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| author | Mike Snitzer <snitzer@redhat.com> | 2015-10-08 18:05:41 -0400 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2015-10-09 16:57:03 -0400 |
| commit | b0d3cc011e532d8c9db76cf717bcafa53c135595 (patch) | |
| tree | d74330dcf71a599d637a7eecad8b56cdbd4487b9 /drivers/md/dm-snap-persistent.c | |
| parent | 2bffa1503c5c06192eb1459180fac4416575a966 (diff) | |
| download | lwn-b0d3cc011e532d8c9db76cf717bcafa53c135595.tar.gz lwn-b0d3cc011e532d8c9db76cf717bcafa53c135595.zip | |
dm snapshot: add new persistent store option to support overflow
Commit 76c44f6d80 introduced the possibly for "Overflow" to be reported
by the snapshot device's status. Older userspace (e.g. lvm2) does not
handle the "Overflow" status response.
Fix this incompatibility by requiring newer userspace code, that can
cope with "Overflow", request the persistent store with overflow support
by using "PO" (Persistent with Overflow) for the snapshot store type.
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Fixes: 76c44f6d80 ("dm snapshot: don't invalidate on-disk image on snapshot write overflow")
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-snap-persistent.c')
| -rw-r--r-- | drivers/md/dm-snap-persistent.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/drivers/md/dm-snap-persistent.c b/drivers/md/dm-snap-persistent.c index bf71583296f7..aeacad9be51d 100644 --- a/drivers/md/dm-snap-persistent.c +++ b/drivers/md/dm-snap-persistent.c @@ -7,6 +7,7 @@ #include "dm-exception-store.h" +#include <linux/ctype.h> #include <linux/mm.h> #include <linux/pagemap.h> #include <linux/vmalloc.h> @@ -843,8 +844,7 @@ static void persistent_drop_snapshot(struct dm_exception_store *store) DMWARN("write header failed"); } -static int persistent_ctr(struct dm_exception_store *store, - unsigned argc, char **argv) +static int persistent_ctr(struct dm_exception_store *store, char *options) { struct pstore *ps; @@ -873,6 +873,16 @@ static int persistent_ctr(struct dm_exception_store *store, return -ENOMEM; } + if (options) { + char overflow = toupper(options[0]); + if (overflow == 'O') + store->userspace_supports_overflow = true; + else { + DMERR("Unsupported persistent store option: %s", options); + return -EINVAL; + } + } + store->context = ps; return 0; @@ -888,7 +898,8 @@ static unsigned persistent_status(struct dm_exception_store *store, case STATUSTYPE_INFO: break; case STATUSTYPE_TABLE: - DMEMIT(" P %llu", (unsigned long long)store->chunk_size); + DMEMIT(" %s %llu", store->userspace_supports_overflow ? "PO" : "P", + (unsigned long long)store->chunk_size); } return sz; |