1 files changed, 53 insertions, 35 deletions

diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c
index 6e3fe4f14934..d5b2e08750d5 100644
--- a/drivers/md/dm-snap-persistent.c
+++ b/drivers/md/dm-snap-persistent.c
@@ -106,6 +106,13 @@ struct pstore {
         void *zero_area;
 
         /*
+         * An area used for header. The header can be written
+         * concurrently with metadata (when invalidating the snapshot),
+         * so it needs a separate buffer.
+         */
+        void *header_area;
+
+        /*
          * Used to keep track of which metadata area the data in
          * 'chunk' refers to.
          */
@@ -148,16 +155,27 @@ static int alloc_area(struct pstore *ps)
          */
         ps->area = vmalloc(len);
         if (!ps->area)
-                return r;
+                goto err_area;
 
         ps->zero_area = vmalloc(len);
-        if (!ps->zero_area) {
-                vfree(ps->area);
-                return r;
-        }
+        if (!ps->zero_area)
+                goto err_zero_area;
         memset(ps->zero_area, 0, len);
 
+        ps->header_area = vmalloc(len);
+        if (!ps->header_area)
+                goto err_header_area;
+
         return 0;
+
+err_header_area:
+        vfree(ps->zero_area);
+
+err_zero_area:
+        vfree(ps->area);
+
+err_area:
+        return r;
 }
 
 static void free_area(struct pstore *ps)
@@ -169,6 +187,10 @@ static void free_area(struct pstore *ps)
         if (ps->zero_area)
                 vfree(ps->zero_area);
         ps->zero_area = NULL;
+
+        if (ps->header_area)
+                vfree(ps->header_area);
+        ps->header_area = NULL;
 }
 
 struct mdata_req {
@@ -188,7 +210,8 @@ static void do_metadata(struct work_struct *work)
 /*
  * 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)
+static int chunk_io(struct pstore *ps, void *area, chunk_t chunk, int rw,
+                    int metadata)
 {
         struct dm_io_region where = {
                 .bdev = ps->store->cow->bdev,
@@ -198,7 +221,7 @@ static int chunk_io(struct pstore *ps, chunk_t chunk, int rw, int metadata)
         struct dm_io_request io_req = {
                 .bi_rw = rw,
                 .mem.type = DM_IO_VMA,
-                .mem.ptr.vma = ps->area,
+                .mem.ptr.vma = area,
                 .client = ps->io_client,
                 .notify.fn = NULL,
         };
@@ -240,7 +263,7 @@ static int area_io(struct pstore *ps, int rw)
 
         chunk = area_location(ps, ps->current_area);
 
-        r = chunk_io(ps, chunk, rw, 0);
+        r = chunk_io(ps, ps->area, chunk, rw, 0);
         if (r)
                 return r;
 
@@ -254,20 +277,7 @@ static void zero_memory_area(struct pstore *ps)
 
 static int zero_disk_area(struct pstore *ps, chunk_t area)
 {
-        struct dm_io_region where = {
-                .bdev = ps->store->cow->bdev,
-                .sector = ps->store->chunk_size * area_location(ps, area),
-                .count = ps->store->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);
+        return chunk_io(ps, ps->zero_area, area_location(ps, area), WRITE, 0);
 }
 
 static int read_header(struct pstore *ps, int *new_snapshot)
@@ -276,6 +286,7 @@ static int read_header(struct pstore *ps, int *new_snapshot)
         struct disk_header *dh;
         chunk_t chunk_size;
         int chunk_size_supplied = 1;
+        char *chunk_err;
 
         /*
          * Use default chunk size (or hardsect_size, if larger) if none supplied
@@ -297,11 +308,11 @@ static int read_header(struct pstore *ps, int *new_snapshot)
         if (r)
                 return r;
 
-        r = chunk_io(ps, 0, READ, 1);
+        r = chunk_io(ps, ps->header_area, 0, READ, 1);
         if (r)
                 goto bad;
 
-        dh = (struct disk_header *) ps->area;
+        dh = ps->header_area;
 
         if (le32_to_cpu(dh->magic) == 0) {
                 *new_snapshot = 1;
@@ -319,20 +330,25 @@ static int read_header(struct pstore *ps, int *new_snapshot)
         ps->version = le32_to_cpu(dh->version);
         chunk_size = le32_to_cpu(dh->chunk_size);
 
-        if (!chunk_size_supplied || ps->store->chunk_size == chunk_size)
+        if (ps->store->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->store->chunk_size);
+        if (chunk_size_supplied)
+                DMWARN("chunk size %llu in device metadata overrides "
+                       "table chunk size of %llu.",
+                       (unsigned long long)chunk_size,
+                       (unsigned long long)ps->store->chunk_size);
 
         /* We had a bogus chunk_size. Fix stuff up. */
         free_area(ps);
 
-        ps->store->chunk_size = chunk_size;
-        ps->store->chunk_mask = chunk_size - 1;
-        ps->store->chunk_shift = ffs(chunk_size) - 1;
+        r = dm_exception_store_set_chunk_size(ps->store, chunk_size,
+                                              &chunk_err);
+        if (r) {
+                DMERR("invalid on-disk chunk size %llu: %s.",
+                      (unsigned long long)chunk_size, chunk_err);
+                return r;
+        }
 
         r = dm_io_client_resize(sectors_to_pages(ps->store->chunk_size),
                                 ps->io_client);
@@ -351,15 +367,15 @@ static int write_header(struct pstore *ps)
 {
         struct disk_header *dh;
 
-        memset(ps->area, 0, ps->store->chunk_size << SECTOR_SHIFT);
+        memset(ps->header_area, 0, ps->store->chunk_size << SECTOR_SHIFT);
 
-        dh = (struct disk_header *) ps->area;
+        dh = ps->header_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->store->chunk_size);
 
-        return chunk_io(ps, 0, WRITE, 1);
+        return chunk_io(ps, ps->header_area, 0, WRITE, 1);
 }
 
 /*
@@ -679,6 +695,8 @@ static int persistent_ctr(struct dm_exception_store *store,
         ps->valid = 1;
         ps->version = SNAPSHOT_DISK_VERSION;
         ps->area = NULL;
+        ps->zero_area = NULL;
+        ps->header_area = NULL;
         ps->next_free = 2;      /* skipping the header and first area */
         ps->current_committed = 0;