1 files changed, 28 insertions, 8 deletions

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 292722327811..4027c2065842 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -131,6 +131,27 @@ ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
         return prz;
 }
 
+static void ramoops_read_kmsg_hdr(char *buffer, struct timespec *time,
+                                  bool *compressed)
+{
+        char data_type;
+
+        if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n",
+                        &time->tv_sec, &time->tv_nsec, &data_type) == 3) {
+                if (data_type == 'C')
+                        *compressed = true;
+                else
+                        *compressed = false;
+        } else if (sscanf(buffer, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
+                        &time->tv_sec, &time->tv_nsec) == 2) {
+                        *compressed = false;
+        } else {
+                time->tv_sec = 0;
+                time->tv_nsec = 0;
+                *compressed = false;
+        }
+}
+
 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
                                    int *count, struct timespec *time,
                                    char **buf, bool *compressed,
@@ -153,10 +174,6 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
         if (!prz)
                 return 0;
 
-        /* TODO(kees): Bogus time for the moment. */
-        time->tv_sec = 0;
-        time->tv_nsec = 0;
-
         size = persistent_ram_old_size(prz);
 
         /* ECC correction notice */
@@ -167,12 +184,14 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
                 return -ENOMEM;
 
         memcpy(*buf, persistent_ram_old(prz), size);
+        ramoops_read_kmsg_hdr(*buf, time, compressed);
         persistent_ram_ecc_string(prz, *buf + size, ecc_notice_size + 1);
 
         return size + ecc_notice_size;
 }
 
-static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
+static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz,
+                                     bool compressed)
 {
         char *hdr;
         struct timespec timestamp;
@@ -183,8 +202,9 @@ static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
                 timestamp.tv_sec = 0;
                 timestamp.tv_nsec = 0;
         }
-        hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu\n",
-                (long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000));
+        hdr = kasprintf(GFP_ATOMIC, RAMOOPS_KERNMSG_HDR "%lu.%lu-%c\n",
+                (long)timestamp.tv_sec, (long)(timestamp.tv_nsec / 1000),
+                compressed ? 'C' : 'D');
         WARN_ON_ONCE(!hdr);
         len = hdr ? strlen(hdr) : 0;
         persistent_ram_write(prz, hdr, len);
@@ -243,7 +263,7 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
 
         prz = cxt->przs[cxt->dump_write_cnt];
 
-        hlen = ramoops_write_kmsg_hdr(prz);
+        hlen = ramoops_write_kmsg_hdr(prz, compressed);
         if (size + hlen > prz->buffer_size)
                 size = prz->buffer_size - hlen;
         persistent_ram_write(prz, buf, size);