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authorMark McLoughlin <markmc@redhat.com>2006-10-03 12:15:25 +0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-03 19:04:14 +0400
commit4c7e3bf44d0ae227ea1ee87c2197212e65d043d7 (patch)
tree658140b966d78f4709de10cd03e0bfdade6bc13e /drivers/md/dm-exception-store.c
parent92c060a692a0c3482cdfcaf346cb2f7572368895 (diff)
downloadlinux-4c7e3bf44d0ae227ea1ee87c2197212e65d043d7.tar.xz
[PATCH] dm snapshot: allow zero chunk_size
The chunk size of snapshots cannot be changed so it is redundant to require it as a parameter when activating an existing snapshot. Allow a value of zero in this case and ignore it. For a new snapshot, use a default value if zero is specified. Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/md/dm-exception-store.c')
-rw-r--r--drivers/md/dm-exception-store.c124
1 files changed, 69 insertions, 55 deletions
diff --git a/drivers/md/dm-exception-store.c b/drivers/md/dm-exception-store.c
index d12379b5cdb5..8b4cd02f75a8 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -17,6 +17,7 @@
#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
@@ -150,6 +151,7 @@ static int alloc_area(struct pstore *ps)
static void free_area(struct pstore *ps)
{
vfree(ps->area);
+ ps->area = NULL;
}
/*
@@ -198,48 +200,79 @@ 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;
- 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);
- chunk_size = le32_to_cpu(dh->chunk_size);
- if (ps->snap->chunk_size != chunk_size) {
- 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 = alloc_area(ps);
- if (r)
- return r;
-
- r = dm_io_get(sectors_to_pages(chunk_size));
- if (r)
- return r;
- }
- } 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;
}
@@ -547,32 +580,22 @@ 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->area = NULL;
ps->next_free = 2; /* skipping the header and first area */
ps->current_committed = 0;
- r = alloc_area(ps);
- if (r)
- goto bad;
-
ps->callback_count = 0;
atomic_set(&ps->pending_count, 0);
ps->callbacks = NULL;
@@ -586,13 +609,6 @@ int dm_create_persistent(struct exception_store *store, uint32_t chunk_size)
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;
}
/*-----------------------------------------------------------------
@@ -642,18 +658,16 @@ static void transient_fraction_full(struct exception_store *store,
*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)