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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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um: Add support for DISCARD in the UBD Driver
Support for DISCARD and WRITE_ZEROES in the ubd driver using fallocate. DISCARD is enabled by default and can be disabled using a new UBD command line flag. If the underlying fs on which the UBD image is stored does not support DISCARD the support for both DISCARD and WRITE_ZEROES is turned off. Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
parent
a41421edb9
commit
50109b5a03
3 changed files with 65 additions and 11 deletions
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@ -154,6 +154,7 @@ struct ubd {
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struct openflags openflags;
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unsigned shared:1;
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unsigned no_cow:1;
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unsigned no_trim:1;
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struct cow cow;
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struct platform_device pdev;
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struct request_queue *queue;
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@ -177,6 +178,7 @@ struct ubd {
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.boot_openflags = OPEN_FLAGS, \
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.openflags = OPEN_FLAGS, \
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.no_cow = 0, \
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.no_trim = 0, \
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.shared = 0, \
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.cow = DEFAULT_COW, \
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.lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \
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@ -323,7 +325,7 @@ static int ubd_setup_common(char *str, int *index_out, char **error_out)
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*index_out = n;
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err = -EINVAL;
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for (i = 0; i < sizeof("rscd="); i++) {
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for (i = 0; i < sizeof("rscdt="); i++) {
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switch (*str) {
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case 'r':
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flags.w = 0;
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@ -337,12 +339,15 @@ static int ubd_setup_common(char *str, int *index_out, char **error_out)
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case 'c':
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ubd_dev->shared = 1;
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break;
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case 't':
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ubd_dev->no_trim = 1;
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break;
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case '=':
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str++;
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goto break_loop;
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default:
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*error_out = "Expected '=' or flag letter "
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"(r, s, c, or d)";
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"(r, s, c, t or d)";
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goto out;
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}
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str++;
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@ -415,6 +420,7 @@ __uml_help(ubd_setup,
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" 'c' will cause the device to be treated as being shared between multiple\n"
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" UMLs and file locking will be turned off - this is appropriate for a\n"
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" cluster filesystem and inappropriate at almost all other times.\n\n"
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" 't' will disable trim/discard support on the device (enabled by default).\n\n"
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);
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static int udb_setup(char *str)
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@ -513,9 +519,17 @@ static void ubd_handler(void)
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for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
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struct io_thread_req *io_req = (*irq_req_buffer)[count];
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if (!blk_update_request(io_req->req, io_req->error, io_req->length))
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__blk_mq_end_request(io_req->req, io_req->error);
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if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) {
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blk_queue_max_discard_sectors(io_req->req->q, 0);
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blk_queue_max_write_zeroes_sectors(io_req->req->q, 0);
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blk_queue_flag_clear(QUEUE_FLAG_DISCARD, io_req->req->q);
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}
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if ((io_req->error) || (io_req->buffer == NULL))
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blk_mq_end_request(io_req->req, io_req->error);
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else {
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if (!blk_update_request(io_req->req, io_req->error, io_req->length))
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__blk_mq_end_request(io_req->req, io_req->error);
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}
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kfree(io_req);
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}
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}
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@ -829,6 +843,13 @@ static int ubd_open_dev(struct ubd *ubd_dev)
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if(err < 0) goto error;
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ubd_dev->cow.fd = err;
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}
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if (ubd_dev->no_trim == 0) {
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ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE;
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ubd_dev->queue->limits.discard_alignment = SECTOR_SIZE;
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blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
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blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
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blk_queue_flag_set(QUEUE_FLAG_DISCARD, ubd_dev->queue);
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}
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blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue);
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return 0;
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error:
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@ -1372,6 +1393,10 @@ static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
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case REQ_OP_WRITE:
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ret = queue_rw_req(hctx, req);
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break;
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case REQ_OP_DISCARD:
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case REQ_OP_WRITE_ZEROES:
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ret = ubd_queue_one_vec(hctx, req, (u64)blk_rq_pos(req) << 9, NULL);
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break;
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default:
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WARN_ON_ONCE(1);
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res = BLK_STS_NOTSUPP;
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@ -1463,7 +1488,7 @@ static int update_bitmap(struct io_thread_req *req)
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n = os_pwrite_file(req->fds[1], &req->bitmap_words,
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sizeof(req->bitmap_words), req->cow_offset);
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if(n != sizeof(req->bitmap_words))
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if (n != sizeof(req->bitmap_words))
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return map_error(-n);
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return map_error(0);
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@ -1471,11 +1496,13 @@ static int update_bitmap(struct io_thread_req *req)
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static void do_io(struct io_thread_req *req)
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{
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char *buf;
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char *buf = NULL;
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unsigned long len;
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int n, nsectors, start, end, bit;
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__u64 off;
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/* FLUSH is really a special case, we cannot "case" it with others */
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if (req_op(req->req) == REQ_OP_FLUSH) {
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/* fds[0] is always either the rw image or our cow file */
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req->error = map_error(-os_sync_file(req->fds[0]));
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@ -1495,26 +1522,42 @@ static void do_io(struct io_thread_req *req)
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off = req->offset + req->offsets[bit] +
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start * req->sectorsize;
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len = (end - start) * req->sectorsize;
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buf = &req->buffer[start * req->sectorsize];
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if (req->buffer != NULL)
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buf = &req->buffer[start * req->sectorsize];
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if (req_op(req->req) == REQ_OP_READ) {
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switch (req_op(req->req)) {
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case REQ_OP_READ:
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n = 0;
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do {
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buf = &buf[n];
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len -= n;
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n = os_pread_file(req->fds[bit], buf, len, off);
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if(n < 0){
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if (n < 0) {
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req->error = map_error(-n);
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return;
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}
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} while((n < len) && (n != 0));
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if (n < len) memset(&buf[n], 0, len - n);
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} else {
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break;
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case REQ_OP_WRITE:
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n = os_pwrite_file(req->fds[bit], buf, len, off);
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if(n != len){
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req->error = map_error(-n);
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return;
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}
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break;
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case REQ_OP_DISCARD:
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case REQ_OP_WRITE_ZEROES:
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n = os_falloc_punch(req->fds[bit], off, len);
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if (n) {
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req->error = map_error(-n);
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return;
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}
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break;
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default:
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WARN_ON_ONCE(1);
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req->error = BLK_STS_NOTSUPP;
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return;
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}
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start = end;
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@ -175,6 +175,7 @@ extern int os_fchange_dir(int fd);
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extern unsigned os_major(unsigned long long dev);
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extern unsigned os_minor(unsigned long long dev);
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extern unsigned long long os_makedev(unsigned major, unsigned minor);
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extern int os_falloc_punch(int fd, unsigned long long offset, int count);
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/* start_up.c */
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extern void os_early_checks(void);
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@ -610,3 +610,13 @@ unsigned long long os_makedev(unsigned major, unsigned minor)
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{
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return makedev(major, minor);
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}
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int os_falloc_punch(int fd, unsigned long long offset, int len)
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{
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int n = fallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, offset, len);
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if (n < 0)
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return -errno;
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return n;
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}
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