diff options
| -rw-r--r-- | drivers/md/Makefile | 5 | ||||
| -rw-r--r-- | drivers/md/dm-crypt.c | 6 | ||||
| -rw-r--r-- | drivers/md/dm-delay.c | 6 | ||||
| -rw-r--r-- | drivers/md/dm-exception-store.c | 749 | ||||
| -rw-r--r-- | drivers/md/dm-exception-store.h | 148 | ||||
| -rw-r--r-- | drivers/md/dm-ioctl.c | 16 | ||||
| -rw-r--r-- | drivers/md/dm-linear.c | 6 | ||||
| -rw-r--r-- | drivers/md/dm-log.c | 40 | ||||
| -rw-r--r-- | drivers/md/dm-mpath.c | 14 | ||||
| -rw-r--r-- | drivers/md/dm-raid1.c | 24 | ||||
| -rw-r--r-- | drivers/md/dm-snap-persistent.c | 704 | ||||
| -rw-r--r-- | drivers/md/dm-snap-transient.c | 98 | ||||
| -rw-r--r-- | drivers/md/dm-snap.c | 48 | ||||
| -rw-r--r-- | drivers/md/dm-snap.h | 129 | ||||
| -rw-r--r-- | drivers/md/dm-stripe.c | 4 | ||||
| -rw-r--r-- | drivers/md/dm-sysfs.c | 99 | ||||
| -rw-r--r-- | drivers/md/dm-table.c | 47 | ||||
| -rw-r--r-- | drivers/md/dm-target.c | 15 | ||||
| -rw-r--r-- | drivers/md/dm-zero.c | 5 | ||||
| -rw-r--r-- | drivers/md/dm.c | 101 | ||||
| -rw-r--r-- | drivers/md/dm.h | 10 | ||||
| -rw-r--r-- | include/linux/device-mapper.h | 28 |
22 files changed, 1319 insertions, 983 deletions
diff --git a/drivers/md/Makefile b/drivers/md/Makefile index 1c61580..72880b7 100644 --- a/drivers/md/Makefile +++ b/drivers/md/Makefile @@ -3,9 +3,10 @@ # dm-mod-objs := dm.o dm-table.o dm-target.o dm-linear.o dm-stripe.o \ - dm-ioctl.o dm-io.o dm-kcopyd.o + dm-ioctl.o dm-io.o dm-kcopyd.o dm-sysfs.o dm-multipath-objs := dm-path-selector.o dm-mpath.o -dm-snapshot-objs := dm-snap.o dm-exception-store.o +dm-snapshot-objs := dm-snap.o dm-exception-store.o dm-snap-transient.o \ + dm-snap-persistent.o dm-mirror-objs := dm-raid1.o md-mod-objs := md.o bitmap.o raid456-objs := raid5.o raid6algos.o raid6recov.o raid6tables.o \ diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 3326750..35bda49 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -1322,11 +1322,7 @@ static int __init dm_crypt_init(void) static void __exit dm_crypt_exit(void) { - int r = dm_unregister_target(&crypt_target); - - if (r < 0) - DMERR("unregister failed %d", r); - + dm_unregister_target(&crypt_target); kmem_cache_destroy(_crypt_io_pool); } diff --git a/drivers/md/dm-delay.c b/drivers/md/dm-delay.c index 848b381..59ee1b0 100644 --- a/drivers/md/dm-delay.c +++ b/drivers/md/dm-delay.c @@ -364,11 +364,7 @@ bad_queue: static void __exit dm_delay_exit(void) { - int r = dm_unregister_target(&delay_target); - - if (r < 0) - DMERR("unregister failed %d", r); - + dm_unregister_target(&delay_target); kmem_cache_destroy(delayed_cache); destroy_workqueue(kdelayd_wq); } diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c index 01590f3e..dccbfb0 100644 --- a/drivers/md/dm-exception-store.c +++ b/drivers/md/dm-exception-store.c @@ -1,756 +1,45 @@ /* - * dm-exception-store.c - * * Copyright (C) 2001-2002 Sistina Software (UK) Limited. - * Copyright (C) 2006 Red Hat GmbH + * Copyright (C) 2006-2008 Red Hat GmbH * * This file is released under the GPL. */ -#include "dm-snap.h" +#include "dm-exception-store.h" #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/vmalloc.h> #include <linux/slab.h> -#include <linux/dm-io.h> -#include <linux/dm-kcopyd.h> - -#define DM_MSG_PREFIX "snapshots" -#define DM_CHUNK_SIZE_DEFAULT_SECTORS 32 /* 16KB */ - -/*----------------------------------------------------------------- - * Persistent snapshots, by persistent we mean that the snapshot - * will survive a reboot. - *---------------------------------------------------------------*/ - -/* - * We need to store a record of which parts of the origin have - * been copied to the snapshot device. The snapshot code - * requires that we copy exception chunks to chunk aligned areas - * of the COW store. It makes sense therefore, to store the - * metadata in chunk size blocks. - * - * There is no backward or forward compatibility implemented, - * snapshots with different disk versions than the kernel will - * not be usable. It is expected that "lvcreate" will blank out - * the start of a fresh COW device before calling the snapshot - * constructor. - * - * The first chunk of the COW device just contains the header. - * After this there is a chunk filled with exception metadata, - * followed by as many exception chunks as can fit in the - * metadata areas. - * - * All on disk structures are in little-endian format. The end - * of the exceptions info is indicated by an exception with a - * new_chunk of 0, which is invalid since it would point to the - * header chunk. - */ - -/* - * Magic for persistent snapshots: "SnAp" - Feeble isn't it. - */ -#define SNAP_MAGIC 0x70416e53 - -/* - * The on-disk version of the metadata. - */ -#define SNAPSHOT_DISK_VERSION 1 - -struct disk_header { - uint32_t magic; - - /* - * Is this snapshot valid. There is no way of recovering - * an invalid snapshot. - */ - uint32_t valid; - - /* - * Simple, incrementing version. no backward - * compatibility. - */ - uint32_t version; - - /* In sectors */ - uint32_t chunk_size; -}; - -struct disk_exception { - uint64_t old_chunk; - uint64_t new_chunk; -}; - -struct commit_callback { - void (*callback)(void *, int success); - void *context; -}; - -/* - * The top level structure for a persistent exception store. - */ -struct pstore { - struct dm_snapshot *snap; /* up pointer to my snapshot */ - int version; - int valid; - uint32_t exceptions_per_area; - - /* - * Now that we have an asynchronous kcopyd there is no - * need for large chunk sizes, so it wont hurt to have a - * whole chunks worth of metadata in memory at once. - */ - void *area; - - /* - * An area of zeros used to clear the next area. - */ - void *zero_area; - - /* - * Used to keep track of which metadata area the data in - * 'chunk' refers to. - */ - chunk_t current_area; - - /* - * The next free chunk for an exception. - */ - chunk_t next_free; - - /* - * The index of next free exception in the current - * metadata area. - */ - uint32_t current_committed; - - atomic_t pending_count; - uint32_t callback_count; - struct commit_callback *callbacks; - struct dm_io_client *io_client; - - struct workqueue_struct *metadata_wq; -}; - -static unsigned sectors_to_pages(unsigned sectors) -{ - return DIV_ROUND_UP(sectors, PAGE_SIZE >> 9); -} - -static int alloc_area(struct pstore *ps) -{ - int r = -ENOMEM; - size_t len; - - len = ps->snap->chunk_size << SECTOR_SHIFT; - - /* - * Allocate the chunk_size block of memory that will hold - * a single metadata area. - */ - ps->area = vmalloc(len); - if (!ps->area) - return r; - - ps->zero_area = vmalloc(len); - if (!ps->zero_area) { - vfree(ps->area); - return r; - } - memset(ps->zero_area, 0, len); - - return 0; -} - -static void free_area(struct pstore *ps) -{ - vfree(ps->area); - ps->area = NULL; - vfree(ps->zero_area); - ps->zero_area = NULL; -} - -struct mdata_req { - struct dm_io_region *where; - struct dm_io_request *io_req; - struct work_struct work; - int result; -}; - -static void do_metadata(struct work_struct *work) -{ - struct mdata_req *req = container_of(work, struct mdata_req, work); - - req->result = dm_io(req->io_req, 1, req->where, NULL); -} - -/* - * Read or write a chunk aligned and sized block of data from a device. - */ -static int chunk_io(struct pstore *ps, chunk_t chunk, int rw, int metadata) -{ - struct dm_io_region where = { - .bdev = ps->snap->cow->bdev, - .sector = ps->snap->chunk_size * chunk, - .count = ps->snap->chunk_size, - }; - struct dm_io_request io_req = { - .bi_rw = rw, - .mem.type = DM_IO_VMA, - .mem.ptr.vma = ps->area, - .client = ps->io_client, - .notify.fn = NULL, - }; - struct mdata_req req; - - if (!metadata) - return dm_io(&io_req, 1, &where, NULL); - - req.where = &where; - req.io_req = &io_req; - - /* - * Issue the synchronous I/O from a different thread - * to avoid generic_make_request recursion. - */ - INIT_WORK(&req.work, do_metadata); - queue_work(ps->metadata_wq, &req.work); - flush_workqueue(ps->metadata_wq); - - return req.result; -} - -/* - * Convert a metadata area index to a chunk index. - */ -static chunk_t area_location(struct pstore *ps, chunk_t area) -{ - return 1 + ((ps->exceptions_per_area + 1) * area); -} - -/* - * Read or write a metadata area. Remembering to skip the first - * chunk which holds the header. - */ -static int area_io(struct pstore *ps, int rw) -{ - int r; - chunk_t chunk; - - chunk = area_location(ps, ps->current_area); - - r = chunk_io(ps, chunk, rw, 0); - if (r) - return r; - - return 0; -} - -static void zero_memory_area(struct pstore *ps) -{ - memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT); -} - -static int zero_disk_area(struct pstore *ps, chunk_t area) -{ - struct dm_io_region where = { - .bdev = ps->snap->cow->bdev, - .sector = ps->snap->chunk_size * area_location(ps, area), - .count = ps->snap->chunk_size, - }; - struct dm_io_request io_req = { - .bi_rw = WRITE, - .mem.type = DM_IO_VMA, - .mem.ptr.vma = ps->zero_area, - .client = ps->io_client, - .notify.fn = NULL, - }; - - return dm_io(&io_req, 1, &where, NULL); -} - -static int read_header(struct pstore *ps, int *new_snapshot) -{ - int r; - struct disk_header *dh; - chunk_t chunk_size; - int chunk_size_supplied = 1; - - /* - * Use default chunk size (or hardsect_size, if larger) if none supplied - */ - if (!ps->snap->chunk_size) { - ps->snap->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS, - bdev_hardsect_size(ps->snap->cow->bdev) >> 9); - ps->snap->chunk_mask = ps->snap->chunk_size - 1; - ps->snap->chunk_shift = ffs(ps->snap->chunk_size) - 1; - chunk_size_supplied = 0; - } - - ps->io_client = dm_io_client_create(sectors_to_pages(ps->snap-> - chunk_size)); - if (IS_ERR(ps->io_client)) - return PTR_ERR(ps->io_client); - - r = alloc_area(ps); - if (r) - return r; - - r = chunk_io(ps, 0, READ, 1); - if (r) - goto bad; - - dh = (struct disk_header *) ps->area; - - if (le32_to_cpu(dh->magic) == 0) { - *new_snapshot = 1; - return 0; - } - - if (le32_to_cpu(dh->magic) != SNAP_MAGIC) { - DMWARN("Invalid or corrupt snapshot"); - r = -ENXIO; - goto bad; - } - - *new_snapshot = 0; - ps->valid = le32_to_cpu(dh->valid); - ps->version = le32_to_cpu(dh->version); - chunk_size = le32_to_cpu(dh->chunk_size); - - if (!chunk_size_supplied || ps->snap->chunk_size == chunk_size) - return 0; - - DMWARN("chunk size %llu in device metadata overrides " - "table chunk size of %llu.", - (unsigned long long)chunk_size, - (unsigned long long)ps->snap->chunk_size); - - /* We had a bogus chunk_size. Fix stuff up. */ - free_area(ps); - - ps->snap->chunk_size = chunk_size; - ps->snap->chunk_mask = chunk_size - 1; - ps->snap->chunk_shift = ffs(chunk_size) - 1; - - r = dm_io_client_resize(sectors_to_pages(ps->snap->chunk_size), - ps->io_client); - if (r) - return r; - - r = alloc_area(ps); - return r; - -bad: - free_area(ps); - return r; -} - -static int write_header(struct pstore *ps) -{ - struct disk_header *dh; - - memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT); - - dh = (struct disk_header *) ps->area; - dh->magic = cpu_to_le32(SNAP_MAGIC); - dh->valid = cpu_to_le32(ps->valid); - dh->version = cpu_to_le32(ps->version); - dh->chunk_size = cpu_to_le32(ps->snap->chunk_size); - - return chunk_io(ps, 0, WRITE, 1); -} - -/* - * Access functions for the disk exceptions, these do the endian conversions. - */ -static struct disk_exception *get_exception(struct pstore *ps, uint32_t index) -{ - BUG_ON(index >= ps->exceptions_per_area); - - return ((struct disk_exception *) ps->area) + index; -} -static void read_exception(struct pstore *ps, - uint32_t index, struct disk_exception *result) -{ - struct disk_exception *e = get_exception(ps, index); - - /* copy it */ - result->old_chunk = le64_to_cpu(e->old_chunk); - result->new_chunk = le64_to_cpu(e->new_chunk); -} - -static void write_exception(struct pstore *ps, - uint32_t index, struct disk_exception *de) -{ - struct disk_exception *e = get_exception(ps, index); - - /* copy it */ - e->old_chunk = cpu_to_le64(de->old_chunk); - e->new_chunk = cpu_to_le64(de->new_chunk); -} +#define DM_MSG_PREFIX "snapshot exception stores" -/* - * Registers the exceptions that are present in the current area. - * 'full' is filled in to indicate if the area has been - * filled. - */ -static int insert_exceptions(struct pstore *ps, int *full) +int dm_exception_store_init(void) { int r; - unsigned int i; - struct disk_exception de; - - /* presume the area is full */ - *full = 1; - - for (i = 0; i < ps->exceptions_per_area; i++) { - read_exception(ps, i, &de); - - /* - * If the new_chunk is pointing at the start of - * the COW device, where the first metadata area - * is we know that we've hit the end of the - * exceptions. Therefore the area is not full. - */ - if (de.new_chunk == 0LL) { - ps->current_committed = i; - *full = 0; - break; - } - - /* - * Keep track of the start of the free chunks. - */ - if (ps->next_free <= de.new_chunk) - ps->next_free = de.new_chunk + 1; - - /* - * Otherwise we add the exception to the snapshot. - */ - r = dm_add_exception(ps->snap, de.old_chunk, de.new_chunk); - if (r) - return r; - } - - return 0; -} - -static int read_exceptions(struct pstore *ps) -{ - int r, full = 1; - - /* - * Keeping reading chunks and inserting exceptions until - * we find a partially full area. - */ - for (ps->current_area = 0; full; ps->current_area++) { - r = area_io(ps, READ); - if (r) - return r; - r = insert_exceptions(ps, &full); - if (r) - return r; + r = dm_transient_snapshot_init(); + if (r) { + DMERR("Unable to register transient exception store type."); + goto transient_fail; } - ps->current_area--; - - return 0; -} - -static struct pstore *get_info(struct exception_store *store) -{ - return (struct pstore *) store->context; -} - -static void persistent_fraction_full(struct exception_store *store, - sector_t *numerator, sector_t *denominator) -{ - *numerator = get_info(store)->next_free * store->snap->chunk_size; - *denominator = get_dev_size(store->snap->cow->bdev); -} - -static void persistent_destroy(struct exception_store *store) -{ - struct pstore *ps = get_info(store); - - destroy_workqueue(ps->metadata_wq); - dm_io_client_destroy(ps->io_client); - vfree(ps->callbacks); - free_area(ps); - kfree(ps); -} - -static int persistent_read_metadata(struct exception_store *store) -{ - int r, uninitialized_var(new_snapshot); - struct pstore *ps = get_info(store); - - /* - * Read the snapshot header. - */ - r = read_header(ps, &new_snapshot); - if (r) - return r; - - /* - * Now we know correct chunk_size, complete the initialisation. - */ - ps->exceptions_per_area = (ps->snap->chunk_size << SECTOR_SHIFT) / - sizeof(struct disk_exception); - ps->callbacks = dm_vcalloc(ps->exceptions_per_area, - sizeof(*ps->callbacks)); - if (!ps->callbacks) - return -ENOMEM; - - /* - * Do we need to setup a new snapshot ? - */ - if (new_snapshot) { - r = write_header(ps); - if (r) { - DMWARN("write_header failed"); - return r; - } - - ps->current_area = 0; - zero_memory_area(ps); - r = zero_disk_area(ps, 0); - if (r) { - DMWARN("zero_disk_area(0) failed"); - return r; - } - } else { - /* - * Sanity checks. - */ - if (ps->version != SNAPSHOT_DISK_VERSION) { - DMWARN("unable to handle snapshot disk version %d", - ps->version); - return -EINVAL; - } - - /* - * Metadata are valid, but snapshot is invalidated - */ - if (!ps->valid) - return 1; - - /* - * Read the metadata. - */ - r = read_exceptions(ps); - if (r) - return r; + r = dm_persistent_snapshot_init(); + if (r) { + DMERR("Unable to register persistent exception store type"); + goto persistent_fail; } return 0; -} - -static int persistent_prepare(struct exception_store *store, - struct dm_snap_exception *e) -{ - struct pstore *ps = get_info(store); - uint32_t stride; - chunk_t next_free; - sector_t size = get_dev_size(store->snap->cow->bdev); - - /* Is there enough room ? */ - if (size < ((ps->next_free + 1) * store->snap->chunk_size)) - return -ENOSPC; - e->new_chunk = ps->next_free; - - /* - * Move onto the next free pending, making sure to take - * into account the location of the metadata chunks. - */ - stride = (ps->exceptions_per_area + 1); - next_free = ++ps->next_free; - if (sector_div(next_free, stride) == 1) - ps->next_free++; - - atomic_inc(&ps->pending_count); - return 0; -} - -static void persistent_commit(struct exception_store *store, - struct dm_snap_exception *e, - void (*callback) (void *, int success), - void *callback_context) -{ - unsigned int i; - struct pstore *ps = get_info(store); - struct disk_exception de; - struct commit_callback *cb; - - de.old_chunk = e->old_chunk; - de.new_chunk = e->new_chunk; - write_exception(ps, ps->current_committed++, &de); - - /* - * Add the callback to the back of the array. This code - * is the only place where the callback array is - * manipulated, and we know that it will never be called - * multiple times concurrently. - */ - cb = ps->callbacks + ps->callback_count++; - cb->callback = callback; - cb->context = callback_context; - - /* - * If there are exceptions in flight and we have not yet - * filled this metadata area there's nothing more to do. - */ - if (!atomic_dec_and_test(&ps->pending_count) && - (ps->current_committed != ps->exceptions_per_area)) - return; - - /* - * If we completely filled the current area, then wipe the next one. - */ - if ((ps->current_committed == ps->exceptions_per_area) && - zero_disk_area(ps, ps->current_area + 1)) - ps->valid = 0; - - /* - * Commit exceptions to disk. - */ - if (ps->valid && area_io(ps, WRITE)) - ps->valid = 0; - - /* - * Advance to the next area if this one is full. - */ - if (ps->current_committed == ps->exceptions_per_area) { - ps->current_committed = 0; - ps->current_area++; - zero_memory_area(ps); - } - - for (i = 0; i < ps->callback_count; i++) { - cb = ps->callbacks + i; - cb->callback(cb->context, ps->valid); - } - - ps->callback_count = 0; -} - -static void persistent_drop(struct exception_store *store) -{ - struct pstore *ps = get_info(store); - - ps->valid = 0; - if (write_header(ps)) - DMWARN("write header failed"); -} - -int dm_create_persistent(struct exception_store *store) -{ - struct pstore *ps; - - /* allocate the pstore */ - ps = kmalloc(sizeof(*ps), GFP_KERNEL); - if (!ps) - return -ENOMEM; - - ps->snap = store->snap; - ps->valid = 1; - ps->version = SNAPSHOT_DISK_VERSION; - ps->area = NULL; - ps->next_free = 2; /* skipping the header and first area */ - ps->current_committed = 0; - - ps->callback_count = 0; - atomic_set(&ps->pending_count, 0); - ps->callbacks = NULL; - - ps->metadata_wq = create_singlethread_workqueue("ksnaphd"); - if (!ps->metadata_wq) { - kfree(ps); - DMERR("couldn't start header metadata update thread"); - return -ENOMEM; - } - - store->destroy = persistent_destroy; - store->read_metadata = persistent_read_metadata; - store->prepare_exception = persistent_prepare; - store->commit_exception = persistent_commit; - store->drop_snapshot = persistent_drop; - store->fraction_full = persistent_fraction_full; - store->context = ps; - - return 0; -} - -/*----------------------------------------------------------------- - * Implementation of the store for non-persistent snapshots. - *---------------------------------------------------------------*/ -struct transient_c { - sector_t next_free; -}; - -static void transient_destroy(struct exception_store *store) -{ - kfree(store->context); -} - -static int transient_read_metadata(struct exception_store *store) -{ - return 0; -} - -static int transient_prepare(struct exception_store *store, - struct dm_snap_exception *e) -{ - struct transient_c *tc = (struct transient_c *) store->context; - sector_t size = get_dev_size(store->snap->cow->bdev); - - if (size < (tc->next_free + store->snap->chunk_size)) - return -1; - - e->new_chunk = sector_to_chunk(store->snap, tc->next_free); - tc->next_free += store->snap->chunk_size; - - return 0; -} - -static void transient_commit(struct exception_store *store, - struct dm_snap_exception *e, - void (*callback) (void *, int success), - void *callback_context) -{ - /* Just succeed */ - callback(callback_context, 1); -} - -static void transient_fraction_full(struct exception_store *store, - sector_t *numerator, sector_t *denominator) -{ - *numerator = ((struct transient_c *) store->context)->next_free; - *denominator = get_dev_size(store->snap->cow->bdev); +persistent_fail: + dm_persistent_snapshot_exit(); +transient_fail: + return r; } -int dm_create_transient(struct exception_store *store) +void dm_exception_store_exit(void) { - struct transient_c *tc; - - store->destroy = transient_destroy; - store->read_metadata = transient_read_metadata; - store->prepare_exception = transient_prepare; - store->commit_exception = transient_commit; - store->drop_snapshot = NULL; - store->fraction_full = transient_fraction_full; - - tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL); - if (!tc) - return -ENOMEM; - - tc->next_free = 0; - store->context = tc; - - return 0; + dm_persistent_snapshot_exit(); + dm_transient_snapshot_exit(); } diff --git a/drivers/md/dm-exception-store.h b/drivers/md/dm-exception-store.h new file mode 100644 index 0000000..bb9f33d --- /dev/null +++ b/drivers/md/dm-exception-store.h @@ -0,0 +1,148 @@ +/* + * Copyright (C) 2001-2002 Sistina Software (UK) Limited. + * Copyright (C) 2008 Red Hat, Inc. All rights reserved. + * + * Device-mapper snapshot exception store. + * + * This file is released under the GPL. + */ + +#ifndef _LINUX_DM_EXCEPTION_STORE +#define _LINUX_DM_EXCEPTION_STORE + +#include <linux/blkdev.h> +#include <linux/device-mapper.h> + +/* + * The snapshot code deals with largish chunks of the disk at a + * time. Typically 32k - 512k. + */ +typedef sector_t chunk_t; + +/* + * An exception is used where an old chunk of data has been + * replaced by a new one. + * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number + * of chunks that follow contiguously. Remaining bits hold the number of the + * chunk within the device. + */ +struct dm_snap_exception { + struct list_head hash_list; + + chunk_t old_chunk; + chunk_t new_chunk; +}; + +/* + * Abstraction to handle the meta/layout of exception stores (the + * COW device). + */ +struct dm_exception_store { + /* + * Destroys this object when you've finished with it. + */ + void (*destroy) (struct dm_exception_store *store); + + /* + * The target shouldn't read the COW device until this is + * called. As exceptions are read from the COW, they are + * reported back via the callback. + */ + int (*read_metadata) (struct dm_exception_store *store, + int (*callback)(void *callback_context, + chunk_t old, chunk_t new), + void *callback_context); + + /* + * Find somewhere to store the next exception. + */ + int (*prepare_exception) (struct dm_exception_store *store, + struct dm_snap_exception *e); + + /* + * Update the metadata with this exception. + */ + void (*commit_exception) (struct dm_exception_store *store, + struct dm_snap_exception *e, + void (*callback) (void *, int success), + void *callback_context); + + /* + * The snapshot is invalid, note this in the metadata. + */ + void (*drop_snapshot) (struct dm_exception_store *store); + + int (*status) (struct dm_exception_store *store, status_type_t status, + char *result, unsigned int maxlen); + + /* + * Return how full the snapshot is. + */ + void (*fraction_full) (struct dm_exception_store *store, + sector_t *numerator, + sector_t *denominator); + + struct dm_snapshot *snap; + void *context; +}; + +/* + * Funtions to manipulate consecutive chunks + */ +# if defined(CONFIG_LBD) || (BITS_PER_LONG == 64) +# define DM_CHUNK_CONSECUTIVE_BITS 8 +# define DM_CHUNK_NUMBER_BITS 56 + +static inline chunk_t dm_chunk_number(chunk_t chunk) +{ + return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL); +} + +static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e) +{ + return e->new_chunk >> DM_CHUNK_NUMBER_BITS; +} + +static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e) +{ + e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS); + + BUG_ON(!dm_consecutive_chunk_count(e)); +} + +# else +# define DM_CHUNK_CONSECUTIVE_BITS 0 + +static inline chunk_t dm_chunk_number(chunk_t chunk) +{ + return chunk; +} + +static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e) +{ + return 0; +} + +static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e) +{ +} + +# endif + +int dm_exception_store_init(void); +void dm_exception_store_exit(void); + +/* + * Two exception store implementations. + */ +int dm_persistent_snapshot_init(void); +void dm_persistent_snapshot_exit(void); + +int dm_transient_snapshot_init(void); +void dm_transient_snapshot_exit(void); + +int dm_create_persistent(struct dm_exception_store *store); + +int dm_create_transient(struct dm_exception_store *store); + +#endif /* _LINUX_DM_EXCEPTION_STORE */ diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 777c948..54d0588 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -233,7 +233,7 @@ static void __hash_remove(struct hash_cell *hc) } if (hc->new_map) - dm_table_put(hc->new_map); + dm_table_destroy(hc->new_map); dm_put(hc->md); free_cell(hc); } @@ -827,8 +827,8 @@ static int do_resume(struct dm_ioctl *param) r = dm_swap_table(md, new_map); if (r) { + dm_table_destroy(new_map); dm_put(md); - dm_table_put(new_map); return r; } @@ -836,8 +836,6 @@ static int do_resume(struct dm_ioctl *param) set_disk_ro(dm_disk(md), 0); else set_disk_ro(dm_disk(md), 1); - - dm_table_put(new_map); } if (dm_suspended(md)) @@ -1080,7 +1078,7 @@ static int table_load(struct dm_ioctl *param, size_t param_size) } if (hc->new_map) - dm_table_put(hc->new_map); + dm_table_destroy(hc->new_map); hc->new_map = t; up_write(&_hash_lock); @@ -1109,7 +1107,7 @@ static int table_clear(struct dm_ioctl *param, size_t param_size) } if (hc->new_map) { - dm_table_put(hc->new_map); + dm_table_destroy(hc->new_map); hc->new_map = NULL; } @@ -1550,8 +1548,10 @@ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid) goto out; } - strcpy(name, hc->name); - strcpy(uuid, hc->uuid ? : ""); + if (name) + strcpy(name, hc->name); + if (uuid) + strcpy(uuid, hc->uuid ? : ""); out: up_read(&_hash_lock); diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c index 44042be..bfa107f 100644 --- a/drivers/md/dm-linear.c +++ b/drivers/md/dm-linear.c @@ -142,6 +142,7 @@ static struct target_type linear_target = { .status = linear_status, .ioctl = linear_ioctl, .merge = linear_merge, + .features = DM_TARGET_SUPPORTS_BARRIERS, }; int __init dm_linear_init(void) @@ -156,8 +157,5 @@ int __init dm_linear_init(void) void dm_linear_exit(void) { - int r = dm_unregister_target(&linear_target); - - if (r < 0) - DMERR("unregister failed %d", r); + dm_unregister_target(&linear_target); } diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c index a8c0fc7..737961f 100644 --- a/drivers/md/dm-log.c +++ b/drivers/md/dm-log.c @@ -326,8 +326,6 @@ static void header_from_disk(struct log_header *core, struct log_header *disk) static int rw_header(struct log_c *lc, int rw) { lc->io_req.bi_rw = rw; - lc->io_req.mem.ptr.vma = lc->disk_header; - lc->io_req.notify.fn = NULL; return dm_io(&lc->io_req, 1, &lc->header_location, NULL); } @@ -362,10 +360,15 @@ static int read_header(struct log_c *log) return 0; } -static inline int write_header(struct log_c *log) +static int _check_region_size(struct dm_target *ti, uint32_t region_size) { - header_to_disk(&log->header, log->disk_header); - return rw_header(log, WRITE); + if (region_size < 2 || region_size > ti->len) + return 0; + + if (!is_power_of_2(region_size)) + return 0; + + return 1; } /*---------------------------------------------------------------- @@ -403,8 +406,9 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti, } } - if (sscanf(argv[0], "%u", ®ion_size) != 1) { - DMWARN("invalid region size string"); + if (sscanf(argv[0], "%u", ®ion_size) != 1 || + !_check_region_size(ti, region_size)) { + DMWARN("invalid region size %s", argv[0]); return -EINVAL; } @@ -453,8 +457,18 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti, */ buf_size = dm_round_up((LOG_OFFSET << SECTOR_SHIFT) + bitset_size, ti->limits.hardsect_size); + + if (buf_size > dev->bdev->bd_inode->i_size) { + DMWARN("log device %s too small: need %llu bytes", + dev->name, (unsigned long long)buf_size); + kfree(lc); + return -EINVAL; + } + lc->header_location.count = buf_size >> SECTOR_SHIFT; + lc->io_req.mem.type = DM_IO_VMA; + lc->io_req.notify.fn = NULL; lc->io_req.client = dm_io_client_create(dm_div_up(buf_size, PAGE_SIZE)); if (IS_ERR(lc->io_req.client)) { @@ -467,10 +481,12 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti, lc->disk_header = vmalloc(buf_size); if (!lc->disk_header) { DMWARN("couldn't allocate disk log buffer"); + dm_io_client_destroy(lc->io_req.client); kfree(lc); return -ENOMEM; } + lc->io_req.mem.ptr.vma = lc->disk_header; lc->clean_bits = (void *)lc->disk_header + (LOG_OFFSET << SECTOR_SHIFT); } @@ -482,6 +498,8 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti, DMWARN("couldn't allocate sync bitset"); if (!dev) vfree(lc->clean_bits); + else + dm_io_client_destroy(lc->io_req.client); vfree(lc->disk_header); kfree(lc); return -ENOMEM; @@ -495,6 +513,8 @@ static int create_log_context(struct dm_dirty_log *log, struct dm_target *ti, vfree(lc->sync_bits); if (!dev) vfree(lc->clean_bits); + else + dm_io_client_destroy(lc->io_req.client); vfree(lc->disk_header); kfree(lc); return -ENOMEM; @@ -631,8 +651,10 @@ static int disk_resume(struct dm_dirty_log *log) /* set the correct number of regions in the header */ lc->header.nr_regions = lc->region_count; + header_to_disk(&lc->header, lc->disk_header); + /* write the new header */ - r = write_header(lc); + r = rw_header(lc, WRITE); if (r) { DMWARN("%s: Failed to write header on dirty region log device", lc->log_dev->name); @@ -682,7 +704,7 @@ static int disk_flush(struct dm_dirty_log *log) if (!lc->touched) return 0; - r = write_header(lc); + r = rw_header(lc, WRITE); if (r) fail_log_device(lc); else diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 3d7f492..095f77b 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -889,7 +889,7 @@ static int fail_path(struct pgpath *pgpath) dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti, pgpath->path.dev->name, m->nr_valid_paths); - queue_work(kmultipathd, &m->trigger_event); + schedule_work(&m->trigger_event); queue_work(kmultipathd, &pgpath->deactivate_path); out: @@ -932,7 +932,7 @@ static int reinstate_path(struct pgpath *pgpath) dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti, pgpath->path.dev->name, m->nr_valid_paths); - queue_work(kmultipathd, &m->trigger_event); + schedule_work(&m->trigger_event); out: spin_unlock_irqrestore(&m->lock, flags); @@ -976,7 +976,7 @@ static void bypass_pg(struct multipath *m, struct priority_group *pg, spin_unlock_irqrestore(&m->lock, flags); - queue_work(kmultipathd, &m->trigger_event); + schedule_work(&m->trigger_event); } /* @@ -1006,7 +1006,7 @@ static int switch_pg_num(struct multipath *m, const char *pgstr) } spin_unlock_irqrestore(&m->lock, flags); - queue_work(kmultipathd, &m->trigger_event); + schedule_work(&m->trigger_event); return 0; } @@ -1495,14 +1495,10 @@ static int __init dm_multipath_init(void) static void __exit dm_multipath_exit(void) { - int r; - destroy_workqueue(kmpath_handlerd); destroy_workqueue(kmultipathd); - r = dm_unregister_target(&multipath_target); - if (r < 0) - DMERR("target unregister failed %d", r); + dm_unregister_target(&multipath_target); kmem_cache_destroy(_mpio_cache); } diff --git a/drivers/md/dm-raid1.c b/drivers/md/dm-raid1.c index ec43f9f..4d6bc10 100644 --- a/drivers/md/dm-raid1.c +++ b/drivers/md/dm-raid1.c @@ -197,9 +197,6 @@ static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type) struct mirror_set *ms = m->ms; struct mirror *new; - if (!errors_handled(ms)) - return; - /* * error_count is used for nothing more than a * simple way to tell if a device has encountered @@ -210,6 +207,9 @@ static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type) if (test_and_set_bit(error_type, &m->error_type)) return; + if (!errors_handled(ms)) + return; + if (m != get_default_mirror(ms)) goto out; @@ -808,12 +808,6 @@ static void free_context(struct mirror_set *ms, struct dm_target *ti, kfree(ms); } -static inline int _check_region_size(struct dm_target *ti, uint32_t size) -{ - return !(size % (PAGE_SIZE >> 9) || !is_power_of_2(size) || - size > ti->len); -} - static int get_mirror(struct mirror_set *ms, struct dm_target *ti, unsigned int mirror, char **argv) { @@ -872,12 +866,6 @@ static struct dm_dirty_log *create_dirty_log(struct dm_target *ti, return NULL; } - if (!_check_region_size(ti, dl->type->get_region_size(dl))) { - ti->error = "Invalid region size"; - dm_dirty_log_destroy(dl); - return NULL; - } - return dl; } @@ -1300,11 +1288,7 @@ static int __init dm_mirror_init(void) static void __exit dm_mirror_exit(void) { - int r; - - r = dm_unregister_target(&mirror_target); - if (r < 0) - DMERR("unregister failed %d", r); + dm_unregister_target(&mirror_target); } /* Module hooks */ diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c new file mode 100644 index 0000000..936b34e --- /dev/null +++ b/drivers/md/dm-snap-persistent.c @@ -0,0 +1,704 @@ +/* + * Copyright (C) 2001-2002 Sistina Software (UK) Limited. + * Copyright (C) 2006-2008 Red Hat GmbH + * + * This file is released under the GPL. + */ + +#include "dm-exception-store.h" +#include "dm-snap.h" + +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/vmalloc.h> +#include <linux/slab.h> +#include <linux/dm-io.h> + +#define DM_MSG_PREFIX "persistent snapshot" +#define DM_CHUNK_SIZE_DEFAULT_SECTORS 32 /* 16KB */ + +/*----------------------------------------------------------------- + * Persistent snapshots, by persistent we mean that the snapshot + * will survive a reboot. + *---------------------------------------------------------------*/ + +/* + * We need to store a record of which parts of the origin have + * been copied to the snapshot device. The snapshot code + * requires that we copy exception chunks to chunk aligned areas + * of the COW store. It makes sense therefore, to store the + * metadata in chunk size blocks. + * + * There is no backward or forward compatibility implemented, + * snapshots with different disk versions than the kernel will + * not be usable. It is expected that "lvcreate" will blank out + * the start of a fresh COW device before calling the snapshot + * constructor. + * + * The first chunk of the COW device just contains the header. + * After this there is a chunk filled with exception metadata, + * followed by as many exception chunks as can fit in the + * metadata areas. + * + * All on disk structures are in little-endian format. The end + * of the exceptions info is indicated by an exception with a + * new_chunk of 0, which is invalid since it would point to the + * header chunk. + */ + +/* + * Magic for persistent snapshots: "SnAp" - Feeble isn't it. + */ +#define SNAP_MAGIC 0x70416e53 + +/* + * The on-disk version of the metadata. + */ +#define SNAPSHOT_DISK_VERSION 1 + +struct disk_header { + uint32_t magic; + + /* + * Is this snapshot valid. There is no way of recovering + * an invalid snapshot. + */ + uint32_t valid; + + /* + * Simple, incrementing version. no backward + * compatibility. + */ + uint32_t version; + + /* In sectors */ + uint32_t chunk_size; +}; + +struct disk_exception { + uint64_t old_chunk; + uint64_t new_chunk; +}; + +struct commit_callback { + void (*callback)(void *, int success); + void *context; +}; + +/* + * The top level structure for a persistent exception store. + */ +struct pstore { + struct dm_snapshot *snap; /* up pointer to my snapshot */ + int version; + int valid; + uint32_t exceptions_per_area; + + /* + * Now that we have an asynchronous kcopyd there is no + * need for large chunk sizes, so it wont hurt to have a + * whole chunks worth of metadata in memory at once. + */ + void *area; + + /* + * An area of zeros used to clear the next area. + */ + void *zero_area; + + /* + * Used to keep track of which metadata area the data in + * 'chunk' refers to. + */ + chunk_t current_area; + + /* + * The next free chunk for an exception. + */ + chunk_t next_free; + + /* + * The index of next free exception in the current + * metadata area. + */ + uint32_t current_committed; + + atomic_t pending_count; + uint32_t callback_count; + struct commit_callback *callbacks; + struct dm_io_client *io_client; + + struct workqueue_struct *metadata_wq; +}; + +static unsigned sectors_to_pages(unsigned sectors) +{ + return DIV_ROUND_UP(sectors, PAGE_SIZE >> 9); +} + +static int alloc_area(struct pstore *ps) +{ + int r = -ENOMEM; + size_t len; + + len = ps->snap->chunk_size << SECTOR_SHIFT; + + /* + * Allocate the chunk_size block of memory that will hold + * a single metadata area. + */ + ps->area = vmalloc(len); + if (!ps->area) + return r; + + ps->zero_area = vmalloc(len); + if (!ps->zero_area) { + vfree(ps->area); + return r; + } + memset(ps->zero_area, 0, len); + + return 0; +} + +static void free_area(struct pstore *ps) +{ + vfree(ps->area); + ps->area = NULL; + vfree(ps->zero_area); + ps->zero_area = NULL; +} + +struct mdata_req { + struct dm_io_region *where; + struct dm_io_request *io_req; + struct work_struct work; + int result; +}; + +static void do_metadata(struct work_struct *work) +{ + struct mdata_req *req = container_of(work, struct mdata_req, work); + + req->result = dm_io(req->io_req, 1, req->where, NULL); +} + +/* + * Read or write a chunk aligned and sized block of data from a device. + */ +static int chunk_io(struct pstore *ps, chunk_t chunk, int rw, int metadata) +{ + struct dm_io_region where = { + .bdev = ps->snap->cow->bdev, + .sector = ps->snap->chunk_size * chunk, + .count = ps->snap->chunk_size, + }; + struct dm_io_request io_req = { + .bi_rw = rw, + .mem.type = DM_IO_VMA, + .mem.ptr.vma = ps->area, + .client = ps->io_client, + .notify.fn = NULL, + }; + struct mdata_req req; + + if (!metadata) + return dm_io(&io_req, 1, &where, NULL); + + req.where = &where; + req.io_req = &io_req; + + /* + * Issue the synchronous I/O from a different thread + * to avoid generic_make_request recursion. + */ + INIT_WORK(&req.work, do_metadata); + queue_work(ps->metadata_wq, &req.work); + flush_workqueue(ps->metadata_wq); + + return req.result; +} + +/* + * Convert a metadata area index to a chunk index. + */ +static chunk_t area_location(struct pstore *ps, chunk_t area) +{ + return 1 + ((ps->exceptions_per_area + 1) * area); +} + +/* + * Read or write a metadata area. Remembering to skip the first + * chunk which holds the header. + */ +static int area_io(struct pstore *ps, int rw) +{ + int r; + chunk_t chunk; + + chunk = area_location(ps, ps->current_area); + + r = chunk_io(ps, chunk, rw, 0); + if (r) + return r; + + return 0; +} + +static void zero_memory_area(struct pstore *ps) +{ + memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT); +} + +static int zero_disk_area(struct pstore *ps, chunk_t area) +{ + struct dm_io_region where = { + .bdev = ps->snap->cow->bdev, + .sector = ps->snap->chunk_size * area_location(ps, area), + .count = ps->snap->chunk_size, + }; + struct dm_io_request io_req = { + .bi_rw = WRITE, + .mem.type = DM_IO_VMA, + .mem.ptr.vma = ps->zero_area, + .client = ps->io_client, + .notify.fn = NULL, + }; + + return dm_io(&io_req, 1, &where, NULL); +} + +static int read_header(struct pstore *ps, int *new_snapshot) +{ + int r; + struct disk_header *dh; + chunk_t chunk_size; + int chunk_size_supplied = 1; + + /* + * Use default chunk size (or hardsect_size, if larger) if none supplied + */ + if (!ps->snap->chunk_size) { + ps->snap->chunk_size = max(DM_CHUNK_SIZE_DEFAULT_SECTORS, + bdev_hardsect_size(ps->snap->cow->bdev) >> 9); + ps->snap->chunk_mask = ps->snap->chunk_size - 1; + ps->snap->chunk_shift = ffs(ps->snap->chunk_size) - 1; + chunk_size_supplied = 0; + } + + ps->io_client = dm_io_client_create(sectors_to_pages(ps->snap-> + chunk_size)); + if (IS_ERR(ps->io_client)) + return PTR_ERR(ps->io_client); + + r = alloc_area(ps); + if (r) + return r; + + r = chunk_io(ps, 0, READ, 1); + if (r) + goto bad; + + dh = (struct disk_header *) ps->area; + + if (le32_to_cpu(dh->magic) == 0) { + *new_snapshot = 1; + return 0; + } + + if (le32_to_cpu(dh->magic) != SNAP_MAGIC) { + DMWARN("Invalid or corrupt snapshot"); + r = -ENXIO; + goto bad; + } + + *new_snapshot = 0; + ps->valid = le32_to_cpu(dh->valid); + ps->version = le32_to_cpu(dh->version); + chunk_size = le32_to_cpu(dh->chunk_size); + + if (!chunk_size_supplied || ps->snap->chunk_size == chunk_size) + return 0; + + DMWARN("chunk size %llu in device metadata overrides " + "table chunk size of %llu.", + (unsigned long long)chunk_size, + (unsigned long long)ps->snap->chunk_size); + + /* We had a bogus chunk_size. Fix stuff up. */ + free_area(ps); + + ps->snap->chunk_size = chunk_size; + ps->snap->chunk_mask = chunk_size - 1; + ps->snap->chunk_shift = ffs(chunk_size) - 1; + + r = dm_io_client_resize(sectors_to_pages(ps->snap->chunk_size), + ps->io_client); + if (r) + return r; + + r = alloc_area(ps); + return r; + +bad: + free_area(ps); + return r; +} + +static int write_header(struct pstore *ps) +{ + struct disk_header *dh; + + memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT); + + dh = (struct disk_header *) ps->area; + dh->magic = cpu_to_le32(SNAP_MAGIC); + dh->valid = cpu_to_le32(ps->valid); + dh->version = cpu_to_le32(ps->version); + dh->chunk_size = cpu_to_le32(ps->snap->chunk_size); + + return chunk_io(ps, 0, WRITE, 1); +} + +/* + * Access functions for the disk exceptions, these do the endian conversions. + */ +static struct disk_exception *get_exception(struct pstore *ps, uint32_t index) +{ + BUG_ON(index >= ps->exceptions_per_area); + + return ((struct disk_exception *) ps->area) + index; +} + +static void read_exception(struct pstore *ps, + uint32_t index, struct disk_exception *result) +{ + struct disk_exception *e = get_exception(ps, index); + + /* copy it */ + result->old_chunk = le64_to_cpu(e->old_chunk); + result->new_chunk = le64_to_cpu(e->new_chunk); +} + +static void write_exception(struct pstore *ps, + uint32_t index, struct disk_exception *de) +{ + struct disk_exception *e = get_exception(ps, index); + + /* copy it */ + e->old_chunk = cpu_to_le64(de->old_chunk); + e->new_chunk = cpu_to_le64(de->new_chunk); +} + +/* + * Registers the exceptions that are present in the current area. + * 'full' is filled in to indicate if the area has been + * filled. + */ +static int insert_exceptions(struct pstore *ps, + int (*callback)(void *callback_context, + chunk_t old, chunk_t new), + void *callback_context, + int *full) +{ + int r; + unsigned int i; + struct disk_exception de; + + /* presume the area is full */ + *full = 1; + + for (i = 0; i < ps->exceptions_per_area; i++) { + read_exception(ps, i, &de); + + /* + * If the new_chunk is pointing at the start of + * the COW device, where the first metadata area + * is we know that we've hit the end of the + * exceptions. Therefore the area is not full. + */ + if (de.new_chunk == 0LL) { + ps->current_committed = i; + *full = 0; + break; + } + + /* + * Keep track of the start of the free chunks. + */ + if (ps->next_free <= de.new_chunk) + ps->next_free = de.new_chunk + 1; + + /* + * Otherwise we add the exception to the snapshot. + */ + r = callback(callback_context, de.old_chunk, de.new_chunk); + if (r) + return r; + } + + return 0; +} + +static int read_exceptions(struct pstore *ps, + int (*callback)(void *callback_context, chunk_t old, + chunk_t new), + void *callback_context) +{ + int r, full = 1; + + /* + * Keeping reading chunks and inserting exceptions until + * we find a partially full area. + */ + for (ps->current_area = 0; full; ps->current_area++) { + r = area_io(ps, READ); + if (r) + return r; + + r = insert_exceptions(ps, callback, callback_context, &full); + if (r) + return r; + } + + ps->current_area--; + + return 0; +} + +static struct pstore *get_info(struct dm_exception_store *store) +{ + return (struct pstore *) store->context; +} + +static void persistent_fraction_full(struct dm_exception_store *store, + sector_t *numerator, sector_t *denominator) +{ + *numerator = get_info(store)->next_free * store->snap->chunk_size; + *denominator = get_dev_size(store->snap->cow->bdev); +} + +static void persistent_destroy(struct dm_exception_store *store) +{ + struct pstore *ps = get_info(store); + + destroy_workqueue(ps->metadata_wq); + dm_io_client_destroy(ps->io_client); + vfree(ps->callbacks); + free_area(ps); + kfree(ps); +} + +static int persistent_read_metadata(struct dm_exception_store *store, + int (*callback)(void *callback_context, + chunk_t old, chunk_t new), + void *callback_context) +{ + int r, uninitialized_var(new_snapshot); + struct pstore *ps = get_info(store); + + /* + * Read the snapshot header. + */ + r = read_header(ps, &new_snapshot); + if (r) + return r; + + /* + * Now we know correct chunk_size, complete the initialisation. + */ + ps->exceptions_per_area = (ps->snap->chunk_size << SECTOR_SHIFT) / + sizeof(struct disk_exception); + ps->callbacks = dm_vcalloc(ps->exceptions_per_area, + sizeof(*ps->callbacks)); + if (!ps->callbacks) + return -ENOMEM; + + /* + * Do we need to setup a new snapshot ? + */ + if (new_snapshot) { + r = write_header(ps); + if (r) { + DMWARN("write_header failed"); + return r; + } + + ps->current_area = 0; + zero_memory_area(ps); + r = zero_disk_area(ps, 0); + if (r) { + DMWARN("zero_disk_area(0) failed"); + return r; + } + } else { + /* + * Sanity checks. + */ + if (ps->version != SNAPSHOT_DISK_VERSION) { + DMWARN("unable to handle snapshot disk version %d", + ps->version); + return -EINVAL; + } + + /* + * Metadata are valid, but snapshot is invalidated + */ + if (!ps->valid) + return 1; + + /* + * Read the metadata. + */ + r = read_exceptions(ps, callback, callback_context); + if (r) + return r; + } + + return 0; +} + +static int persistent_prepare_exception(struct dm_exception_store *store, + struct dm_snap_exception *e) +{ + struct pstore *ps = get_info(store); + uint32_t stride; + chunk_t next_free; + sector_t size = get_dev_size(store->snap->cow->bdev); + + /* Is there enough room ? */ + if (size < ((ps->next_free + 1) * store->snap->chunk_size)) + return -ENOSPC; + + e->new_chunk = ps->next_free; + + /* + * Move onto the next free pending, making sure to take + * into account the location of the metadata chunks. + */ + stride = (ps->exceptions_per_area + 1); + next_free = ++ps->next_free; + if (sector_div(next_free, stride) == 1) + ps->next_free++; + + atomic_inc(&ps->pending_count); + return 0; +} + +static void persistent_commit_exception(struct dm_exception_store *store, + struct dm_snap_exception *e, + void (*callback) (void *, int success), + void *callback_context) +{ + unsigned int i; + struct pstore *ps = get_info(store); + struct disk_exception de; + struct commit_callback *cb; + + de.old_chunk = e->old_chunk; + de.new_chunk = e->new_chunk; + write_exception(ps, ps->current_committed++, &de); + + /* + * Add the callback to the back of the array. This code + * is the only place where the callback array is + * manipulated, and we know that it will never be called + * multiple times concurrently. + */ + cb = ps->callbacks + ps->callback_count++; + cb->callback = callback; + cb->context = callback_context; + + /* + * If there are exceptions in flight and we have not yet + * filled this metadata area there's nothing more to do. + */ + if (!atomic_dec_and_test(&ps->pending_count) && + (ps->current_committed != ps->exceptions_per_area)) + return; + + /* + * If we completely filled the current area, then wipe the next one. + */ + if ((ps->current_committed == ps->exceptions_per_area) && + zero_disk_area(ps, ps->current_area + 1)) + ps->valid = 0; + + /* + * Commit exceptions to disk. + */ + if (ps->valid && area_io(ps, WRITE)) + ps->valid = 0; + + /* + * Advance to the next area if this one is full. + */ + if (ps->current_committed == ps->exceptions_per_area) { + ps->current_committed = 0; + ps->current_area++; + zero_memory_area(ps); + } + + for (i = 0; i < ps->callback_count; i++) { + cb = ps->callbacks + i; + cb->callback(cb->context, ps->valid); + } + + ps->callback_count = 0; +} + +static void persistent_drop_snapshot(struct dm_exception_store *store) +{ + struct pstore *ps = get_info(store); + + ps->valid = 0; + if (write_header(ps)) + DMWARN("write header failed"); +} + +int dm_create_persistent(struct dm_exception_store *store) +{ + struct pstore *ps; + + /* allocate the pstore */ + ps = kmalloc(sizeof(*ps), GFP_KERNEL); + if (!ps) + return -ENOMEM; + + ps->snap = store->snap; + ps->valid = 1; + ps->version = SNAPSHOT_DISK_VERSION; + ps->area = NULL; + ps->next_free = 2; /* skipping the header and first area */ + ps->current_committed = 0; + + ps->callback_count = 0; + atomic_set(&ps->pending_count, 0); + ps->callbacks = NULL; + + ps->metadata_wq = create_singlethread_workqueue("ksnaphd"); + if (!ps->metadata_wq) { + kfree(ps); + DMERR("couldn't start header metadata update thread"); + return -ENOMEM; + } + + store->destroy = persistent_destroy; + store->read_metadata = persistent_read_metadata; + store->prepare_exception = persistent_prepare_exception; + store->commit_exception = persistent_commit_exception; + store->drop_snapshot = persistent_drop_snapshot; + store->fraction_full = persistent_fraction_full; + store->context = ps; + + return 0; +} + +int dm_persistent_snapshot_init(void) +{ + return 0; +} + +void dm_persistent_snapshot_exit(void) +{ +} diff --git a/drivers/md/dm-snap-transient.c b/drivers/md/dm-snap-transient.c new file mode 100644 index 0000000..7f6e2e6 --- /dev/null +++ b/drivers/md/dm-snap-transient.c @@ -0,0 +1,98 @@ +/* + * Copyright (C) 2001-2002 Sistina Software (UK) Limited. + * Copyright (C) 2006-2008 Red Hat GmbH + * + * This file is released under the GPL. + */ + +#include "dm-exception-store.h" +#include "dm-snap.h" + +#include <linux/mm.h> +#include <linux/pagemap.h> +#include <linux/vmalloc.h> +#include <linux/slab.h> +#include <linux/dm-io.h> + +#define DM_MSG_PREFIX "transient snapshot" + +/*----------------------------------------------------------------- + * Implementation of the store for non-persistent snapshots. + *---------------------------------------------------------------*/ +struct transient_c { + sector_t next_free; +}; + +static void transient_destroy(struct dm_exception_store *store) +{ + kfree(store->context); +} + +static int transient_read_metadata(struct dm_exception_store *store, + int (*callback)(void *callback_context, + chunk_t old, chunk_t new), + void *callback_context) +{ + return 0; +} + +static int transient_prepare_exception(struct dm_exception_store *store, + struct dm_snap_exception *e) +{ + struct transient_c *tc = (struct transient_c *) store->context; + sector_t size = get_dev_size(store->snap->cow->bdev); + + if (size < (tc->next_free + store->snap->chunk_size)) + return -1; + + e->new_chunk = sector_to_chunk(store->snap, tc->next_free); + tc->next_free += store->snap->chunk_size; + + return 0; +} + +static void transient_commit_exception(struct dm_exception_store *store, + struct dm_snap_exception *e, + void (*callback) (void *, int success), + void *callback_context) +{ + /* Just succeed */ + callback(callback_context, 1); +} + +static void transient_fraction_full(struct dm_exception_store *store, + sector_t *numerator, sector_t *denominator) +{ + *numerator = ((struct transient_c *) store->context)->next_free; + *denominator = get_dev_size(store->snap->cow->bdev); +} + +int dm_create_transient(struct dm_exception_store *store) +{ + struct transient_c *tc; + + store->destroy = transient_destroy; + store->read_metadata = transient_read_metadata; + store->prepare_exception = transient_prepare_exception; + store->commit_exception = transient_commit_exception; + store->drop_snapshot = NULL; + store->fraction_full = transient_fraction_full; + + tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL); + if (!tc) + return -ENOMEM; + + tc->next_free = 0; + store->context = tc; + + return 0; +} + +int dm_transient_snapshot_init(void) +{ + return 0; +} + +void dm_transient_snapshot_exit(void) +{ +} diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 6c96db2..65ff82f 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -9,6 +9,7 @@ #include <linux/blkdev.h> #include <linux/ctype.h> #include <linux/device-mapper.h> +#include <linux/delay.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/kdev_t.h> @@ -20,6 +21,7 @@ #include <linux/log2.h> #include <linux/dm-kcopyd.h> +#include "dm-exception-store.h" #include "dm-snap.h" #include "dm-bio-list.h" @@ -428,8 +430,13 @@ out: list_add(&new_e->hash_list, e ? &e->hash_list : l); } -int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new) +/* + * Callback used by the exception stores to load exceptions when + * initialising. + */ +static int dm_add_exception(void *context, chunk_t old, chunk_t new) { + struct dm_snapshot *s = context; struct dm_snap_exception *e; e = alloc_exception(); @@ -658,7 +665,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) spin_lock_init(&s->tracked_chunk_lock); /* Metadata must only be loaded into one table at once */ - r = s->store.read_metadata(&s->store); + r = s->store.read_metadata(&s->store, dm_add_exception, (void *)s); if (r < 0) { ti->error = "Failed to read snapshot metadata"; goto bad_load_and_register; @@ -735,7 +742,7 @@ static void snapshot_dtr(struct dm_target *ti) unregister_snapshot(s); while (atomic_read(&s->pending_exceptions_count)) - yield(); + msleep(1); /* * Ensure instructions in mempool_destroy aren't reordered * before atomic_read. @@ -888,10 +895,10 @@ static void pending_complete(struct dm_snap_pending_exception *pe, int success) /* * Check for conflicting reads. This is extremely improbable, - * so yield() is sufficient and there is no need for a wait queue. + * so msleep(1) is sufficient and there is no need for a wait queue. */ while (__chunk_is_tracked(s, pe->e.old_chunk)) - yield(); + msleep(1); /* * Add a proper exception, and remove the @@ -1404,6 +1411,12 @@ static int __init dm_snapshot_init(void) { int r; + r = dm_exception_store_init(); + if (r) { + DMERR("Failed to initialize exception stores"); + return r; + } + r = dm_register_target(&snapshot_target); if (r) { DMERR("snapshot target register failed %d", r); @@ -1452,39 +1465,34 @@ static int __init dm_snapshot_init(void) return 0; - bad_pending_pool: +bad_pending_pool: kmem_cache_destroy(tracked_chunk_cache); - bad5: +bad5: kmem_cache_destroy(pending_cache); - bad4: +bad4: kmem_cache_destroy(exception_cache); - bad3: +bad3: exit_origin_hash(); - bad2: +bad2: dm_unregister_target(&origin_target); - bad1: +bad1: dm_unregister_target(&snapshot_target); return r; } static void __exit dm_snapshot_exit(void) { - int r; - destroy_workqueue(ksnapd); - r = dm_unregister_target(&snapshot_target); - if (r) - DMERR("snapshot unregister failed %d", r); - - r = dm_unregister_target(&origin_target); - if (r) - DMERR("origin unregister failed %d", r); + dm_unregister_target(&snapshot_target); + dm_unregister_target(&origin_target); exit_origin_hash(); kmem_cache_destroy(pending_cache); kmem_cache_destroy(exception_cache); kmem_cache_destroy(tracked_chunk_cache); + + dm_exception_store_exit(); } /* Module hooks */ diff --git a/drivers/md/dm-snap.h b/drivers/md/dm-snap.h index 99c0106..d9e62b4 100644 --- a/drivers/md/dm-snap.h +++ b/drivers/md/dm-snap.h @@ -1,6 +1,4 @@ /* - * dm-snapshot.c - * * Copyright (C) 2001-2002 Sistina Software (UK) Limited. * * This file is released under the GPL. @@ -10,6 +8,7 @@ #define DM_SNAPSHOT_H #include <linux/device-mapper.h> +#include "dm-exception-store.h" #include "dm-bio-list.h" #include <linux/blkdev.h> #include <linux/workqueue.h> @@ -20,116 +19,6 @@ struct exception_table { struct list_head *table; }; -/* - * The snapshot code deals with largish chunks of the disk at a - * time. Typically 32k - 512k. - */ -typedef sector_t chunk_t; - -/* - * An exception is used where an old chunk of data has been - * replaced by a new one. - * If chunk_t is 64 bits in size, the top 8 bits of new_chunk hold the number - * of chunks that follow contiguously. Remaining bits hold the number of the - * chunk within the device. - */ -struct dm_snap_exception { - struct list_head hash_list; - - chunk_t old_chunk; - chunk_t new_chunk; -}; - -/* - * Funtions to manipulate consecutive chunks - */ -# if defined(CONFIG_LBD) || (BITS_PER_LONG == 64) -# define DM_CHUNK_CONSECUTIVE_BITS 8 -# define DM_CHUNK_NUMBER_BITS 56 - -static inline chunk_t dm_chunk_number(chunk_t chunk) -{ - return chunk & (chunk_t)((1ULL << DM_CHUNK_NUMBER_BITS) - 1ULL); -} - -static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e) -{ - return e->new_chunk >> DM_CHUNK_NUMBER_BITS; -} - -static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e) -{ - e->new_chunk += (1ULL << DM_CHUNK_NUMBER_BITS); - - BUG_ON(!dm_consecutive_chunk_count(e)); -} - -# else -# define DM_CHUNK_CONSECUTIVE_BITS 0 - -static inline chunk_t dm_chunk_number(chunk_t chunk) -{ - return chunk; -} - -static inline unsigned dm_consecutive_chunk_count(struct dm_snap_exception *e) -{ - return 0; -} - -static inline void dm_consecutive_chunk_count_inc(struct dm_snap_exception *e) -{ -} - -# endif - -/* - * Abstraction to handle the meta/layout of exception stores (the - * COW device). - */ -struct exception_store { - - /* - * Destroys this object when you've finished with it. - */ - void (*destroy) (struct exception_store *store); - - /* - * The target shouldn't read the COW device until this is - * called. - */ - int (*read_metadata) (struct exception_store *store); - - /* - * Find somewhere to store the next exception. - */ - int (*prepare_exception) (struct exception_store *store, - struct dm_snap_exception *e); - - /* - * Update the metadata with this exception. - */ - void (*commit_exception) (struct exception_store *store, - struct dm_snap_exception *e, - void (*callback) (void *, int success), - void *callback_context); - - /* - * The snapshot is invalid, note this in the metadata. - */ - void (*drop_snapshot) (struct exception_store *store); - - /* - * Return how full the snapshot is. - */ - void (*fraction_full) (struct exception_store *store, - sector_t *numerator, - sector_t *denominator); - - struct dm_snapshot *snap; - void *context; -}; - #define DM_TRACKED_CHUNK_HASH_SIZE 16 #define DM_TRACKED_CHUNK_HASH(x) ((unsigned long)(x) & \ (DM_TRACKED_CHUNK_HASH_SIZE - 1)) @@ -172,7 +61,7 @@ struct dm_snapshot { spinlock_t pe_lock; /* The on disk metadata handler */ - struct exception_store store; + struct dm_exception_store store; struct dm_kcopyd_client *kcopyd_client; @@ -187,20 +76,6 @@ struct dm_snapshot { }; /* - * Used by the exception stores to load exceptions hen - * initialising. - */ -int dm_add_exception(struct dm_snapshot *s, chunk_t old, chunk_t new); - -/* - * Constructor and destructor for the default persistent - * store. - */ -int dm_create_persistent(struct exception_store *store); - -int dm_create_transient(struct exception_store *store); - -/* * Return the number of sectors in the device. */ static inline sector_t get_dev_size(struct block_device *bdev) diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c index 9e4ef88..41569bc 100644 --- a/drivers/md/dm-stripe.c +++ b/drivers/md/dm-stripe.c @@ -337,9 +337,7 @@ int __init dm_stripe_init(void) void dm_stripe_exit(void) { - if (dm_unregister_target(&stripe_target)) - DMWARN("target unregistration failed"); - + dm_unregister_target(&stripe_target); destroy_workqueue(kstriped); return; diff --git a/drivers/md/dm-sysfs.c b/drivers/md/dm-sysfs.c new file mode 100644 index 0000000..a2a45e6 --- /dev/null +++ b/drivers/md/dm-sysfs.c @@ -0,0 +1,99 @@ +/* + * Copyright (C) 2008 Red Hat, Inc. All rights reserved. + * + * This file is released under the GPL. + */ + +#include <linux/sysfs.h> +#include <linux/dm-ioctl.h> +#include "dm.h" + +struct dm_sysfs_attr { + struct attribute attr; + ssize_t (*show)(struct mapped_device *, char *); + ssize_t (*store)(struct mapped_device *, char *); +}; + +#define DM_ATTR_RO(_name) \ +struct dm_sysfs_attr dm_attr_##_name = \ + __ATTR(_name, S_IRUGO, dm_attr_##_name##_show, NULL) + +static ssize_t dm_attr_show(struct kobject *kobj, struct attribute *attr, + char *page) +{ + struct dm_sysfs_attr *dm_attr; + struct mapped_device *md; + ssize_t ret; + + dm_attr = container_of(attr, struct dm_sysfs_attr, attr); + if (!dm_attr->show) + return -EIO; + + md = dm_get_from_kobject(kobj); + if (!md) + return -EINVAL; + + ret = dm_attr->show(md, page); + dm_put(md); + + return ret; +} + +static ssize_t dm_attr_name_show(struct mapped_device *md, char *buf) +{ + if (dm_copy_name_and_uuid(md, buf, NULL)) + return -EIO; + + strcat(buf, "\n"); + return strlen(buf); +} + +static ssize_t dm_attr_uuid_show(struct mapped_device *md, char *buf) +{ + if (dm_copy_name_and_uuid(md, NULL, buf)) + return -EIO; + + strcat(buf, "\n"); + return strlen(buf); +} + +static DM_ATTR_RO(name); +static DM_ATTR_RO(uuid); + +static struct attribute *dm_attrs[] = { + &dm_attr_name.attr, + &dm_attr_uuid.attr, + NULL, +}; + +static struct sysfs_ops dm_sysfs_ops = { + .show = dm_attr_show, +}; + +/* + * dm kobject is embedded in mapped_device structure + * no need to define release function here + */ +static struct kobj_type dm_ktype = { + .sysfs_ops = &dm_sysfs_ops, + .default_attrs = dm_attrs, +}; + +/* + * Initialize kobj + * because nobody using md yet, no need to call explicit dm_get/put + */ +int dm_sysfs_init(struct mapped_device *md) +{ + return kobject_init_and_add(dm_kobject(md), &dm_ktype, + &disk_to_dev(dm_disk(md))->kobj, + "%s", "dm"); +} + +/* + * Remove kobj, called after all references removed + */ +void dm_sysfs_exit(struct mapped_device *md) +{ + kobject_put(dm_kobject(md)); +} diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 04e5fd7..2fd66c3 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -1,6 +1,6 @@ /* * Copyright (C) 2001 Sistina Software (UK) Limited. - * Copyright (C) 2004 Red Hat, Inc. All rights reserved. + * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. */ @@ -15,6 +15,7 @@ #include <linux/slab.h> #include <linux/interrupt.h> #include <linux/mutex.h> +#include <linux/delay.h> #include <asm/atomic.h> #define DM_MSG_PREFIX "table" @@ -24,6 +25,19 @@ #define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t)) #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1) +/* + * The table has always exactly one reference from either mapped_device->map + * or hash_cell->new_map. This reference is not counted in table->holders. + * A pair of dm_create_table/dm_destroy_table functions is used for table + * creation/destruction. + * + * Temporary references from the other code increase table->holders. A pair + * of dm_table_get/dm_table_put functions is used to manipulate it. + * + * When the table is about to be destroyed, we wait for table->holders to + * drop to zero. + */ + struct dm_table { struct mapped_device *md; atomic_t holders; @@ -38,6 +52,8 @@ struct dm_table { sector_t *highs; struct dm_target *targets; + unsigned barriers_supported:1; + /* * Indicates the rw permissions for the new logical * device. This should be a combination of FMODE_READ @@ -226,7 +242,8 @@ int dm_table_create(struct dm_table **result, fmode_t mode, return -ENOMEM; INIT_LIST_HEAD(&t->devices); - atomic_set(&t->holders, 1); + atomic_set(&t->holders, 0); + t->barriers_supported = 1; if (!num_targets) num_targets = KEYS_PER_NODE; @@ -256,10 +273,14 @@ static void free_devices(struct list_head *devices) } } -static void table_destroy(struct dm_table *t) +void dm_table_destroy(struct dm_table *t) { unsigned int i; + while (atomic_read(&t->holders)) + msleep(1); + smp_mb(); + /* free the indexes (see dm_table_complete) */ if (t->depth >= 2) vfree(t->index[t->depth - 2]); @@ -297,8 +318,8 @@ void dm_table_put(struct dm_table *t) if (!t) return; - if (atomic_dec_and_test(&t->holders)) - table_destroy(t); + smp_mb__before_atomic_dec(); + atomic_dec(&t->holders); } /* @@ -728,6 +749,10 @@ int dm_table_add_target(struct dm_table *t, const char *type, /* FIXME: the plan is to combine high here and then have * the merge fn apply the target level restrictions. */ combine_restrictions_low(&t->limits, &tgt->limits); + + if (!(tgt->type->features & DM_TARGET_SUPPORTS_BARRIERS)) + t->barriers_supported = 0; + return 0; bad: @@ -772,6 +797,12 @@ int dm_table_complete(struct dm_table *t) check_for_valid_limits(&t->limits); + /* + * We only support barriers if there is exactly one underlying device. + */ + if (!list_is_singular(&t->devices)) + t->barriers_supported = 0; + /* how many indexes will the btree have ? */ leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE); t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE); @@ -986,6 +1017,12 @@ struct mapped_device *dm_table_get_md(struct dm_table *t) return t->md; } +int dm_table_barrier_ok(struct dm_table *t) +{ + return t->barriers_supported; +} +EXPORT_SYMBOL(dm_table_barrier_ok); + EXPORT_SYMBOL(dm_vcalloc); EXPORT_SYMBOL(dm_get_device); EXPORT_SYMBOL(dm_put_device); diff --git a/drivers/md/dm-target.c b/drivers/md/dm-target.c index 835cf95..7decf10 100644 --- a/drivers/md/dm-target.c +++ b/drivers/md/dm-target.c @@ -130,26 +130,26 @@ int dm_register_target(struct target_type *t) return rv; } -int dm_unregister_target(struct target_type *t) +void dm_unregister_target(struct target_type *t) { struct tt_internal *ti; down_write(&_lock); if (!(ti = __find_target_type(t->name))) { - up_write(&_lock); - return -EINVAL; + DMCRIT("Unregistering unrecognised target: %s", t->name); + BUG(); } if (ti->use) { - up_write(&_lock); - return -ETXTBSY; + DMCRIT("Attempt to unregister target still in use: %s", + t->name); + BUG(); } list_del(&ti->list); kfree(ti); up_write(&_lock); - return 0; } /* @@ -187,8 +187,7 @@ int __init dm_target_init(void) void dm_target_exit(void) { - if (dm_unregister_target(&error_target)) - DMWARN("error target unregistration failed"); + dm_unregister_target(&error_target); } EXPORT_SYMBOL(dm_register_target); diff --git a/drivers/md/dm-zero.c b/drivers/md/dm-zero.c index cdbf126..bbc9703 100644 --- a/drivers/md/dm-zero.c +++ b/drivers/md/dm-zero.c @@ -69,10 +69,7 @@ static int __init dm_zero_init(void) static void __exit dm_zero_exit(void) { - int r = dm_unregister_target(&zero_target); - - if (r < 0) - DMERR("unregister failed %d", r); + dm_unregister_target(&zero_target); } module_init(dm_zero_init) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 421c9f0..51ba1db 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1,6 +1,6 @@ /* * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. - * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved. + * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. */ @@ -32,6 +32,7 @@ static unsigned int _major = 0; static DEFINE_SPINLOCK(_minor_lock); /* + * For bio-based dm. * One of these is allocated per bio. */ struct dm_io { @@ -43,6 +44,7 @@ struct dm_io { }; /* + * For bio-based dm. * One of these is allocated per target within a bio. Hopefully * this will be simplified out one day. */ @@ -54,6 +56,27 @@ struct dm_target_io { DEFINE_TRACE(block_bio_complete); +/* + * For request-based dm. + * One of these is allocated per request. + */ +struct dm_rq_target_io { + struct mapped_device *md; + struct dm_target *ti; + struct request *orig, clone; + int error; + union map_info info; +}; + +/* + * For request-based dm. + * One of these is allocated per bio. + */ +struct dm_rq_clone_bio_info { + struct bio *orig; + struct request *rq; +}; + union map_info *dm_get_mapinfo(struct bio *bio) { if (bio && bio->bi_private) @@ -144,11 +167,16 @@ struct mapped_device { /* forced geometry settings */ struct hd_geometry geometry; + + /* sysfs handle */ + struct kobject kobj; }; #define MIN_IOS 256 static struct kmem_cache *_io_cache; static struct kmem_cache *_tio_cache; +static struct kmem_cache *_rq_tio_cache; +static struct kmem_cache *_rq_bio_info_cache; static int __init local_init(void) { @@ -164,9 +192,17 @@ static int __init local_init(void) if (!_tio_cache) goto out_free_io_cache; + _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0); + if (!_rq_tio_cache) + goto out_free_tio_cache; + + _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0); + if (!_rq_bio_info_cache) + goto out_free_rq_tio_cache; + r = dm_uevent_init(); if (r) - goto out_free_tio_cache; + goto out_free_rq_bio_info_cache; _major = major; r = register_blkdev(_major, _name); @@ -180,6 +216,10 @@ static int __init local_init(void) out_uevent_exit: dm_uevent_exit(); +out_free_rq_bio_info_cache: + kmem_cache_destroy(_rq_bio_info_cache); +out_free_rq_tio_cache: + kmem_cache_destroy(_rq_tio_cache); out_free_tio_cache: kmem_cache_destroy(_tio_cache); out_free_io_cache: @@ -190,6 +230,8 @@ out_free_io_cache: static void local_exit(void) { + kmem_cache_destroy(_rq_bio_info_cache); + kmem_cache_destroy(_rq_tio_cache); kmem_cache_destroy(_tio_cache); kmem_cache_destroy(_io_cache); unregister_blkdev(_major, _name); @@ -796,7 +838,11 @@ static int __split_bio(struct mapped_device *md, struct bio *bio) ci.map = dm_get_table(md); if (unlikely(!ci.map)) return -EIO; - + if (unlikely(bio_barrier(bio) && !dm_table_barrier_ok(ci.map))) { + dm_table_put(ci.map); + bio_endio(bio, -EOPNOTSUPP); + return 0; + } ci.md = md; ci.bio = bio; ci.io = alloc_io(md); @@ -880,15 +926,6 @@ static int dm_request(struct request_queue *q, struct bio *bio) struct mapped_device *md = q->queuedata; int cpu; - /* - * There is no use in forwarding any barrier request since we can't - * guarantee it is (or can be) handled by the targets correctly. - */ - if (unlikely(bio_barrier(bio))) { - bio_endio(bio, -EOPNOTSUPP); - return 0; - } - down_read(&md->io_lock); cpu = part_stat_lock(); @@ -943,8 +980,6 @@ static int dm_any_congested(void *congested_data, int bdi_bits) struct mapped_device *md = congested_data; struct dm_table *map; - atomic_inc(&md->pending); - if (!test_bit(DMF_BLOCK_IO, &md->flags)) { map = dm_get_table(md); if (map) { @@ -953,10 +988,6 @@ static int dm_any_congested(void *congested_data, int bdi_bits) } } - if (!atomic_dec_return(&md->pending)) - /* nudge anyone waiting on suspend queue */ - wake_up(&md->wait); - return r; } @@ -1216,10 +1247,12 @@ static int __bind(struct mapped_device *md, struct dm_table *t) if (md->suspended_bdev) __set_size(md, size); - if (size == 0) + + if (!size) { + dm_table_destroy(t); return 0; + } - dm_table_get(t); dm_table_event_callback(t, event_callback, md); write_lock(&md->map_lock); @@ -1241,7 +1274,7 @@ static void __unbind(struct mapped_device *md) write_lock(&md->map_lock); md->map = NULL; write_unlock(&md->map_lock); - dm_table_put(map); + dm_table_destroy(map); } /* @@ -1255,6 +1288,8 @@ int dm_create(int minor, struct mapped_device **result) if (!md) return -ENXIO; + dm_sysfs_init(md); + *result = md; return 0; } @@ -1330,8 +1365,9 @@ void dm_put(struct mapped_device *md) dm_table_presuspend_targets(map); dm_table_postsuspend_targets(map); } - __unbind(md); + dm_sysfs_exit(md); dm_table_put(map); + __unbind(md); free_dev(md); } } @@ -1669,6 +1705,27 @@ struct gendisk *dm_disk(struct mapped_device *md) return md->disk; } +struct kobject *dm_kobject(struct mapped_device *md) +{ + return &md->kobj; +} + +/* + * struct mapped_device should not be exported outside of dm.c + * so use this check to verify that kobj is part of md structure + */ +struct mapped_device *dm_get_from_kobject(struct kobject *kobj) +{ + struct mapped_device *md; + + md = container_of(kobj, struct mapped_device, kobj); + if (&md->kobj != kobj) + return NULL; + + dm_get(md); + return md; +} + int dm_suspended(struct mapped_device *md) { return test_bit(DMF_SUSPENDED, &md->flags); diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 0ade60c..20194e0 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -36,6 +36,7 @@ struct dm_table; /*----------------------------------------------------------------- * Internal table functions. *---------------------------------------------------------------*/ +void dm_table_destroy(struct dm_table *t); void dm_table_event_callback(struct dm_table *t, void (*fn)(void *), void *context); struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index); @@ -51,6 +52,7 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits); * To check the return value from dm_table_find_target(). */ #define dm_target_is_valid(t) ((t)->table) +int dm_table_barrier_ok(struct dm_table *t); /*----------------------------------------------------------------- * A registry of target types. @@ -72,6 +74,14 @@ int dm_interface_init(void); void dm_interface_exit(void); /* + * sysfs interface + */ +int dm_sysfs_init(struct mapped_device *md); +void dm_sysfs_exit(struct mapped_device *md); +struct kobject *dm_kobject(struct mapped_device *md); +struct mapped_device *dm_get_from_kobject(struct kobject *kobj); + +/* * Targets for linear and striped mappings */ int dm_linear_init(void); diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index c17fd33..8209e08 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -45,6 +45,8 @@ typedef void (*dm_dtr_fn) (struct dm_target *ti); */ typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, union map_info *map_context); +typedef int (*dm_map_request_fn) (struct dm_target *ti, struct request *clone, + union map_info *map_context); /* * Returns: @@ -57,6 +59,9 @@ typedef int (*dm_map_fn) (struct dm_target *ti, struct bio *bio, typedef int (*dm_endio_fn) (struct dm_target *ti, struct bio *bio, int error, union map_info *map_context); +typedef int (*dm_request_endio_fn) (struct dm_target *ti, + struct request *clone, int error, + union map_info *map_context); typedef void (*dm_flush_fn) (struct dm_target *ti); typedef void (*dm_presuspend_fn) (struct dm_target *ti); @@ -75,6 +80,13 @@ typedef int (*dm_ioctl_fn) (struct dm_target *ti, unsigned int cmd, typedef int (*dm_merge_fn) (struct dm_target *ti, struct bvec_merge_data *bvm, struct bio_vec *biovec, int max_size); +/* + * Returns: + * 0: The target can handle the next I/O immediately. + * 1: The target can't handle the next I/O immediately. + */ +typedef int (*dm_busy_fn) (struct dm_target *ti); + void dm_error(const char *message); /* @@ -100,14 +112,23 @@ void dm_put_device(struct dm_target *ti, struct dm_dev *d); /* * Information about a target type */ + +/* + * Target features + */ +#define DM_TARGET_SUPPORTS_BARRIERS 0x00000001 + struct target_type { + uint64_t features; const char *name; struct module *module; unsigned version[3]; dm_ctr_fn ctr; dm_dtr_fn dtr; dm_map_fn map; + dm_map_request_fn map_rq; dm_endio_fn end_io; + dm_request_endio_fn rq_end_io; dm_flush_fn flush; dm_presuspend_fn presuspend; dm_postsuspend_fn postsuspend; @@ -117,6 +138,7 @@ struct target_type { dm_message_fn message; dm_ioctl_fn ioctl; dm_merge_fn merge; + dm_busy_fn busy; }; struct io_restrictions { @@ -157,8 +179,7 @@ struct dm_target { }; int dm_register_target(struct target_type *t); -int dm_unregister_target(struct target_type *t); - +void dm_unregister_target(struct target_type *t); /*----------------------------------------------------------------- * Functions for creating and manipulating mapped devices. @@ -276,6 +297,9 @@ void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size); *---------------------------------------------------------------*/ #define DM_NAME "device-mapper" +#define DMCRIT(f, arg...) \ + printk(KERN_CRIT DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) + #define DMERR(f, arg...) \ printk(KERN_ERR DM_NAME ": " DM_MSG_PREFIX ": " f "\n", ## arg) #define DMERR_LIMIT(f, arg...) \ |
