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| -rw-r--r-- | Documentation/filesystems/zonefs.txt | 404 | ||||
| -rw-r--r-- | MAINTAINERS | 10 | ||||
| -rw-r--r-- | fs/Kconfig | 1 | ||||
| -rw-r--r-- | fs/Makefile | 1 | ||||
| -rw-r--r-- | fs/zonefs/Kconfig | 9 | ||||
| -rw-r--r-- | fs/zonefs/Makefile | 4 | ||||
| -rw-r--r-- | fs/zonefs/super.c | 1439 | ||||
| -rw-r--r-- | fs/zonefs/zonefs.h | 189 | ||||
| -rw-r--r-- | include/uapi/linux/magic.h | 1 |
9 files changed, 2058 insertions, 0 deletions
diff --git a/Documentation/filesystems/zonefs.txt b/Documentation/filesystems/zonefs.txt new file mode 100644 index 000000000000..935bf22031ca --- /dev/null +++ b/Documentation/filesystems/zonefs.txt @@ -0,0 +1,404 @@ +ZoneFS - Zone filesystem for Zoned block devices + +Introduction +============ + +zonefs is a very simple file system exposing each zone of a zoned block device +as a file. Unlike a regular POSIX-compliant file system with native 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 the entire disk. 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. + +Zoned block devices +------------------- + +Zoned storage devices belong to a class of storage devices with an address +space that is divided into zones. A zone is a group of consecutive LBAs and all +zones are contiguous (there are no LBA gaps). Zones may have different types. +* Conventional zones: there are no access constraints to LBAs belonging to + conventional zones. Any read or write access can be executed, similarly to a + regular block device. +* Sequential zones: these zones accept random reads but must be written + sequentially. Each sequential zone has a write pointer maintained by the + device that keeps track of the mandatory start LBA position of the next write + to the device. As a result of this write constraint, LBAs in a sequential zone + cannot be overwritten. Sequential zones must first be erased using a special + command (zone reset) before rewriting. + +Zoned storage devices can be implemented using various recording and media +technologies. The most common form of zoned storage today uses the SCSI Zoned +Block Commands (ZBC) and Zoned ATA Commands (ZAC) interfaces on Shingled +Magnetic Recording (SMR) HDDs. + +Solid State Disks (SSD) storage devices can also implement a zoned interface +to, for instance, reduce internal write amplification due to garbage collection. +The NVMe Zoned NameSpace (ZNS) is a technical proposal of the NVMe standard +committee aiming at adding a zoned storage interface to the NVMe protocol. + +Zonefs Overview +=============== + +Zonefs exposes the zones of a zoned block device as files. The files +representing zones are grouped by zone type, which are themselves represented +by sub-directories. This file structure is built entirely using zone information +provided by the device and so does not require any complex on-disk metadata +structure. + +On-disk metadata +---------------- + +zonefs on-disk metadata is reduced to an immutable super block which +persistently stores 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. File sizes come from the device zone type and write pointer +position managed by the device itself. + +The super block is always written on disk at sector 0. The first zone of the +device storing the super block is never exposed as a zone file by zonefs. If +the zone containing the super block is a sequential zone, the mkzonefs format +tool always "finishes" the zone, that is, it transitions the zone to a full +state to make it read-only, preventing any data write. + +Zone type sub-directories +------------------------- + +Files representing zones of the same type are grouped together under the same +sub-directory automatically created on mount. + +For conventional zones, the sub-directory "cnv" is used. This directory is +however created if and only if the device has usable conventional zones. If +the device only has a single conventional zone at sector 0, the zone will not +be exposed as a file as it will be used to store the zonefs super block. For +such devices, the "cnv" sub-directory will not be created. + +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. + +The size of the directories indicated by the st_size field of struct stat, +obtained with the stat() or fstat() system calls, indicates the number of files +existing under the directory. + +Zone files +---------- + +Zone files are named using the number of the zone they represent within the set +of zones of a particular type. That is, both the "cnv" and "seq" directories +contain files named "0", "1", "2", ... The file numbers also represent +increasing zone start sector on the device. + +All read and write operations to zone files are not allowed beyond the file +maximum size, that is, beyond the zone size. Any access exceeding the zone +size is failed with the -EFBIG error. + +Creating, deleting, renaming or modifying any attribute of files and +sub-directories is not allowed. + +The number of blocks of a file as reported by stat() and fstat() indicates the +size of the file zone, or in other words, the maximum file size. + +Conventional zone files +----------------------- + +The size of conventional zone files is fixed to the size of the zone they +represent. Conventional zone files cannot be truncated. + +These files can be randomly read and written using any type of I/O operation: +buffered I/Os, direct I/Os, memory mapped I/Os (mmap), etc. There are no I/O +constraint for these files beyond the file size limit mentioned above. + +Sequential zone files +--------------------- + +The size of sequential zone files grouped in the "seq" sub-directory represents +the file's zone write pointer position relative to the zone start sector. + +Sequential zone files can only be written sequentially, starting from the file +end, that is, write operations can only be append writes. Zonefs makes no +attempt at accepting random writes and will fail any write request that has a +start offset not corresponding to the end of the file, or to the end of the last +write issued and still in-flight (for asynchrnous I/O operations). + +Since dirty page writeback by the page cache does not guarantee a sequential +write pattern, zonefs prevents buffered writes and writeable shared mappings +on sequential files. Only direct I/O writes are accepted for these files. +zonefs relies on the sequential delivery of write I/O requests to the device +implemented by the block layer elevator. An elevator implementing the sequential +write feature for zoned block device (ELEVATOR_F_ZBD_SEQ_WRITE elevator feature) +must be used. This type of elevator (e.g. mq-deadline) is the set by default +for zoned block devices on device initialization. + +There are no restrictions on the type of I/O used for read operations in +sequential zone files. Buffered I/Os, direct I/Os and shared read mappings are +all accepted. + +Truncating sequential zone files is allowed only down to 0, in which case, the +zone is reset to rewind the file 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). + +Format options +-------------- + +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. + +IO error handling +----------------- + +Zoned block devices may fail I/O requests for reasons similar to regular block +devices, e.g. due to bad sectors. However, in addition to such known I/O +failure pattern, the standards governing zoned block devices behavior define +additional conditions that result in I/O errors. + +* A zone may transition to the read-only condition (BLK_ZONE_COND_READONLY): + While the data already written in the zone is still readable, the zone can + no longer be written. No user action on the zone (zone management command or + read/write access) can change the zone condition back to a normal read/write + state. While the reasons for the device to transition a zone to read-only + state are not defined by the standards, a typical cause for such transition + would be a defective write head on an HDD (all zones under this head are + changed to read-only). + +* A zone may transition to the offline condition (BLK_ZONE_COND_OFFLINE): + An offline zone cannot be read nor written. No user action can transition an + offline zone back to an operational good state. Similarly to zone read-only + transitions, the reasons for a drive to transition a zone to the offline + condition are undefined. A typical cause would be a defective read-write head + on an HDD causing all zones on the platter under the broken head to be + inaccessible. + +* Unaligned write errors: These errors result from the host issuing write + requests with a start sector that does not correspond to a zone write pointer + position when the write request is executed by the device. Even though zonefs + enforces sequential file write for sequential zones, unaligned write errors + may still happen in the case of a partial failure of a very large direct I/O + operation split into multiple BIOs/requests or asynchronous I/O operations. + If one of the write request within the set of sequential write requests + issued to the device fails, all write requests after queued after it will + become unaligned and fail. + +* Delayed write errors: similarly to regular block devices, if the device side + write cache is enabled, write errors may occur in ranges of previously + completed writes when the device write cache is flushed, e.g. on fsync(). + Similarly to the previous immediate unaligned write error case, delayed write + errors can propagate through a stream of cached sequential data for a zone + causing all data to be dropped after the sector that caused the error. + +All I/O errors detected by zonefs are notified to the user with an error code +return for the system call that trigered or detected the error. The recovery +actions taken by zonefs in response to I/O errors depend on the I/O type (read +vs write) and on the reason for the error (bad sector, unaligned writes or zone +condition change). + +* For read I/O errors, zonefs does not execute any particular recovery action, + but only if the file zone is still in a good condition and there is no + inconsistency between the file inode size and its zone write pointer position. + If a problem is detected, I/O error recovery is executed (see below table). + +* For write I/O errors, zonefs I/O error recovery is always executed. + +* A zone condition change to read-only or offline also always triggers zonefs + I/O error recovery. + +Zonefs minimal I/O error recovery may change a file size and a file access +permissions. + +* File size changes: + Immediate or delayed write errors in a sequential zone file may cause the file + inode size to be inconsistent with the amount of data successfully written in + the file zone. For instance, the partial failure of a multi-BIO large write + operation will cause the zone write pointer to advance partially, even though + the entire write operation will be reported as failed to the user. In such + case, the file inode size must be advanced to reflect the zone write pointer + change and eventually allow the user to restart writing at the end of the + file. + A file size may also be reduced to reflect a delayed write error detected on + fsync(): in this case, the amount of data effectively written in the zone may + be less than originally indicated by the file inode size. After such I/O + error, zonefs always fixes a file inode size to reflect the amount of data + persistently stored in the file zone. + +* Access permission changes: + A zone condition change to read-only is indicated with a change in the file + access permissions to render the file read-only. This disables changes to the + file attributes and data modification. For offline zones, all permissions + (read and write) to the file are disabled. + +Further action taken by zonefs I/O error recovery can be controlled by the user +with the "errors=xxx" mount option. The table below summarizes the result of +zonefs I/O error processing depending on the mount option and on the zone +conditions. + + +--------------+-----------+-----------------------------------------+ + | | | Post error state | + | "errors=xxx" | device | access permissions | + | mount | zone | file file device zone | + | option | condition | size read write read write | + +--------------+-----------+-----------------------------------------+ + | | good | fixed yes no yes yes | + | remount-ro | read-only | fixed yes no yes no | + | (default) | offline | 0 no no no no | + +--------------+-----------+-----------------------------------------+ + | | good | fixed yes no yes yes | + | zone-ro | read-only | fixed yes no yes no | + | | offline | 0 no no no no | + +--------------+-----------+-----------------------------------------+ + | | good | 0 no no yes yes | + | zone-offline | read-only | 0 no no yes no | + | | offline | 0 no no no no | + +--------------+-----------+-----------------------------------------+ + | | good | fixed yes yes yes yes | + | repair | read-only | fixed yes no yes no | + | | offline | 0 no no no no | + +--------------+-----------+-----------------------------------------+ + +Further notes: +* The "errors=remount-ro" mount option is the default behavior of zonefs I/O + error processing if no errors mount option is specified. +* With the "errors=remount-ro" mount option, the change of the file access + permissions to read-only applies to all files. The file system is remounted + read-only. +* Access permission and file size changes due to the device transitioning zones + to the offline condition are permanent. Remounting or reformating the device + with mkfs.zonefs (mkzonefs) will not change back offline zone files to a good + state. +* File access permission changes to read-only due to the device transitioning + zones to the read-only condition are permanent. Remounting or reformating + the device will not re-enable file write access. +* File access permission changes implied by the remount-ro, zone-ro and + zone-offline mount options are temporary for zones in a good condition. + Unmounting and remounting the file system will restore the previous default + (format time values) access rights to the files affected. +* The repair mount option triggers only the minimal set of I/O error recovery + actions, that is, file size fixes for zones in a good condition. Zones + indicated as being read-only or offline by the device still imply changes to + the zone file access permissions as noted in the table above. + +Mount options +------------- + +zonefs define the "errors=<behavior>" mount option to allow the user to specify +zonefs behavior in response to I/O errors, inode size inconsistencies or zone +condition chages. The defined behaviors are as follow: +* remount-ro (default) +* zone-ro +* zone-offline +* repair + +The I/O error actions defined for each behavior is detailed in the previous +section. + +Zonefs User Space Tools +======================= + +The mkzonefs tool is used to format zoned block devices for use with zonefs. +This tool is available on Github at: + +https://github.com/damien-lemoal/zonefs-tools + +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. + +Examples +-------- + +The following formats a 15TB host-managed SMR HDD with 256 MB zones +with the conventional zones aggregation feature enabled. + +# mkzonefs -o aggr_cnv /dev/sdX +# 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. + +# mkfs.ext4 /mnt/cnv/0 +# 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=4096 count=1 conv=notrunc oflag=direct +1+0 records in +1+0 records out +4096 bytes (4.1 kB, 4.0 KiB) copied, 0.00044121 s, 9.3 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 I/O size for writes and corresponds to the device physical sector size. diff --git a/MAINTAINERS b/MAINTAINERS index 575d386e6583..38fe2f3f7b6f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18496,6 +18496,16 @@ L: linux-kernel@vger.kernel.org S: Maintained F: arch/x86/kernel/cpu/zhaoxin.c +ZONEFS FILESYSTEM +M: Damien Le Moal <damien.lemoal@wdc.com> +M: Naohiro Aota <naohiro.aota@wdc.com> +R: Johannes Thumshirn <jth@kernel.org> +L: linux-fsdevel@vger.kernel.org +T: git git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs.git +S: Maintained +F: fs/zonefs/ +F: Documentation/filesystems/zonefs.txt + ZPOOL COMPRESSED PAGE STORAGE API M: Dan Streetman <ddstreet@ieee.org> L: linux-mm@kvack.org diff --git a/fs/Kconfig b/fs/Kconfig index 8493a3f0c4b1..708ba336e689 100644 --- a/fs/Kconfig +++ b/fs/Kconfig @@ -40,6 +40,7 @@ source "fs/ocfs2/Kconfig" source "fs/btrfs/Kconfig" source "fs/nilfs2/Kconfig" source "fs/f2fs/Kconfig" +source "fs/zonefs/Kconfig" config FS_DAX bool "Direct Access (DAX) support" diff --git a/fs/Makefile b/fs/Makefile index 96520ba7bd64..505e51166973 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -134,3 +134,4 @@ obj-$(CONFIG_PSTORE) += pstore/ obj-$(CONFIG_EFIVAR_FS) += efivarfs/ obj-$(CONFIG_EROFS_FS) += erofs/ obj-$(CONFIG_VBOXSF_FS) += vboxsf/ +obj-$(CONFIG_ZONEFS_FS) += zonefs/ diff --git a/fs/zonefs/Kconfig b/fs/zonefs/Kconfig new file mode 100644 index 000000000000..fb87ad372e29 --- /dev/null +++ b/fs/zonefs/Kconfig @@ -0,0 +1,9 @@ +config ZONEFS_FS + tristate "zonefs filesystem support" + depends on BLOCK + depends on BLK_DEV_ZONED + help + zonefs is a simple file system which exposes zones of a zoned block + device (e.g. host-managed or host-aware SMR disk drives) as files. + + If unsure, say N. diff --git a/fs/zonefs/Makefile b/fs/zonefs/Makefile new file mode 100644 index 000000000000..75a380aa1ae1 --- /dev/null +++ b/fs/zonefs/Makefile @@ -0,0 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 +obj-$(CONFIG_ZONEFS_FS) += zonefs.o + +zonefs-y := super.o diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c new file mode 100644 index 000000000000..8bc6ef82d693 --- /dev/null +++ b/fs/zonefs/super.c @@ -0,0 +1,1439 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Simple file system for zoned block devices exposing zones as files. + * + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + */ +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/magic.h> +#include <linux/iomap.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/blkdev.h> +#include <linux/statfs.h> +#include <linux/writeback.h> +#include <linux/quotaops.h> +#include <linux/seq_file.h> +#include <linux/parser.h> +#include <linux/uio.h> +#include <linux/mman.h> +#include <linux/sched/mm.h> +#include <linux/crc32.h> + +#include "zonefs.h" + +static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, + unsigned int flags, struct iomap *iomap, + struct iomap *srcmap) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct super_block *sb = inode->i_sb; + loff_t isize; + + /* All I/Os should always be within the file maximum size */ + if (WARN_ON_ONCE(offset + length > zi->i_max_size)) + return -EIO; + + /* + * Sequential zones can only accept direct writes. This is already + * checked when writes are issued, so warn if we see a page writeback + * operation. + */ + if (WARN_ON_ONCE(zi->i_ztype == ZONEFS_ZTYPE_SEQ && + (flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT))) + return -EIO; + + /* + * For conventional zones, all blocks are always mapped. For sequential + * zones, all blocks after always mapped below the inode size (zone + * write pointer) and unwriten beyond. + */ + mutex_lock(&zi->i_truncate_mutex); + isize = i_size_read(inode); + if (offset >= isize) + iomap->type = IOMAP_UNWRITTEN; + else + iomap->type = IOMAP_MAPPED; + if (flags & IOMAP_WRITE) + length = zi->i_max_size - offset; + else + length = min(length, isize - offset); + mutex_unlock(&zi->i_truncate_mutex); + + iomap->offset = ALIGN_DOWN(offset, sb->s_blocksize); + iomap->length = ALIGN(offset + length, sb->s_blocksize) - iomap->offset; + iomap->bdev = inode->i_sb->s_bdev; + iomap->addr = (zi->i_zsector << SECTOR_SHIFT) + iomap->offset; + + return 0; +} + +static const struct iomap_ops zonefs_iomap_ops = { + .iomap_begin = zonefs_iomap_begin, +}; + +static int zonefs_readpage(struct file *unused, struct page *page) +{ + return iomap_readpage(page, &zonefs_iomap_ops); +} + +static int zonefs_readpages(struct file *unused, struct address_space *mapping, + struct list_head *pages, unsigned int nr_pages) +{ + return iomap_readpages(mapping, pages, nr_pages, &zonefs_iomap_ops); +} + +/* + * Map blocks for page writeback. This is used only on conventional zone files, + * which implies that the page range can only be within the fixed inode size. + */ +static int zonefs_map_blocks(struct iomap_writepage_ctx *wpc, + struct inode *inode, loff_t offset) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + + if (WARN_ON_ONCE(zi->i_ztype != ZONEFS_ZTYPE_CNV)) + return -EIO; + if (WARN_ON_ONCE(offset >= i_size_read(inode))) + return -EIO; + + /* If the mapping is already OK, nothing needs to be done */ + if (offset >= wpc->iomap.offset && + offset < wpc->iomap.offset + wpc->iomap.length) + return 0; + + return zonefs_iomap_begin(inode, offset, zi->i_max_size - offset, + IOMAP_WRITE, &wpc->iomap, NULL); +} + +static const struct iomap_writeback_ops zonefs_writeback_ops = { + .map_blocks = zonefs_map_blocks, +}; + +static int zonefs_writepage(struct page *page, struct writeback_control *wbc) +{ + struct iomap_writepage_ctx wpc = { }; + + return iomap_writepage(page, wbc, &wpc, &zonefs_writeback_ops); +} + +static int zonefs_writepages(struct address_space *mapping, + struct writeback_control *wbc) +{ + struct iomap_writepage_ctx wpc = { }; + + return iomap_writepages(mapping, wbc, &wpc, &zonefs_writeback_ops); +} + +static const struct address_space_operations zonefs_file_aops = { + .readpage = zonefs_readpage, + .readpages = zonefs_readpages, + .writepage = zonefs_writepage, + .writepages = zonefs_writepages, + .set_page_dirty = iomap_set_page_dirty, + .releasepage = iomap_releasepage, + .invalidatepage = iomap_invalidatepage, + .migratepage = iomap_migrate_page, + .is_partially_uptodate = iomap_is_partially_uptodate, + .error_remove_page = generic_error_remove_page, + .direct_IO = noop_direct_IO, +}; + +static void zonefs_update_stats(struct inode *inode, loff_t new_isize) +{ + struct super_block *sb = inode->i_sb; + struct zonefs_sb_info *sbi = ZONEFS_SB(sb); + loff_t old_isize = i_size_read(inode); + loff_t nr_blocks; + + if (new_isize == old_isize) + return; + + spin_lock(&sbi->s_lock); + + /* + * This may be called for an update after an IO error. + * So beware of the values seen. + */ + if (new_isize < old_isize) { + nr_blocks = (old_isize - new_isize) >> sb->s_blocksize_bits; + if (sbi->s_used_blocks > nr_blocks) + sbi->s_used_blocks -= nr_blocks; + else + sbi->s_used_blocks = 0; + } else { + sbi->s_used_blocks += + (new_isize - old_isize) >> sb->s_blocksize_bits; + if (sbi->s_used_blocks > sbi->s_blocks) + sbi->s_used_blocks = sbi->s_blocks; + } + + spin_unlock(&sbi->s_lock); +} + +/* + * Check a zone condition and adjust its file inode access permissions for + * offline and readonly zones. Return the inode size corresponding to the + * amount of readable data in the zone. + */ +static loff_t zonefs_check_zone_condition(struct inode *inode, + struct blk_zone *zone, bool warn) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + + switch (zone->cond) { + case BLK_ZONE_COND_OFFLINE: + /* + * Dead zone: make the inode immutable, disable all accesses + * and set the file size to 0 (zone wp set to zone start). + */ + if (warn) + zonefs_warn(inode->i_sb, "inode %lu: offline zone\n", + inode->i_ino); + inode->i_flags |= S_IMMUTABLE; + inode->i_mode &= ~0777; + zone->wp = zone->start; + return 0; + case BLK_ZONE_COND_READONLY: + /* Do not allow writes in read-only zones */ + if (warn) + zonefs_warn(inode->i_sb, "inode %lu: read-only zone\n", + inode->i_ino); + inode->i_flags |= S_IMMUTABLE; + inode->i_mode &= ~0222; + /* fallthrough */ + default: + if (zi->i_ztype == ZONEFS_ZTYPE_CNV) + return zi->i_max_size; + return (zone->wp - zone->start) << SECTOR_SHIFT; + } +} + +struct zonefs_ioerr_data { + struct inode *inode; + bool write; +}; + +static int zonefs_io_error_cb(struct blk_zone *zone, unsigned int idx, + void *data) +{ + struct zonefs_ioerr_data *err = data; + struct inode *inode = err->inode; + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct super_block *sb = inode->i_sb; + struct zonefs_sb_info *sbi = ZONEFS_SB(sb); + loff_t isize, data_size; + + /* + * Check the zone condition: if the zone is not "bad" (offline or + * read-only), read errors are simply signaled to the IO issuer as long + * as there is no inconsistency between the inode size and the amount of + * data writen in the zone (data_size). + */ + data_size = zonefs_check_zone_condition(inode, zone, true); + isize = i_size_read(inode); + if (zone->cond != BLK_ZONE_COND_OFFLINE && + zone->cond != BLK_ZONE_COND_READONLY && + !err->write && isize == data_size) + return 0; + + /* + * At this point, we detected either a bad zone or an inconsistency + * between the inode size and the amount of data written in the zone. + * For the latter case, the cause may be a write IO error or an external + * action on the device. Two error patterns exist: + * 1) The inode size is lower than the amount of data in the zone: + * a write operation partially failed and data was writen at the end + * of the file. This can happen in the case of a large direct IO + * needing several BIOs and/or write requests to be processed. + * 2) The inode size is larger than the amount of data in the zone: + * this can happen with a deferred write error with the use of the + * device side write cache after getting successful write IO + * completions. Other possibilities are (a) an external corruption, + * e.g. an application reset the zone directly, or (b) the device + * has a serious problem (e.g. firmware bug). + * + * In all cases, warn about inode size inconsistency and handle the + * IO error according to the zone condition and to the mount options. + */ + if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && isize != data_size) + zonefs_warn(sb, "inode %lu: invalid size %lld (should be %lld)\n", + inode->i_ino, isize, data_size); + + /* + * First handle bad zones signaled by hardware. The mount options + * errors=zone-ro and errors=zone-offline result in changing the + * zone condition to read-only and offline respectively, as if the + * condition was signaled by the hardware. + */ + if (zone->cond == BLK_ZONE_COND_OFFLINE || + sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZOL) { + zonefs_warn(sb, "inode %lu: read/write access disabled\n", + inode->i_ino); + if (zone->cond != BLK_ZONE_COND_OFFLINE) { + zone->cond = BLK_ZONE_COND_OFFLINE; + data_size = zonefs_check_zone_condition(inode, zone, + false); + } + } else if (zone->cond == BLK_ZONE_COND_READONLY || + sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZRO) { + zonefs_warn(sb, "inode %lu: write access disabled\n", + inode->i_ino); + if (zone->cond != BLK_ZONE_COND_READONLY) { + zone->cond = BLK_ZONE_COND_READONLY; + data_size = zonefs_check_zone_condition(inode, zone, + false); + } + } + + /* + * If error=remount-ro was specified, any error result in remounting + * the volume as read-only. + */ + if ((sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_RO) && !sb_rdonly(sb)) { + zonefs_warn(sb, "remounting filesystem read-only\n"); + sb->s_flags |= SB_RDONLY; + } + + /* + * Update block usage stats and the inode size to prevent access to + * invalid data. + */ + zonefs_update_stats(inode, data_size); + i_size_write(inode, data_size); + zi->i_wpoffset = data_size; + + return 0; +} + +/* + * When an file IO error occurs, check the file zone to see if there is a change + * in the zone condition (e.g. offline or read-only). For a failed write to a + * sequential zone, the zone write pointer position must also be checked to + * eventually correct the file size and zonefs inode write pointer offset + * (which can be out of sync with the drive due to partial write failures). + */ +static void zonefs_io_error(struct inode *inode, bool write) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct super_block *sb = inode->i_sb; + struct zonefs_sb_info *sbi = ZONEFS_SB(sb); + unsigned int noio_flag; + unsigned int nr_zones = + zi->i_max_size >> (sbi->s_zone_sectors_shift + SECTOR_SHIFT); + struct zonefs_ioerr_data err = { + .inode = inode, + .write = write, + }; + int ret; + + mutex_lock(&zi->i_truncate_mutex); + + /* + * Memory allocations in blkdev_report_zones() can trigger a memory + * reclaim which may in turn cause a recursion into zonefs as well as + * struct request allocations for the same device. The former case may + * end up in a deadlock on the inode truncate mutex, while the latter + * may prevent IO forward progress. Executing the report zones under + * the GFP_NOIO context avoids both problems. + */ + noio_flag = memalloc_noio_save(); + ret = blkdev_report_zones(sb->s_bdev, zi->i_zsector, nr_zones, + zonefs_io_error_cb, &err); + if (ret != nr_zones) + zonefs_err(sb, "Get inode %lu zone information failed %d\n", + inode->i_ino, ret); + memalloc_noio_restore(noio_flag); + + mutex_unlock(&zi->i_truncate_mutex); +} + +static int zonefs_file_truncate(struct inode *inode, loff_t isize) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + loff_t old_isize; + enum req_opf op; + int ret = 0; + + /* + * Only sequential zone files can be truncated and truncation is allowed + * only down to a 0 size, which is equivalent to a zone reset, and to + * the maximum file size, which is equivalent to a zone finish. + */ + if (zi->i_ztype != ZONEFS_ZTYPE_SEQ) + return -EPERM; + + if (!isize) + op = REQ_OP_ZONE_RESET; + else if (isize == zi->i_max_size) + op = REQ_OP_ZONE_FINISH; + else + return -EPERM; + + inode_dio_wait(inode); + + /* Serialize against page faults */ + down_write(&zi->i_mmap_sem); + + /* Serialize against zonefs_iomap_begin() */ + mutex_lock(&zi->i_truncate_mutex); + + old_isize = i_size_read(inode); + if (isize == old_isize) + goto unlock; + + ret = blkdev_zone_mgmt(inode->i_sb->s_bdev, op, zi->i_zsector, + zi->i_max_size >> SECTOR_SHIFT, GFP_NOFS); + if (ret) { + zonefs_err(inode->i_sb, + "Zone management operation at %llu failed %d", + zi->i_zsector, ret); + goto unlock; + } + + zonefs_update_stats(inode, isize); + truncate_setsize(inode, isize); + zi->i_wpoffset = isize; + +unlock: + mutex_unlock(&zi->i_truncate_mutex); + up_write(&zi->i_mmap_sem); + + return ret; +} + +static int zonefs_inode_setattr(struct dentry *dentry, struct iattr *iattr) +{ + struct inode *inode = d_inode(dentry); + int ret; + + if (unlikely(IS_IMMUTABLE(inode))) + return -EPERM; + + ret = setattr_prepare(dentry, iattr); + if (ret) + return ret; + + /* + * Since files and directories cannot be created nor deleted, do not + * allow setting any write attributes on the sub-directories grouping + * files by zone type. + */ + if ((iattr->ia_valid & ATTR_MODE) && S_ISDIR(inode->i_mode) && + (iattr->ia_mode & 0222)) + return -EPERM; + + if (((iattr->ia_valid & ATTR_UID) && + !uid_eq(iattr->ia_uid, inode->i_uid)) || + ((iattr->ia_valid & ATTR_GID) && + !gid_eq(iattr->ia_gid, inode->i_gid))) { + ret = dquot_transfer(inode, iattr); + if (ret) + return ret; + } + + if (iattr->ia_valid & ATTR_SIZE) { + ret = zonefs_file_truncate(inode, iattr->ia_size); + if (ret) + return ret; + } + + setattr_copy(inode, iattr); + + return 0; +} + +static const struct inode_operations zonefs_file_inode_operations = { + .setattr = zonefs_inode_setattr, +}; + +static int zonefs_file_fsync(struct file *file, loff_t start, loff_t end, + int datasync) +{ + struct inode *inode = file_inode(file); + int ret = 0; + + if (unlikely(IS_IMMUTABLE(inode))) + return -EPERM; + + /* + * Since only direct writes are allowed in sequential files, page cache + * flush is needed only for conventional zone files. + */ + if (ZONEFS_I(inode)->i_ztype == ZONEFS_ZTYPE_CNV) + ret = file_write_and_wait_range(file, start, end); + if (!ret) + ret = blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL); + + if (ret) + zonefs_io_error(inode, true); + + return ret; +} + +static vm_fault_t zonefs_filemap_fault(struct vm_fault *vmf) +{ + struct zonefs_inode_info *zi = ZONEFS_I(file_inode(vmf->vma->vm_file)); + vm_fault_t ret; + + down_read(&zi->i_mmap_sem); + ret = filemap_fault(vmf); + up_read(&zi->i_mmap_sem); + + return ret; +} + +static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf) +{ + struct inode *inode = file_inode(vmf->vma->vm_file); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + vm_fault_t ret; + + if (unlikely(IS_IMMUTABLE(inode))) + return VM_FAULT_SIGBUS; + + /* + * Sanity check: only conventional zone files can have shared + * writeable mappings. + */ + if (WARN_ON_ONCE(zi->i_ztype != ZONEFS_ZTYPE_CNV)) + return VM_FAULT_NOPAGE; + + sb_start_pagefault(inode->i_sb); + file_update_time(vmf->vma->vm_file); + + /* Serialize against truncates */ + down_read(&zi->i_mmap_sem); + ret = iomap_page_mkwrite(vmf, &zonefs_iomap_ops); + up_read(&zi->i_mmap_sem); + + sb_end_pagefault(inode->i_sb); + return ret; +} + +static const struct vm_operations_struct zonefs_file_vm_ops = { + .fault = zonefs_filemap_fault, + .map_pages = filemap_map_pages, + .page_mkwrite = zonefs_filemap_page_mkwrite, +}; + +static int zonefs_file_mmap(struct file *file, struct vm_area_struct *vma) +{ + /* + * Conventional zones accept random writes, so their files can support + * shared writable mappings. For sequential zone files, only read + * mappings are possible since there are no guarantees for write + * ordering between msync() and page cache writeback. + */ + if (ZONEFS_I(file_inode(file))->i_ztype == ZONEFS_ZTYPE_SEQ && + (vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) + return -EINVAL; + + file_accessed(file); + vma->vm_ops = &zonefs_file_vm_ops; + + return 0; +} + +static loff_t zonefs_file_llseek(struct file *file, loff_t offset, int whence) +{ + loff_t isize = i_size_read(file_inode(file)); + + /* + * Seeks are limited to below the zone size for conventional zones + * and below the zone write pointer for sequential zones. In both + * cases, this limit is the inode size. + */ + return generic_file_llseek_size(file, offset, whence, isize, isize); +} + +static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size, + int error, unsigned int flags) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + + if (error) { + zonefs_io_error(inode, true); + return error; + } + + if (size && zi->i_ztype != ZONEFS_ZTYPE_CNV) { + /* + * Note that we may be seeing completions out of order, + * but that is not a problem since a write completed + * successfully necessarily means that all preceding writes + * were also successful. So we can safely increase the inode + * size to the write end location. + */ + mutex_lock(&zi->i_truncate_mutex); + if (i_size_read(inode) < iocb->ki_pos + size) { + zonefs_update_stats(inode, iocb->ki_pos + size); + i_size_write(inode, iocb->ki_pos + size); + } + mutex_unlock(&zi->i_truncate_mutex); + } + + return 0; +} + +static const struct iomap_dio_ops zonefs_write_dio_ops = { + .end_io = zonefs_file_write_dio_end_io, +}; + +/* + * Handle direct writes. For sequential zone files, this is the only possible + * write path. For these files, check that the user is issuing writes + * sequentially from the end of the file. This code assumes that the block layer + * delivers write requests to the device in sequential order. This is always the + * case if a block IO scheduler implementing the ELEVATOR_F_ZBD_SEQ_WRITE + * elevator feature is being used (e.g. mq-deadline). The block layer always + * automatically select such an elevator for zoned block devices during the + * device initialization. + */ +static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct super_block *sb = inode->i_sb; + size_t count; + ssize_t ret; + + /* + * For async direct IOs to sequential zone files, ignore IOCB_NOWAIT + * as this can cause write reordering (e.g. the first aio gets EAGAIN + * on the inode lock but the second goes through but is now unaligned). + */ + if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && !is_sync_kiocb(iocb) + && (iocb->ki_flags & IOCB_NOWAIT)) + iocb->ki_flags &= ~IOCB_NOWAIT; + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock(inode)) + return -EAGAIN; + } else { + inode_lock(inode); + } + + ret = generic_write_checks(iocb, from); + if (ret <= 0) + goto inode_unlock; + + iov_iter_truncate(from, zi->i_max_size - iocb->ki_pos); + count = iov_iter_count(from); + + if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) { + ret = -EINVAL; + goto inode_unlock; + } + + /* Enforce sequential writes (append only) in sequential zones */ + mutex_lock(&zi->i_truncate_mutex); + if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && iocb->ki_pos != zi->i_wpoffset) { + mutex_unlock(&zi->i_truncate_mutex); + ret = -EINVAL; + goto inode_unlock; + } + mutex_unlock(&zi->i_truncate_mutex); + + ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops, + &zonefs_write_dio_ops, is_sync_kiocb(iocb)); + if (zi->i_ztype == ZONEFS_ZTYPE_SEQ && + (ret > 0 || ret == -EIOCBQUEUED)) { + if (ret > 0) + count = ret; + mutex_lock(&zi->i_truncate_mutex); + zi->i_wpoffset += count; + mutex_unlock(&zi->i_truncate_mutex); + } + +inode_unlock: + inode_unlock(inode); + + return ret; +} + +static ssize_t zonefs_file_buffered_write(struct kiocb *iocb, + struct iov_iter *from) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + ssize_t ret; + + /* + * Direct IO writes are mandatory for sequential zone files so that the + * write IO issuing order is preserved. + */ + if (zi->i_ztype != ZONEFS_ZTYPE_CNV) + return -EIO; + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock(inode)) + return -EAGAIN; + } else { + inode_lock(inode); + } + + ret = generic_write_checks(iocb, from); + if (ret <= 0) + goto inode_unlock; + + iov_iter_truncate(from, zi->i_max_size - iocb->ki_pos); + + ret = iomap_file_buffered_write(iocb, from, &zonefs_iomap_ops); + if (ret > 0) + iocb->ki_pos += ret; + else if (ret == -EIO) + zonefs_io_error(inode, true); + +inode_unlock: + inode_unlock(inode); + if (ret > 0) + ret = generic_write_sync(iocb, ret); + + return ret; +} + +static ssize_t zonefs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + struct inode *inode = file_inode(iocb->ki_filp); + + if (unlikely(IS_IMMUTABLE(inode))) + return -EPERM; + + if (sb_rdonly(inode->i_sb)) + return -EROFS; + + /* Write operations beyond the zone size are not allowed */ + if (iocb->ki_pos >= ZONEFS_I(inode)->i_max_size) + return -EFBIG; + + if (iocb->ki_flags & IOCB_DIRECT) + return zonefs_file_dio_write(iocb, from); + + return zonefs_file_buffered_write(iocb, from); +} + +static int zonefs_file_read_dio_end_io(struct kiocb *iocb, ssize_t size, + int error, unsigned int flags) +{ + if (error) { + zonefs_io_error(file_inode(iocb->ki_filp), false); + return error; + } + + return 0; +} + +static const struct iomap_dio_ops zonefs_read_dio_ops = { + .end_io = zonefs_file_read_dio_end_io, +}; + +static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct super_block *sb = inode->i_sb; + loff_t isize; + ssize_t ret; + + /* Offline zones cannot be read */ + if (unlikely(IS_IMMUTABLE(inode) && !(inode->i_mode & 0777))) + return -EPERM; + + if (iocb->ki_pos >= zi->i_max_size) + return 0; + + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock_shared(inode)) + return -EAGAIN; + } else { + inode_lock_shared(inode); + } + + /* Limit read operations to written data */ + mutex_lock(&zi->i_truncate_mutex); + isize = i_size_read(inode); + if (iocb->ki_pos >= isize) { + mutex_unlock(&zi->i_truncate_mutex); + ret = 0; + goto inode_unlock; + } + iov_iter_truncate(to, isize - iocb->ki_pos); + mutex_unlock(&zi->i_truncate_mutex); + + if (iocb->ki_flags & IOCB_DIRECT) { + size_t count = iov_iter_count(to); + + if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) { + ret = -EINVAL; + goto inode_unlock; + } + file_accessed(iocb->ki_filp); + ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops, + &zonefs_read_dio_ops, is_sync_kiocb(iocb)); + } else { + ret = generic_file_read_iter(iocb, to); + if (ret == -EIO) + zonefs_io_error(inode, false); + } + +inode_unlock: + inode_unlock_shared(inode); + + return ret; +} + +static const struct file_operations zonefs_file_operations = { + .open = generic_file_open, + .fsync = zonefs_file_fsync, + .mmap = zonefs_file_mmap, + .llseek = zonefs_file_llseek, + .read_iter = zonefs_file_read_iter, + .write_iter = zonefs_file_write_iter, + .splice_read = generic_file_splice_read, + .splice_write = iter_file_splice_write, + .iopoll = iomap_dio_iopoll, +}; + +static struct kmem_cache *zonefs_inode_cachep; + +static struct inode *zonefs_alloc_inode(struct super_block *sb) +{ + struct zonefs_inode_info *zi; + + zi = kmem_cache_alloc(zonefs_inode_cachep, GFP_KERNEL); + if (!zi) + return NULL; + + inode_init_once(&zi->i_vnode); + mutex_init(&zi->i_truncate_mutex); + init_rwsem(&zi->i_mmap_sem); + + return &zi->i_vnode; +} + +static void zonefs_free_inode(struct inode *inode) +{ + kmem_cache_free(zonefs_inode_cachep, ZONEFS_I(inode)); +} + +/* + * File system stat. + */ +static int zonefs_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + struct super_block *sb = dentry->d_sb; + struct zonefs_sb_info *sbi = ZONEFS_SB(sb); + enum zonefs_ztype t; + u64 fsid; + + buf->f_type = ZONEFS_MAGIC; + buf->f_bsize = sb->s_blocksize; + buf->f_namelen = ZONEFS_NAME_MAX; + + spin_lock(&sbi->s_lock); + + buf->f_blocks = sbi->s_blocks; + if (WARN_ON(sbi->s_used_blocks > sbi->s_blocks)) + buf->f_bfree = 0; + else + buf->f_bfree = buf->f_blocks - sbi->s_used_blocks; + buf->f_bavail = buf->f_bfree; + + for (t = 0; t < ZONEFS_ZTYPE_MAX; t++) { + if (sbi->s_nr_files[t]) + buf->f_files += sbi->s_nr_files[t] + 1; + } + buf->f_ffree = 0; + + spin_unlock(&sbi->s_lock); + + fsid = le64_to_cpup((void *)sbi->s_uuid.b) ^ + le64_to_cpup((void *)sbi->s_uuid.b + sizeof(u64)); + buf->f_fsid.val[0] = (u32)fsid; + buf->f_fsid.val[1] = (u32)(fsid >> 32); + + return 0; +} + +enum { + Opt_errors_ro, Opt_errors_zro, Opt_errors_zol, Opt_errors_repair, + Opt_err, +}; + +static const match_table_t tokens = { + { Opt_errors_ro, "errors=remount-ro"}, + { Opt_errors_zro, "errors=zone-ro"}, + { Opt_errors_zol, "errors=zone-offline"}, + { Opt_errors_repair, "errors=repair"}, + { Opt_err, NULL} +}; + +static int zonefs_parse_options(struct super_block *sb, char *options) +{ + struct zonefs_sb_info *sbi = ZONEFS_SB(sb); + substring_t args[MAX_OPT_ARGS]; + char *p; + + if (!options) + return 0; + + while ((p = strsep(&options, ",")) != NULL) { + int token; + + if (!*p) + continue; + + token = match_token(p, tokens, args); + switch (token) { + case Opt_errors_ro: + sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK; + sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_RO; + break; + case Opt_errors_zro: + sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK; + sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_ZRO; + break; + case Opt_errors_zol: + sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK; + sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_ZOL; + break; + case Opt_errors_repair: + sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK; + sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_REPAIR; + break; + default: + return -EINVAL; + } + } + + return 0; +} + +static int zonefs_show_options(struct seq_file *seq, struct dentry *root) +{ + struct zonefs_sb_info *sbi = ZONEFS_SB(root->d_sb); + + if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_RO) + seq_puts(seq, ",errors=remount-ro"); + if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZRO) + seq_puts(seq, ",errors=zone-ro"); + if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_ZOL) + seq_puts(seq, ",errors=zone-offline"); + if (sbi->s_mount_opts & ZONEFS_MNTOPT_ERRORS_REPAIR) + seq_puts(seq, ",errors=repair"); + + return 0; +} + +static int zonefs_remount(struct super_block *sb, int *flags, char *data) +{ + sync_filesystem(sb); + + return zonefs_parse_options(sb, data); +} + +static const struct super_operations zonefs_sops = { + .alloc_inode = zonefs_alloc_inode, + .free_inode = zonefs_free_inode, + .statfs = zonefs_statfs, + .remount_fs = zonefs_remount, + .show_options = zonefs_show_options, +}; + +static const struct inode_operations zonefs_dir_inode_operations = { + .lookup = simple_lookup, + .setattr = zonefs_inode_setattr, +}; + +static void zonefs_init_dir_inode(struct inode *parent, struct inode *inode, + enum zonefs_ztype type) +{ + struct super_block *sb = parent->i_sb; + + inode->i_ino = blkdev_nr_zones(sb->s_bdev->bd_disk) + type + 1; + inode_init_owner(inode, parent, S_IFDIR | 0555); + inode->i_op = &zonefs_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + set_nlink(inode, 2); + inc_nlink(parent); +} + +static void zonefs_init_file_inode(struct inode *inode, struct blk_zone *zone, + enum zonefs_ztype type) +{ + struct super_block *sb = inode->i_sb; + struct zonefs_sb_info *sbi = ZONEFS_SB(sb); + struct zonefs_inode_info *zi = ZONEFS_I(inode); + + inode->i_ino = zone->start >> sbi->s_zone_sectors_shift; + inode->i_mode = S_IFREG | sbi->s_perm; + + zi->i_ztype = type; + zi->i_zsector = zone->start; + zi->i_max_size = min_t(loff_t, MAX_LFS_FILESIZE, + zone->len << SECTOR_SHIFT); + zi->i_wpoffset = zonefs_check_zone_condition(inode, zone, true); + + inode->i_uid = sbi->s_uid; + inode->i_gid = sbi->s_gid; + inode->i_size = zi->i_wpoffset; + inode->i_blocks = zone->len; + + inode->i_op = &zonefs_file_inode_operations; + inode->i_fop = &zonefs_file_operations; + inode->i_mapping->a_ops = &zonefs_file_aops; + + sb->s_maxbytes = max(zi->i_max_size, sb->s_maxbytes); + sbi->s_blocks += zi->i_max_size >> sb->s_blocksize_bits; + sbi->s_used_blocks += zi->i_wpoffset >> sb->s_blocksize_bits; +} + +static struct dentry *zonefs_create_inode(struct dentry *parent, + const char *name, struct blk_zone *zone, + enum zonefs_ztype type) +{ + struct inode *dir = d_inode(parent); + struct dentry *dentry; + struct inode *inode; + + dentry = d_alloc_name(parent, name); + if (!dentry) + return NULL; + + inode = new_inode(parent->d_sb); + if (!inode) + goto dput; + + inode->i_ctime = inode->i_mtime = inode->i_atime = dir->i_ctime; + if (zone) + zonefs_init_file_inode(inode, zone, type); + else + zonefs_init_dir_inode(dir, inode, type); + d_add(dentry, inode); + dir->i_size++; + + return dentry; + +dput: + dput(dentry); + + return NULL; +} + +struct zonefs_zone_data { + struct super_block *sb; + unsigned int nr_zones[ZONEFS_ZTYPE_MAX]; + struct blk_zone *zones; +}; + +/* + * Create a zone group and populate it with zone files. + */ +static int zonefs_create_zgroup(struct zonefs_zone_data *zd, + enum zonefs_ztype type) +{ + struct super_block *sb = zd->sb; + struct zonefs_sb_info *sbi = ZONEFS_SB(sb); + struct blk_zone *zone, *next, *end; + const char *zgroup_name; + char *file_name; + struct dentry *dir; + unsigned int n = 0; + int ret = -ENOMEM; + + /* If the group is empty, there is nothing to do */ + if (!zd->nr_zones[type]) + return 0; + + file_name = kmalloc(ZONEFS_NAME_MAX, GFP_KERNEL); + if (!file_name) + return -ENOMEM; + + if (type == ZONEFS_ZTYPE_CNV) + zgroup_name = "cnv"; + else + zgroup_name = "seq"; + + dir = zonefs_create_inode(sb->s_root, zgroup_name, NULL, type); + if (!dir) + goto free; + + /* + * The first zone contains the super block: skip it. + */ + end = zd->zones + blkdev_nr_zones(sb->s_bdev->bd_disk); + for (zone = &zd->zones[1]; zone < end; zone = next) { + + next = zone + 1; + if (zonefs_zone_type(zone) != type) + continue; + + /* + * For conventional zones, contiguous zones can be aggregated + * together to form larger files. Note that this overwrites the + * length of the first zone of the set of contiguous zones + * aggregated together. If one offline or read-only zone is + * found, assume that all zones aggregated have the same + * condition. + */ + if (type == ZONEFS_ZTYPE_CNV && + (sbi->s_features & ZONEFS_F_AGGRCNV)) { + for (; next < end; next++) { + if (zonefs_zone_type(next) != type) + break; + zone->len += next->len; + if (next->cond == BLK_ZONE_COND_READONLY && + zone->cond != BLK_ZONE_COND_OFFLINE) + zone->cond = BLK_ZONE_COND_READONLY; + else if (next->cond == BLK_ZONE_COND_OFFLINE) + zone->cond = BLK_ZONE_COND_OFFLINE; + } + } + + /* + * Use the file number within its group as file name. + */ + snprintf(file_name, ZONEFS_NAME_MAX - 1, "%u", n); + if (!zonefs_create_inode(dir, file_name, zone, type)) + goto free; + + n++; + } + + zonefs_info(sb, "Zone group \"%s\" has %u file%s\n", + zgroup_name, n, n > 1 ? "s" : ""); + + sbi->s_nr_files[type] = n; + ret = 0; + +free: + kfree(file_name); + + return ret; +} + +static int zonefs_get_zone_info_cb(struct blk_zone *zone, unsigned int idx, + void *data) +{ + struct zonefs_zone_data *zd = data; + + /* + * Count the number of usable zones: the first zone at index 0 contains + * the super block and is ignored. + */ + switch (zone->type) { + case BLK_ZONE_TYPE_CONVENTIONAL: + zone->wp = zone->start + zone->len; + if (idx) + zd->nr_zones[ZONEFS_ZTYPE_CNV]++; + break; + case BLK_ZONE_TYPE_SEQWRITE_REQ: + case BLK_ZONE_TYPE_SEQWRITE_PREF: + if (idx) + zd->nr_zones[ZONEFS_ZTYPE_SEQ]++; + break; + default: + zonefs_err(zd->sb, "Unsupported zone type 0x%x\n", + zone->type); + return -EIO; + } + + memcpy(&zd->zones[idx], zone, sizeof(struct blk_zone)); + + return 0; +} + +static int zonefs_get_zone_info(struct zonefs_zone_data *zd) +{ + struct block_device *bdev = zd->sb->s_bdev; + int ret; + + zd->zones = kvcalloc(blkdev_nr_zones(bdev->bd_disk), + sizeof(struct blk_zone), GFP_KERNEL); + if (!zd->zones) + return -ENOMEM; + + /* Get zones information from the device */ + ret = blkdev_report_zones(bdev, 0, BLK_ALL_ZONES, + zonefs_get_zone_info_cb, zd); + if (ret < 0) { + zonefs_err(zd->sb, "Zone report failed %d\n", ret); + return ret; + } + + if (ret != blkdev_nr_zones(bdev->bd_disk)) { + zonefs_err(zd->sb, "Invalid zone report (%d/%u zones)\n", + ret, blkdev_nr_zones(bdev->bd_disk)); + return -EIO; + } + + return 0; +} + +static inline void zonefs_cleanup_zone_info(struct zonefs_zone_data *zd) +{ + kvfree(zd->zones); +} + +/* + * Read super block information from the device. + */ +static int zonefs_read_super(struct super_block *sb) +{ + struct zonefs_sb_info *sbi = ZONEFS_SB(sb); + struct zonefs_super *super; + u32 crc, stored_crc; + struct page *page; + struct bio_vec bio_vec; + struct bio bio; + int ret; + + page = alloc_page(GFP_KERNEL); + if (!page) + return -ENOMEM; + + bio_init(&bio, &bio_vec, 1); + bio.bi_iter.bi_sector = 0; + bio.bi_opf = REQ_OP_READ; + bio_set_dev(&bio, sb->s_bdev); + bio_add_page(&bio, page, PAGE_SIZE, 0); + + ret = submit_bio_wait(&bio); + if (ret) + goto free_page; + + super = kmap(page); + + ret = -EINVAL; + if (le32_to_cpu(super->s_magic) != ZONEFS_MAGIC) + goto unmap; + + stored_crc = le32_to_cpu(super->s_crc); + super->s_crc = 0; + crc = crc32(~0U, (unsigned char *)super, sizeof(struct zonefs_super)); + if (crc != stored_crc) { + zonefs_err(sb, "Invalid checksum (Expected 0x%08x, got 0x%08x)", + crc, stored_crc); + goto unmap; + } + + sbi->s_features = le64_to_cpu(super->s_features); + if (sbi->s_features & ~ZONEFS_F_DEFINED_FEATURES) { + zonefs_err(sb, "Unknown features set 0x%llx\n", + sbi->s_features); + goto unmap; + } + + if (sbi->s_features & ZONEFS_F_UID) { + sbi->s_uid = make_kuid(current_user_ns(), + le32_to_cpu(super->s_uid)); + if (!uid_valid(sbi->s_uid)) { + zonefs_err(sb, "Invalid UID feature\n"); + goto unmap; + } + } + + if (sbi->s_features & ZONEFS_F_GID) { + sbi->s_gid = make_kgid(current_user_ns(), + le32_to_cpu(super->s_gid)); + if (!gid_valid(sbi->s_gid)) { + zonefs_err(sb, "Invalid GID feature\n"); + goto unmap; + } + } + + if (sbi->s_features & ZONEFS_F_PERM) + sbi->s_perm = le32_to_cpu(super->s_perm); + + if (memchr_inv(super->s_reserved, 0, sizeof(super->s_reserved))) { + zonefs_err(sb, "Reserved area is being used\n"); + goto unmap; + } + + uuid_copy(&sbi->s_uuid, (uuid_t *)super->s_uuid); + ret = 0; + +unmap: + kunmap(page); +free_page: + __free_page(page); + + return ret; +} + +/* + * Check that the device is zoned. If it is, get the list of zones and create + * sub-directories and files according to the device zone configuration and + * format options. + */ +static int zonefs_fill_super(struct super_block *sb, void *data, int silent) +{ + struct zonefs_zone_data zd; + struct zonefs_sb_info *sbi; + struct inode *inode; + enum zonefs_ztype t; + int ret; + + if (!bdev_is_zoned(sb->s_bdev)) { + zonefs_err(sb, "Not a zoned block device\n"); + return -EINVAL; + } + + /* + * Initialize super block information: the maximum file size is updated + * when the zone files are created so that the format option + * ZONEFS_F_AGGRCNV which increases the maximum file size of a file + * beyond the zone size is taken into account. + */ + sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); + if (!sbi) + return -ENOMEM; + + spin_lock_init(&sbi->s_lock); + sb->s_fs_info = sbi; + sb->s_magic = ZONEFS_MAGIC; + sb->s_maxbytes = 0; + sb->s_op = &zonefs_sops; + sb->s_time_gran = 1; + + /* + * The block size is set to the device physical sector size to ensure + * that write operations on 512e devices (512B logical block and 4KB + * physical block) are always aligned to the device physical blocks, + * as mandated by the ZBC/ZAC specifications. + */ + sb_set_blocksize(sb, bdev_physical_block_size(sb->s_bdev)); + sbi->s_zone_sectors_shift = ilog2(bdev_zone_sectors(sb->s_bdev)); + sbi->s_uid = GLOBAL_ROOT_UID; + sbi->s_gid = GLOBAL_ROOT_GID; + sbi->s_perm = 0640; + sbi->s_mount_opts = ZONEFS_MNTOPT_ERRORS_RO; + + ret = zonefs_read_super(sb); + if (ret) + return ret; + + ret = zonefs_parse_options(sb, data); + if (ret) + return ret; + + memset(&zd, 0, sizeof(struct zonefs_zone_data)); + zd.sb = sb; + ret = zonefs_get_zone_info(&zd); + if (ret) + goto cleanup; + + zonefs_info(sb, "Mounting %u zones", + blkdev_nr_zones(sb->s_bdev->bd_disk)); + + /* Create root directory inode */ + ret = -ENOMEM; + inode = new_inode(sb); + if (!inode) + goto cleanup; + + inode->i_ino = blkdev_nr_zones(sb->s_bdev->bd_disk); + inode->i_mode = S_IFDIR | 0555; + inode->i_ctime = inode->i_mtime = inode->i_atime = current_time(inode); + inode->i_op = &zonefs_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + set_nlink(inode, 2); + + sb->s_root = d_make_root(inode); + if (!sb->s_root) + goto cleanup; + + /* Create and populate files in zone groups directories */ + for (t = 0; t < ZONEFS_ZTYPE_MAX; t++) { + ret = zonefs_create_zgroup(&zd, t); + if (ret) + break; + } + +cleanup: + zonefs_cleanup_zone_info(&zd); + + return ret; +} + +static struct dentry *zonefs_mount(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + return mount_bdev(fs_type, flags, dev_name, data, zonefs_fill_super); +} + +static void zonefs_kill_super(struct super_block *sb) +{ + struct zonefs_sb_info *sbi = ZONEFS_SB(sb); + + if (sb->s_root) + d_genocide(sb->s_root); + kill_block_super(sb); + kfree(sbi); +} + +/* + * File system definition and registration. + */ +static struct file_system_type zonefs_type = { + .owner = THIS_MODULE, + .name = "zonefs", + .mount = zonefs_mount, + .kill_sb = zonefs_kill_super, + .fs_flags = FS_REQUIRES_DEV, +}; + +static int __init zonefs_init_inodecache(void) +{ + zonefs_inode_cachep = kmem_cache_create("zonefs_inode_cache", + sizeof(struct zonefs_inode_info), 0, + (SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD | SLAB_ACCOUNT), + NULL); + if (zonefs_inode_cachep == NULL) + return -ENOMEM; + return 0; +} + +static void zonefs_destroy_inodecache(void) +{ + /* + * Make sure all delayed rcu free inodes are flushed before we + * destroy the inode cache. + */ + rcu_barrier(); + kmem_cache_destroy(zonefs_inode_cachep); +} + +static int __init zonefs_init(void) +{ + int ret; + + BUILD_BUG_ON(sizeof(struct zonefs_super) != ZONEFS_SUPER_SIZE); + + ret = zonefs_init_inodecache(); + if (ret) + return ret; + + ret = register_filesystem(&zonefs_type); + if (ret) { + zonefs_destroy_inodecache(); + return ret; + } + + return 0; +} + +static void __exit zonefs_exit(void) +{ + zonefs_destroy_inodecache(); + unregister_filesystem(&zonefs_type); +} + +MODULE_AUTHOR("Damien Le Moal"); +MODULE_DESCRIPTION("Zone file system for zoned block devices"); +MODULE_LICENSE("GPL"); +module_init(zonefs_init); +module_exit(zonefs_exit); diff --git a/fs/zonefs/zonefs.h b/fs/zonefs/zonefs.h new file mode 100644 index 000000000000..ad17fef7ce91 --- /dev/null +++ b/fs/zonefs/zonefs.h @@ -0,0 +1,189 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Simple zone file system for zoned block devices. + * + * Copyright (C) 2019 Western Digital Corporation or its affiliates. + */ +#ifndef __ZONEFS_H__ +#define __ZONEFS_H__ + +#include <linux/fs.h> +#include <linux/magic.h> +#include <linux/uuid.h> +#include <linux/mutex.h> +#include <linux/rwsem.h> + +/* + * Maximum length of file names: this only needs to be large enough to fit + * the zone group directory names and a decimal zone number for file names. + * 16 characters is plenty. + */ +#define ZONEFS_NAME_MAX 16 + +/* + * Zone types: ZONEFS_ZTYPE_SEQ is used for all sequential zone types + * defined in linux/blkzoned.h, that is, BLK_ZONE_TYPE_SEQWRITE_REQ and + * BLK_ZONE_TYPE_SEQWRITE_PREF. + */ +enum zonefs_ztype { + ZONEFS_ZTYPE_CNV, + ZONEFS_ZTYPE_SEQ, + ZONEFS_ZTYPE_MAX, +}; + +static inline enum zonefs_ztype zonefs_zone_type(struct blk_zone *zone) +{ + if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL) + return ZONEFS_ZTYPE_CNV; + return ZONEFS_ZTYPE_SEQ; +} + +/* + * In-memory inode data. + */ +struct zonefs_inode_info { + struct inode i_vnode; + + /* File zone type */ + enum zonefs_ztype i_ztype; + + /* File zone start sector (512B unit) */ + sector_t i_zsector; + + /* File zone write pointer position (sequential zones only) */ + loff_t i_wpoffset; + + /* File maximum size */ + loff_t i_max_size; + + /* + * To serialise fully against both syscall and mmap based IO and + * sequential file truncation, two locks are used. For serializing + * zonefs_seq_file_truncate() against zonefs_iomap_begin(), that is, + * file truncate operations against block mapping, i_truncate_mutex is + * used. i_truncate_mutex also protects against concurrent accesses + * and changes to the inode private data, and in particular changes to + * a sequential file size on completion of direct IO writes. + * Serialization of mmap read IOs with truncate and syscall IO + * operations is done with i_mmap_sem in addition to i_truncate_mutex. + * Only zonefs_seq_file_truncate() takes both lock (i_mmap_sem first, + * i_truncate_mutex second). + */ + struct mutex i_truncate_mutex; + struct rw_semaphore i_mmap_sem; +}; + +static inline struct zonefs_inode_info *ZONEFS_I(struct inode *inode) +{ + return container_of(inode, struct zonefs_inode_info, i_vnode); +} + +/* + * On-disk super block (block 0). + */ +#define ZONEFS_LABEL_LEN 64 +#define ZONEFS_UUID_SIZE 16 +#define ZONEFS_SUPER_SIZE 4096 + +struct zonefs_super { + + /* Magic number */ + __le32 s_magic; + + /* Checksum */ + __le32 s_crc; + + /* Volume label */ + char s_label[ZONEFS_LABEL_LEN]; + + /* 128-bit uuid */ + __u8 s_uuid[ZONEFS_UUID_SIZE]; + + /* Features */ + __le64 s_features; + + /* UID/GID to use for files */ + __le32 s_uid; + __le32 s_gid; + + /* File permissions */ + __le32 s_perm; + + /* Padding to ZONEFS_SUPER_SIZE bytes */ + __u8 s_reserved[3988]; + +} __packed; + +/* + * Feature flags: specified in the s_features field of the on-disk super + * block struct zonefs_super and in-memory in the s_feartures field of + * struct zonefs_sb_info. + */ +enum zonefs_features { + /* + * Aggregate contiguous conventional zones into a single file. + */ + ZONEFS_F_AGGRCNV = 1ULL << 0, + /* + * Use super block specified UID for files instead of default 0. + */ + ZONEFS_F_UID = 1ULL << 1, + /* + * Use super block specified GID for files instead of default 0. + */ + ZONEFS_F_GID = 1ULL << 2, + /* + * Use super block specified file permissions instead of default 640. + */ + ZONEFS_F_PERM = 1ULL << 3, +}; + +#define ZONEFS_F_DEFINED_FEATURES \ + (ZONEFS_F_AGGRCNV | ZONEFS_F_UID | ZONEFS_F_GID | ZONEFS_F_PERM) + +/* + * Mount options for zone write pointer error handling. + */ +#define ZONEFS_MNTOPT_ERRORS_RO (1 << 0) /* Make zone file readonly */ +#define ZONEFS_MNTOPT_ERRORS_ZRO (1 << 1) /* Make zone file offline */ +#define ZONEFS_MNTOPT_ERRORS_ZOL (1 << 2) /* Make zone file offline */ +#define ZONEFS_MNTOPT_ERRORS_REPAIR (1 << 3) /* Remount read-only */ +#define ZONEFS_MNTOPT_ERRORS_MASK \ + (ZONEFS_MNTOPT_ERRORS_RO | ZONEFS_MNTOPT_ERRORS_ZRO | \ + ZONEFS_MNTOPT_ERRORS_ZOL | ZONEFS_MNTOPT_ERRORS_REPAIR) + +/* + * In-memory Super block information. + */ +struct zonefs_sb_info { + + unsigned long s_mount_opts; + + spinlock_t s_lock; + + unsigned long long s_features; + kuid_t s_uid; + kgid_t s_gid; + umode_t s_perm; + uuid_t s_uuid; + unsigned int s_zone_sectors_shift; + + unsigned int s_nr_files[ZONEFS_ZTYPE_MAX]; + + loff_t s_blocks; + loff_t s_used_blocks; +}; + +static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb) +{ + return sb->s_fs_info; +} + +#define zonefs_info(sb, format, args...) \ + pr_info("zonefs (%s): " format, sb->s_id, ## args) +#define zonefs_err(sb, format, args...) \ + pr_err("zonefs (%s) ERROR: " format, sb->s_id, ## args) +#define zonefs_warn(sb, format, args...) \ + pr_warn("zonefs (%s) WARNING: " format, sb->s_id, ## args) + +#endif diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h index 3ac436376d79..d78064007b17 100644 --- a/include/uapi/linux/magic.h +++ b/include/uapi/linux/magic.h @@ -87,6 +87,7 @@ #define NSFS_MAGIC 0x6e736673 #define BPF_FS_MAGIC 0xcafe4a11 #define AAFS_MAGIC 0x5a3c69f0 +#define ZONEFS_MAGIC 0x5a4f4653 /* Since UDF 2.01 is ISO 13346 based... */ #define UDF_SUPER_MAGIC 0x15013346 |