ore: Support for short read/writes
Memory conditions and max_bio constraints might cause us to not comply to the full length of the requested IO. Instead of failing the complete IO we can issue a shorter read/write and report how much was actually executed in the ios->length member. All users must check ios->length at IO_done or upon return of ore_read/write and re-issue the reminder of the bytes. Because other wise there is no error returned like before. This is part of the effort to support the pnfs-obj layout driver. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>hifive-unleashed-5.1
parent
154a9300cd
commit
bbf9a31bba
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@ -377,8 +377,8 @@ static int _add_stripe_unit(struct ore_io_state *ios, unsigned *cur_pg,
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unsigned pg = *cur_pg;
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unsigned pg = *cur_pg;
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struct request_queue *q =
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struct request_queue *q =
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osd_request_queue(_ios_od(ios, per_dev->dev));
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osd_request_queue(_ios_od(ios, per_dev->dev));
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unsigned len = cur_len;
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per_dev->length += cur_len;
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int ret;
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if (per_dev->bio == NULL) {
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if (per_dev->bio == NULL) {
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unsigned pages_in_stripe = ios->layout->group_width *
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unsigned pages_in_stripe = ios->layout->group_width *
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@ -390,7 +390,8 @@ static int _add_stripe_unit(struct ore_io_state *ios, unsigned *cur_pg,
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if (unlikely(!per_dev->bio)) {
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if (unlikely(!per_dev->bio)) {
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ORE_DBGMSG("Failed to allocate BIO size=%u\n",
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ORE_DBGMSG("Failed to allocate BIO size=%u\n",
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bio_size);
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bio_size);
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return -ENOMEM;
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ret = -ENOMEM;
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goto out;
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}
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}
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}
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}
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@ -403,15 +404,24 @@ static int _add_stripe_unit(struct ore_io_state *ios, unsigned *cur_pg,
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added_len = bio_add_pc_page(q, per_dev->bio, ios->pages[pg],
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added_len = bio_add_pc_page(q, per_dev->bio, ios->pages[pg],
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pglen, pgbase);
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pglen, pgbase);
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if (unlikely(pglen != added_len))
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if (unlikely(pglen != added_len)) {
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return -ENOMEM;
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ret = -ENOMEM;
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goto out;
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}
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pgbase = 0;
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pgbase = 0;
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++pg;
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++pg;
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}
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}
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BUG_ON(cur_len);
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BUG_ON(cur_len);
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per_dev->length += len;
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*cur_pg = pg;
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*cur_pg = pg;
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return 0;
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ret = 0;
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out: /* we fail the complete unit on an error eg don't advance
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* per_dev->length and cur_pg. This means that we might have a bigger
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* bio than the CDB requested length (per_dev->length). That's fine
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* only the oposite is fatal.
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*/
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return ret;
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}
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}
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static int _prepare_for_striping(struct ore_io_state *ios)
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static int _prepare_for_striping(struct ore_io_state *ios)
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@ -472,7 +482,13 @@ static int _prepare_for_striping(struct ore_io_state *ios)
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out:
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out:
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ios->numdevs = devs_in_group;
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ios->numdevs = devs_in_group;
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ios->pages_consumed = cur_pg;
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ios->pages_consumed = cur_pg;
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return ret;
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if (unlikely(ret)) {
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if (length == ios->length)
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return ret;
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else
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ios->length -= length;
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}
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return 0;
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}
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}
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int ore_create(struct ore_io_state *ios)
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int ore_create(struct ore_io_state *ios)
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