[RFC][PATCH V3]efi_pstore: hold multiple logs to avoid losingcritical message
From: Seiji Aguchi
Date: Mon Jul 30 2012 - 09:46:13 EST
This patchset avoids losing a critical message like panic in NVRAM.
Change v2 -> v3
- Merged previous 1/3 and 2/3 patches.
- Dropped previous a 3/3 patch.
- Remove a kernel parameter ,efi_pstore_log_num.
- Check if there is enough space to log with QueryVariableInfo().
- Pass oopscount to arguments of write/erase/read callbacks
to handle multiple events.
Change v1 -> v2
1/3
- Freshly created to avoid overwriting entries.
2/3
- Freshly created to handle multiple logs.
- Add an additional change passing ctime to arguments of erase_callback.
3/3
- This is based on previous 2/2 patch
- Add comments to kernel/printk.h in preparation for future change
without considering this patch.
- Remove infinite loop to avoid potential hang up.
- Add CFLAGS, -Wswitch-enum and remove default case from switch sentence
in preparation for future change without considering this patch.
- Change a return value to -EEXIST when an erasable entry is not found.
- Remove KMSG_DUMP_UNDEF from kmsg_dump_reason because no one uses it.
[Problem]
Currently, efi_pstore driver simply overwrites existing panic messages in NVRAM.
So, in the following scenario, we will lose 1st panic messages.
1. kernel panics.
2. efi_pstore is kicked and write panic messages to NVRAM.
3. system reboots.
4. kernel panics again before a user checks the 1st panic messages in NVRAM.
[Solution]
To avoid losing a critical message, this patch takes an approach holding multiple
logs.
Also, to avoid handling out of space situation, it checks if there are enough spaces
to write logs with QueryVariableInfo().
[Patch Descriptions]
This patch makes efi_pstore hold multiple logs.
Once a critical message is logged, users can see it via /dev/pstore
without being influenced by subsequent events.
Specific changes are as follows.
- Check if there are enough spaces to write logs with QueryVariableInfo().
- Remove a logic erasing existing entries from write callback.
- Add the logic above to erase callback.
- Pass oopscount to arguments of write/erase/read callbacks to handle multiple events.
- Pass ctime to arguments of erase_callback to avoid invisible entries via /dev/pstore.
Signed-off-by: Seiji Aguchi <seiji.aguchi@xxxxxxx>
Suggested-by: Matthew Garrett <mjg@xxxxxxxxxx>
---
drivers/acpi/apei/erst.c | 16 ++++----
drivers/firmware/efivars.c | 93 ++++++++++++++++++++++++++++----------------
fs/pstore/inode.c | 7 ++-
fs/pstore/internal.h | 2 +-
fs/pstore/platform.c | 12 +++---
fs/pstore/ram.c | 11 ++---
include/linux/efi.h | 1 +
include/linux/pstore.h | 6 ++-
8 files changed, 89 insertions(+), 59 deletions(-)
diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index e4d9d24..833a9f4 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -931,14 +931,14 @@ static int erst_check_table(struct acpi_table_erst *erst_tab)
static int erst_open_pstore(struct pstore_info *psi);
static int erst_close_pstore(struct pstore_info *psi);
-static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
+static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, u64 *count,
struct timespec *time, char **buf,
struct pstore_info *psi);
static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
- u64 *id, unsigned int part,
+ u64 *id, unsigned int part, u64 count,
size_t size, struct pstore_info *psi);
-static int erst_clearer(enum pstore_type_id type, u64 id,
- struct pstore_info *psi);
+static int erst_clearer(enum pstore_type_id type, u64 id, u64 count,
+ struct timespec time, struct pstore_info *psi);
static struct pstore_info erst_info = {
.owner = THIS_MODULE,
@@ -987,7 +987,7 @@ static int erst_close_pstore(struct pstore_info *psi)
return 0;
}
-static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
+static ssize_t erst_reader(u64 *id, enum pstore_type_id *type, u64 *count,
struct timespec *time, char **buf,
struct pstore_info *psi)
{
@@ -1055,7 +1055,7 @@ out:
}
static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
- u64 *id, unsigned int part,
+ u64 *id, unsigned int part, u64 count,
size_t size, struct pstore_info *psi)
{
struct cper_pstore_record *rcd = (struct cper_pstore_record *)
@@ -1101,8 +1101,8 @@ static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
return ret;
}
-static int erst_clearer(enum pstore_type_id type, u64 id,
- struct pstore_info *psi)
+static int erst_clearer(enum pstore_type_id type, u64 id, u64 count,
+ struct timespec time, struct pstore_info *psi)
{
return erst_clear(id);
}
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 47408e8..9966fe3 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -647,7 +647,7 @@ static int efi_pstore_close(struct pstore_info *psi)
}
static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
- struct timespec *timespec,
+ u64 *count, struct timespec *timespec,
char **buf, struct pstore_info *psi)
{
efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
@@ -655,6 +655,7 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
char name[DUMP_NAME_LEN];
int i;
unsigned int part, size;
+ u64 cnt;
unsigned long time;
while (&efivars->walk_entry->list != &efivars->list) {
@@ -663,8 +664,10 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
for (i = 0; i < DUMP_NAME_LEN; i++) {
name[i] = efivars->walk_entry->var.VariableName[i];
}
- if (sscanf(name, "dump-type%u-%u-%lu", type, &part, &time) == 3) {
+ if (sscanf(name, "dump-type%u-%u-%llu-%lu",
+ type, &part, &cnt, &time) == 4) {
*id = part;
+ *count = cnt;
timespec->tv_sec = time;
timespec->tv_nsec = 0;
get_var_data_locked(efivars, &efivars->walk_entry->var);
@@ -687,18 +690,62 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
static int efi_pstore_write(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
- unsigned int part, size_t size, struct pstore_info *psi)
+ unsigned int part, u64 count, size_t size,
+ struct pstore_info *psi)
{
char name[DUMP_NAME_LEN];
+ efi_char16_t efi_name[DUMP_NAME_LEN];
+ efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
+ struct efivars *efivars = psi->data;
+ int i, ret = 0;
+ u64 storage_space, remaining_space, max_variable_size;
+ efi_status_t status = EFI_NOT_FOUND;
+
+ spin_lock(&efivars->lock);
+
+ status = efivars->ops->query_variable_info(PSTORE_EFI_ATTRIBUTES,
+ &storage_space,
+ &remaining_space,
+ &max_variable_size);
+ if (status || remaining_space < max_variable_size) {
+ spin_unlock(&efivars->lock);
+ *id = part;
+ return -EEXIST;
+ }
+
+ sprintf(name, "dump-type%u-%u-%llu-%lu", type, part, count,
+ get_seconds());
+
+ for (i = 0; i < DUMP_NAME_LEN; i++)
+ efi_name[i] = name[i];
+
+ efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
+ size, psi->buf);
+
+ spin_unlock(&efivars->lock);
+
+ if (size)
+ ret = efivar_create_sysfs_entry(efivars,
+ utf16_strsize(efi_name,
+ DUMP_NAME_LEN * 2),
+ efi_name, &vendor);
+
+ *id = part;
+ return ret;
+};
+
+static int efi_pstore_erase(enum pstore_type_id type, u64 id, u64 count,
+ struct timespec time, struct pstore_info *psi)
+{
char stub_name[DUMP_NAME_LEN];
efi_char16_t efi_name[DUMP_NAME_LEN];
efi_guid_t vendor = LINUX_EFI_CRASH_GUID;
struct efivars *efivars = psi->data;
struct efivar_entry *entry, *found = NULL;
- int i, ret = 0;
+ int i;
- sprintf(stub_name, "dump-type%u-%u-", type, part);
- sprintf(name, "%s%lu", stub_name, get_seconds());
+ sprintf(stub_name, "dump-type%u-%llu-%llu-%lu", type, id, count,
+ time.tv_sec);
spin_lock(&efivars->lock);
@@ -717,9 +764,6 @@ static int efi_pstore_write(enum pstore_type_id type,
if (utf16_strncmp(entry->var.VariableName, efi_name,
utf16_strlen(efi_name)))
continue;
- /* Needs to be a prefix */
- if (entry->var.VariableName[utf16_strlen(efi_name)] == 0)
- continue;
/* found */
found = entry;
@@ -732,32 +776,11 @@ static int efi_pstore_write(enum pstore_type_id type,
if (found)
list_del(&found->list);
- for (i = 0; i < DUMP_NAME_LEN; i++)
- efi_name[i] = name[i];
-
- efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
- size, psi->buf);
-
spin_unlock(&efivars->lock);
if (found)
efivar_unregister(found);
- if (size)
- ret = efivar_create_sysfs_entry(efivars,
- utf16_strsize(efi_name,
- DUMP_NAME_LEN * 2),
- efi_name, &vendor);
-
- *id = part;
- return ret;
-};
-
-static int efi_pstore_erase(enum pstore_type_id type, u64 id,
- struct pstore_info *psi)
-{
- efi_pstore_write(type, 0, &id, (unsigned int)id, 0, psi);
-
return 0;
}
#else
@@ -771,7 +794,7 @@ static int efi_pstore_close(struct pstore_info *psi)
return 0;
}
-static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
+static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, u64 *count,
struct timespec *timespec,
char **buf, struct pstore_info *psi)
{
@@ -780,13 +803,14 @@ static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type,
static int efi_pstore_write(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
- unsigned int part, size_t size, struct pstore_info *psi)
+ unsigned int part, u64 count, size_t size,
+ struct pstore_info *psi)
{
return 0;
}
-static int efi_pstore_erase(enum pstore_type_id type, u64 id,
- struct pstore_info *psi)
+static int efi_pstore_erase(enum pstore_type_id type, u64 id, u64 count,
+ struct timespec time, struct pstore_info *psi)
{
return 0;
}
@@ -1226,6 +1250,7 @@ efivars_init(void)
ops.get_variable = efi.get_variable;
ops.set_variable = efi.set_variable;
ops.get_next_variable = efi.get_next_variable;
+ ops.query_variable_info = efi.query_variable_info;
error = register_efivars(&__efivars, &ops, efi_kobj);
if (error)
goto err_put;
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 11a2aa2..ca1b6c9 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -48,6 +48,7 @@ struct pstore_private {
struct pstore_info *psi;
enum pstore_type_id type;
u64 id;
+ u64 count;
ssize_t size;
char data[];
};
@@ -75,7 +76,8 @@ 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, p->psi);
+ p->psi->erase(p->type, p->id, p->count,
+ dentry->d_inode->i_ctime, p->psi);
return simple_unlink(dir, dentry);
}
@@ -170,7 +172,7 @@ 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, u64 count,
char *data, size_t size, struct timespec time,
struct pstore_info *psi)
{
@@ -206,6 +208,7 @@ 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 3bde461..d93e20e 100644
--- a/fs/pstore/internal.h
+++ b/fs/pstore/internal.h
@@ -1,6 +1,6 @@
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,
+ u64 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 03ce7a9..371a184 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -66,7 +66,7 @@ void pstore_set_kmsg_bytes(int bytes)
}
/* Tag each group of saved records with a sequence number */
-static int oopscount;
+unsigned int oopscount;
static const char *get_reason_str(enum kmsg_dump_reason reason)
{
@@ -128,7 +128,7 @@ 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;
@@ -202,7 +202,7 @@ void pstore_get_records(int quiet)
struct pstore_info *psi = psinfo;
char *buf = NULL;
ssize_t size;
- u64 id;
+ u64 id, count;
enum pstore_type_id type;
struct timespec time;
int failed = 0, rc;
@@ -214,9 +214,9 @@ 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 453030f..2bdd4f2 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -86,9 +86,8 @@ static int ramoops_pstore_open(struct pstore_info *psi)
}
static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
- struct timespec *time,
- char **buf,
- struct pstore_info *psi)
+ u64 *count, struct timespec *time,
+ char **buf, struct pstore_info *psi)
{
ssize_t size;
struct ramoops_context *cxt = psi->data;
@@ -137,7 +136,7 @@ static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
static int ramoops_pstore_write(enum pstore_type_id type,
enum kmsg_dump_reason reason,
u64 *id,
- unsigned int part,
+ unsigned int part, u64 count,
size_t size, struct pstore_info *psi)
{
struct ramoops_context *cxt = psi->data;
@@ -177,8 +176,8 @@ static int ramoops_pstore_write(enum pstore_type_id type,
return 0;
}
-static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,
- struct pstore_info *psi)
+static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, u64 count,
+ timespec time, struct pstore_info *psi)
{
struct ramoops_context *cxt = psi->data;
diff --git a/include/linux/efi.h b/include/linux/efi.h
index ec45ccd..b19bef5 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -635,6 +635,7 @@ struct efivar_operations {
efi_get_variable_t *get_variable;
efi_get_next_variable_t *get_next_variable;
efi_set_variable_t *set_variable;
+ efi_query_variable_info_t *query_variable_info;
};
struct efivars {
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index e1461e1..9fd1fc8 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -42,12 +42,14 @@ struct pstore_info {
int (*open)(struct pstore_info *psi);
int (*close)(struct pstore_info *psi);
ssize_t (*read)(u64 *id, enum pstore_type_id *type,
- struct timespec *time, char **buf,
+ u64 *count, struct timespec *time, char **buf,
struct pstore_info *psi);
int (*write)(enum pstore_type_id type,
enum kmsg_dump_reason reason, u64 *id,
- unsigned int part, size_t size, struct pstore_info *psi);
+ unsigned int part, u64 count, size_t size,
+ struct pstore_info *psi);
int (*erase)(enum pstore_type_id type, u64 id,
+ u64 count, struct timespec time,
struct pstore_info *psi);
void *data;
};
-- 1.7.1
--
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