_req
- smb2_hdr_assemble
- smb2_reconnect
- fill_small_buf
- smb2_plain_req_init
- __smb2_plain_req_init
The read/write codepath is different than the rest as it is using
pages, io iterators and async calls. To deal with those we add a
server pointer in the cifs_writedata/cifs_readdata/cifs_io_parms
context struct and set it in:
- cifs_writepages (wdata)
- cifs_write_from_iter (wdata)
- cifs_readpages (rdata)
- cifs_send_async_read (rdata)
The [rw]data->server pointer is eventually copied to
cifs_io_parms->server to pass it down to SMB2_read/SMB2_write.
If SMB2_read/SMB2_write is called from a different place that doesn't
set the server field it will pick a channel.
Some places do not pick a channel and just use ses->server or
cifs_ses_server(ses). All cifs_ses_server(ses) calls are in codepaths
involving negprot/sess.setup.
- SMB2_negotiate (binding channel)
- SMB2_sess_alloc_buffer (binding channel)
- SMB2_echo (uses provided one)
- SMB2_logoff (uses master)
- SMB2_tdis (uses master)
(list not exhaustive)
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
SMB2_read/SMB2_write check and use cifs_io_parms->server, which might
be uninitialized memory.
This change makes all callers zero-initialize the struct.
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
They're the same function, and for the purpose of all callers they are
equivalent to lru_cache_add().
[akpm@linux-foundation.org: fix it for local_lock changes]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Link: http://lkml.kernel.org/r/20200520232525.798933-5-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use pr_fmt to standardize all logging for fs/cifs.
Some logging output had no CIFS: specific prefix.
Now all output has one of three prefixes:
o CIFS:
o CIFS: VFS:
o Root-CIFS:
Miscellanea:
o Convert printks to pr_<level>
o Neaten macro definitions
o Remove embedded CIFS: prefixes from formats
o Convert "illegal" to "invalid"
o Coalesce formats
o Add missing '\n' format terminations
o Consolidate multiple cifs_dbg continuations into single calls
o More consistent use of upper case first word output logging
o Multiline statement argument alignment and wrapping
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Add experimental support for allowing a swap file to be on an SMB3
mount. There are use cases where swapping over a secure network
filesystem is preferable. In some cases there are no local
block devices large enough, and network block devices can be
hard to setup and secure. And in some cases there are no
local block devices at all (e.g. with the recent addition of
remote boot over SMB3 mounts).
There are various enhancements that can be added later e.g.:
- doing a mandatory byte range lock over the swapfile (until
the Linux VFS is modified to notify the file system that an open
is for a swapfile, when the file can be opened "DENY_ALL" to prevent
others from opening it).
- pinning more buffers in the underlying transport to minimize memory
allocations in the TCP stack under the fs
- documenting how to create ACLs (on the server) to secure the
swapfile (or adding additional tools to cifs-utils to make it easier)
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
This patch is used to fix the bug in collect_uncached_read_data()
that rc is automatically converted from a signed number to an
unsigned number when the CIFS asynchronous read fails.
It will cause ctx->rc is error.
Example:
Share a directory and create a file on the Windows OS.
Mount the directory to the Linux OS using CIFS.
On the CIFS client of the Linux OS, invoke the pread interface to
deliver the read request.
The size of the read length plus offset of the read request is greater
than the maximum file size.
In this case, the CIFS server on the Windows OS returns a failure
message (for example, the return value of
smb2.nt_status is STATUS_INVALID_PARAMETER).
After receiving the response message, the CIFS client parses
smb2.nt_status to STATUS_INVALID_PARAMETER
and converts it to the Linux error code (rdata->result=-22).
Then the CIFS client invokes the collect_uncached_read_data function to
assign the value of rdata->result to rc, that is, rc=rdata->result=-22.
The type of the ctx->total_len variable is unsigned integer,
the type of the rc variable is integer, and the type of
the ctx->rc variable is ssize_t.
Therefore, during the ternary operation, the value of rc is
automatically converted to an unsigned number. The final result is
ctx->rc=4294967274. However, the expected result is ctx->rc=-22.
Signed-off-by: Yilu Lin <linyilu@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
There is measurable performance impact in some synthetic tests due to
commit 6d390e4b5d (locks: fix a potential use-after-free problem when
wakeup a waiter). Fix the race condition instead by clearing the
fl_blocker pointer after the wake_up, using explicit acquire/release
semantics.
This does mean that we can no longer use the clearing of fl_blocker as
the wait condition, so switch the waiters over to checking whether the
fl_blocked_member list_head is empty.
Reviewed-by: yangerkun <yangerkun@huawei.com>
Reviewed-by: NeilBrown <neilb@suse.de>
Fixes: 6d390e4b5d (locks: fix a potential use-after-free problem when wakeup a waiter)
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To rename a file in SMB2 we open it with the DELETE access and do a
special SetInfo on it. If the handle is missing the DELETE bit the
server will fail the SetInfo with STATUS_ACCESS_DENIED.
We currently try to reuse any existing opened handle we have with
cifs_get_writable_path(). That function looks for handles with WRITE
access but doesn't check for DELETE, making rename() fail if it finds
a handle to reuse. Simple reproducer below.
To select handles with the DELETE bit, this patch adds a flag argument
to cifs_get_writable_path() and find_writable_file() and the existing
'bool fsuid_only' argument is converted to a flag.
The cifsFileInfo struct only stores the UNIX open mode but not the
original SMB access flags. Since the DELETE bit is not mapped in that
mode, this patch stores the access mask in cifs_fid on file open,
which is accessible from cifsFileInfo.
Simple reproducer:
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#define E(s) perror(s), exit(1)
int main(int argc, char *argv[])
{
int fd, ret;
if (argc != 3) {
fprintf(stderr, "Usage: %s A B\n"
"create&open A in write mode, "
"rename A to B, close A\n", argv[0]);
return 0;
}
fd = openat(AT_FDCWD, argv[1], O_WRONLY|O_CREAT|O_SYNC, 0666);
if (fd == -1) E("openat()");
ret = rename(argv[1], argv[2]);
if (ret) E("rename()");
ret = close(fd);
if (ret) E("close()");
return ret;
}
$ gcc -o bugrename bugrename.c
$ ./bugrename /mnt/a /mnt/b
rename(): Permission denied
Fixes: 8de9e86c67 ("cifs: create a helper to find a writeable handle by path name")
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
We didn't have a dynamic trace point for catching errors in
file_write_and_wait_range error cases in cifs_strict_fsync.
Since not all apps check for write behind errors, it can be
important for debugging to be able to trace these error
paths.
Suggested-and-reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Makes it easier to debug errors on writeback that happen later,
and are being returned on flush or fsync
For example:
writetest-17829 [002] .... 13583.407859: cifs_flush_err: ino=90 rc=-28
Signed-off-by: Steve French <stfrench@microsoft.com>
When "backup intent" is requested on the mount (e.g. backupuid or
backupgid mount options), the corresponding flag was missing from
some of the operations.
Change all operations to use the macro cifs_create_options() to
set the backup intent flag if needed.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Don't use iov_iter::type directly, but rather use the new accessor
functions that have been added. This allows the .type field to be split
and rearranged without the need to update the filesystems.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Since timestamps on files on most servers can be updated at
close, and since timestamps on our dentries default to one
second we can have stale timestamps in some common cases
(e.g. open, write, close, stat, wait one second, stat - will
show different mtime for the first and second stat).
The SMB2/SMB3 protocol allows querying timestamps at close
so add the code to request timestamp and attr information
(which is cheap for the server to provide) to be returned
when a file is closed (it is not needed for the many
paths that call SMB2_close that are from compounded
query infos and close nor is it needed for some of
the cases where a directory close immediately follows a
directory open.
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Currently when the client creates a cifsFileInfo structure for
a newly opened file, it allocates a list of byte-range locks
with a pointer to the new cfile and attaches this list to the
inode's lock list. The latter happens before initializing all
other fields, e.g. cfile->tlink. Thus a partially initialized
cifsFileInfo structure becomes available to other threads that
walk through the inode's lock list. One example of such a thread
may be an oplock break worker thread that tries to push all
cached byte-range locks. This causes NULL-pointer dereference
in smb2_push_mandatory_locks() when accessing cfile->tlink:
[598428.945633] BUG: kernel NULL pointer dereference, address: 0000000000000038
...
[598428.945749] Workqueue: cifsoplockd cifs_oplock_break [cifs]
[598428.945793] RIP: 0010:smb2_push_mandatory_locks+0xd6/0x5a0 [cifs]
...
[598428.945834] Call Trace:
[598428.945870] ? cifs_revalidate_mapping+0x45/0x90 [cifs]
[598428.945901] cifs_oplock_break+0x13d/0x450 [cifs]
[598428.945909] process_one_work+0x1db/0x380
[598428.945914] worker_thread+0x4d/0x400
[598428.945921] kthread+0x104/0x140
[598428.945925] ? process_one_work+0x380/0x380
[598428.945931] ? kthread_park+0x80/0x80
[598428.945937] ret_from_fork+0x35/0x40
Fix this by reordering initialization steps of the cifsFileInfo
structure: initialize all the fields first and then add the new
byte-range lock list to the inode's lock list.
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currenly we doesn't assume that a server may break a lease
from RWH to RW which causes us setting a wrong lease state
on a file and thus mistakenly flushing data and byte-range
locks and purging cached data on the client. This leads to
performance degradation because subsequent IOs go directly
to the server.
Fix this by propagating new lease state and epoch values
to the oplock break handler through cifsFileInfo structure
and removing the use of cifsInodeInfo flags for that. It
allows to avoid some races of several lease/oplock breaks
using those flags in parallel.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
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>
Currently the client translates O_SYNC and O_DIRECT flags
into corresponding SMB create options when openning a file.
The problem is that on reconnect when the file is being
re-opened the client doesn't set those flags and it causes
a server to reject re-open requests because create options
don't match. The latter means that any subsequent system
call against that open file fail until a share is re-mounted.
Fix this by properly setting SMB create options when
re-openning files after reconnects.
Fixes: 1013e760d1: ("SMB3: Don't ignore O_SYNC/O_DSYNC and O_DIRECT flags")
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
On re-send, there might be a reconnect and all prevoius memory registrations
need to be invalidated and deregistered.
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Fixes gcc '-Wunused-but-set-variable' warning:
fs/cifs/file.c: In function 'cifs_flock':
fs/cifs/file.c:1704:8: warning:
variable 'netfid' set but not used [-Wunused-but-set-variable]
fs/cifs/file.c:1702:24: warning:
variable 'cinode' set but not used [-Wunused-but-set-variable]
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
The flock system call locks the whole file rather than a byte
range and so is currently emulated by various other file systems
by simply sending a byte range lock for the whole file.
Add flock handling for cifs.ko in similar way.
xfstest generic/504 passes with this as well
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
There's a deadlock that is possible and can easily be seen with
a test where multiple readers open/read/close of the same file
and a disruption occurs causing reconnect. The deadlock is due
a reader thread inside cifs_strict_readv calling down_read and
obtaining lock_sem, and then after reconnect inside
cifs_reopen_file calling down_read a second time. If in
between the two down_read calls, a down_write comes from
another process, deadlock occurs.
CPU0 CPU1
---- ----
cifs_strict_readv()
down_read(&cifsi->lock_sem);
_cifsFileInfo_put
OR
cifs_new_fileinfo
down_write(&cifsi->lock_sem);
cifs_reopen_file()
down_read(&cifsi->lock_sem);
Fix the above by changing all down_write(lock_sem) calls to
down_write_trylock(lock_sem)/msleep() loop, which in turn
makes the second down_read call benign since it will never
block behind the writer while holding lock_sem.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Suggested-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed--by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Currently the code assumes that if a file info entry belongs
to lists of open file handles of an inode and a tcon then
it has non-zero reference. The recent changes broke that
assumption when putting the last reference of the file info.
There may be a situation when a file is being deleted but
nothing prevents another thread to reference it again
and start using it. This happens because we do not hold
the inode list lock while checking the number of references
of the file info structure. Fix this by doing the proper
locking when doing the check.
Fixes: 487317c994 ("cifs: add spinlock for the openFileList to cifsInodeInfo")
Fixes: cb248819d2 ("cifs: use cifsInodeInfo->open_file_lock while iterating to avoid a panic")
Cc: Stable <stable@vger.kernel.org>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currently if the client identifies problems when processing
metadata returned in CREATE response, the open handle is being
leaked. This causes multiple problems like a file missing a lease
break by that client which causes high latencies to other clients
accessing the file. Another side-effect of this is that the file
can't be deleted.
Fix this by closing the file after the client hits an error after
the file was opened and the open descriptor wasn't returned to
the user space. Also convert -ESTALE to -EOPENSTALE to allow
the VFS to revalidate a dentry and retry the open.
Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
and convert smb2_query_path_info() to use it.
This will eliminate the need for a SMB2_Create when we already have an
open handle that can be used. This will also prevent a oplock break
in case the other handle holds a lease.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
rename() takes a path for old_file and in SMB2 we used to just create
a compound for create(old_path)/rename/close().
If we already have a writable handle we can avoid the create() and close()
altogether and just use the existing handle.
For this situation, as we avoid doing the create()
we also avoid triggering an oplock break for the existing handle.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Fixes gcc '-Wunused-but-set-variable' warning:
fs/cifs/file.c: In function cifs_lock:
fs/cifs/file.c:1696:24: warning: variable cinode set but not used [-Wunused-but-set-variable]
fs/cifs/file.c: In function cifs_write:
fs/cifs/file.c:1765:23: warning: variable cifs_sb set but not used [-Wunused-but-set-variable]
fs/cifs/file.c: In function collect_uncached_read_data:
fs/cifs/file.c:3578:20: warning: variable tcon set but not used [-Wunused-but-set-variable]
'cinode' is never used since introduced by
commit 03776f4516 ("CIFS: Simplify byte range locking code")
'cifs_sb' is not used since commit cb7e9eabb2 ("CIFS: Use
multicredits for SMB 2.1/3 writes").
'tcon' is not used since commit d26e2903fc ("smb3: fix bytes_read statistics")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
In smb3_punch_hole, variable cifsi set but not used, remove it.
In cifs_lock, variable netfid set but not used, remove it.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
We can not depend on the tcon->open_file_lock here since in multiuser mode
we may have the same file/inode open via multiple different tcons.
The current code is race prone and will crash if one user deletes a file
at the same time a different user opens/create the file.
To avoid this we need to have a spinlock attached to the inode and not the tcon.
RHBZ: 1580165
CC: Stable <stable@vger.kernel.org>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
In cifs_read_allocate_pages, in case of ENOMEM, we go through
whole rdata->pages array but we have failed the allocation before
nr_pages, therefore we may end up calling put_page with NULL
pointer, causing oops
Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Originally, filemap_write_and_wait took the i_mutex internally, but
commit 02c24a8218 pushed the mutex acquisition into the individual
fsync routines, leaving it up to the subsystem maintainers to remove
it if it wasn't needed.
For cifs, I see no reason to take the inode_lock here. All of the
operations inside that lock are protected in other ways.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
CIFS can leak pages reference gotten through GUP (get_user_pages*()
through iov_iter_get_pages()). This happen if cifs_send_async_read()
or cifs_write_from_iter() calls fail from within __cifs_readv() and
__cifs_writev() respectively. This patch move page unreference to
cifs_aio_ctx_release() which will happens on all code paths this is
all simpler to follow for correctness.
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
In the oplock break handler, writing pending changes from pages puts
the FileInfo handle. If the refcount reaches zero it closes the handle
and waits for any oplock break handler to return, thus causing a deadlock.
To prevent this situation:
* We add a wait flag to cifsFileInfo_put() to decide whether we should
wait for running/pending oplock break handlers
* We keep an additionnal reference of the SMB FileInfo handle so that
for the rest of the handler putting the handle won't close it.
- The ref is bumped everytime we queue the handler via the
cifs_queue_oplock_break() helper.
- The ref is decremented at the end of the handler
This bug was triggered by xfstest 464.
Also important fix to address the various reports of
oops in smb2_push_mandatory_locks
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
CC: Stable <stable@vger.kernel.org>
When sending a rdata, transport may return -EAGAIN. In this case
we should re-obtain credits because the session may have been
reconnected.
Change in v2: adjust_credits before re-sending
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
When sending a wdata, transport may return -EAGAIN. In this case
we should re-obtain credits because the session may have been
reconnected.
Change in v2: adjust_credits before re-sending
Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
We have a customer reporting crashes in lock_get_status() with many
"Leaked POSIX lock" messages preceeding the crash.
Leaked POSIX lock on dev=0x0:0x56 ...
Leaked POSIX lock on dev=0x0:0x56 ...
Leaked POSIX lock on dev=0x0:0x56 ...
Leaked POSIX lock on dev=0x0:0x53 ...
Leaked POSIX lock on dev=0x0:0x53 ...
Leaked POSIX lock on dev=0x0:0x53 ...
Leaked POSIX lock on dev=0x0:0x53 ...
POSIX: fl_owner=ffff8900e7b79380 fl_flags=0x1 fl_type=0x1 fl_pid=20709
Leaked POSIX lock on dev=0x0:0x4b ino...
Leaked locks on dev=0x0:0x4b ino=0xf911400000029:
POSIX: fl_owner=ffff89f41c870e00 fl_flags=0x1 fl_type=0x1 fl_pid=19592
stack segment: 0000 [#1] SMP
Modules linked in: binfmt_misc msr tcp_diag udp_diag inet_diag unix_diag af_packet_diag netlink_diag rpcsec_gss_krb5 arc4 ecb auth_rpcgss nfsv4 md4 nfs nls_utf8 lockd grace cifs sunrpc ccm dns_resolver fscache af_packet iscsi_ibft iscsi_boot_sysfs vmw_vsock_vmci_transport vsock xfs libcrc32c sb_edac edac_core crct10dif_pclmul crc32_pclmul ghash_clmulni_intel drbg ansi_cprng vmw_balloon aesni_intel aes_x86_64 lrw gf128mul glue_helper ablk_helper cryptd joydev pcspkr vmxnet3 i2c_piix4 vmw_vmci shpchp fjes processor button ac btrfs xor raid6_pq sr_mod cdrom ata_generic sd_mod ata_piix vmwgfx crc32c_intel drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm serio_raw ahci libahci drm libata vmw_pvscsi sg dm_multipath dm_mod scsi_dh_rdac scsi_dh_emc scsi_dh_alua scsi_mod autofs4
Supported: Yes
CPU: 6 PID: 28250 Comm: lsof Not tainted 4.4.156-94.64-default #1
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/05/2016
task: ffff88a345f28740 ti: ffff88c74005c000 task.ti: ffff88c74005c000
RIP: 0010:[<ffffffff8125dcab>] [<ffffffff8125dcab>] lock_get_status+0x9b/0x3b0
RSP: 0018:ffff88c74005fd90 EFLAGS: 00010202
RAX: ffff89bde83e20ae RBX: ffff89e870003d18 RCX: 0000000049534f50
RDX: ffffffff81a3541f RSI: ffffffff81a3544e RDI: ffff89bde83e20ae
RBP: 0026252423222120 R08: 0000000020584953 R09: 000000000000ffff
R10: 0000000000000000 R11: ffff88c74005fc70 R12: ffff89e5ca7b1340
R13: 00000000000050e5 R14: ffff89e870003d30 R15: ffff89e5ca7b1340
FS: 00007fafd64be800(0000) GS:ffff89f41fd00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001c80018 CR3: 000000a522048000 CR4: 0000000000360670
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
0000000000000208 ffffffff81a3d6b6 ffff89e870003d30 ffff89e870003d18
ffff89e5ca7b1340 ffff89f41738d7c0 ffff89e870003d30 ffff89e5ca7b1340
ffffffff8125e08f 0000000000000000 ffff89bc22b67d00 ffff88c74005ff28
Call Trace:
[<ffffffff8125e08f>] locks_show+0x2f/0x70
[<ffffffff81230ad1>] seq_read+0x251/0x3a0
[<ffffffff81275bbc>] proc_reg_read+0x3c/0x70
[<ffffffff8120e456>] __vfs_read+0x26/0x140
[<ffffffff8120e9da>] vfs_read+0x7a/0x120
[<ffffffff8120faf2>] SyS_read+0x42/0xa0
[<ffffffff8161cbc3>] entry_SYSCALL_64_fastpath+0x1e/0xb7
When Linux closes a FD (close(), close-on-exec, dup2(), ...) it calls
filp_close() which also removes all posix locks.
The lock struct is initialized like so in filp_close() and passed
down to cifs
...
lock.fl_type = F_UNLCK;
lock.fl_flags = FL_POSIX | FL_CLOSE;
lock.fl_start = 0;
lock.fl_end = OFFSET_MAX;
...
Note the FL_CLOSE flag, which hints the VFS code that this unlocking
is done for closing the fd.
filp_close()
locks_remove_posix(filp, id);
vfs_lock_file(filp, F_SETLK, &lock, NULL);
return filp->f_op->lock(filp, cmd, fl) => cifs_lock()
rc = cifs_setlk(file, flock, type, wait_flag, posix_lck, lock, unlock, xid);
rc = server->ops->mand_unlock_range(cfile, flock, xid);
if (flock->fl_flags & FL_POSIX && !rc)
rc = locks_lock_file_wait(file, flock)
Notice how we don't call locks_lock_file_wait() which does the
generic VFS lock/unlock/wait work on the inode if rc != 0.
If we are closing the handle, the SMB server is supposed to remove any
locks associated with it. Similarly, cifs.ko frees and wakes up any
lock and lock waiter when closing the file:
cifs_close()
cifsFileInfo_put(file->private_data)
/*
* Delete any outstanding lock records. We'll lose them when the file
* is closed anyway.
*/
down_write(&cifsi->lock_sem);
list_for_each_entry_safe(li, tmp, &cifs_file->llist->locks, llist) {
list_del(&li->llist);
cifs_del_lock_waiters(li);
kfree(li);
}
list_del(&cifs_file->llist->llist);
kfree(cifs_file->llist);
up_write(&cifsi->lock_sem);
So we can safely ignore unlocking failures in cifs_lock() if they
happen with the FL_CLOSE flag hint set as both the server and the
client take care of it during the actual closing.
This is not a proper fix for the unlocking failure but it's safe and
it seems to prevent the lock leakages and crashes the customer
experiences.
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: NeilBrown <neil@brown.name>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
When we have a READ lease for a file and have just issued a write
operation to the server we need to purge the cache and set oplock/lease
level to NONE to avoid reading stale data. Currently we do that
only if a write operation succedeed thus not covering cases when
a request was sent to the server but a negative error code was
returned later for some other reasons (e.g. -EIOCBQUEUED or -EINTR).
Fix this by turning off caching regardless of the error code being
returned.
The patches fixes generic tests 075 and 112 from the xfs-tests.
Cc: <stable@vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Now we just return NULL cifsFileInfo pointer in cases we didn't find
or couldn't reopen a file. This hides errors from cifs_reopen_file()
especially retryable errors which should be handled appropriately.
Create new cifs_get_writable_file() routine that returns error codes
from cifs_reopen_file() and use it in the writeback codepath.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currently we check for an open file existence in wdata_send_pages()
which doesn't provide an easy way to handle error codes that will
be returned from find_writable_filehandle() once it is changed.
Move the check to writepages.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currently wdata_send_pages() unlocks pages after sending.
This complicates further refactoring and doesn't align
with the function name. Move unlocking to writepages.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reorder finding and reopening a writable handle file and getting
MTU credits in writepages because we may be stuck on low credits
otherwise.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currently we get MTU credits before we check an open file if
it needs to be reopened. Reopening the file in such conditions
leads to a possibility of being stuck waiting indefinitely
for credits in the transport layer. Fix this by reopening the
file first if needed and then getting MTU credits for async IO.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Currently we adjust MTU credits before sending an IO request
and after reopening a file. This approach doesn't allow the
reopen routine to use existing credits that are not needed
for IO. Reorder credit adjustment and reopening a file to
use credits available to the client more efficiently. Also
unwrap complex if statement into few pieces to improve
readability.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Every time after a session reconnect we don't need to account for
credits obtained in previous sessions. Introduce new struct cifs_credits
which contains both credits value and reconnect instance of the
time those credits were taken. Modify a routine that add credits
back to handle the reconnect instance by assuming zero credits
if the reconnect happened after the credits were obtained and
before we decided to add them back due to some errors during sending.
This patch fixes the MTU credits cases. The subsequent patch
will handle non-MTU ones.
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
/proc/fs/cifs/Stats bytes_read was double counting reads when
uncached (ie mounted with cache=none)
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
