nvmet: use bvec_set_page to initialize bvecs

Use the bvec_set_page helper to initialize bvecs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Link: https://lore.kernel.org/r/20230203150634.3199647-7-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

use less confusing names for iov_iter direction initializers

READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

nvmet: only allocate a single slab for bvecs

There is no need to have a separate slab cache for each namespace,
and having separate ones creates duplicate debugs file names as well.

Fixes: d5eff33ee6f8 ("nvmet: add simple file backed ns support")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

keep iocb_flags() result cached in struct file

* calculate at the time we set FMODE_OPENED (do_dentry_open() for normal
opens, alloc_file() for pipe()/socket()/etc.)
* update when handling F_SETFL
* keep in a new field - file->f_iocb_flags; since that thing is needed only
before the refcount reaches zero, we can put it into the same anon union
where ->f_rcuhead and ->f_llist live - those are used only after refcount
reaches zero.

Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

nvmet: use a private workqueue instead of the system workqueue

Any attempt to flush kernel-global WQs has possibility of deadlock
so we should simply stop using them, instead introduce nvmet_wq
which is the generic nvmet workqueue for work elements that
don't explicitly require a dedicated workqueue (by the mere fact
that they are using the system_wq).

Changes were done using the following replaces:

- s/schedule_work(/queue_work(nvmet_wq, /g
- s/schedule_delayed_work(/queue_delayed_work(nvmet_wq, /g
- s/flush_scheduled_work()/flush_workqueue(nvmet_wq)/g

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: use i_size_read() to set size for file-ns

Instead of calling vfs_getattr() use i_size_read() to read the size of
file so we can read the size of not only file type but also block type
with one call. This is needed to implement buffered_io support for the
NVMeOF block device backend.

We also change return type of function nvmet_file_ns_revalidate() from
int to void, since this function does not return any meaning value.

Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: use IOCB_NOWAIT only if the filesystem supports it

Submit I/O requests with the IOCB_NOWAIT flag set only if
the underlying filesystem supports it.

Fixes: 50a909db36f2 ("nvmet: use IOCB_NOWAIT for file-ns buffered I/O")
Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

fs: get rid of the res2 iocb->ki_complete argument

The second argument was only used by the USB gadget code, yet everyone
pays the overhead of passing a zero to be passed into aio, where it
ends up being part of the aio res2 value.

Now that everybody is passing in zero, kill off the extra argument.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvmet: use req->cmd directly in file-ns fast path

The function nvmet_file_parse_io_cmd() is called from the fast path. The
local variable to that function cmd is only used once.

Remove the local variable and use req->cmd directly.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: seset ns->file when open fails

Reset the ns->file value to NULL also in the error case in
nvmet_file_ns_enable().

The ns->file variable points either to file object or contains the
error code after the filp_open() call. This can lead to following
problem:

When the user first setups an invalid file backend and tries to enable
the ns, it will fail. Then the user switches over to a bdev backend
and enables successfully the ns. The first received I/O will crash the
system because the IO backend is chosen based on the ns->file value:

static u16 nvmet_parse_io_cmd(struct nvmet_req *req)
{
[...]

if (req->ns->file)
return nvmet_file_parse_io_cmd(req);

return nvmet_bdev_parse_io_cmd(req);
}

Reported-by: Enzo Matsumiya <ematsumiya@suse.com>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: use invalid cmd opcode helper

In the NVMeOF block device backend, file backend, and passthru backend
we reject and report the commands if opcode is not handled.

Use the previously introduced helper in file backend to reduce the
duplicate code and make the error message uniform.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: rename nvmet_check_data_len to nvmet_check_transfer_len

The function doesn't check only the data length, because the transfer
length includes also the metadata length in some cases. This is
preparation for adding metadata (T10-PI) support.

Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: rename nvmet_rw_len to nvmet_rw_data_len

The function doesn't add the metadata length (only data length is
calculated). This is preparation for adding metadata (T10-PI) support.

Signed-off-by: Israel Rukshin <israelr@mellanox.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: add ns revalidation support

Add support for detecting capacity changes on nvmet blockdev and file
backed namespaces. This allows for emulating and testing online resizing
of nvme devices and filesystems on top.

Signed-off-by: Anthony Iliopoulos <ailiop@suse.com>
[chaitanya: Fix comments posted on V1]
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
[hch: reuse code a bit more]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvmet: fix dsm failure when payload does not match sgl descriptor

The host is allowed to pass the controller an sgl describing a buffer
that is larger than the dsm payload itself, allow it when executing
dsm.

Reported-by: Dakshaja Uppalapati <dakshaja@chelsio.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>,
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>

nvmet: Remove the data_len field from the nvmet_req struct

Instead of storing the expected length and checking it when it's
executed, just check the length inside the command themselves.

A new helper, nvmet_check_data_len() is created to help with this
check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
[split patch, udpate changelog]
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvmet: Introduce nvmet_dsm_len() helper

Similar to the nvmet_rw_len helper.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
[split patch, update changelog]
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvmet-file: clamp-down file namespace lba_shift

When the backing file is a tempfile for example, the inode i_blkbits
can be 1M in size which causes problems for hosts to support as the
disk block size. Instead, expose the minimum between i_blkbits and
12 (4K sector size).

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by:- Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: fix building bvec from sg list

There are two mistakes for building bvec from sg list for file
backed ns:

- use request data length to compute number of io vector, this way
doesn't consider sg->offset, and the result may be smaller than required
io vectors

- bvec->bv_len isn't capped by sg->length

This patch fixes this issue by building bvec from sg directly, given
the whole IO stack is ready for multi-page bvec.

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Fixes: 3a85a5de29ea ("nvme-loop: add a NVMe loopback host driver")

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: ignore EOPNOTSUPP for discard

NVMe DSM is a pure hint, so if the underlying device / file system
does not support discard-like operations we should not fail the
operation but rather return success.

Fixes: 3b031d15995f ("nvmet: add error log support for bdev backend")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Tested-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

nvmet: add error log support for file backend

This patch adds support for the file backend to populate the
error log entries. Here we map the errno to the NVMe status codes.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: use IOCB_NOWAIT for file-ns buffered I/O

This patch optimizes read command behavior when file-ns configured
with buffered I/O. Instead of offloading the buffered I/O read operations
to the worker threads, we first issue the read operation with IOCB_NOWAIT
and try and access the data from the cache. Here we only offload the
request to the worker thread and complete the request in the worker
thread context when IOCB_NOWAIT request fails.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

iov_iter: Separate type from direction and use accessor functions

In the iov_iter struct, separate the iterator type from the iterator
direction and use accessor functions to access them in most places.

Convert a bunch of places to use switch-statements to access them rather
then chains of bitwise-AND statements. This makes it easier to add further
iterator types. Also, this can be more efficient as to implement a switch
of small contiguous integers, the compiler can use ~50% fewer compare
instructions than it has to use bitwise-and instructions.

Further, cease passing the iterator type into the iterator setup function.
The iterator function can set that itself. Only the direction is required.

Signed-off-by: David Howells <dhowells@redhat.com>

nvmet: avoid integer overflow in the discard code

Although I'm not sure whether it is a good idea to support large discard
commands, I think integer overflow for discard ranges larger than 4 GB
should be avoided. This patch avoids that smatch reports the following:

drivers/nvme/target/io-cmd-file.c:249:1 nvmet_file_execute_discard() warn: should '((range.nlb)) << req->ns->blksize_shift' be a 64 bit type?

Fixes: d5eff33ee6f8 ("nvmet: add simple file backed ns support")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: add ns write protect support

This patch implements the Namespace Write Protect feature described in
"NVMe TP 4005a Namespace Write Protect". In this version, we implement
No Write Protect and Write Protect states for target ns which can be
toggled by set-features commands from the host side.

For write-protect state transition, we need to flush the ns specified
as a part of command so we also add helpers for carrying out synchronous
flush operations.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
[hch: fixed an incorrect endianess conversion, minor cleanups]
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: check fileio lba range access boundaries

Fail out-of-bounds with a proper status code.

Fixes: d5eff33ee6f8 ("nvmet: add simple file backed ns support")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: fix file discard return status

If nvmet_copy_from_sgl failed, we falsly return successful
completion status.

Fixes: d5eff33ee6f8 ("nvmet: add simple file backed ns support")
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: add buffered I/O support for file backed ns

Add a new "buffered_io" attribute, which disabled direct I/O and thus
enables page cache based caching when enabled. The attribute can only
be changed when the namespace is disabled as the file has to be reopend
for the change to take effect.

The possibly blocking read/write are deferred to a newly introduced
global workqueue.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: fix error return code in nvmet_file_ns_enable()

Fix to return error code -ENOMEM from the memory alloc fail error
handling case instead of 0, as done elsewhere in this function.

Fixes: d5eff33ee6f8 ("nvmet: add simple file backed ns support")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.e>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: fix a typo in nvmet_file_ns_enable()

Fix a typo in nvmet_file_ns_enable().

Fixes: d5eff33ee6f8 ("nvmet: add simple file backed ns support")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.e>
Signed-off-by: Christoph Hellwig <hch@lst.de>

nvmet: add simple file backed ns support

This patch adds simple file backed namespace support for NVMeOF target.

The new file io-cmd-file.c is responsible for handling the code for I/O
commands when ns is file backed. Also, we introduce mempools based slow
path using sync I/Os for file backed ns to ensure forward progress under
reclaim.

The old block device based implementation is moved to io-cmd-bdev.c and
use a "nvmet_bdev_" symbol prefix. The enable/disable calls are also
move into the respective files.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
[hch: updated changelog, fixed double req->ns lookup in bdev case]
Signed-off-by: Christoph Hellwig <hch@lst.de>