kernel.git/fs/zonefs/super.c, branch linux-6.5.y

zonefs: fix synchronous direct writes to sequential files

2023-08-10T03:59:47Z

Commit 16d7fd3cfa72 ("zonefs: use iomap for synchronous direct writes") changes zonefs code from a self-built zone append BIO to using iomap for synchronous direct writes. This change relies on iomap submit BIO callback to change the write BIO built by iomap to a zone append BIO. However, this change overlooked the fact that a write BIO may be very large as it is split when issued. The change from a regular write to a zone append operation for the built BIO can result in a block layer warning as zone append BIO are not allowed to be split. WARNING: CPU: 18 PID: 202210 at block/bio.c:1644 bio_split+0x288/0x350 Call Trace: ? __warn+0xc9/0x2b0 ? bio_split+0x288/0x350 ? report_bug+0x2e6/0x390 ? handle_bug+0x41/0x80 ? exc_invalid_op+0x13/0x40 ? asm_exc_invalid_op+0x16/0x20 ? bio_split+0x288/0x350 bio_split_rw+0x4bc/0x810 ? __pfx_bio_split_rw+0x10/0x10 ? lockdep_unlock+0xf2/0x250 __bio_split_to_limits+0x1d8/0x900 blk_mq_submit_bio+0x1cf/0x18a0 ? __pfx_iov_iter_extract_pages+0x10/0x10 ? __pfx_blk_mq_submit_bio+0x10/0x10 ? find_held_lock+0x2d/0x110 ? lock_release+0x362/0x620 ? mark_held_locks+0x9e/0xe0 __submit_bio+0x1ea/0x290 ? __pfx___submit_bio+0x10/0x10 ? seqcount_lockdep_reader_access.constprop.0+0x82/0x90 submit_bio_noacct_nocheck+0x675/0xa20 ? __pfx_bio_iov_iter_get_pages+0x10/0x10 ? __pfx_submit_bio_noacct_nocheck+0x10/0x10 iomap_dio_bio_iter+0x624/0x1280 __iomap_dio_rw+0xa22/0x18a0 ? lock_is_held_type+0xe3/0x140 ? __pfx___iomap_dio_rw+0x10/0x10 ? lock_release+0x362/0x620 ? zonefs_file_write_iter+0x74c/0xc80 [zonefs] ? down_write+0x13d/0x1e0 iomap_dio_rw+0xe/0x40 zonefs_file_write_iter+0x5ea/0xc80 [zonefs] do_iter_readv_writev+0x18b/0x2c0 ? __pfx_do_iter_readv_writev+0x10/0x10 ? inode_security+0x54/0xf0 do_iter_write+0x13b/0x7c0 ? lock_is_held_type+0xe3/0x140 vfs_writev+0x185/0x550 ? __pfx_vfs_writev+0x10/0x10 ? __handle_mm_fault+0x9bd/0x1c90 ? find_held_lock+0x2d/0x110 ? lock_release+0x362/0x620 ? find_held_lock+0x2d/0x110 ? lock_release+0x362/0x620 ? __up_read+0x1ea/0x720 ? do_pwritev+0x136/0x1f0 do_pwritev+0x136/0x1f0 ? __pfx_do_pwritev+0x10/0x10 ? syscall_enter_from_user_mode+0x22/0x90 ? lockdep_hardirqs_on+0x7d/0x100 do_syscall_64+0x58/0x80 This error depends on the hardware used, specifically on the max zone append bytes and max_[hw_]sectors limits. Tests using AMD Epyc machines that have low limits did not reveal this issue while runs on Intel Xeon machines with larger limits trigger it. Manually splitting the zone append BIO using bio_split_rw() can solve this issue but also requires issuing the fragment BIOs synchronously with submit_bio_wait(), to avoid potential reordering of the zone append BIO fragments, which would lead to data corruption. That is, this solution is not better than using regular write BIOs which are subject to serialization using zone write locking at the IO scheduler level. Given this, fix the issue by removing zone append support and using regular write BIOs for synchronous direct writes. This allows preseving the use of iomap and having identical synchronous and asynchronous sequential file write path. Zone append support will be reintroduced later through io_uring commands to ensure that the needed special handling is done correctly. Reported-by: Shin'ichiro Kawasaki Fixes: 16d7fd3cfa72 ("zonefs: use iomap for synchronous direct writes") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal Tested-by: Shin'ichiro Kawasaki Reviewed-by: Christoph Hellwig

Merge tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux

2023-06-26T19:47:20Z

Pull block updates from Jens Axboe: - NVMe pull request via Keith: - Various cleanups all around (Irvin, Chaitanya, Christophe) - Better struct packing (Christophe JAILLET) - Reduce controller error logs for optional commands (Keith) - Support for >=64KiB block sizes (Daniel Gomez) - Fabrics fixes and code organization (Max, Chaitanya, Daniel Wagner) - bcache updates via Coly: - Fix a race at init time (Mingzhe Zou) - Misc fixes and cleanups (Andrea, Thomas, Zheng, Ye) - use page pinning in the block layer for dio (David) - convert old block dio code to page pinning (David, Christoph) - cleanups for pktcdvd (Andy) - cleanups for rnbd (Guoqing) - use the unchecked __bio_add_page() for the initial single page additions (Johannes) - fix overflows in the Amiga partition handling code (Michael) - improve mq-deadline zoned device support (Bart) - keep passthrough requests out of the IO schedulers (Christoph, Ming) - improve support for flush requests, making them less special to deal with (Christoph) - add bdev holder ops and shutdown methods (Christoph) - fix the name_to_dev_t() situation and use cases (Christoph) - decouple the block open flags from fmode_t (Christoph) - ublk updates and cleanups, including adding user copy support (Ming) - BFQ sanity checking (Bart) - convert brd from radix to xarray (Pankaj) - constify various structures (Thomas, Ivan) - more fine grained persistent reservation ioctl capability checks (Jingbo) - misc fixes and cleanups (Arnd, Azeem, Demi, Ed, Hengqi, Hou, Jan, Jordy, Li, Min, Yu, Zhong, Waiman) * tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux: (266 commits) scsi/sg: don't grab scsi host module reference ext4: Fix warning in blkdev_put() block: don't return -EINVAL for not found names in devt_from_devname cdrom: Fix spectre-v1 gadget block: Improve kernel-doc headers blk-mq: don't insert passthrough request into sw queue bsg: make bsg_class a static const structure ublk: make ublk_chr_class a static const structure aoe: make aoe_class a static const structure block/rnbd: make all 'class' structures const block: fix the exclusive open mask in disk_scan_partitions block: add overflow checks for Amiga partition support block: change all __u32 annotations to __be32 in affs_hardblocks.h block: fix signed int overflow in Amiga partition support block: add capacity validation in bdev_add_partition() block: fine-granular CAP_SYS_ADMIN for Persistent Reservation block: disallow Persistent Reservation on partitions reiserfs: fix blkdev_put() warning from release_journal_dev() block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions() block: document the holder argument to blkdev_get_by_path ...

zonefs: use iomap for synchronous direct writes

2023-06-13T23:51:05Z

Remove the function zonefs_file_dio_append() that is used to manually issue REQ_OP_ZONE_APPEND BIOs for processing synchronous direct writes and use iomap instead. To preserve the use of zone append operations for synchronous writes, different struct iomap_dio_ops are defined. For synchronous direct writes using zone append, zonefs_zone_append_dio_ops is introduced. The submit_bio operation of this structure is defined as the function zonefs_file_zone_append_dio_submit_io() which is used to change the BIO opreation for synchronous direct IO writes to REQ_OP_ZONE_APPEND. In order to preserve the write location check on completion of zone append BIOs, the end_io operation is also defined using the function zonefs_file_zone_append_dio_bio_end_io(). This check now relies on the zonefs_zone_append_bio structure, allocated together with zone append BIOs with a dedicated BIO set. This structure include the target inode of a zone append BIO as well as the target append offset location for the zone append operation. This is used to perform a check against bio->bi_iter.bi_sector when the BIO completes, without needing to use the zone information z_wpoffset field, thus removing the need for taking the inode truncate mutex. Signed-off-by: Damien Le Moal Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Himanshu Madhani

zonefs: use __bio_add_page for adding single page to bio

2023-05-31T15:50:02Z

The zonefs superblock reading code uses bio_add_page() to add a page to a newly created bio. bio_add_page() can fail, but the return value is never checked. Use __bio_add_page() as adding a single page to a newly created bio is guaranteed to succeed. This brings us a step closer to marking bio_add_page() as __must_check. Acked-by: Damien Le Moal Reviewed-by: Christoph Hellwig Signed-off-by: Johannes Thumshirn Link: https://lore.kernel.org/r/04c9978ccaa0fc9871cd4248356638d98daccf0c.1685532726.git.johannes.thumshirn@wdc.com Signed-off-by: Jens Axboe

Merge tag 'zonefs-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs

2023-02-22T22:11:54Z

Pull zonefs updates from Damien Le Moal: - Reorganize zonefs code to split file related operations to a new fs/zonefs/file.c file (me) - Modify zonefs to use dynamically allocated inodes and dentries (using the inode and dentry caches) instead of statically allocating everything on mount. This saves a significant amount of memory for very large zoned block devices with 10s of thousands of zones (me) - Make zonefs_sb_ktype a const struct kobj_type (Thomas) * tag 'zonefs-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs: zonefs: make kobj_type structure constant zonefs: Cache zone group directory inodes zonefs: Dynamically create file inodes when needed zonefs: Separate zone information from inode information zonefs: Reduce struct zonefs_inode_info size zonefs: Simplify IO error handling zonefs: Reorganize code

Merge tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

2023-02-20T19:53:11Z

Pull vfs idmapping updates from Christian Brauner: - Last cycle we introduced the dedicated struct mnt_idmap type for mount idmapping and the required infrastucture in 256c8aed2b42 ("fs: introduce dedicated idmap type for mounts"). As promised in last cycle's pull request message this converts everything to rely on struct mnt_idmap. Currently we still pass around the plain namespace that was attached to a mount. This is in general pretty convenient but it makes it easy to conflate namespaces that are relevant on the filesystem with namespaces that are relevant on the mount level. Especially for non-vfs developers without detailed knowledge in this area this was a potential source for bugs. This finishes the conversion. Instead of passing the plain namespace around this updates all places that currently take a pointer to a mnt_userns with a pointer to struct mnt_idmap. Now that the conversion is done all helpers down to the really low-level helpers only accept a struct mnt_idmap argument instead of two namespace arguments. Conflating mount and other idmappings will now cause the compiler to complain loudly thus eliminating the possibility of any bugs. This makes it impossible for filesystem developers to mix up mount and filesystem idmappings as they are two distinct types and require distinct helpers that cannot be used interchangeably. Everything associated with struct mnt_idmap is moved into a single separate file. With that change no code can poke around in struct mnt_idmap. It can only be interacted with through dedicated helpers. That means all filesystems are and all of the vfs is completely oblivious to the actual implementation of idmappings. We are now also able to extend struct mnt_idmap as we see fit. For example, we can decouple it completely from namespaces for users that don't require or don't want to use them at all. We can also extend the concept of idmappings so we can cover filesystem specific requirements. In combination with the vfs{g,u}id_t work we finished in v6.2 this makes this feature substantially more robust and thus difficult to implement wrong by a given filesystem and also protects the vfs. - Enable idmapped mounts for tmpfs and fulfill a longstanding request. A long-standing request from users had been to make it possible to create idmapped mounts for tmpfs. For example, to share the host's tmpfs mount between multiple sandboxes. This is a prerequisite for some advanced Kubernetes cases. Systemd also has a range of use-cases to increase service isolation. And there are more users of this. However, with all of the other work going on this was way down on the priority list but luckily someone other than ourselves picked this up. As usual the patch is tiny as all the infrastructure work had been done multiple kernel releases ago. In addition to all the tests that we already have I requested that Rodrigo add a dedicated tmpfs testsuite for idmapped mounts to xfstests. It is to be included into xfstests during the v6.3 development cycle. This should add a slew of additional tests. * tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits) shmem: support idmapped mounts for tmpfs fs: move mnt_idmap fs: port vfs{g,u}id helpers to mnt_idmap fs: port fs{g,u}id helpers to mnt_idmap fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap fs: port i_{g,u}id_{needs_}update() to mnt_idmap quota: port to mnt_idmap fs: port privilege checking helpers to mnt_idmap fs: port inode_owner_or_capable() to mnt_idmap fs: port inode_init_owner() to mnt_idmap fs: port acl to mnt_idmap fs: port xattr to mnt_idmap fs: port ->permission() to pass mnt_idmap fs: port ->fileattr_set() to pass mnt_idmap fs: port ->set_acl() to pass mnt_idmap fs: port ->get_acl() to pass mnt_idmap fs: port ->tmpfile() to pass mnt_idmap fs: port ->rename() to pass mnt_idmap fs: port ->mknod() to pass mnt_idmap fs: port ->mkdir() to pass mnt_idmap ...

zonefs: Cache zone group directory inodes

2023-01-23T00:25:51Z

Since looking up any zone file inode requires looking up first the inode for the directory representing the zone group of the file, ensuring that the zone group inodes are always cached is desired. To do so, take an extra reference on the zone groups directory inodes on mount, thus avoiding the eviction of these inodes from the inode cache until the volume is unmounted. Signed-off-by: Damien Le Moal Reviewed-by: Johannes Thumshirn

zonefs: Dynamically create file inodes when needed

2023-01-23T00:25:51Z

Allocating and initializing all inodes and dentries for all files results in a very large memory usage with high capacity zoned block devices. For instance, with a 26 TB SMR HDD with over 96000 zones, mounting the disk with zonefs results in about 130 MB of memory used, the vast majority of this space being used for vfs inodes and dentries. However, since a user will rarely access all zones at the same time, dynamically creating file inodes and dentries on demand, similarly to regular file systems, can significantly reduce memory usage. This patch modifies mount processing to not create the inodes and dentries for zone files. Instead, the directory inode operation zonefs_lookup() and directory file operation zonefs_readdir() are introduced to allocate and initialize inodes on-demand using the helper functions zonefs_get_dir_inode() and zonefs_get_zgroup_inode(). Implementation of these functions is simple, relying on the static nature of zonefs directories and files. Directory inodes are linked to the volume zone groups (struct zonefs_zone_group) they represent by using the directory inode i_private field. This simplifies the implementation of the lookup and readdir operations. Unreferenced zone file inodes can be evicted from the inode cache at any time. In such case, the only inode information that cannot be recreated from the zone information that is saved in the zone group data structures attached to the volume super block is the inode uid, gid and access rights. These values may have been changed by the user. To keep these attributes for the life time of the mount, as before, the inode mode, uid and gid are saved in the inode zone information and the saved values are used to initialize regular file inodes when an inode lookup happens. The zone information mode, uid and gid are initialized in zonefs_init_zgroup() using the default values. With these changes, the static minimal memory usage of a zonefs volume is mostly reduced to the array of zone information for each zone group. For the 26 TB SMR hard-disk mentioned above, the memory usage after mount becomes about 5.4 MB, a reduction by a factor of 24 from the initial 130 MB memory use. Co-developed-by: Jorgen Hansen Signed-off-by: Damien Le Moal Reviewed-by: Johannes Thumshirn

zonefs: Separate zone information from inode information

2023-01-23T00:25:51Z

In preparation for adding dynamic inode allocation, separate an inode zone information from the zonefs inode structure. The new data structure zonefs_zone is introduced to store in memory information about a zone that must be kept throughout the lifetime of the device mount. Linking between a zone file inode and its zone information is done by setting the inode i_private field to point to a struct zonefs_zone. Using the i_private pointer avoids the need for adding a pointer in struct zonefs_inode_info. Beside the vfs inode, this structure is reduced to a mutex and a write open counter. One struct zonefs_zone is created per file inode on mount. These structures are organized in an array using the new struct zonefs_zone_group data structure to represent zone groups. The zonefs_zone arrays are indexed per file number (the index of a struct zonefs_zone in its array directly gives the file number/name for that zone file inode). Signed-off-by: Damien Le Moal Reviewed-by: Johannes Thumshirn

zonefs: Reduce struct zonefs_inode_info size

2023-01-23T00:25:51Z

Instead of using the i_ztype field in struct zonefs_inode_info to indicate the zone type of an inode, introduce the new inode flag ZONEFS_ZONE_CNV to be set in the i_flags field of struct zonefs_inode_info to identify conventional zones. If this flag is not set, the zone of an inode is considered to be a sequential zone. The helpers zonefs_zone_is_cnv(), zonefs_zone_is_seq(), zonefs_inode_is_cnv() and zonefs_inode_is_seq() are introduced to simplify testing the zone type of a struct zonefs_inode_info and of a struct inode. Signed-off-by: Damien Le Moal Reviewed-by: Johannes Thumshirn