smb3: retrying on failed server close

In the current implementation, CIFS close sends a close to the
server and does not check for the success of the server close.
This patch adds functionality to check for server close return
status and retries in case of an EBUSY or EAGAIN error.

This can help avoid handle leaks

Cc: stable@vger.kernel.org
Signed-off-by: Ritvik Budhiraja <rbudhiraja@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: Fix caching to try to do open O_WRONLY as rdwr on server

When we're engaged in local caching of a cifs filesystem, we cannot perform
caching of a partially written cache granule unless we can read the rest of
the granule. This can result in unexpected access errors being reported to
the user.

Fix this by the following: if a file is opened O_WRONLY locally, but the
mount was given the "-o fsc" flag, try first opening the remote file with
GENERIC_READ|GENERIC_WRITE and if that returns -EACCES, try dropping the
GENERIC_READ and doing the open again. If that last succeeds, invalidate
the cache for that file as for O_DIRECT.

Fixes: 70431bfd825d ("cifs: Support fscache indexing rewrite")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: fixes for get_inode_info

Fix potential memory leaks, add error checking, remove unnecessary
initialisation of status_file_deleted and do not use cifs_iget() to get
inode in reparse_info_to_fattr since fattrs may not be fully set.

Fixes: ffceb7640cbf ("smb: client: do not defer close open handles to deleted files")
Reported-by: Paulo Alcantara <pc@manguebit.com>
Signed-off-by: Meetakshi Setiya <msetiya@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: defer close file handles having RH lease

Previously we only deferred closing file handles with RHW
lease. To enhance performance benefits from deferred closes,
we now include handles with RH leases as well.

Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: Fix writeback data corruption

cifs writeback doesn't correctly handle the case where
cifs_extend_writeback() hits a point where it is considering an additional
folio, but this would overrun the wsize - at which point it drops out of
the xarray scanning loop and calls xas_pause(). The problem is that
xas_pause() advances the loop counter - thereby skipping that page.

What needs to happen is for xas_reset() to be called any time we decide we
don't want to process the page we're looking at, but rather send the
request we are building and start a new one.

Fix this by copying and adapting the netfslib writepages code as a
temporary measure, with cifs writeback intending to be offloaded to
netfslib in the near future.

This also fixes the issue with the use of filemap_get_folios_tag() causing
retry of a bunch of pages which the extender already dealt with.

This can be tested by creating, say, a 64K file somewhere not on cifs
(otherwise copy-offload may get underfoot), mounting a cifs share with a
wsize of 64000, copying the file to it and then comparing the original file
and the copy:

dd if=/dev/urandom of=/tmp/64K bs=64k count=1
mount //192.168.6.1/test /mnt -o user=...,pass=...,wsize=64000
cp /tmp/64K /mnt/64K
cmp /tmp/64K /mnt/64K

Without the fix, the cmp fails at position 64000 (or shortly thereafter).

Fixes: d08089f649a0 ("cifs: Change the I/O paths to use an iterator rather than a page list")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
cc: Shyam Prasad N <sprasad@microsoft.com>
cc: Tom Talpey <tom@talpey.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: client: do not defer close open handles to deleted files

When a file/dentry has been deleted before closing all its open
handles, currently, closing them can add them to the deferred
close list. This can lead to problems in creating file with the
same name when the file is re-created before the deferred close
completes. This issue was seen while reusing a client's already
existing lease on a file for compound operations and xfstest 591
failed because of the deferred close handle that remained valid
even after the file was deleted and was being reused to create a
file with the same name. The server in this case returns an error
on open with STATUS_DELETE_PENDING. Recreating the file would
fail till the deferred handles are closed (duration specified in
closetimeo).

This patch fixes the issue by flagging all open handles for the
deleted file (file path to be precise) by setting
status_file_deleted to true in the cifsFileInfo structure. As per
the information classes specified in MS-FSCC, SMB2 query info
response from the server has a DeletePending field, set to true
to indicate that deletion has been requested on that file. If
this is the case, flag the open handles for this file too.

When doing close in cifs_close for each of these handles, check the
value of this boolean field and do not defer close these handles
if the corresponding filepath has been deleted.

Signed-off-by: Meetakshi Setiya <msetiya@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb3: update allocation size more accurately on write completion

Changes to allocation size are approximated for extending writes of cached
files until the server returns the actual value (on SMB3 close or query info
for example), but it was setting the estimated value for number of blocks
to larger than the file size even if the file is likely sparse which
breaks various xfstests (e.g. generic/129, 130, 221, 228).

When i_size and i_blocks are updated in write completion do not increase
allocation size more than what was written (rounded up to 512 bytes).

Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: prevent updating file size from server if we have a read/write lease

In cases of large directories, the readdir operation may span multiple
round trips to retrieve contents. This introduces a potential race
condition in case of concurrent write and readdir operations. If the
readdir operation initiates before a write has been processed by the
server, it may update the file size attribute to an older value.
Address this issue by avoiding file size updates from readdir when we
have read/write lease.

Scenario:
1) process1: open dir xyz
2) process1: readdir instance 1 on xyz
3) process2: create file.txt for write
4) process2: write x bytes to file.txt
5) process2: close file.txt
6) process2: open file.txt for read
7) process1: readdir 2 - overwrites file.txt inode size to 0
8) process2: read contents of file.txt - bug, short read with 0 bytes

Cc: stable@vger.kernel.org
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb/client: adapt to breakup of struct file_lock

Most of the existing APIs have remained the same, but subsystems that
access file_lock fields directly need to reach into struct
file_lock_core now.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-44-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

filelock: split common fields into struct file_lock_core

In a future patch, we're going to split file leases into their own
structure. Since a lot of the underlying machinery uses the same fields
move those into a new file_lock_core, and embed that inside struct
file_lock.

For now, add some macros to ensure that we can continue to build while
the conversion is in progress.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-17-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

smb/client: convert to using new filelock helpers

Convert to using the new file locking helper functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-14-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

cifs: change tcon status when need_reconnect is set on it

When a tcon is marked for need_reconnect, the intention
is to have it reconnected.

This change adjusts tcon->status in cifs_tree_connect
when need_reconnect is set. Also, this change has a minor
correction in resetting need_reconnect on success. It makes
sure that it is done with tc_lock held.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: set replay flag for retries of write command

Similar to the rest of the commands, this is a change
to add replay flags on retry. This one does not add a
back-off, considering that we may want to flush a write
ASAP to the server. Considering that this will be a
flush of cached pages, the retrans value is also not
honoured.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: Share server EOF pos with netfslib

Use cifsi->netfs_ctx.remote_i_size instead of cifsi->server_eof so that
netfslib can refer to it to.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Shyam Prasad N <nspmangalore@gmail.com>
cc: Rohith Surabattula <rohiths.msft@gmail.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cifs@vger.kernel.org
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: Don't use certain unnecessary folio_*() functions

Filesystems should use folio->index and folio->mapping, instead of
folio_index(folio), folio_mapping() and folio_file_mapping() since
they know that it's in the pagecache.

Change this automagically with:

perl -p -i -e 's/folio_mapping[(]([^)]*)[)]/\1->mapping/g' fs/smb/client/*.c
perl -p -i -e 's/folio_file_mapping[(]([^)]*)[)]/\1->mapping/g' fs/smb/client/*.c
perl -p -i -e 's/folio_index[(]([^)]*)[)]/\1->index/g' fs/smb/client/*.c

Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: Steve French <sfrench@samba.org>
cc: Paulo Alcantara <pc@manguebit.com>
cc: Ronnie Sahlberg <lsahlber@redhat.com>
cc: Shyam Prasad N <sprasad@microsoft.com>
cc: Tom Talpey <tom@talpey.com>
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org

netfs: Move pinning-for-writeback from fscache to netfs

Move the resource pinning-for-writeback from fscache code to netfslib code.
This is used to keep a cache backing object pinned whilst we have dirty
pages on the netfs inode in the pagecache such that VM writeback will be
able to reach it.

Whilst we're at it, switch the parameters of netfs_unpin_writeback() to
match ->write_inode() so that it can be used for that directly.

Note that this mechanism could be more generically useful than that for
network filesystems. Quite often they have to keep around other resources
(e.g. authentication tokens or network connections) until the writeback is
complete.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org

smb: client: allow creating special files via reparse points

Add support for creating special files (e.g. char/block devices,
sockets, fifos) via NFS reparse points on SMB2+, which are fully
supported by most SMB servers and documented in MS-FSCC.

smb2_get_reparse_inode() creates the file with a corresponding reparse
point buffer set in @iov through a single roundtrip to the server.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202311260746.HOJ039BV-lkp@intel.com/
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: do not test the return value of folio_start_writeback()

In preparation for removing the return value entirely, stop testing it
in smb.

Link: https://lkml.kernel.org/r/20231108204605.745109-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Steve French <sfrench@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs: cifs: Fix atime update check

Commit 9b9c5bea0b96 ("cifs: do not return atime less than mtime") indicates
that in cifs, if atime is less than mtime, some apps will break.
Therefore, it introduce a function to compare this two variables in two
places where atime is updated. If atime is less than mtime, update it to
mtime.

However, the patch was handled incorrectly, resulting in atime and mtime
being exactly equal. A previous commit 69738cfdfa70 ("fs: cifs: Fix atime
update check vs mtime") fixed one place and forgot to fix another. Fix it.

Fixes: 9b9c5bea0b96 ("cifs: do not return atime less than mtime")
Cc: stable@vger.kernel.org
Signed-off-by: Zizhi Wo <wozizhi@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

client: convert to new timestamp accessors

Convert to using the new inode timestamp accessor functions.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20231004185347.80880-66-jlayton@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

smb: convert to ctime accessor functions

In later patches, we're going to change how the inode's ctime field is
used. Switch to using accessor functions instead of raw accesses of
inode->i_ctime.

Acked-by: Tom Talpey <tom@talpey.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Steve French <stfrench@microsoft.com>
Message-Id: <20230705190309.579783-72-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

cifs: update the ctime on a partial page write

POSIX says:

"Upon successful completion, where nbyte is greater than 0, write()
shall mark for update the last data modification and last file status
change timestamps of the file..."

Add the missing ctime update.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Steve French <stfrench@microsoft.com>
Message-Id: <20230705190309.579783-6-jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

cifs: Release folio lock on fscache read hit.

Under the current code, when cifs_readpage_worker is called, the call
contract is that the callee should unlock the page. This is documented
in the read_folio section of Documentation/filesystems/vfs.rst as:

> The filesystem should unlock the folio once the read has completed,
> whether it was successful or not.

Without this change, when fscache is in use and cache hit occurs during
a read, the page lock is leaked, producing the following stack on
subsequent reads (via mmap) to the page:

$ cat /proc/3890/task/12864/stack
[<0>] folio_wait_bit_common+0x124/0x350
[<0>] filemap_read_folio+0xad/0xf0
[<0>] filemap_fault+0x8b1/0xab0
[<0>] __do_fault+0x39/0x150
[<0>] do_fault+0x25c/0x3e0
[<0>] __handle_mm_fault+0x6ca/0xc70
[<0>] handle_mm_fault+0xe9/0x350
[<0>] do_user_addr_fault+0x225/0x6c0
[<0>] exc_page_fault+0x84/0x1b0
[<0>] asm_exc_page_fault+0x27/0x30

This requires a reboot to resolve; it is a deadlock.

Note however that the call to cifs_readpage_from_fscache does mark the
page clean, but does not free the folio lock. This happens in
__cifs_readpage_from_fscache on success. Releasing the lock at that
point however is not appropriate as cifs_readahead also calls
cifs_readpage_from_fscache and *does* unconditionally release the lock
after its return. This change therefore effectively makes
cifs_readpage_worker work like cifs_readahead.

Signed-off-by: Russell Harmon <russ@har.mn>
Acked-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: fix potential oops in cifs_oplock_break

With deferred close we can have closes that race with lease breaks,
and so with the current checks for whether to send the lease response,
oplock_response(), this can mean that an unmount (kill_sb) can occur
just before we were checking if the tcon->ses is valid. See below:

[Fri Aug 4 04:12:50 2023] RIP: 0010:cifs_oplock_break+0x1f7/0x5b0 [cifs]
[Fri Aug 4 04:12:50 2023] Code: 7d a8 48 8b 7d c0 c0 e9 02 48 89 45 b8 41 89 cf e8 3e f5 ff ff 4c 89 f7 41 83 e7 01 e8 82 b3 03 f2 49 8b 45 50 48 85 c0 74 5e <48> 83 78 60 00 74 57 45 84 ff 75 52 48 8b 43 98 48 83 eb 68 48 39
[Fri Aug 4 04:12:50 2023] RSP: 0018:ffffb30607ddbdf8 EFLAGS: 00010206
[Fri Aug 4 04:12:50 2023] RAX: 632d223d32612022 RBX: ffff97136944b1e0 RCX: 0000000080100009
[Fri Aug 4 04:12:50 2023] RDX: 0000000000000001 RSI: 0000000080100009 RDI: ffff97136944b188
[Fri Aug 4 04:12:50 2023] RBP: ffffb30607ddbe58 R08: 0000000000000001 R09: ffffffffc08e0900
[Fri Aug 4 04:12:50 2023] R10: 0000000000000001 R11: 000000000000000f R12: ffff97136944b138
[Fri Aug 4 04:12:50 2023] R13: ffff97149147c000 R14: ffff97136944b188 R15: 0000000000000000
[Fri Aug 4 04:12:50 2023] FS: 0000000000000000(0000) GS:ffff9714f7c00000(0000) knlGS:0000000000000000
[Fri Aug 4 04:12:50 2023] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[Fri Aug 4 04:12:50 2023] CR2: 00007fd8de9c7590 CR3: 000000011228e000 CR4: 0000000000350ef0
[Fri Aug 4 04:12:50 2023] Call Trace:
[Fri Aug 4 04:12:50 2023] <TASK>
[Fri Aug 4 04:12:50 2023] process_one_work+0x225/0x3d0
[Fri Aug 4 04:12:50 2023] worker_thread+0x4d/0x3e0
[Fri Aug 4 04:12:50 2023] ? process_one_work+0x3d0/0x3d0
[Fri Aug 4 04:12:50 2023] kthread+0x12a/0x150
[Fri Aug 4 04:12:50 2023] ? set_kthread_struct+0x50/0x50
[Fri Aug 4 04:12:50 2023] ret_from_fork+0x22/0x30
[Fri Aug 4 04:12:50 2023] </TASK>

To fix this change the ordering of the checks before sending the oplock_response
to first check if the openFileList is empty.

Fixes: da787d5b7498 ("SMB3: Do not send lease break acknowledgment if all file handles have been closed")
Suggested-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: if deferred close is disabled then close files immediately

If defer close timeout value is set to 0, then there is no
need to include files in the deferred close list and utilize
the delayed worker for closing. Instead, we can close them
immediately.

Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

SMB3: Do not send lease break acknowledgment if all file handles have been closed

In case if all existing file handles are deferred handles and if all of
them gets closed due to handle lease break then we dont need to send
lease break acknowledgment to server, because last handle close will be
considered as lease break ack.
After closing deferred handels, we check for openfile list of inode,
if its empty then we skip sending lease break ack.

Fixes: 59a556aebc43 ("SMB3: drop reference to cfile before sending oplock break")
Reviewed-by: Tom Talpey <tom@talpey.com>
Signed-off-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

cifs: fix lease break oops in xfstest generic/098

umount can race with lease break so need to check if
tcon->ses->server is still valid to send the lease
break response.

Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Fixes: 59a556aebc43 ("SMB3: drop reference to cfile before sending oplock break")
Signed-off-by: Steve French <stfrench@microsoft.com>

smb: move client and server files to common directory fs/smb

Move CIFS/SMB3 related client and server files (cifs.ko and ksmbd.ko
and helper modules) to new fs/smb subdirectory:

fs/cifs --> fs/smb/client
fs/ksmbd --> fs/smb/server
fs/smbfs_common --> fs/smb/common

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>