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zfs/include/sys/zvol.h

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Initial Linux ZFS GIT Repo
2008-11-20 20:01:55 +00:00
/*
* CDDL HEADER START
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* Common Development and Distribution License (the "License").
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/*
Update core ZFS code from build 121 to build 141.
2010-05-28 20:45:14 +00:00
* Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
Add support for asynchronous zvol minor operations zfsonlinux issue #2217 - zvol minor operations: check snapdev property before traversing snapshots of a dataset zfsonlinux issue #3681 - lock order inversion between zvol_open() and dsl_pool_sync()...zvol_rename_minors() Create a per-pool zvol taskq for asynchronous zvol tasks. There are a few key design decisions to be aware of. * Each taskq must be single threaded to ensure tasks are always processed in the order in which they were dispatched. * There is a taskq per-pool in order to keep the pools independent. This way if one pool is suspended it will not impact another. * The preferred location to dispatch a zvol minor task is a sync task. In this context there is easy access to the spa_t and minimal error handling is required because the sync task must succeed. Support for asynchronous zvol minor operations address issue #3681. Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #2217 Closes #3678 Closes #3681
2014-03-22 09:07:14 +00:00
* Copyright (c) 2016 Actifio, Inc. All rights reserved.
Initial Linux ZFS GIT Repo
2008-11-20 20:01:55 +00:00
*/
#ifndef _SYS_ZVOL_H
#define _SYS_ZVOL_H
#include <sys/zfs_context.h>
#define ZVOL_OBJ 1ULL
#define ZVOL_ZAP_OBJ 2ULL
Fix 32-bit maximum volume size A limit of 1TB exists for zvols on 32-bit systems. Update the code to correctly reflect this limitation in a similar manor as the OpenZFS implementation. Reviewed-by: Tom Caputi <tcaputi@datto.com> Reviewed-by: Tim Chase <tim@chase2k.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #5347
2016-10-28 23:53:24 +00:00
#define SPEC_MAXOFFSET_T ((1LL << ((NBBY * sizeof (daddr32_t)) + \
DEV_BSHIFT - 1)) - 1)
async zvol minor node creation interferes with receive When we finish a zfs receive, dmu_recv_end_sync() calls zvol_create_minors(async=TRUE). This kicks off some other threads that create the minor device nodes (in /dev/zvol/poolname/...). These async threads call zvol_prefetch_minors_impl() and zvol_create_minor(), which both call dmu_objset_own(), which puts a "long hold" on the dataset. Since the zvol minor node creation is asynchronous, this can happen after the `ZFS_IOC_RECV[_NEW]` ioctl and `zfs receive` process have completed. After the first receive ioctl has completed, userland may attempt to do another receive into the same dataset (e.g. the next incremental stream). This second receive and the asynchronous minor node creation can interfere with one another in several different ways, because they both require exclusive access to the dataset: 1. When the second receive is finishing up, dmu_recv_end_check() does dsl_dataset_handoff_check(), which can fail with EBUSY if the async minor node creation already has a "long hold" on this dataset. This causes the 2nd receive to fail. 2. The async udev rule can fail if zvol_id and/or systemd-udevd try to open the device while the the second receive's async attempt at minor node creation owns the dataset (via zvol_prefetch_minors_impl). This causes the minor node (/dev/zd*) to exist, but the udev-generated /dev/zvol/... to not exist. 3. The async minor node creation can silently fail with EBUSY if the first receive's zvol_create_minor() trys to own the dataset while the second receive's zvol_prefetch_minors_impl already owns the dataset. To address these problems, this change synchronously creates the minor node. To avoid the lock ordering problems that the asynchrony was introduced to fix (see #3681), we create the minor nodes from open context, with no locks held, rather than from syncing contex as was originally done. Implementation notes: We generally do not need to traverse children or prefetch anything (e.g. when running the recv, snapshot, create, or clone subcommands of zfs). We only need recursion when importing/opening a pool and when loading encryption keys. The existing recursive, asynchronous, prefetching code is preserved for use in these cases. Channel programs may need to create zvol minor nodes, when creating a snapshot of a zvol with the snapdev property set. We figure out what snapshots are created when running the LUA program in syncing context. In this case we need to remember what snapshots were created, and then try to create their minor nodes from open context, after the LUA code has completed. There are additional zvol use cases that asynchronously own the dataset, which can cause similar problems. E.g. changing the volmode or snapdev properties. These are less problematic because they are not recursive and don't touch datasets that are not involved in the operation, there is still potential for interference with subsequent operations. In the future, these cases should be similarly converted to create the zvol minor node synchronously from open context. The async tasks of removing and renaming minors do not own the objset, so they do not have this problem. However, it may make sense to also convert these operations to happen synchronously from open context, in the future. Reviewed-by: Paul Dagnelie <pcd@delphix.com> Reviewed-by: Prakash Surya <prakash.surya@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Matthew Ahrens <mahrens@delphix.com> External-issue: DLPX-65948 Closes #7863 Closes #9885
2020-02-03 17:33:14 +00:00
extern void zvol_create_minor(const char *);
extern void zvol_create_minors_recursive(const char *);
extern void zvol_remove_minors(spa_t *, const char *, boolean_t);
extern void zvol_rename_minors(spa_t *, const char *, const char *, boolean_t);
Add linux kernel disk support Native Linux vdev disk interfaces Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2010-08-26 18:45:02 +00:00
Add support for asynchronous zvol minor operations zfsonlinux issue #2217 - zvol minor operations: check snapdev property before traversing snapshots of a dataset zfsonlinux issue #3681 - lock order inversion between zvol_open() and dsl_pool_sync()...zvol_rename_minors() Create a per-pool zvol taskq for asynchronous zvol tasks. There are a few key design decisions to be aware of. * Each taskq must be single threaded to ensure tasks are always processed in the order in which they were dispatched. * There is a taskq per-pool in order to keep the pools independent. This way if one pool is suspended it will not impact another. * The preferred location to dispatch a zvol minor task is a sync task. In this context there is easy access to the spa_t and minimal error handling is required because the sync task must succeed. Support for asynchronous zvol minor operations address issue #3681. Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #2217 Closes #3678 Closes #3681
2014-03-22 09:07:14 +00:00
#ifdef _KERNEL
OpenZFS restructuring - zvol Refactor the zvol in to platform dependent and independent bits. Reviewed-by: Allan Jude <allanjude@freebsd.org> Reviewed-by: Jorgen Lundman <lundman@lundman.net> Reviewed-by: Igor Kozhukhov <igor@dilos.org> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Matt Macy <mmacy@FreeBSD.org> Closes #9295
2019-09-25 16:20:30 +00:00
struct zvol_state;
typedef struct zvol_state zvol_state_handle_t;
Suspend/resume zvol for recv and rollback When doing recv and rollback, dsl_dataset_clone_swap_sync_impl will be called to swap out the ds_objset and do dmu_objset_evict on the old one. However, currently zv->zv_objset will not be swapped out accordingly, so if anyone currently holds a fd on the zvol, we risk hitting a use-after-free. We fix this by introducing the suspend and resume mechanism of zsb to zv. Before recv or rollback, we use zvol_suspend to block all access to zv_objset and shut it down. After the recv or rollback, we use zvol_resume to swap in zv_objset with the new ds_objset and unblock the access. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Chunwei Chen <david.chen@osnexus.com> Closes #4866 Closes #5609
2017-01-19 21:56:36 +00:00
async zvol minor node creation interferes with receive When we finish a zfs receive, dmu_recv_end_sync() calls zvol_create_minors(async=TRUE). This kicks off some other threads that create the minor device nodes (in /dev/zvol/poolname/...). These async threads call zvol_prefetch_minors_impl() and zvol_create_minor(), which both call dmu_objset_own(), which puts a "long hold" on the dataset. Since the zvol minor node creation is asynchronous, this can happen after the `ZFS_IOC_RECV[_NEW]` ioctl and `zfs receive` process have completed. After the first receive ioctl has completed, userland may attempt to do another receive into the same dataset (e.g. the next incremental stream). This second receive and the asynchronous minor node creation can interfere with one another in several different ways, because they both require exclusive access to the dataset: 1. When the second receive is finishing up, dmu_recv_end_check() does dsl_dataset_handoff_check(), which can fail with EBUSY if the async minor node creation already has a "long hold" on this dataset. This causes the 2nd receive to fail. 2. The async udev rule can fail if zvol_id and/or systemd-udevd try to open the device while the the second receive's async attempt at minor node creation owns the dataset (via zvol_prefetch_minors_impl). This causes the minor node (/dev/zd*) to exist, but the udev-generated /dev/zvol/... to not exist. 3. The async minor node creation can silently fail with EBUSY if the first receive's zvol_create_minor() trys to own the dataset while the second receive's zvol_prefetch_minors_impl already owns the dataset. To address these problems, this change synchronously creates the minor node. To avoid the lock ordering problems that the asynchrony was introduced to fix (see #3681), we create the minor nodes from open context, with no locks held, rather than from syncing contex as was originally done. Implementation notes: We generally do not need to traverse children or prefetch anything (e.g. when running the recv, snapshot, create, or clone subcommands of zfs). We only need recursion when importing/opening a pool and when loading encryption keys. The existing recursive, asynchronous, prefetching code is preserved for use in these cases. Channel programs may need to create zvol minor nodes, when creating a snapshot of a zvol with the snapdev property set. We figure out what snapshots are created when running the LUA program in syncing context. In this case we need to remember what snapshots were created, and then try to create their minor nodes from open context, after the LUA code has completed. There are additional zvol use cases that asynchronously own the dataset, which can cause similar problems. E.g. changing the volmode or snapdev properties. These are less problematic because they are not recursive and don't touch datasets that are not involved in the operation, there is still potential for interference with subsequent operations. In the future, these cases should be similarly converted to create the zvol minor node synchronously from open context. The async tasks of removing and renaming minors do not own the objset, so they do not have this problem. However, it may make sense to also convert these operations to happen synchronously from open context, in the future. Reviewed-by: Paul Dagnelie <pcd@delphix.com> Reviewed-by: Prakash Surya <prakash.surya@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Matthew Ahrens <mahrens@delphix.com> External-issue: DLPX-65948 Closes #7863 Closes #9885
2020-02-03 17:33:14 +00:00
extern int zvol_check_volsize(uint64_t, uint64_t);
extern int zvol_check_volblocksize(const char *, uint64_t);
extern int zvol_get_stats(objset_t *, nvlist_t *);
Fix using zvol as slog device During the original ZoL port the vdev_uses_zvols() function was disabled until it could be properly implemented. This prevented a zpool from use a zvol for its slog device. This patch implements that missing functionality by adding a zvol_is_zvol() function to zvol.c. Given the full path to a device it will lookup the device and verify its major number against the registered zvol major number for the system. If they match we know the device is a zvol. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #1131
2012-12-17 01:33:57 +00:00
extern boolean_t zvol_is_zvol(const char *);
async zvol minor node creation interferes with receive When we finish a zfs receive, dmu_recv_end_sync() calls zvol_create_minors(async=TRUE). This kicks off some other threads that create the minor device nodes (in /dev/zvol/poolname/...). These async threads call zvol_prefetch_minors_impl() and zvol_create_minor(), which both call dmu_objset_own(), which puts a "long hold" on the dataset. Since the zvol minor node creation is asynchronous, this can happen after the `ZFS_IOC_RECV[_NEW]` ioctl and `zfs receive` process have completed. After the first receive ioctl has completed, userland may attempt to do another receive into the same dataset (e.g. the next incremental stream). This second receive and the asynchronous minor node creation can interfere with one another in several different ways, because they both require exclusive access to the dataset: 1. When the second receive is finishing up, dmu_recv_end_check() does dsl_dataset_handoff_check(), which can fail with EBUSY if the async minor node creation already has a "long hold" on this dataset. This causes the 2nd receive to fail. 2. The async udev rule can fail if zvol_id and/or systemd-udevd try to open the device while the the second receive's async attempt at minor node creation owns the dataset (via zvol_prefetch_minors_impl). This causes the minor node (/dev/zd*) to exist, but the udev-generated /dev/zvol/... to not exist. 3. The async minor node creation can silently fail with EBUSY if the first receive's zvol_create_minor() trys to own the dataset while the second receive's zvol_prefetch_minors_impl already owns the dataset. To address these problems, this change synchronously creates the minor node. To avoid the lock ordering problems that the asynchrony was introduced to fix (see #3681), we create the minor nodes from open context, with no locks held, rather than from syncing contex as was originally done. Implementation notes: We generally do not need to traverse children or prefetch anything (e.g. when running the recv, snapshot, create, or clone subcommands of zfs). We only need recursion when importing/opening a pool and when loading encryption keys. The existing recursive, asynchronous, prefetching code is preserved for use in these cases. Channel programs may need to create zvol minor nodes, when creating a snapshot of a zvol with the snapdev property set. We figure out what snapshots are created when running the LUA program in syncing context. In this case we need to remember what snapshots were created, and then try to create their minor nodes from open context, after the LUA code has completed. There are additional zvol use cases that asynchronously own the dataset, which can cause similar problems. E.g. changing the volmode or snapdev properties. These are less problematic because they are not recursive and don't touch datasets that are not involved in the operation, there is still potential for interference with subsequent operations. In the future, these cases should be similarly converted to create the zvol minor node synchronously from open context. The async tasks of removing and renaming minors do not own the objset, so they do not have this problem. However, it may make sense to also convert these operations to happen synchronously from open context, in the future. Reviewed-by: Paul Dagnelie <pcd@delphix.com> Reviewed-by: Prakash Surya <prakash.surya@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Matthew Ahrens <mahrens@delphix.com> External-issue: DLPX-65948 Closes #7863 Closes #9885
2020-02-03 17:33:14 +00:00
extern void zvol_create_cb(objset_t *, void *, cred_t *, dmu_tx_t *);
Add linux kernel disk support Native Linux vdev disk interfaces Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2010-08-26 18:45:02 +00:00
extern int zvol_set_volsize(const char *, uint64_t);
Add support for asynchronous zvol minor operations zfsonlinux issue #2217 - zvol minor operations: check snapdev property before traversing snapshots of a dataset zfsonlinux issue #3681 - lock order inversion between zvol_open() and dsl_pool_sync()...zvol_rename_minors() Create a per-pool zvol taskq for asynchronous zvol tasks. There are a few key design decisions to be aware of. * Each taskq must be single threaded to ensure tasks are always processed in the order in which they were dispatched. * There is a taskq per-pool in order to keep the pools independent. This way if one pool is suspended it will not impact another. * The preferred location to dispatch a zvol minor task is a sync task. In this context there is easy access to the spa_t and minimal error handling is required because the sync task must succeed. Support for asynchronous zvol minor operations address issue #3681. Signed-off-by: Boris Protopopov <boris.protopopov@actifio.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #2217 Closes #3678 Closes #3681
2014-03-22 09:07:14 +00:00
extern int zvol_set_snapdev(const char *, zprop_source_t, uint64_t);
Add port of FreeBSD 'volmode' property The volmode property may be set to control the visibility of ZVOL block devices. This allow switching ZVOL between three modes: full - existing fully functional behaviour (default) dev - hide partitions on ZVOL block devices none - not exposing volumes outside ZFS Additionally the new zvol_volmode module parameter can be used to control the default behaviour. This functionality can be used, for instance, on "backup" pools to avoid cluttering /dev with unneeded zd* devices. Original-patch-by: mav <mav@FreeBSD.org> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Ported-by: loli10K <ezomori.nozomu@gmail.com> Signed-off-by: loli10K <ezomori.nozomu@gmail.com> FreeBSD-commit: https://github.com/freebsd/freebsd/commit/dd28e6bb Closes #1796 Closes #3438 Closes #6233
2017-07-12 20:05:37 +00:00
extern int zvol_set_volmode(const char *, zprop_source_t, uint64_t);
OpenZFS restructuring - zvol Refactor the zvol in to platform dependent and independent bits. Reviewed-by: Allan Jude <allanjude@freebsd.org> Reviewed-by: Jorgen Lundman <lundman@lundman.net> Reviewed-by: Igor Kozhukhov <igor@dilos.org> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Matt Macy <mmacy@FreeBSD.org> Closes #9295
2019-09-25 16:20:30 +00:00
extern zvol_state_handle_t *zvol_suspend(const char *);
extern int zvol_resume(zvol_state_handle_t *);
extern void *zvol_tag(zvol_state_handle_t *);
Initial Linux ZFS GIT Repo
2008-11-20 20:01:55 +00:00
Add linux kernel disk support Native Linux vdev disk interfaces Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2010-08-26 18:45:02 +00:00
extern int zvol_init(void);
Initial Linux ZFS GIT Repo
2008-11-20 20:01:55 +00:00
extern void zvol_fini(void);
OpenZFS restructuring - zvol Refactor the zvol in to platform dependent and independent bits. Reviewed-by: Allan Jude <allanjude@freebsd.org> Reviewed-by: Jorgen Lundman <lundman@lundman.net> Reviewed-by: Igor Kozhukhov <igor@dilos.org> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Matt Macy <mmacy@FreeBSD.org> Closes #9295
2019-09-25 16:20:30 +00:00
extern int zvol_busy(void);
Add linux kernel disk support Native Linux vdev disk interfaces Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2010-08-26 18:45:02 +00:00
#endif /* _KERNEL */
#endif /* _SYS_ZVOL_H */