[lustre-devel] [PATCH v3] staging: lustre: llog: fix wrong offset in llog_process_thread()
Greg Kroah-Hartman
gregkh at linuxfoundation.org
Thu Nov 17 23:53:02 PST 2016
On Thu, Nov 17, 2016 at 06:29:08PM -0500, James Simmons wrote:
> From: Mikhail Pershin <mike.pershin at intel.com>
>
> - llh_cat_idx may become bigger than llog bitmap size in
> llog_cat_set_first_idx() function
> - it is wrong to use previous cur_offset as new buffer offset,
> new offset should be calculated from value returned by
> llog_next_block().
> - optimize llog_skip_over() to find llog entry offset by index
> for llog with fixed-size records.
>
> Signed-off-by: Mikhail Pershin <mike.pershin at intel.com>
> Signed-off-by: Bob Glossman <bob.glossman at intel.com>
> Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6714
> Reviewed-on: http://review.whamcloud.com/15316
> Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-6163
> Reviewed-on: http://review.whamcloud.com/18819
> Reviewed-by: John L. Hammond <john.hammond at intel.com>
> Reviewed-by: James Simmons <uja.ornl at yahoo.com>
> Reviewed-by: Oleg Drokin <oleg.drokin at intel.com>
> Signed-off-by: James Simmons <jsimmons at infradead.org>
> ---
>
> ChangeLog:
>
> v1) Initial patch with umoddi issue
> v2) Included fix from patch LU-6163 that fixed umoddi problem
> v3) Remove no longer needed last_offset variable
>
> drivers/staging/lustre/lustre/obdclass/llog.c | 82 +++++++++++++++++-------
> include/linux/fs.h | 2 +-
> 2 files changed, 59 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/staging/lustre/lustre/obdclass/llog.c b/drivers/staging/lustre/lustre/obdclass/llog.c
> index 3bc1789..ae63047 100644
> --- a/drivers/staging/lustre/lustre/obdclass/llog.c
> +++ b/drivers/staging/lustre/lustre/obdclass/llog.c
> @@ -217,8 +217,7 @@ static int llog_process_thread(void *arg)
> struct llog_log_hdr *llh = loghandle->lgh_hdr;
> struct llog_process_cat_data *cd = lpi->lpi_catdata;
> char *buf;
> - __u64 cur_offset;
> - __u64 last_offset;
> + u64 cur_offset, tmp_offset;
> int chunk_size;
> int rc = 0, index = 1, last_index;
> int saved_index = 0;
> @@ -229,6 +228,8 @@ static int llog_process_thread(void *arg)
>
> cur_offset = llh->llh_hdr.lrh_len;
> chunk_size = llh->llh_hdr.lrh_len;
> + /* expect chunk_size to be power of two */
> + LASSERT(is_power_of_2(chunk_size));
>
> buf = libcfs_kvzalloc(chunk_size, GFP_NOFS);
> if (!buf) {
> @@ -245,38 +246,50 @@ static int llog_process_thread(void *arg)
> else
> last_index = LLOG_HDR_BITMAP_SIZE(llh) - 1;
>
> - /* Record is not in this buffer. */
> - if (index > last_index)
> - goto out;
> -
> while (rc == 0) {
> + unsigned int buf_offset = 0;
> struct llog_rec_hdr *rec;
> + bool partial_chunk;
> + off_t chunk_offset;
>
> /* skip records not set in bitmap */
> while (index <= last_index &&
> !ext2_test_bit(index, LLOG_HDR_BITMAP(llh)))
> ++index;
>
> - LASSERT(index <= last_index + 1);
> - if (index == last_index + 1)
> + if (index > last_index)
> break;
> -repeat:
> +
> CDEBUG(D_OTHER, "index: %d last_index %d\n",
> index, last_index);
> -
> +repeat:
> /* get the buf with our target record; avoid old garbage */
> memset(buf, 0, chunk_size);
> - last_offset = cur_offset;
> rc = llog_next_block(lpi->lpi_env, loghandle, &saved_index,
> index, &cur_offset, buf, chunk_size);
> if (rc)
> goto out;
>
> + /*
> + * NB: after llog_next_block() call the cur_offset is the
> + * offset of the next block after read one.
> + * The absolute offset of the current chunk is calculated
> + * from cur_offset value and stored in chunk_offset variable.
> + */
> + tmp_offset = cur_offset;
> + if (do_div(tmp_offset, chunk_size)) {
> + partial_chunk = true;
> + chunk_offset = cur_offset & ~(chunk_size - 1);
> + } else {
> + partial_chunk = false;
> + chunk_offset = cur_offset - chunk_size;
> + }
> +
> /* NB: when rec->lrh_len is accessed it is already swabbed
> * since it is used at the "end" of the loop and the rec
> * swabbing is done at the beginning of the loop.
> */
> - for (rec = (struct llog_rec_hdr *)buf;
> + for (rec = (struct llog_rec_hdr *)(buf + buf_offset);
> (char *)rec < buf + chunk_size;
> rec = llog_rec_hdr_next(rec)) {
> CDEBUG(D_OTHER, "processing rec 0x%p type %#x\n",
> @@ -288,13 +301,28 @@ static int llog_process_thread(void *arg)
> CDEBUG(D_OTHER, "after swabbing, type=%#x idx=%d\n",
> rec->lrh_type, rec->lrh_index);
>
> - if (rec->lrh_index == 0) {
> - /* probably another rec just got added? */
> - rc = 0;
> - if (index <= loghandle->lgh_last_idx)
> - goto repeat;
> - goto out; /* no more records */
> + /*
> + * for partial chunk the end of it is zeroed, check
> + * for index 0 to distinguish it.
> + */
> + if (partial_chunk && !rec->lrh_index) {
> + /* concurrent llog_add() might add new records
> + * while llog_processing, check this is not
> + * the case and re-read the current chunk
> + * otherwise.
> + */
> + if (index > loghandle->lgh_last_idx) {
> + rc = 0;
> + goto out;
> + }
> + CDEBUG(D_OTHER, "Re-read last llog buffer for new records, index %u, last %u\n",
> + index, loghandle->lgh_last_idx);
> + /* save offset inside buffer for the re-read */
> + buf_offset = (char *)rec - (char *)buf;
> + cur_offset = chunk_offset;
> + goto repeat;
> }
> +
> if (!rec->lrh_len || rec->lrh_len > chunk_size) {
> CWARN("invalid length %d in llog record for index %d/%d\n",
> rec->lrh_len,
> @@ -309,6 +337,14 @@ static int llog_process_thread(void *arg)
> continue;
> }
>
> + if (rec->lrh_index != index) {
> + CERROR("%s: Invalid record: index %u but expected %u\n",
> + loghandle->lgh_ctxt->loc_obd->obd_name,
> + rec->lrh_index, index);
> + rc = -ERANGE;
> + goto out;
> + }
> +
> CDEBUG(D_OTHER,
> "lrh_index: %d lrh_len: %d (%d remains)\n",
> rec->lrh_index, rec->lrh_len,
> @@ -316,7 +352,7 @@ static int llog_process_thread(void *arg)
>
> loghandle->lgh_cur_idx = rec->lrh_index;
> loghandle->lgh_cur_offset = (char *)rec - (char *)buf +
> - last_offset;
> + chunk_offset;
>
> /* if set, process the callback on this record */
> if (ext2_test_bit(index, LLOG_HDR_BITMAP(llh))) {
> @@ -325,16 +361,14 @@ static int llog_process_thread(void *arg)
> last_called_index = index;
> if (rc)
> goto out;
> - } else {
> - CDEBUG(D_OTHER, "Skipped index %d\n", index);
> }
>
> - /* next record, still in buffer? */
> - ++index;
> - if (index > last_index) {
> + /* exit if the last index is reached */
> + if (index >= last_index) {
> rc = 0;
> goto out;
> }
> + index++;
> }
> }
>
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index dc0478c..3f70ec3 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2690,7 +2690,7 @@ enum kernel_read_file_id {
>
> static inline const char *kernel_read_file_id_str(enum kernel_read_file_id id)
> {
> - if (id < 0 || id >= READING_MAX_ID)
> + if (id >= READING_MAX_ID)
> return kernel_read_file_str[READING_UNKNOWN];
>
> return kernel_read_file_str[id];
Why are you modifying this fs.h function in this patch? Your changelog
does not talk about it at all. Nor does lustre even call this function,
only a security module, loadpin.
totally confused,
greg k-h
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