Commit Graph

26 Commits

Author SHA1 Message Date
Chao Yu
78486cf1f3 zonefs: fix to update .i_wr_refcnt correctly in zonefs_open_zone()
commit 6980d29ce4da223ad7f0751c7f1d61d3c6b54ab3 upstream.

In zonefs_open_zone(), if opened zone count is larger than
.s_max_open_zones threshold, we missed to recover .i_wr_refcnt,
fix this.

Fixes: b5c00e9757 ("zonefs: open/close zone on file open/close")
Cc: <stable@vger.kernel.org>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-25 09:04:05 +01:00
Damien Le Moal
9c1c5e81a0 zonefs: prevent use of seq files as swap file
commit 1601ea068b886da1f8f8d4e18b9403e9e24adef6 upstream.

The sequential write constraint of sequential zone file prevent their
use as swap files. Only allow conventional zone files to be used as swap
files.

Fixes: 8dcc1a9d90 ("fs: New zonefs file system")
Cc: <stable@vger.kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-25 09:04:05 +01:00
Damien Le Moal
dfbdbf0f35 zonefs: Fix O_APPEND async write handling
commit ebfd68cd0c1e81267c757332385cb96df30dacce upstream.

zonefs updates the size of a sequential zone file inode only on
completion of direct writes. When executing asynchronous append writes
(with a file open with O_APPEND or using RWF_APPEND), the use of the
current inode size in generic_write_checks() to set an iocb offset thus
leads to unaligned write if an application issues an append write
operation with another write already being executed.

Fix this problem by introducing zonefs_write_checks() as a modified
version of generic_write_checks() using the file inode wp_offset for an
append write iocb offset. Also introduce zonefs_write_check_limits() to
replace generic_write_check_limits() call. This zonefs special helper
makes sure that the maximum file limit used is the maximum size of the
file being accessed.

Since zonefs_write_checks() already truncates the iov_iter, the calls
to iov_iter_truncate() in zonefs_file_dio_write() and
zonefs_file_buffered_write() are removed.

Fixes: 8dcc1a9d90 ("fs: New zonefs file system")
Cc: <stable@vger.kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-25 09:04:05 +01:00
Shin'ichiro Kawasaki
834c7ec6af zonefs: Fix file size of zones in full condition
commit 059c01039c0185dbee7ed080f1f2bd22cb1e4dab upstream.

Per ZBC/ZAC/ZNS specifications, write pointers may not have valid values
when zones are in full condition. However, when zonefs mounts a zoned
block device, zonefs refers write pointers to set file size even when
the zones are in full condition. This results in wrong file size. To fix
this, refer maximum file size in place of write pointers for zones in
full condition.

Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Fixes: 8dcc1a9d90 ("fs: New zonefs file system")
Cc: <stable@vger.kernel.org> # 5.6+
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-04 11:38:41 +01:00
Arnd Bergmann
2bbe923d7a zonefs: select CONFIG_CRC32
commit 4f8b848788f77c7f5c3bd98febce66b7aa14785f upstream.

When CRC32 is disabled, zonefs cannot be linked:

ld: fs/zonefs/super.o: in function `zonefs_fill_super':

Add a Kconfig 'select' statement for it.

Fixes: 8dcc1a9d90 ("fs: New zonefs file system")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-17 14:17:03 +01:00
Damien Le Moal
6bea0225a4 zonefs: fix page reference and BIO leak
In zonefs_file_dio_append(), the pages obtained using
bio_iov_iter_get_pages() are not released on completion of the
REQ_OP_APPEND BIO, nor when bio_iov_iter_get_pages() fails.
Furthermore, a call to bio_put() is missing when
bio_iov_iter_get_pages() fails.

Fix these resource leaks by adding BIO resource release code (bio_put()i
and bio_release_pages()) at the end of the function after the BIO
execution and add a jump to this resource cleanup code in case of
bio_iov_iter_get_pages() failure.

While at it, also fix the call to task_io_account_write() to be passed
the correct BIO size instead of bio_iov_iter_get_pages() return value.

Reported-by: Christoph Hellwig <hch@lst.de>
Fixes: 02ef12a663 ("zonefs: use REQ_OP_ZONE_APPEND for sync DIO")
Cc: stable@vger.kernel.org
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-12-10 15:14:19 +09:00
Linus Torvalds
0eac1102e9 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "Assorted stuff all over the place (the largest group here is
  Christoph's stat cleanups)"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: remove KSTAT_QUERY_FLAGS
  fs: remove vfs_stat_set_lookup_flags
  fs: move vfs_fstatat out of line
  fs: implement vfs_stat and vfs_lstat in terms of vfs_fstatat
  fs: remove vfs_statx_fd
  fs: omfs: use kmemdup() rather than kmalloc+memcpy
  [PATCH] reduce boilerplate in fsid handling
  fs: Remove duplicated flag O_NDELAY occurring twice in VALID_OPEN_FLAGS
  selftests: mount: add nosymfollow tests
  Add a "nosymfollow" mount option.
2020-10-24 12:26:05 -07:00
Al Viro
6d1349c769 [PATCH] reduce boilerplate in fsid handling
Get rid of boilerplate in most of ->statfs()
instances...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-09-18 16:45:50 -04:00
Johannes Thumshirn
b5c00e9757 zonefs: open/close zone on file open/close
NVMe Zoned Namespace introduced the concept of active zones, which are
zones in the implicit open, explicit open or closed condition. Drives may
have a limit on the number of zones that can be simultaneously active.
This potential limitation translate into a risk for applications to see
write IO errors due to this limit if the zone of a file being written to is
not already active when a write request is issued.

To avoid these potential errors, the zone of a file can explicitly be made
active using an open zone command when the file is open for the first
time. If the zone open command succeeds, the application is then
guaranteed that write requests can be processed. This indirect management
of active zones relies on the maximum number of open zones of a drive,
which is always lower or equal to the maximum number of active zones.

On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN
command to the block device. Conversely, on the last release of a zone
file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or
empty.

As truncating a zone file to 0 or max can deactivate a zone as well, we
need to serialize against truncates and also be careful not to close a
zone as the file may still be open for writing, e.g. the user called
ftruncate(). If the zone file is not open and a process does a truncate(),
then no close operation is needed.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-15 18:32:52 +09:00
Johannes Thumshirn
48d546a8da zonefs: provide no-lock zonefs_io_error variant
Subsequent patches need to call zonefs_io_error() with the i_truncate_mutex
already held, so factor out the body of zonefs_io_error() into
__zonefs_io_error() which can be called from with the i_truncate_mutex
held.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-15 18:32:48 +09:00
Johannes Thumshirn
5498d5f932 zonefs: introduce helper for zone management
Introduce a helper function for sending zone management commands to the
block device.

As zone management commands can change a zone write pointer position
reflected in the size of the zone file, this function expects the truncate
mutex to be held.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-09-15 18:32:40 +09:00
Johannes Thumshirn
e3c3155bc9 zonefs: add zone-capacity support
In the zoned storage model, the sectors within a zone are typically all
writeable. With the introduction of the Zoned Namespace (ZNS) Command
Set in the NVM Express organization, the model was extended to have a
specific writeable capacity.

This zone capacity can be less than the overall zone size for a NVMe ZNS
device or null_blk in zoned-mode. For other ZBC/ZAC devices the zone
capacity is always equal to the zone size.

Use the zone capacity field instead from blk_zone for determining the
maximum inode size and inode blocks in zonefs.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-08-11 17:42:24 +09:00
Linus Torvalds
0e4656a299 New code for 5.9:
- Make sure we call ->iomap_end with a failure code if ->iomap_begin
   failed in any way; some filesystems need to try to undo things.
 - Don't invalidate the page cache during direct reads since we already
   sync'd the cache with disk.
 - Make direct writes fall back to the page cache if the pre-write
   cache invalidation fails.  This avoids a cache coherency problem.
 - Fix some idiotic virus scanner warning bs in the previous tag.
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Merge tag 'iomap-5.9-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull iomap updates from Darrick Wong:
 "The most notable changes are:

   - iomap no longer invalidates the page cache when performing a direct
     read, since doing so is unnecessary and the old directio code
     doesn't do that either.

   - iomap embraced the use of returning ENOTBLK from a direct write to
     trigger falling back to a buffered write since ext4 already did
     this and btrfs wants it for their port.

   - iomap falls back to buffered writes if we're doing a direct write
     and the page cache invalidation after the flush fails; this was
     necessary to handle a corner case in the btrfs port.

   - Remove email virus scanner detritus that was accidentally included
     in yesterday's pull request. Clearly I need(ed) to update my git
     branch checker scripts. :("

* tag 'iomap-5.9-merge-5' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  iomap: fall back to buffered writes for invalidation failures
  xfs: use ENOTBLK for direct I/O to buffered I/O fallback
  iomap: Only invalidate page cache pages on direct IO writes
  iomap: Make sure iomap_end is called after iomap_begin
2020-08-06 19:35:12 -07:00
Christoph Hellwig
60263d5889 iomap: fall back to buffered writes for invalidation failures
Failing to invalid the page cache means data in incoherent, which is
a very bad state for the system.  Always fall back to buffered I/O
through the page cache if we can't invalidate mappings.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Acked-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Theodore Ts'o <tytso@mit.edu> # for ext4
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com> # for gfs2
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
2020-08-05 09:24:16 -07:00
Johannes Thumshirn
89ee72376b zonefs: count pages after truncating the iterator
Count pages after possibly truncating the iterator to the maximum zone
append size, not before.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-07-20 17:59:31 +09:00
Damien Le Moal
01b2651cfb zonefs: Fix compilation warning
Avoid the compilation warning "Variable 'ret' is reassigned a value
before the old one has been used." in zonefs_create_zgroup() by setting
ret for the error path only if an error happens.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-07-20 17:57:50 +09:00
Linus Torvalds
d77d1dbba9 zonefs changes for 5.8
Only one patch in this pull request to cleanup handling of uuid using
 the import_uuid() helper, from Andy.
 
 Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
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Merge tag 'zonefs-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs

Pull zonefs update from Damien Le Moal:
 "Only one patch in this pull request to cleanup handling of uuid using
  the import_uuid() helper, from Andy"

* tag 'zonefs-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs:
  zonefs: Replace uuid_copy() with import_uuid()
2020-06-04 13:50:13 -07:00
Linus Torvalds
750a02ab8d for-5.8/block-2020-06-01
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Merge tag 'for-5.8/block-2020-06-01' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:
 "Core block changes that have been queued up for this release:

   - Remove dead blk-throttle and blk-wbt code (Guoqing)

   - Include pid in blktrace note traces (Jan)

   - Don't spew I/O errors on wouldblock termination (me)

   - Zone append addition (Johannes, Keith, Damien)

   - IO accounting improvements (Konstantin, Christoph)

   - blk-mq hardware map update improvements (Ming)

   - Scheduler dispatch improvement (Salman)

   - Inline block encryption support (Satya)

   - Request map fixes and improvements (Weiping)

   - blk-iocost tweaks (Tejun)

   - Fix for timeout failing with error injection (Keith)

   - Queue re-run fixes (Douglas)

   - CPU hotplug improvements (Christoph)

   - Queue entry/exit improvements (Christoph)

   - Move DMA drain handling to the few drivers that use it (Christoph)

   - Partition handling cleanups (Christoph)"

* tag 'for-5.8/block-2020-06-01' of git://git.kernel.dk/linux-block: (127 commits)
  block: mark bio_wouldblock_error() bio with BIO_QUIET
  blk-wbt: rename __wbt_update_limits to wbt_update_limits
  blk-wbt: remove wbt_update_limits
  blk-throttle: remove tg_drain_bios
  blk-throttle: remove blk_throtl_drain
  null_blk: force complete for timeout request
  blk-mq: drain I/O when all CPUs in a hctx are offline
  blk-mq: add blk_mq_all_tag_iter
  blk-mq: open code __blk_mq_alloc_request in blk_mq_alloc_request_hctx
  blk-mq: use BLK_MQ_NO_TAG in more places
  blk-mq: rename BLK_MQ_TAG_FAIL to BLK_MQ_NO_TAG
  blk-mq: move more request initialization to blk_mq_rq_ctx_init
  blk-mq: simplify the blk_mq_get_request calling convention
  blk-mq: remove the bio argument to ->prepare_request
  nvme: force complete cancelled requests
  blk-mq: blk-mq: provide forced completion method
  block: fix a warning when blkdev.h is included for !CONFIG_BLOCK builds
  block: blk-crypto-fallback: remove redundant initialization of variable err
  block: reduce part_stat_lock() scope
  block: use __this_cpu_add() instead of access by smp_processor_id()
  ...
2020-06-02 15:29:19 -07:00
Matthew Wilcox (Oracle)
9d24a13a93 iomap: convert from readpages to readahead
Use the new readahead operation in iomap.  Convert XFS and ZoneFS to use
it.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Gao Xiang <gaoxiang25@huawei.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Cc: Miklos Szeredi <mszeredi@redhat.com>
Link: http://lkml.kernel.org/r/20200414150233.24495-26-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-06-02 10:59:07 -07:00
Christoph Hellwig
9398554fb3 block: remove the error_sector argument to blkdev_issue_flush
The argument isn't used by any caller, and drivers don't fill out
bi_sector for flush requests either.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-22 08:45:46 -06:00
Johannes Thumshirn
02ef12a663 zonefs: use REQ_OP_ZONE_APPEND for sync DIO
Synchronous direct I/O to a sequential write only zone can be issued using
the new REQ_OP_ZONE_APPEND request operation. As dispatching multiple
BIOs can potentially result in reordering, we cannot support asynchronous
IO via this interface.

We also can only dispatch up to queue_max_zone_append_sectors() via the
new zone-append method and have to return a short write back to user-space
in case an IO larger than queue_max_zone_append_sectors() has been issued.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-12 20:36:28 -06:00
Andy Shevchenko
568776f992 zonefs: Replace uuid_copy() with import_uuid()
There is a specific API to treat raw data as UUID, i.e. import_uuid().
Use it instead of uuid_copy() with explicit casting.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-04-27 08:51:39 +09:00
Damien Le Moal
ccf4ad7da0 zonfs: Fix handling of read-only zones
The write pointer of zones in the read-only consition is defined as
invalid by the SCSI ZBC and ATA ZAC specifications. It is thus not
possible to determine the correct size of a read-only zone file on
mount. Fix this by handling read-only zones in the same manner as
offline zones by disabling all accesses to the zone (read and write)
and initializing the inode size of the read-only zone to 0).

For zones found to be in the read-only condition at runtime, only
disable write access to the zone and keep the size of the zone file to
its last updated value to allow the user to recover previously written
data.

Also fix zonefs documentation file to reflect this change.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
2020-03-25 11:28:26 +09:00
Johannes Thumshirn
0dda2ddb7d zonefs: select FS_IOMAP
Zonefs makes use of iomap internally, so it should also select iomap in
Kconfig.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-02-26 16:58:15 +09:00
Christoph Hellwig
7c69eb84d9 zonefs: fix IOCB_NOWAIT handling
IOCB_NOWAIT can't just be ignored as it breaks applications expecting
it not to block.  Just refuse the operation as applications must handle
that (e.g. by falling back to a thread pool).

Fixes: 8dcc1a9d90 ("fs: New zonefs file system")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
2020-02-26 16:57:35 +09:00
Damien Le Moal
8dcc1a9d90 fs: New zonefs file system
zonefs is a very simple file system exposing each zone of a zoned block
device as a file. Unlike a regular file system with zoned block device
support (e.g. f2fs), zonefs does not hide the sequential write
constraint of zoned block devices to the user. Files representing
sequential write zones of the device must be written sequentially
starting from the end of the file (append only writes).

As such, zonefs is in essence closer to a raw block device access
interface than to a full featured POSIX file system. The goal of zonefs
is to simplify the implementation of zoned block device support in
applications by replacing raw block device file accesses with a richer
file API, avoiding relying on direct block device file ioctls which may
be more obscure to developers. One example of this approach is the
implementation of LSM (log-structured merge) tree structures (such as
used in RocksDB and LevelDB) on zoned block devices by allowing SSTables
to be stored in a zone file similarly to a regular file system rather
than as a range of sectors of a zoned device. The introduction of the
higher level construct "one file is one zone" can help reducing the
amount of changes needed in the application as well as introducing
support for different application programming languages.

Zonefs on-disk metadata is reduced to an immutable super block to
persistently store a magic number and optional feature flags and
values. On mount, zonefs uses blkdev_report_zones() to obtain the device
zone configuration and populates the mount point with a static file tree
solely based on this information. E.g. file sizes come from the device
zone type and write pointer offset managed by the device itself.

The zone files created on mount have the following characteristics.
1) Files representing zones of the same type are grouped together
   under a common sub-directory:
     * For conventional zones, the sub-directory "cnv" is used.
     * For sequential write zones, the sub-directory "seq" is used.
  These two directories are the only directories that exist in zonefs.
  Users cannot create other directories and cannot rename nor delete
  the "cnv" and "seq" sub-directories.
2) The name of zone files is the number of the file within the zone
   type sub-directory, in order of increasing zone start sector.
3) The size of conventional zone files is fixed to the device zone size.
   Conventional zone files cannot be truncated.
4) The size of sequential zone files represent the file's zone write
   pointer position relative to the zone start sector. Truncating these
   files is allowed only down to 0, in which case, the zone is reset to
   rewind the zone write pointer position to the start of the zone, or
   up to the zone size, in which case the file's zone is transitioned
   to the FULL state (finish zone operation).
5) All read and write operations to files are not allowed beyond the
   file zone size. Any access exceeding the zone size is failed with
   the -EFBIG error.
6) Creating, deleting, renaming or modifying any attribute of files and
   sub-directories is not allowed.
7) There are no restrictions on the type of read and write operations
   that can be issued to conventional zone files. Buffered, direct and
   mmap read & write operations are accepted. For sequential zone files,
   there are no restrictions on read operations, but all write
   operations must be direct IO append writes. mmap write of sequential
   files is not allowed.

Several optional features of zonefs can be enabled at format time.
* Conventional zone aggregation: ranges of contiguous conventional
  zones can be aggregated into a single larger file instead of the
  default one file per zone.
* File ownership: The owner UID and GID of zone files is by default 0
  (root) but can be changed to any valid UID/GID.
* File access permissions: the default 640 access permissions can be
  changed.

The mkzonefs tool is used to format zoned block devices for use with
zonefs. This tool is available on Github at:

git@github.com:damien-lemoal/zonefs-tools.git.

zonefs-tools also includes a test suite which can be run against any
zoned block device, including null_blk block device created with zoned
mode.

Example: the following formats a 15TB host-managed SMR HDD with 256 MB
zones with the conventional zones aggregation feature enabled.

$ sudo mkzonefs -o aggr_cnv /dev/sdX
$ sudo mount -t zonefs /dev/sdX /mnt
$ ls -l /mnt/
total 0
dr-xr-xr-x 2 root root     1 Nov 25 13:23 cnv
dr-xr-xr-x 2 root root 55356 Nov 25 13:23 seq

The size of the zone files sub-directories indicate the number of files
existing for each type of zones. In this example, there is only one
conventional zone file (all conventional zones are aggregated under a
single file).

$ ls -l /mnt/cnv
total 137101312
-rw-r----- 1 root root 140391743488 Nov 25 13:23 0

This aggregated conventional zone file can be used as a regular file.

$ sudo mkfs.ext4 /mnt/cnv/0
$ sudo mount -o loop /mnt/cnv/0 /data

The "seq" sub-directory grouping files for sequential write zones has
in this example 55356 zones.

$ ls -lv /mnt/seq
total 14511243264
-rw-r----- 1 root root 0 Nov 25 13:23 0
-rw-r----- 1 root root 0 Nov 25 13:23 1
-rw-r----- 1 root root 0 Nov 25 13:23 2
...
-rw-r----- 1 root root 0 Nov 25 13:23 55354
-rw-r----- 1 root root 0 Nov 25 13:23 55355

For sequential write zone files, the file size changes as data is
appended at the end of the file, similarly to any regular file system.

$ dd if=/dev/zero of=/mnt/seq/0 bs=4K count=1 conv=notrunc oflag=direct
1+0 records in
1+0 records out
4096 bytes (4.1 kB, 4.0 KiB) copied, 0.000452219 s, 9.1 MB/s

$ ls -l /mnt/seq/0
-rw-r----- 1 root root 4096 Nov 25 13:23 /mnt/seq/0

The written file can be truncated to the zone size, preventing any
further write operation.

$ truncate -s 268435456 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 268435456 Nov 25 13:49 /mnt/seq/0

Truncation to 0 size allows freeing the file zone storage space and
restart append-writes to the file.

$ truncate -s 0 /mnt/seq/0
$ ls -l /mnt/seq/0
-rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0

Since files are statically mapped to zones on the disk, the number of
blocks of a file as reported by stat() and fstat() indicates the size
of the file zone.

$ stat /mnt/seq/0
  File: /mnt/seq/0
  Size: 0       Blocks: 524288     IO Block: 4096   regular empty file
Device: 870h/2160d      Inode: 50431       Links: 1
Access: (0640/-rw-r-----)  Uid: (    0/    root)   Gid: (    0/  root)
Access: 2019-11-25 13:23:57.048971997 +0900
Modify: 2019-11-25 13:52:25.553805765 +0900
Change: 2019-11-25 13:52:25.553805765 +0900
 Birth: -

The number of blocks of the file ("Blocks") in units of 512B blocks
gives the maximum file size of 524288 * 512 B = 256 MB, corresponding
to the device zone size in this example. Of note is that the "IO block"
field always indicates the minimum IO size for writes and corresponds
to the device physical sector size.

This code contains contributions from:
* Johannes Thumshirn <jthumshirn@suse.de>,
* Darrick J. Wong <darrick.wong@oracle.com>,
* Christoph Hellwig <hch@lst.de>,
* Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> and
* Ting Yao <tingyao@hust.edu.cn>.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-02-07 14:39:38 +09:00