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pstore/ram: Read and write to the 'compressed' flag of pstore

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In pstore write, add character 'C'(compressed) or 'D'(decompressed)
in the header while writing to Ram persistent buffer. In pstore read,
read the header and update the 'compressed' flag accordingly.

Signed-off-by: Aruna Balakrishnaiah <aruna@linux.vnet.ibm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This commit is contained in:
Aruna Balakrishnaiah 2013-08-16 13:58:00 -07:00 committed by Tony Luck
parent f8c62f34fe
commit 3f8f80f0cf
1 changed files with 28 additions and 8 deletions
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36
fs/pstore/ram.c
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@ -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);