#include <linux/vmalloc.h>
#include <linux/slab.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.
struct dm_snapshot *snap; /* up pointer to my snapshot */
int version;
int valid;
- uint32_t chunk_size;
uint32_t exceptions_per_area;
/*
int r = -ENOMEM;
size_t len;
- len = ps->chunk_size << SECTOR_SHIFT;
+ len = ps->snap->chunk_size << SECTOR_SHIFT;
/*
* Allocate the chunk_size block of memory that will hold
static void free_area(struct pstore *ps)
{
vfree(ps->area);
+ ps->area = NULL;
}
/*
unsigned long bits;
where.bdev = ps->snap->cow->bdev;
- where.sector = ps->chunk_size * chunk;
- where.count = ps->chunk_size;
+ where.sector = ps->snap->chunk_size * chunk;
+ where.count = ps->snap->chunk_size;
return dm_io_sync_vm(1, &where, rw, ps->area, &bits);
}
static int zero_area(struct pstore *ps, uint32_t area)
{
- memset(ps->area, 0, ps->chunk_size << SECTOR_SHIFT);
+ memset(ps->area, 0, ps->snap->chunk_size << SECTOR_SHIFT);
return area_io(ps, area, WRITE);
}
{
int r;
struct disk_header *dh;
+ chunk_t chunk_size;
+ int chunk_size_supplied = 1;
- r = chunk_io(ps, 0, READ);
+ /*
+ * 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;
+ }
+
+ r = dm_io_get(sectors_to_pages(ps->snap->chunk_size));
if (r)
return r;
+ r = alloc_area(ps);
+ if (r)
+ goto bad1;
+
+ r = chunk_io(ps, 0, READ);
+ if (r)
+ goto bad2;
+
dh = (struct disk_header *) ps->area;
if (le32_to_cpu(dh->magic) == 0) {
*new_snapshot = 1;
+ return 0;
+ }
- } else if (le32_to_cpu(dh->magic) == SNAP_MAGIC) {
- *new_snapshot = 0;
- ps->valid = le32_to_cpu(dh->valid);
- ps->version = le32_to_cpu(dh->version);
- ps->chunk_size = le32_to_cpu(dh->chunk_size);
-
- } else {
- DMWARN("Invalid/corrupt snapshot");
+ if (le32_to_cpu(dh->magic) != SNAP_MAGIC) {
+ DMWARN("Invalid or corrupt snapshot");
r = -ENXIO;
+ goto bad2;
}
+ *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. */
+ dm_io_put(sectors_to_pages(ps->snap->chunk_size));
+ 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_get(sectors_to_pages(chunk_size));
+ if (r)
+ return r;
+
+ r = alloc_area(ps);
+ if (r)
+ goto bad1;
+
+ return 0;
+
+bad2:
+ free_area(ps);
+bad1:
+ dm_io_put(sectors_to_pages(ps->snap->chunk_size));
return r;
}
{
struct disk_header *dh;
- memset(ps->area, 0, ps->chunk_size << SECTOR_SHIFT);
+ 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->chunk_size);
+ dh->chunk_size = cpu_to_le32(ps->snap->chunk_size);
return chunk_io(ps, 0, WRITE);
}
*/
static struct disk_exception *get_exception(struct pstore *ps, uint32_t index)
{
- if (index >= ps->exceptions_per_area)
- return NULL;
+ BUG_ON(index >= ps->exceptions_per_area);
return ((struct disk_exception *) ps->area) + index;
}
-static int read_exception(struct pstore *ps,
- uint32_t index, struct disk_exception *result)
+static void read_exception(struct pstore *ps,
+ uint32_t index, struct disk_exception *result)
{
- struct disk_exception *e;
-
- e = get_exception(ps, index);
- if (!e)
- return -EINVAL;
+ 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);
-
- return 0;
}
-static int write_exception(struct pstore *ps,
- uint32_t index, struct disk_exception *de)
+static void write_exception(struct pstore *ps,
+ uint32_t index, struct disk_exception *de)
{
- struct disk_exception *e;
-
- e = get_exception(ps, index);
- if (!e)
- return -EINVAL;
+ 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);
-
- return 0;
}
/*
*full = 1;
for (i = 0; i < ps->exceptions_per_area; i++) {
- r = read_exception(ps, i, &de);
-
- if (r)
- return r;
+ read_exception(ps, i, &de);
/*
* If the new_chunk is pointing at the start of
{
struct pstore *ps = get_info(store);
- dm_io_put(sectors_to_pages(ps->chunk_size));
+ dm_io_put(sectors_to_pages(ps->snap->chunk_size));
vfree(ps->callbacks);
free_area(ps);
kfree(ps);
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 (r)
ps->valid = 0;
+ /*
+ * Have we completely filled the current area ?
+ */
+ if (ps->current_committed == ps->exceptions_per_area) {
+ ps->current_committed = 0;
+ r = zero_area(ps, ps->current_area + 1);
+ if (r)
+ ps->valid = 0;
+ }
+
for (i = 0; i < ps->callback_count; i++) {
cb = ps->callbacks + i;
cb->callback(cb->context, r == 0 ? 1 : 0);
ps->callback_count = 0;
}
-
- /*
- * Have we completely filled the current area ?
- */
- if (ps->current_committed == ps->exceptions_per_area) {
- ps->current_committed = 0;
- r = zero_area(ps, ps->current_area + 1);
- if (r)
- ps->valid = 0;
- }
}
static void persistent_drop(struct exception_store *store)
DMWARN("write header failed");
}
-int dm_create_persistent(struct exception_store *store, uint32_t chunk_size)
+int dm_create_persistent(struct exception_store *store)
{
- int r;
struct pstore *ps;
- r = dm_io_get(sectors_to_pages(chunk_size));
- if (r)
- return r;
-
/* allocate the pstore */
ps = kmalloc(sizeof(*ps), GFP_KERNEL);
- if (!ps) {
- r = -ENOMEM;
- goto bad;
- }
+ if (!ps)
+ return -ENOMEM;
ps->snap = store->snap;
ps->valid = 1;
ps->version = SNAPSHOT_DISK_VERSION;
- ps->chunk_size = chunk_size;
- ps->exceptions_per_area = (chunk_size << SECTOR_SHIFT) /
- sizeof(struct disk_exception);
+ ps->area = NULL;
ps->next_free = 2; /* skipping the header and first area */
ps->current_committed = 0;
- r = alloc_area(ps);
- if (r)
- goto bad;
-
- /*
- * Allocate space for all the callbacks.
- */
ps->callback_count = 0;
atomic_set(&ps->pending_count, 0);
- ps->callbacks = dm_vcalloc(ps->exceptions_per_area,
- sizeof(*ps->callbacks));
-
- if (!ps->callbacks) {
- r = -ENOMEM;
- goto bad;
- }
+ ps->callbacks = NULL;
store->destroy = persistent_destroy;
store->read_metadata = persistent_read_metadata;
store->context = ps;
return 0;
-
- bad:
- dm_io_put(sectors_to_pages(chunk_size));
- if (ps && ps->area)
- free_area(ps);
- kfree(ps);
- return r;
}
/*-----------------------------------------------------------------
*denominator = get_dev_size(store->snap->cow->bdev);
}
-int dm_create_transient(struct exception_store *store,
- struct dm_snapshot *s, int blocksize)
+int dm_create_transient(struct exception_store *store)
{
struct transient_c *tc;
- memset(store, 0, sizeof(*store));
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;
- store->snap = s;
tc = kmalloc(sizeof(struct transient_c), GFP_KERNEL);
if (!tc)
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