diff options
| -rw-r--r-- | drivers/md/dm-snap-persistent.c | 44 |
1 files changed, 34 insertions, 10 deletions
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c index 2a3d626a98d9..5d1a97580cb7 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 { @@ -285,11 +307,11 @@ static int read_header(struct pstore *ps, int *new_snapshot) if (r) return r; - r = chunk_io(ps, ps->area, 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; @@ -339,15 +361,15 @@ 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, ps->area, 0, WRITE, 1); + return chunk_io(ps, ps->header_area, 0, WRITE, 1); } /* @@ -667,6 +689,8 @@ 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; |