Use the actual length of volume coherency data when setting the
xattr to avoid the following KASAN report.

 BUG: KASAN: slab-out-of-bounds in cachefiles_set_volume_xattr+0xa0/0x350 [cachefiles]
 Write of size 4 at addr ffff888101e02af4 by task kworker/6:0/1347

 CPU: 6 PID: 1347 Comm: kworker/6:0 Kdump: loaded Not tainted 5.18.0-rc1-nfs-fscache-netfs+ #13
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-4.fc34 04/01/2014
 Workqueue: events fscache_create_volume_work [fscache]
 Call Trace:
  <TASK>
  dump_stack_lvl+0x45/0x5a
  print_report.cold+0x5e/0x5db
  ? __lock_text_start+0x8/0x8
  ? cachefiles_set_volume_xattr+0xa0/0x350 [cachefiles]
  kasan_report+0xab/0x120
  ? cachefiles_set_volume_xattr+0xa0/0x350 [cachefiles]
  kasan_check_range+0xf5/0x1d0
  memcpy+0x39/0x60
  cachefiles_set_volume_xattr+0xa0/0x350 [cachefiles]
  cachefiles_acquire_volume+0x2be/0x500 [cachefiles]
  ? __cachefiles_free_volume+0x90/0x90 [cachefiles]
  fscache_create_volume_work+0x68/0x160 [fscache]
  process_one_work+0x3b7/0x6a0
  worker_thread+0x2c4/0x650
  ? process_one_work+0x6a0/0x6a0
  kthread+0x16c/0x1a0
  ? kthread_complete_and_exit+0x20/0x20
  ret_from_fork+0x22/0x30
  </TASK>

 Allocated by task 1347:
  kasan_save_stack+0x1e/0x40
  __kasan_kmalloc+0x81/0xa0
  cachefiles_set_volume_xattr+0x76/0x350 [cachefiles]
  cachefiles_acquire_volume+0x2be/0x500 [cachefiles]
  fscache_create_volume_work+0x68/0x160 [fscache]
  process_one_work+0x3b7/0x6a0
  worker_thread+0x2c4/0x650
  kthread+0x16c/0x1a0
  ret_from_fork+0x22/0x30

 The buggy address belongs to the object at ffff888101e02af0
 which belongs to the cache kmalloc-8 of size 8
 The buggy address is located 4 bytes inside of
 8-byte region [ffff888101e02af0, ffff888101e02af8)

 The buggy address belongs to the physical page:
 page:00000000a2292d70 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x101e02
 flags: 0x17ffffc0000200(slab|node=0|zone=2|lastcpupid=0x1fffff)
 raw: 0017ffffc0000200 0000000000000000 dead000000000001 ffff888100042280
 raw: 0000000000000000 0000000080660066 00000001ffffffff 0000000000000000
 page dumped because: kasan: bad access detected

 Memory state around the buggy address:
 ffff888101e02980: fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc
 ffff888101e02a00: 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00
 >ffff888101e02a80: fc fc fc fc 00 fc fc fc fc 00 fc fc fc fc 04 fc
                                                            ^
 ffff888101e02b00: fc fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc
 ffff888101e02b80: fc fc 00 fc fc fc fc 00 fc fc fc fc 00 fc fc fc
 ==================================================================

Fixes: 413a4a6b0b55 "cachefiles: Fix volume coherency attribute"
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/20220405134649.6579-1-dwysocha@redhat.com/ # v1
Link: https://lore.kernel.org/r/20220405142810.8208-1-dwysocha@redhat.com/ # Incorrect v2

Unmark inode in use if error encountered. If the in-use flag leakage
occurs in cachefiles_open_file(), Cachefiles will complain "Inode
already in use" when later another cookie with the same index key is
looked up.

If the in-use flag leakage occurs in cachefiles_create_tmpfile(), though
the "Inode already in use" warning won't be triggered, fix the leakage
anyway.

Reported-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Fixes: 1f08c925e7a3 ("cachefiles: Implement backing file wrangling")
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://listman.redhat.com/archives/linux-cachefs/2022-March/006615.html # v1
Link: https://listman.redhat.com/archives/linux-cachefs/2022-March/006618.html # v2

Pull netfs updates from David Howells:
 "Netfs prep for write helpers.

  Having had a go at implementing write helpers and content encryption
  support in netfslib, it seems that the netfs_read_{,sub}request
  structs and the equivalent write request structs were almost the same
  and so should be merged, thereby requiring only one set of
  alloc/get/put functions and a common set of tracepoints.

  Merging the structs also has the advantage that if a bounce buffer is
  added to the request struct, a read operation can be performed to fill
  the bounce buffer, the contents of the buffer can be modified and then
  a write operation can be performed on it to send the data wherever it
  needs to go using the same request structure all the way through. The
  I/O handlers would then transparently perform any required crypto.
  This should make it easier to perform RMW cycles if needed.

  The potentially common functions and structs, however, by their names
  all proclaim themselves to be associated with the read side of things.

  The bulk of these changes alter this in the following ways:

   - Rename struct netfs_read_{,sub}request to netfs_io_{,sub}request.

   - Rename some enums, members and flags to make them more appropriate.

   - Adjust some comments to match.

   - Drop "read"/"rreq" from the names of common functions. For
     instance, netfs_get_read_request() becomes netfs_get_request().

   - The ->init_rreq() and ->issue_op() methods become ->init_request()
     and ->issue_read(). I've kept the latter as a read-specific
     function and in another branch added an ->issue_write() method.

  The driver source is then reorganised into a number of files:

        fs/netfs/buffered_read.c        Create read reqs to the pagecache
        fs/netfs/io.c                   Dispatchers for read and write reqs
        fs/netfs/main.c                 Some general miscellaneous bits
        fs/netfs/objects.c              Alloc, get and put functions
        fs/netfs/stats.c                Optional procfs statistics.

  and future development can be fitted into this scheme, e.g.:

        fs/netfs/buffered_write.c       Modify the pagecache
        fs/netfs/buffered_flush.c       Writeback from the pagecache
        fs/netfs/direct_read.c          DIO read support
        fs/netfs/direct_write.c         DIO write support
        fs/netfs/unbuffered_write.c     Write modifications directly back

  Beyond the above changes, there are also some changes that affect how
  things work:

   - Make fscache_end_operation() generally available.

   - In the netfs tracing header, generate enums from the symbol ->
     string mapping tables rather than manually coding them.

   - Add a struct for filesystems that uses netfslib to put into their
     inode wrapper structs to hold extra state that netfslib is
     interested in, such as the fscache cookie. This allows netfslib
     functions to be set in filesystem operation tables and jumped to
     directly without having to have a filesystem wrapper.

   - Add a member to the struct added above to track the remote inode
     length as that may differ if local modifications are buffered. We
     may need to supply an appropriate EOF pointer when storing data (in
     AFS for example).

   - Pass extra information to netfs_alloc_request() so that the
     ->init_request() hook can access it and retain information to
     indicate the origin of the operation.

   - Make the ->init_request() hook return an error, thereby allowing a
     filesystem that isn't allowed to cache an inode (ceph or cifs, for
     example) to skip readahead.

   - Switch to using refcount_t for subrequests and add tracepoints to
     log refcount changes for the request and subrequest structs.

   - Add a function to consolidate dispatching a read request. Similar
     code is used in three places and another couple are likely to be
     added in the future"

Link: https://lore.kernel.org/all/2639515.1648483225@warthog.procyon.org.uk/

* tag 'netfs-prep-20220318' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Maintain netfs_i_context::remote_i_size
  netfs: Keep track of the actual remote file size
  netfs: Split some core bits out into their own file
  netfs: Split fs/netfs/read_helper.c
  netfs: Rename read_helper.c to io.c
  netfs: Prepare to split read_helper.c
  netfs: Add a function to consolidate beginning a read
  netfs: Add a netfs inode context
  ceph: Make ceph_init_request() check caps on readahead
  netfs: Change ->init_request() to return an error code
  netfs: Refactor arguments for netfs_alloc_read_request
  netfs: Adjust the netfs_failure tracepoint to indicate non-subreq lines
  netfs: Trace refcounting on the netfs_io_subrequest struct
  netfs: Trace refcounting on the netfs_io_request struct
  netfs: Adjust the netfs_rreq tracepoint slightly
  netfs: Split netfs_io_* object handling out
  netfs: Finish off rename of netfs_read_request to netfs_io_request
  netfs: Rename netfs_read_*request to netfs_io_*request
  netfs: Generate enums from trace symbol mapping lists
  fscache: export fscache_end_operation()

Pull NVMe write streams removal from Jens Axboe:
 "This removes the write streams support in NVMe. No vendor ever really
  shipped working support for this, and they are not interested in
  supporting it.

  With the NVMe support gone, we have nothing in the tree that supports
  this. Remove passing around of the hints.

  The only discussion point in this patchset imho is the fact that the
  file specific write hint setting/getting fcntl helpers will now return
  -1/EINVAL like they did before we supported write hints. No known
  applications use these functions, I only know of one prototype that I
  help do for RocksDB, and that's not used. That said, with a change
  like this, it's always a bit controversial. Alternatively, we could
  just make them return 0 and pretend it worked. It's placement based
  hints after all"

* tag 'for-5.18/write-streams-2022-03-18' of git://git.kernel.dk/linux-block:
  fs: remove fs.f_write_hint
  fs: remove kiocb.ki_hint
  block: remove the per-bio/request write hint
  nvme: remove support or stream based temperature hint

Adjust helper function names and comments after mass rename of
struct netfs_read_*request to struct netfs_io_*request.

Changes
=======
ver #2)
 - Make the changes in the docs also.

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

Link: https://lore.kernel.org/r/164622992433.3564931.6684311087845150271.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/164678196111.1200972.5001114956865989528.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692892567.2099075.13895804222087028813.stgit@warthog.procyon.org.uk/ # v3

Rename netfs_read_*request to netfs_io_*request so that the same structures
can be used for the write helpers too.

perl -p -i -e 's/netfs_read_(request|subrequest)/netfs_io_$1/g' \
   `git grep -l 'netfs_read_\(sub\|\)request'`
perl -p -i -e 's/nr_rd_ops/nr_outstanding/g' \
   `git grep -l nr_rd_ops`
perl -p -i -e 's/nr_wr_ops/nr_copy_ops/g' \
   `git grep -l nr_wr_ops`
perl -p -i -e 's/netfs_read_source/netfs_io_source/g' \
   `git grep -l 'netfs_read_source'`
perl -p -i -e 's/netfs_io_request_ops/netfs_request_ops/g' \
   `git grep -l 'netfs_io_request_ops'`
perl -p -i -e 's/init_rreq/init_request/g' \
   `git grep -l 'init_rreq'`

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

Link: https://lore.kernel.org/r/164622988070.3564931.7089670190434315183.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/164678195157.1200972.366609966927368090.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692891535.2099075.18435198075367420588.stgit@warthog.procyon.org.uk/ # v3

A network filesystem may set coherency data on a volume cookie, and if
given, cachefiles will store this in an xattr on the directory in the
cache corresponding to the volume.

The function that sets the xattr just stores the contents of the volume
coherency buffer directly into the xattr, with nothing added; the
checking function, on the other hand, has a cut'n'paste error whereby it
tries to interpret the xattr contents as would be the xattr on an
ordinary file (using the cachefiles_xattr struct).  This results in a
failure to match the coherency data because the buffer ends up being
shifted by 18 bytes.

Fix this by defining a structure specifically for the volume xattr and
making both the setting and checking functions use it.

Since the volume coherency doesn't work if used, take the opportunity to
insert a reserved field for future use, set it to 0 and check that it is
0.  Log mismatch through the appropriate tracepoint.

Note that this only affects cifs; 9p, afs, ceph and nfs don't use the
volume coherency data at the moment.

Fixes: 32e150037dce ("fscache, cachefiles: Store the volume coherency data")
Reported-by: Rohith Surabattula <rohiths.msft@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Steve French <smfrench@gmail.com>
cc: linux-cifs@vger.kernel.org
cc: linux-cachefs@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This field is entirely unused now except for a tracepoint in f2fs, so
remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220308060529.736277-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When cachefiles_shorten_object() calls fallocate() to shape the cache
file to match the DIO size, it passes the total file size it wants to
achieve, not the amount of zeros that should be inserted.  Since this is
meant to preallocate that amount of storage for the file, it can cause
the cache to fill up the disk and hit ENOSPC.

Fix this by passing the length actually required to go from the current
EOF to the desired EOF.

Fixes: 7623ed6772de ("cachefiles: Implement cookie resize for truncate")
Reported-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/164630854858.3665356.17419701804248490708.stgit@warthog.procyon.org.uk # v1
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add a netfs_cache_ops method by which a network filesystem can ask the
cache about what data it has available and where so that it can make a
multipage read more efficient.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Acked-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Rohith Surabattula <rohiths@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>