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Message-ID: <1370062455.3766.31.camel@pasglop>
Date: Sat, 01 Jun 2013 14:54:15 +1000
From: Benjamin Herrenschmidt <benh@...nel.crashing.org>
To: Aruna Balakrishnaiah <aruna@...ux.vnet.ibm.com>
Cc: linuxppc-dev@...abs.org, paulus@...ba.org,
linux-kernel@...r.kernel.org, jkenisto@...ux.vnet.ibm.com,
tony.luck@...el.com, ananth@...ibm.com, mahesh@...ux.vnet.ibm.com,
ccross@...roid.com, anton@...ba.org, cbouatmailru@...il.com,
keescook@...omium.org
Subject: Re: [PATCH 3/3] powerpc/pseries: Support compression of oops text
via pstore
On Fri, 2013-04-26 at 15:26 +0530, Aruna Balakrishnaiah wrote:
> The patch set supports compression of oops messages while writing to NVRAM,
> this helps in capturing more of oops data to lnx,oops-log. The pstore file
> for oops messages will be in decompressed format making it readable.
>
> In case compression fails, the patch takes care of copying the header added
> by pstore and last oops_data_sz bytes of big_oops_buf to NVRAM so that we
> have recent oops messages in lnx,oops-log.
>
> In case decompression fails, it will result in absence of oops file but still
> have files (in /dev/pstore) for other partitions.
Any reason that isn't handled by pstore itself rather than here ? Ie
make a flag indicating that the partition supports compression and have
pstore do it (so we don't compress everything such as ofw common etc...)
Cheers,
Ben.
>
> Signed-off-by: Aruna Balakrishnaiah <aruna@...ux.vnet.ibm.com>
> ---
> arch/powerpc/platforms/pseries/nvram.c | 132 +++++++++++++++++++++++++++++---
> 1 file changed, 118 insertions(+), 14 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/nvram.c b/arch/powerpc/platforms/pseries/nvram.c
> index 0159d74..b5ba5e2 100644
> --- a/arch/powerpc/platforms/pseries/nvram.c
> +++ b/arch/powerpc/platforms/pseries/nvram.c
> @@ -539,6 +539,65 @@ static int zip_oops(size_t text_len)
> }
>
> #ifdef CONFIG_PSTORE
> +/* Derived from logfs_uncompress */
> +int nvram_decompress(void *in, void *out, size_t inlen, size_t outlen)
> +{
> + int err, ret;
> +
> + ret = -EIO;
> + err = zlib_inflateInit(&stream);
> + if (err != Z_OK)
> + goto error;
> +
> + stream.next_in = in;
> + stream.avail_in = inlen;
> + stream.total_in = 0;
> + stream.next_out = out;
> + stream.avail_out = outlen;
> + stream.total_out = 0;
> +
> + err = zlib_inflate(&stream, Z_FINISH);
> + if (err != Z_STREAM_END)
> + goto error;
> +
> + err = zlib_inflateEnd(&stream);
> + if (err != Z_OK)
> + goto error;
> +
> + ret = stream.total_out;
> +error:
> + return ret;
> +}
> +
> +static int unzip_oops(char *oops_buf, char *big_buf)
> +{
> + struct oops_log_info *oops_hdr = (struct oops_log_info *)oops_buf;
> + u64 timestamp = oops_hdr->timestamp;
> + char *big_oops_data = NULL;
> + char *oops_data_buf = NULL;
> + size_t big_oops_data_sz;
> + int unzipped_len;
> +
> + big_oops_data = big_buf + sizeof(struct oops_log_info);
> + big_oops_data_sz = big_oops_buf_sz - sizeof(struct oops_log_info);
> + oops_data_buf = oops_buf + sizeof(struct oops_log_info);
> +
> + unzipped_len = nvram_decompress(oops_data_buf, big_oops_data,
> + oops_hdr->report_length,
> + big_oops_data_sz);
> +
> + if (unzipped_len < 0) {
> + pr_err("nvram: decompression failed; returned %d\n",
> + unzipped_len);
> + return -1;
> + }
> + oops_hdr = (struct oops_log_info *)big_buf;
> + oops_hdr->version = OOPS_HDR_VERSION;
> + oops_hdr->report_length = (u16) unzipped_len;
> + oops_hdr->timestamp = timestamp;
> + return 0;
> +}
> +
> static int nvram_pstore_open(struct pstore_info *psi)
> {
> /* Reset the iterator to start reading partitions again */
> @@ -567,6 +626,7 @@ static int nvram_pstore_write(enum pstore_type_id type,
> size_t size, struct pstore_info *psi)
> {
> int rc;
> + unsigned int err_type = ERR_TYPE_KERNEL_PANIC;
> struct oops_log_info *oops_hdr = (struct oops_log_info *) oops_buf;
>
> /* part 1 has the recent messages from printk buffer */
> @@ -577,8 +637,31 @@ static int nvram_pstore_write(enum pstore_type_id type,
> oops_hdr->version = OOPS_HDR_VERSION;
> oops_hdr->report_length = (u16) size;
> oops_hdr->timestamp = get_seconds();
> +
> + if (big_oops_buf) {
> + rc = zip_oops(size);
> + /*
> + * If compression fails copy recent log messages from
> + * big_oops_buf to oops_data.
> + */
> + if (rc != 0) {
> + int hsize = pstore_get_header_size();
> + size_t diff = size - oops_data_sz + hsize;
> +
> + if (size > oops_data_sz) {
> + memcpy(oops_data, big_oops_buf, hsize);
> + memcpy(oops_data + hsize, big_oops_buf + diff,
> + oops_data_sz - hsize);
> +
> + oops_hdr->report_length = (u16) oops_data_sz;
> + } else
> + memcpy(oops_data, big_oops_buf, size);
> + } else
> + err_type = ERR_TYPE_KERNEL_PANIC_GZ;
> + }
> +
> rc = nvram_write_os_partition(&oops_log_partition, oops_buf,
> - (int) (sizeof(*oops_hdr) + size), ERR_TYPE_KERNEL_PANIC,
> + (int) (sizeof(*oops_hdr) + oops_hdr->report_length), err_type,
> count);
>
> if (rc != 0)
> @@ -600,10 +683,11 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
> struct oops_log_info *oops_hdr;
> unsigned int err_type, id_no, size = 0;
> struct nvram_os_partition *part = NULL;
> - char *buff = NULL;
> - int sig = 0;
> + char *buff = NULL, *big_buff = NULL;
> + int rc, sig = 0;
> loff_t p;
>
> +read_partition:
> read_type++;
>
> switch (nvram_type_ids[read_type]) {
> @@ -666,6 +750,25 @@ static ssize_t nvram_pstore_read(u64 *id, enum pstore_type_id *type,
> if (nvram_type_ids[read_type] == PSTORE_TYPE_DMESG) {
> oops_hdr = (struct oops_log_info *)buff;
> *buf = buff + sizeof(*oops_hdr);
> +
> + if (err_type == ERR_TYPE_KERNEL_PANIC_GZ) {
> + big_buff = kmalloc(big_oops_buf_sz, GFP_KERNEL);
> + if (!big_buff)
> + return -ENOMEM;
> +
> + rc = unzip_oops(buff, big_buff);
> +
> + if (rc != 0) {
> + kfree(buff);
> + kfree(big_buff);
> + goto read_partition;
> + }
> +
> + oops_hdr = (struct oops_log_info *)big_buff;
> + *buf = big_buff + sizeof(*oops_hdr);
> + kfree(buff);
> + }
> +
> time->tv_sec = oops_hdr->timestamp;
> time->tv_nsec = 0;
> return oops_hdr->report_length;
> @@ -687,17 +790,18 @@ static int nvram_pstore_init(void)
> {
> int rc = 0;
>
> - nvram_pstore_info.buf = oops_data;
> - nvram_pstore_info.bufsize = oops_data_sz;
> + if (big_oops_buf) {
> + nvram_pstore_info.buf = big_oops_buf;
> + nvram_pstore_info.bufsize = big_oops_buf_sz;
> + } else {
> + nvram_pstore_info.buf = oops_data;
> + nvram_pstore_info.bufsize = oops_data_sz;
> + }
>
> rc = pstore_register(&nvram_pstore_info);
> if (rc != 0)
> pr_err("nvram: pstore_register() failed, defaults to "
> "kmsg_dump; returned %d\n", rc);
> - else
> - /*TODO: Support compression when pstore is configured */
> - pr_info("nvram: Compression of oops text supported only when "
> - "pstore is not configured");
>
> return rc;
> }
> @@ -731,11 +835,6 @@ static void __init nvram_init_oops_partition(int rtas_partition_exists)
> oops_data = oops_buf + sizeof(struct oops_log_info);
> oops_data_sz = oops_log_partition.size - sizeof(struct oops_log_info);
>
> - rc = nvram_pstore_init();
> -
> - if (!rc)
> - return;
> -
> /*
> * Figure compression (preceded by elimination of each line's <n>
> * severity prefix) will reduce the oops/panic report to at most
> @@ -759,6 +858,11 @@ static void __init nvram_init_oops_partition(int rtas_partition_exists)
> stream.workspace = NULL;
> }
>
> + rc = nvram_pstore_init();
> +
> + if (!rc)
> + return;
> +
> rc = kmsg_dump_register(&nvram_kmsg_dumper);
> if (rc != 0) {
> pr_err("nvram: kmsg_dump_register() failed; returned %d\n", rc);
>
> --
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