diff options
Diffstat (limited to 'module/zfs')
| -rw-r--r-- | module/zfs/dmu.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c index e2abf8cf2..00a7a07f4 100644 --- a/module/zfs/dmu.c +++ b/module/zfs/dmu.c @@ -1022,11 +1022,57 @@ dmu_req_copy(void *arg_buf, int size, int *offset, struct request *req) return 0; } +static void +dmu_bio_put(struct bio *bio) +{ + struct bio *bio_next; + + while (bio) { + bio_next = bio->bi_next; + bio_put(bio); + bio = bio_next; + } +} + +static int +dmu_bio_clone(struct bio *bio, struct bio **bio_copy) +{ + struct bio *bio_root = NULL; + struct bio *bio_last = NULL; + struct bio *bio_new; + + if (bio == NULL) + return EINVAL; + + while (bio) { + bio_new = bio_clone(bio, GFP_NOIO); + if (bio_new == NULL) { + dmu_bio_put(bio_root); + return ENOMEM; + } + + if (bio_last) { + bio_last->bi_next = bio_new; + bio_last = bio_new; + } else { + bio_root = bio_new; + bio_last = bio_new; + } + + bio = bio->bi_next; + } + + *bio_copy = bio_root; + + return 0; +} + int dmu_read_req(objset_t *os, uint64_t object, struct request *req) { uint64_t size = blk_rq_bytes(req); uint64_t offset = blk_rq_pos(req) << 9; + struct bio *bio_saved = req->bio; dmu_buf_t **dbp; int numbufs, i, err; @@ -1039,6 +1085,17 @@ dmu_read_req(objset_t *os, uint64_t object, struct request *req) if (err) return (err); + /* + * Clone the bio list so the bv->bv_offset and bv->bv_len members + * can be safely modified. The original bio list is relinked in to + * the request when the function exits. This is required because + * some file systems blindly assume that these values will remain + * constant between bio_submit() and the IO completion callback. + */ + err = dmu_bio_clone(bio_saved, &req->bio); + if (err) + goto error; + for (i = 0; i < numbufs; i++) { int tocpy, didcpy, bufoff; dmu_buf_t *db = dbp[i]; @@ -1062,6 +1119,10 @@ dmu_read_req(objset_t *os, uint64_t object, struct request *req) offset += didcpy; err = 0; } + + dmu_bio_put(req->bio); + req->bio = bio_saved; +error: dmu_buf_rele_array(dbp, numbufs, FTAG); return (err); @@ -1072,6 +1133,7 @@ dmu_write_req(objset_t *os, uint64_t object, struct request *req, dmu_tx_t *tx) { uint64_t size = blk_rq_bytes(req); uint64_t offset = blk_rq_pos(req) << 9; + struct bio *bio_saved = req->bio; dmu_buf_t **dbp; int numbufs; int err = 0; @@ -1085,6 +1147,17 @@ dmu_write_req(objset_t *os, uint64_t object, struct request *req, dmu_tx_t *tx) if (err) return (err); + /* + * Clone the bio list so the bv->bv_offset and bv->bv_len members + * can be safely modified. The original bio list is relinked in to + * the request when the function exits. This is required because + * some file systems blindly assume that these values will remain + * constant between bio_submit() and the IO completion callback. + */ + err = dmu_bio_clone(bio_saved, &req->bio); + if (err) + goto error; + for (i = 0; i < numbufs; i++) { int tocpy, didcpy, bufoff; dmu_buf_t *db = dbp[i]; @@ -1119,7 +1192,11 @@ dmu_write_req(objset_t *os, uint64_t object, struct request *req, dmu_tx_t *tx) err = 0; } + dmu_bio_put(req->bio); + req->bio = bio_saved; +error: dmu_buf_rele_array(dbp, numbufs, FTAG); + return (err); } |