efi_pstore: Add a sequence counter to a variable name

[Issue]

Currently, a variable name, which identifies each entry, consists of type, id and ctime.
But if multiple events happens in a short time, a second/third event may fail to log because
efi_pstore can't distinguish each event with current variable name.

[Solution]

A reasonable way to identify all events precisely is introducing a sequence counter to
the variable name.

The sequence counter has already supported in a pstore layer with "oopscount".
So, this patch adds it to a variable name.
Also, it is passed to read/erase callbacks of platform drivers in accordance with
the modification of the variable name.

  <before applying this patch>
 a variable name of first event: dump-type0-1-12345678
 a variable name of second event: dump-type0-1-12345678

  type:0
  id:1
  ctime:12345678

 If multiple events happen in a short time, efi_pstore can't distinguish them because
 variable names are same among them.

  <after applying this patch>

 it can be distinguishable by adding a sequence counter as follows.

 a variable name of first event: dump-type0-1-1-12345678
 a variable name of Second event: dump-type0-1-2-12345678

  type:0
  id:1
  sequence counter: 1(first event), 2(second event)
  ctime:12345678

In case of a write callback executed in pstore_console_write(), "0" is added to
an argument of the write callback because it just logs all kernel messages and
doesn't need to care about multiple events.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

4 files changed, 16 insertions, 14 deletions

diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 4300af654710..ed1d8c7212da 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -49,6 +49,7 @@ struct pstore_private {
         struct pstore_info *psi;
         enum pstore_type_id type;
         u64     id;
+        int     count;
         ssize_t size;
         char    data[];
 };
@@ -175,8 +176,8 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
         struct pstore_private *p = dentry->d_inode->i_private;
 
         if (p->psi->erase)
-                p->psi->erase(p->type, p->id, dentry->d_inode->i_ctime,
-                              p->psi);
+                p->psi->erase(p->type, p->id, p->count,
+                              dentry->d_inode->i_ctime, p->psi);
 
         return simple_unlink(dir, dentry);
 }
@@ -271,7 +272,7 @@ int pstore_is_mounted(void)
  * Load it up with "size" bytes of data from "buf".
  * Set the mtime & ctime to the date that this record was originally stored.
  */
-int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
+int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id, int count,
                   char *data, size_t size, struct timespec time,
                   struct pstore_info *psi)
 {
@@ -307,6 +308,7 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
                 goto fail_alloc;
         private->type = type;
         private->id = id;
+        private->count = count;
         private->psi = psi;
 
         switch (type) {
diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
index 4847f588b7d5..937d820f273c 100644
--- a/fs/pstore/internal.h
+++ b/fs/pstore/internal.h
@@ -50,7 +50,7 @@ extern struct pstore_info *psinfo;
 extern void     pstore_set_kmsg_bytes(int);
 extern void     pstore_get_records(int);
 extern int      pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
-                              char *data, size_t size,
+                              int count, char *data, size_t size,
                               struct timespec time, struct pstore_info *psi);
 extern int      pstore_is_mounted(void);
 
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 947fbe06c3b1..5ea2e77ff023 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -136,7 +136,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,
                         break;
 
                 ret = psinfo->write(PSTORE_TYPE_DMESG, reason, &id, part,
-                                    hsize + len, psinfo);
+                                    oopscount, hsize + len, psinfo);
                 if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted())
                         pstore_new_entry = 1;
 
@@ -173,7 +173,7 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c)
                         spin_lock_irqsave(&psinfo->buf_lock, flags);
                 }
                 memcpy(psinfo->buf, s, c);
-                psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, c, psinfo);
+                psinfo->write(PSTORE_TYPE_CONSOLE, 0, &id, 0, 0, c, psinfo);
                 spin_unlock_irqrestore(&psinfo->buf_lock, flags);
                 s += c;
                 c = e - s;
@@ -197,7 +197,7 @@ static void pstore_register_console(void) {}
 
 static int pstore_write_compat(enum pstore_type_id type,
                                enum kmsg_dump_reason reason,
-                               u64 *id, unsigned int part,
+                               u64 *id, unsigned int part, int count,
                                size_t size, struct pstore_info *psi)
 {
         return psi->write_buf(type, reason, id, part, psinfo->buf, size, psi);
@@ -267,6 +267,7 @@ void pstore_get_records(int quiet)
         char                    *buf = NULL;
         ssize_t                 size;
         u64                     id;
+        int                     count;
         enum pstore_type_id     type;
         struct timespec         time;
         int                     failed = 0, rc;
@@ -278,9 +279,9 @@ void pstore_get_records(int quiet)
         if (psi->open && psi->open(psi))
                 goto out;
 
-        while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) {
-                rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size,
-                                  time, psi);
+        while ((size = psi->read(&id, &type, &count, &time, &buf, psi)) > 0) {
+                rc = pstore_mkfile(type, psi->name, id, count, buf,
+                                  (size_t)size, time, psi);
                 kfree(buf);
                 buf = NULL;
                 if (rc && (rc != -EEXIST || !quiet))
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 749693fcb75a..2bfa36e0ffe8 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -132,9 +132,8 @@ ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 }
 
 static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
-                                   struct timespec *time,
-                                   char **buf,
-                                   struct pstore_info *psi)
+                                   int *count, struct timespec *time,
+                                   char **buf, struct pstore_info *psi)
 {
         ssize_t size;
         struct ramoops_context *cxt = psi->data;
@@ -236,7 +235,7 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type,
         return 0;
 }
 
-static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
+static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count,
                                 struct timespec time, struct pstore_info *psi)
 {
         struct ramoops_context *cxt = psi->data;