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Date: Fri, 9 Apr 2021 14:48:03 +0300 Message-ID: <1617968884-15149-4-git-send-email-sergei.shtepa@veeam.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1617968884-15149-1-git-send-email-sergei.shtepa@veeam.com> References: <1617968884-15149-1-git-send-email-sergei.shtepa@veeam.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [172.24.14.5] X-ClientProxiedBy: prgmbx01.amust.local (172.24.0.171) To prgmbx01.amust.local (172.24.0.171) X-EsetResult: clean, is OK X-EsetId: 37303A29D2A50B59657262 X-Veeam-MMEX: True Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * The new flag DM_INTERPOSE_FLAG allows to specify that the dm target will be attached using blk_interposer. * The [interpose] option allows to specify which device will be attached via the interposer. * The connection and disconnection of the interrupter is performed in the functions __dm_suspend() and __dm_resume(). The flag DM_SUSPEND_DETACH_IP_FLAG was added for this purpose. * dm_submit_bio() sets BIO_INTERPOSED for each bio from the interposer. Signed-off-by: Sergei Shtepa --- drivers/md/dm-core.h | 1 + drivers/md/dm-ioctl.c | 95 ++++++++++--- drivers/md/dm-table.c | 68 ++++++++- drivers/md/dm.c | 254 ++++++++++++++++++++++++++++++---- drivers/md/dm.h | 8 +- include/linux/device-mapper.h | 1 + include/uapi/linux/dm-ioctl.h | 6 + 7 files changed, 375 insertions(+), 58 deletions(-) diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h index 5953ff2bd260..431b82461eae 100644 --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -112,6 +112,7 @@ struct mapped_device { /* for blk-mq request-based DM support */ struct blk_mq_tag_set *tag_set; bool init_tio_pdu:1; + bool interpose:1; struct srcu_struct io_barrier; }; diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 1ca65b434f1f..7ec37526920b 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -294,11 +294,29 @@ static void dm_hash_remove_all(bool keep_open_devices, bool mark_deferred, bool md = hc->md; dm_get(md); - if (keep_open_devices && - dm_lock_for_deletion(md, mark_deferred, only_deferred)) { - dm_put(md); - dev_skipped++; - continue; + if (md->interpose) { + int r; + + /* + * Interposer should be suspended and detached + * from the interposed block device. + */ + r = dm_suspend(md, DM_SUSPEND_DETACH_IP_FLAG | + DM_SUSPEND_LOCKFS_FLAG); + if (r) { + DMERR("%s: unable to suspend and detach interposer", + dm_device_name(md)); + dm_put(md); + dev_skipped++; + continue; + } + } else { + if (keep_open_devices && + dm_lock_for_deletion(md, mark_deferred, only_deferred)) { + dm_put(md); + dev_skipped++; + continue; + } } t = __hash_remove(hc); @@ -732,6 +750,9 @@ static void __dev_status(struct mapped_device *md, struct dm_ioctl *param) if (dm_test_deferred_remove_flag(md)) param->flags |= DM_DEFERRED_REMOVE; + if (dm_interposer_attached(md)) + param->flags |= DM_INTERPOSE_FLAG; + param->dev = huge_encode_dev(disk_devt(disk)); /* @@ -878,20 +899,37 @@ static int dev_remove(struct file *filp, struct dm_ioctl *param, size_t param_si md = hc->md; - /* - * Ensure the device is not open and nothing further can open it. - */ - r = dm_lock_for_deletion(md, !!(param->flags & DM_DEFERRED_REMOVE), false); - if (r) { - if (r == -EBUSY && param->flags & DM_DEFERRED_REMOVE) { + if (!md->interpose) { + /* + * Ensure the device is not open and nothing further can open it. + */ + r = dm_lock_for_deletion(md, !!(param->flags & DM_DEFERRED_REMOVE), false); + if (r) { + if (r == -EBUSY && param->flags & DM_DEFERRED_REMOVE) { + up_write(&_hash_lock); + dm_put(md); + return 0; + } + DMDEBUG_LIMIT("unable to remove open device %s", + hc->name); up_write(&_hash_lock); dm_put(md); - return 0; + return r; + } + } else { + /* + * Interposer should be suspended and detached from + * the interposed block device. + */ + r = dm_suspend(md, DM_SUSPEND_DETACH_IP_FLAG | + DM_SUSPEND_LOCKFS_FLAG); + if (r) { + DMERR("%s: unable to suspend and detach interposer", + dm_device_name(md)); + up_write(&_hash_lock); + dm_put(md); + return r; } - DMDEBUG_LIMIT("unable to remove open device %s", hc->name); - up_write(&_hash_lock); - dm_put(md); - return r; } t = __hash_remove(hc); @@ -1050,6 +1088,7 @@ static int do_resume(struct dm_ioctl *param) md = hc->md; + new_map = hc->new_map; hc->new_map = NULL; param->flags &= ~DM_INACTIVE_PRESENT_FLAG; @@ -1063,8 +1102,14 @@ static int do_resume(struct dm_ioctl *param) suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG; if (param->flags & DM_NOFLUSH_FLAG) suspend_flags |= DM_SUSPEND_NOFLUSH_FLAG; - if (!dm_suspended_md(md)) - dm_suspend(md, suspend_flags); + + if (md->interpose) { + if (!dm_suspended_md(md) || dm_interposer_attached(md)) + dm_suspend(md, suspend_flags | DM_SUSPEND_DETACH_IP_FLAG); + } else { + if (!dm_suspended_md(md)) + dm_suspend(md, suspend_flags); + } old_map = dm_swap_table(md, new_map); if (IS_ERR(old_map)) { @@ -1267,6 +1312,11 @@ static inline fmode_t get_mode(struct dm_ioctl *param) return mode; } +static inline bool get_interpose_flag(struct dm_ioctl *param) +{ + return (param->flags & DM_INTERPOSE_FLAG); +} + static int next_target(struct dm_target_spec *last, uint32_t next, void *end, struct dm_target_spec **spec, char **target_params) { @@ -1289,11 +1339,6 @@ static int populate_table(struct dm_table *table, void *end = (void *) param + param_size; char *target_params; - if (!param->target_count) { - DMWARN("populate_table: no targets specified"); - return -EINVAL; - } - for (i = 0; i < param->target_count; i++) { r = next_target(spec, next, end, &spec, &target_params); @@ -1338,6 +1383,8 @@ static int table_load(struct file *filp, struct dm_ioctl *param, size_t param_si if (!md) return -ENXIO; + md->interpose = get_interpose_flag(param); + r = dm_table_create(&t, get_mode(param), param->target_count, md); if (r) goto err; @@ -2098,6 +2145,8 @@ int __init dm_early_create(struct dm_ioctl *dmi, if (r) goto err_hash_remove; + md->interpose = get_interpose_flag(dmi); + /* add targets */ for (i = 0; i < dmi->target_count; i++) { r = dm_table_add_target(t, spec_array[i]->target_type, diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index e5f0f1703c5d..23574c727f2b 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -327,14 +327,14 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev, * it is accessed concurrently. */ static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode, - struct mapped_device *md) + bool interpose, struct mapped_device *md) { int r; struct dm_dev *old_dev, *new_dev; old_dev = dd->dm_dev; - r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev, + r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev, interpose, dd->dm_dev->mode | new_mode, &new_dev); if (r) return r; @@ -367,6 +367,8 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, { int r; dev_t dev; + size_t ofs = 0; + bool interpose = false; unsigned int major, minor; char dummy; struct dm_dev_internal *dd; @@ -374,13 +376,40 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, BUG_ON(!t); - if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) { + /* + * Extract extended options for device + */ + if (path[0] == '[') { + const char *interpose_opt = "interpose"; + size_t opt_pos = 1; + size_t opt_len; + + /* + * Because only one option is supported yet, the parser + * can be simplest. + */ + opt_len = strlen(interpose_opt); + if ((opt_pos + opt_len) < strlen(path) && + memcmp(&path[opt_pos], interpose_opt, opt_len) == 0) { + interpose = true; + + if (!t->md->interpose) + t->md->interpose = true; + } else { + DMERR("Invalid devices extended options %s", path); + return -EINVAL; + } + + ofs = opt_pos + opt_len + 1; + } + + if (sscanf(&path[ofs], "%u:%u%c", &major, &minor, &dummy) == 2) { /* Extract the major/minor numbers */ dev = MKDEV(major, minor); if (MAJOR(dev) != major || MINOR(dev) != minor) return -EOVERFLOW; } else { - dev = dm_get_dev_t(path); + dev = dm_get_dev_t(&path[ofs]); if (!dev) return -ENODEV; } @@ -391,7 +420,8 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, if (!dd) return -ENOMEM; - if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) { + r = dm_get_table_device(t->md, dev, mode, interpose, &dd->dm_dev); + if (r) { kfree(dd); return r; } @@ -401,14 +431,40 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, goto out; } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) { - r = upgrade_mode(dd, mode, t->md); + r = upgrade_mode(dd, mode, interpose, t->md); if (r) return r; } refcount_inc(&dd->count); out: + if (interpose) { + struct block_device *original = dd->dm_dev->bdev; + /* + * Interposer target should cover all underlying device + */ + if (ti->begin != 0) { + DMERR("%s: target offset should be zero for dm interposer", + dm_device_name(t->md)); + r = -EINVAL; + goto fail; + } + if (bdev_nr_sectors(original) != ti->len) { + DMERR("%s: interposer and interposed block device size should be equal", + dm_device_name(t->md)); + r = -EINVAL; + goto fail; + } + } + *result = dd->dm_dev; return 0; +fail: + if (refcount_dec_and_test(&dd->count)) { + dm_put_table_device(t->md, dd->dm_dev); + list_del(&dd->list); + kfree(dd); + } + return r; } EXPORT_SYMBOL(dm_get_device); diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 3f3be9408afa..04142454c4ee 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -149,6 +149,7 @@ EXPORT_SYMBOL_GPL(dm_bio_get_target_bio_nr); #define DMF_DEFERRED_REMOVE 6 #define DMF_SUSPENDED_INTERNALLY 7 #define DMF_POST_SUSPENDING 8 +#define DMF_INTERPOSER_ATTACHED 9 #define DM_NUMA_NODE NUMA_NO_NODE static int dm_numa_node = DM_NUMA_NODE; @@ -757,18 +758,24 @@ static int open_table_device(struct table_device *td, dev_t dev, struct mapped_device *md) { struct block_device *bdev; - + fmode_t mode = td->dm_dev.mode; + void *holder = NULL; int r; BUG_ON(td->dm_dev.bdev); - bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _dm_claim_ptr); + if (!td->dm_dev.interpose) { + mode |= FMODE_EXCL; + holder = _dm_claim_ptr; + } + + bdev = blkdev_get_by_dev(dev, mode, holder); if (IS_ERR(bdev)) return PTR_ERR(bdev); r = bd_link_disk_holder(bdev, dm_disk(md)); if (r) { - blkdev_put(bdev, td->dm_dev.mode | FMODE_EXCL); + blkdev_put(bdev, mode); return r; } @@ -782,11 +789,16 @@ static int open_table_device(struct table_device *td, dev_t dev, */ static void close_table_device(struct table_device *td, struct mapped_device *md) { + fmode_t mode = td->dm_dev.mode; + if (!td->dm_dev.bdev) return; bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md)); - blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL); + if (!td->dm_dev.interpose) + mode |= FMODE_EXCL; + blkdev_put(td->dm_dev.bdev, mode); + put_dax(td->dm_dev.dax_dev); td->dm_dev.bdev = NULL; td->dm_dev.dax_dev = NULL; @@ -805,7 +817,7 @@ static struct table_device *find_table_device(struct list_head *l, dev_t dev, } int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode, - struct dm_dev **result) + bool interpose, struct dm_dev **result) { int r; struct table_device *td; @@ -821,6 +833,7 @@ int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode, td->dm_dev.mode = mode; td->dm_dev.bdev = NULL; + td->dm_dev.interpose = interpose; if ((r = open_table_device(td, dev, md))) { mutex_unlock(&md->table_devices_lock); @@ -1496,13 +1509,12 @@ static int __send_empty_flush(struct clone_info *ci) static int __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti, sector_t sector, unsigned *len) { - struct bio *bio = ci->bio; struct dm_target_io *tio; int r; tio = alloc_tio(ci, ti, 0, GFP_NOIO); tio->len_ptr = len; - r = clone_bio(tio, bio, sector, *len); + r = clone_bio(tio, ci->bio, sector, *len); if (r < 0) { free_tio(tio); return r; @@ -1696,6 +1708,13 @@ static blk_qc_t dm_submit_bio(struct bio *bio) goto out; } + /* + * If md is an interposer, then we must set the BIO_INTERPOSE flag + * so that the request is not re-interposed. + */ + if (md->interpose) + bio_set_flag(bio, BIO_INTERPOSED); + /* If suspended, queue this IO for later */ if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) { if (bio->bi_opf & REQ_NOWAIT) @@ -2410,7 +2429,8 @@ static void dm_queue_flush(struct mapped_device *md) */ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table) { - struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL); + struct dm_table *live_map = NULL; + struct dm_table *map = ERR_PTR(-EINVAL); struct queue_limits limits; int r; @@ -2453,26 +2473,50 @@ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table) * Functions to lock and unlock any filesystem running on the * device. */ -static int lock_fs(struct mapped_device *md) +static int lock_bdev_fs(struct mapped_device *md, struct block_device *bdev) { int r; WARN_ON(test_bit(DMF_FROZEN, &md->flags)); - r = freeze_bdev(md->disk->part0); + r = freeze_bdev(bdev); if (!r) set_bit(DMF_FROZEN, &md->flags); return r; } -static void unlock_fs(struct mapped_device *md) +static void unlock_bdev_fs(struct mapped_device *md, struct block_device *bdev) { if (!test_bit(DMF_FROZEN, &md->flags)) return; - thaw_bdev(md->disk->part0); + thaw_bdev(bdev); clear_bit(DMF_FROZEN, &md->flags); } +static inline int lock_fs(struct mapped_device *md) +{ + return lock_bdev_fs(md, md->disk->part0); +} + +static inline void unlock_fs(struct mapped_device *md) +{ + unlock_bdev_fs(md, md->disk->part0); +} + +static inline struct block_device *get_interposed_bdev(struct dm_table *t) +{ + struct dm_dev_internal *dd; + + /* + * For interposer should be only one device in dm table + */ + list_for_each_entry(dd, dm_table_get_devices(t), list) + if (dd->dm_dev->interpose) + return bdgrab(dd->dm_dev->bdev); + + return NULL; +} + /* * @suspend_flags: DM_SUSPEND_LOCKFS_FLAG and/or DM_SUSPEND_NOFLUSH_FLAG * @task_state: e.g. TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE @@ -2488,7 +2532,10 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, { bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG; bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG; - int r; + bool detach_ip = suspend_flags & DM_SUSPEND_DETACH_IP_FLAG + && md->interpose; + struct block_device *original_bdev = NULL; + int r = 0; lockdep_assert_held(&md->suspend_lock); @@ -2507,18 +2554,50 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, */ dm_table_presuspend_targets(map); + if (!md->interpose) { + /* + * Flush I/O to the device. + * Any I/O submitted after lock_fs() may not be flushed. + * noflush takes precedence over do_lockfs. + * (lock_fs() flushes I/Os and waits for them to complete.) + */ + if (!noflush && do_lockfs) + r = lock_fs(md); + } else if (map) { + /* + * Interposer should not lock mapped device, but + * should freeze interposed device and lock it. + */ + original_bdev = get_interposed_bdev(map); + if (!original_bdev) { + r = -EINVAL; + DMERR("%s: interposer cannot get interposed device from table", + dm_device_name(md)); + goto presuspend_undo; + } + + if (!noflush && do_lockfs) { + r = lock_bdev_fs(md, original_bdev); + if (r) { + DMERR("%s: interposer cannot freeze interposed device", + dm_device_name(md)); + goto presuspend_undo; + } + } + + bdev_interposer_lock(original_bdev); + } /* - * Flush I/O to the device. - * Any I/O submitted after lock_fs() may not be flushed. - * noflush takes precedence over do_lockfs. - * (lock_fs() flushes I/Os and waits for them to complete.) + * If map is not initialized, then we cannot suspend + * interposed device */ - if (!noflush && do_lockfs) { - r = lock_fs(md); - if (r) { - dm_table_presuspend_undo_targets(map); - return r; - } + +presuspend_undo: + if (r) { + if (original_bdev) + bdput(original_bdev); + dm_table_presuspend_undo_targets(map); + return r; } /* @@ -2559,14 +2638,40 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, if (map) synchronize_srcu(&md->io_barrier); - /* were we interrupted ? */ - if (r < 0) { + if (r == 0) { /* the wait ended successfully */ + if (md->interpose && original_bdev) { + if (detach_ip) { + bdev_interposer_detach(original_bdev); + clear_bit(DMF_INTERPOSER_ATTACHED, &md->flags); + } + + bdev_interposer_unlock(original_bdev); + + if (detach_ip) { + /* + * If th interposer is detached, then there is + * no reason in keeping the queue of the + * interposed device stopped. + */ + unlock_bdev_fs(md, original_bdev); + } + + bdput(original_bdev); + } + } else { /* were we interrupted ? */ dm_queue_flush(md); if (dm_request_based(md)) dm_start_queue(md->queue); - unlock_fs(md); + if (md->interpose && original_bdev) { + bdev_interposer_unlock(original_bdev); + unlock_bdev_fs(md, original_bdev); + + bdput(original_bdev); + } else + unlock_fs(md); + dm_table_presuspend_undo_targets(map); /* pushback list is already flushed, so skip flush */ } @@ -2574,6 +2679,88 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, return r; } +int __dm_attach_interposer(struct mapped_device *md) +{ + int r; + struct dm_table *map; + struct block_device *original_bdev = NULL; + + if (dm_interposer_attached(md)) + return 0; + + map = rcu_dereference_protected(md->map, + lockdep_is_held(&md->suspend_lock)); + if (!map) { + DMERR("%s: interposers table is not initialized", + dm_device_name(md)); + return -EINVAL; + } + + original_bdev = get_interposed_bdev(map); + if (!original_bdev) { + DMERR("%s: interposer cannot get interposed device from table", + dm_device_name(md)); + return -EINVAL; + } + + bdev_interposer_lock(original_bdev); + + r = bdev_interposer_attach(original_bdev, dm_disk(md)->part0); + if (r) + DMERR("%s: failed to attach interposer", + dm_device_name(md)); + else + set_bit(DMF_INTERPOSER_ATTACHED, &md->flags); + + bdev_interposer_unlock(original_bdev); + + unlock_bdev_fs(md, original_bdev); + + bdput(original_bdev); + + return r; +} + +int __dm_detach_interposer(struct mapped_device *md) +{ + struct dm_table *map = NULL; + struct block_device *original_bdev; + + if (!dm_interposer_attached(md)) + return 0; + /* + * If mapped device is suspended, but should be detached + * we just detach without freeze fs on interposed device. + */ + map = rcu_dereference_protected(md->map, + lockdep_is_held(&md->suspend_lock)); + if (!map) { + /* + * If table is not initialized then interposed device + * cannot be attached + */ + DMERR("%s: table is not initialized for device", + dm_device_name(md)); + return -EINVAL; + } + + original_bdev = get_interposed_bdev(map); + if (!original_bdev) { + DMERR("%s: interposer cannot get interposed device from table", + dm_device_name(md)); + return -EINVAL; + } + + bdev_interposer_lock(original_bdev); + + bdev_interposer_detach(original_bdev); + clear_bit(DMF_INTERPOSER_ATTACHED, &md->flags); + + bdev_interposer_unlock(original_bdev); + + bdput(original_bdev); + return 0; +} /* * We need to be able to change a mapping table under a mounted * filesystem. For example we might want to move some data in @@ -2599,7 +2786,11 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags) mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING); if (dm_suspended_md(md)) { - r = -EINVAL; + if (suspend_flags & DM_SUSPEND_DETACH_IP_FLAG) + r = __dm_detach_interposer(md); + else + r = -EINVAL; + goto out_unlock; } @@ -2645,8 +2836,10 @@ static int __dm_resume(struct mapped_device *md, struct dm_table *map) if (dm_request_based(md)) dm_start_queue(md->queue); - unlock_fs(md); + if (md->interpose) + return __dm_attach_interposer(md); + unlock_fs(md); return 0; } @@ -2880,6 +3073,11 @@ int dm_suspended_md(struct mapped_device *md) return test_bit(DMF_SUSPENDED, &md->flags); } +int dm_interposer_attached(struct mapped_device *md) +{ + return test_bit(DMF_INTERPOSER_ATTACHED, &md->flags); +} + static int dm_post_suspending_md(struct mapped_device *md) { return test_bit(DMF_POST_SUSPENDING, &md->flags); diff --git a/drivers/md/dm.h b/drivers/md/dm.h index b441ad772c18..35f71e48abd1 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -28,6 +28,7 @@ */ #define DM_SUSPEND_LOCKFS_FLAG (1 << 0) #define DM_SUSPEND_NOFLUSH_FLAG (1 << 1) +#define DM_SUSPEND_DETACH_IP_FLAG (1 << 2) /* * Status feature flags @@ -122,6 +123,11 @@ int dm_deleting_md(struct mapped_device *md); */ int dm_suspended_md(struct mapped_device *md); +/* + * Is the interposer of this mapped_device is attached? + */ +int dm_interposer_attached(struct mapped_device *md); + /* * Internal suspend and resume methods. */ @@ -180,7 +186,7 @@ int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only int dm_cancel_deferred_remove(struct mapped_device *md); int dm_request_based(struct mapped_device *md); int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode, - struct dm_dev **result); + bool interpose, struct dm_dev **result); void dm_put_table_device(struct mapped_device *md, struct dm_dev *d); int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action, diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 5c641f930caf..3a7abb347702 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -159,6 +159,7 @@ struct dm_dev { struct block_device *bdev; struct dax_device *dax_dev; fmode_t mode; + bool interpose; char name[16]; }; diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h index fcff6669137b..73a5b712cd0d 100644 --- a/include/uapi/linux/dm-ioctl.h +++ b/include/uapi/linux/dm-ioctl.h @@ -362,4 +362,10 @@ enum { */ #define DM_INTERNAL_SUSPEND_FLAG (1 << 18) /* Out */ +/* + * If set, the underlying device should open without FMODE_EXCL + * and attach mapped device via bdev_interposer. + */ +#define DM_INTERPOSE_FLAG (1 << 19) /* In/Out */ + #endif /* _LINUX_DM_IOCTL_H */ -- 2.20.1