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um: Add support for DISCARD in the UBD Driver

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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:
Anton Ivanov 2018-11-14 18:41:09 +00:00 committed by Richard Weinberger
parent a41421edb9
commit 50109b5a03
3 changed files with 65 additions and 11 deletions
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65
arch/um/drivers/ubd_kern.c
View File

@ -154,6 +154,7 @@ struct ubd {
struct openflags openflags;
unsigned shared:1;
unsigned no_cow:1;
unsigned no_trim:1;
struct cow cow;
struct platform_device pdev;
struct request_queue *queue;
@ -177,6 +178,7 @@ struct ubd {
.boot_openflags = OPEN_FLAGS, \
.openflags = OPEN_FLAGS, \
.no_cow = 0, \
.no_trim = 0, \
.shared = 0, \
.cow = DEFAULT_COW, \
.lock = __SPIN_LOCK_UNLOCKED(ubd_devs.lock), \
@ -323,7 +325,7 @@ static int ubd_setup_common(char *str, int *index_out, char **error_out)
*index_out = n;
err = -EINVAL;
for (i = 0; i < sizeof("rscd="); i++) {
for (i = 0; i < sizeof("rscdt="); i++) {
switch (*str) {
case 'r':
flags.w = 0;
@ -337,12 +339,15 @@ static int ubd_setup_common(char *str, int *index_out, char **error_out)
case 'c':
ubd_dev->shared = 1;
break;
case 't':
ubd_dev->no_trim = 1;
break;
case '=':
str++;
goto break_loop;
default:
*error_out = "Expected '=' or flag letter "
"(r, s, c, or d)";
"(r, s, c, t or d)";
goto out;
}
str++;
@ -415,6 +420,7 @@ __uml_help(ubd_setup,
" 'c' will cause the device to be treated as being shared between multiple\n"
" UMLs and file locking will be turned off - this is appropriate for a\n"
" cluster filesystem and inappropriate at almost all other times.\n\n"
" 't' will disable trim/discard support on the device (enabled by default).\n\n"
);
static int udb_setup(char *str)
@ -513,9 +519,17 @@ static void ubd_handler(void)
for (count = 0; count < n/sizeof(struct io_thread_req *); count++) {
struct io_thread_req *io_req = (*irq_req_buffer)[count];
if (!blk_update_request(io_req->req, io_req->error, io_req->length))
__blk_mq_end_request(io_req->req, io_req->error);
if ((io_req->error == BLK_STS_NOTSUPP) && (req_op(io_req->req) == REQ_OP_DISCARD)) {
blk_queue_max_discard_sectors(io_req->req->q, 0);
blk_queue_max_write_zeroes_sectors(io_req->req->q, 0);
blk_queue_flag_clear(QUEUE_FLAG_DISCARD, io_req->req->q);
}
if ((io_req->error) || (io_req->buffer == NULL))
blk_mq_end_request(io_req->req, io_req->error);
else {
if (!blk_update_request(io_req->req, io_req->error, io_req->length))
__blk_mq_end_request(io_req->req, io_req->error);
}
kfree(io_req);
}
}
@ -829,6 +843,13 @@ static int ubd_open_dev(struct ubd *ubd_dev)
if(err < 0) goto error;
ubd_dev->cow.fd = err;
}
if (ubd_dev->no_trim == 0) {
ubd_dev->queue->limits.discard_granularity = SECTOR_SIZE;
ubd_dev->queue->limits.discard_alignment = SECTOR_SIZE;
blk_queue_max_discard_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
blk_queue_max_write_zeroes_sectors(ubd_dev->queue, UBD_MAX_REQUEST);
blk_queue_flag_set(QUEUE_FLAG_DISCARD, ubd_dev->queue);
}
blk_queue_flag_set(QUEUE_FLAG_NONROT, ubd_dev->queue);
return 0;
error:
@ -1372,6 +1393,10 @@ static blk_status_t ubd_queue_rq(struct blk_mq_hw_ctx *hctx,
case REQ_OP_WRITE:
ret = queue_rw_req(hctx, req);
break;
case REQ_OP_DISCARD:
case REQ_OP_WRITE_ZEROES:
ret = ubd_queue_one_vec(hctx, req, (u64)blk_rq_pos(req) << 9, NULL);
break;
default:
WARN_ON_ONCE(1);
res = BLK_STS_NOTSUPP;
@ -1463,7 +1488,7 @@ static int update_bitmap(struct io_thread_req *req)
n = os_pwrite_file(req->fds[1], &req->bitmap_words,
sizeof(req->bitmap_words), req->cow_offset);
if(n != sizeof(req->bitmap_words))
if (n != sizeof(req->bitmap_words))
return map_error(-n);
return map_error(0);
@ -1471,11 +1496,13 @@ static int update_bitmap(struct io_thread_req *req)
static void do_io(struct io_thread_req *req)
{
char *buf;
char *buf = NULL;
unsigned long len;
int n, nsectors, start, end, bit;
__u64 off;
/* FLUSH is really a special case, we cannot "case" it with others */
if (req_op(req->req) == REQ_OP_FLUSH) {
/* fds[0] is always either the rw image or our cow file */
req->error = map_error(-os_sync_file(req->fds[0]));
@ -1495,26 +1522,42 @@ static void do_io(struct io_thread_req *req)
off = req->offset + req->offsets[bit] +
start * req->sectorsize;
len = (end - start) * req->sectorsize;
buf = &req->buffer[start * req->sectorsize];
if (req->buffer != NULL)
buf = &req->buffer[start * req->sectorsize];
if (req_op(req->req) == REQ_OP_READ) {
switch (req_op(req->req)) {
case REQ_OP_READ:
n = 0;
do {
buf = &buf[n];
len -= n;
n = os_pread_file(req->fds[bit], buf, len, off);
if(n < 0){
if (n < 0) {
req->error = map_error(-n);
return;
}
} while((n < len) && (n != 0));
if (n < len) memset(&buf[n], 0, len - n);
} else {
break;
case REQ_OP_WRITE:
n = os_pwrite_file(req->fds[bit], buf, len, off);
if(n != len){
req->error = map_error(-n);
return;
}
break;
case REQ_OP_DISCARD:
case REQ_OP_WRITE_ZEROES:
n = os_falloc_punch(req->fds[bit], off, len);
if (n) {
req->error = map_error(-n);
return;
}
break;
default:
WARN_ON_ONCE(1);
req->error = BLK_STS_NOTSUPP;
return;
}
start = end;

1
arch/um/include/shared/os.h
View File

@ -175,6 +175,7 @@ extern int os_fchange_dir(int fd);
extern unsigned os_major(unsigned long long dev);
extern unsigned os_minor(unsigned long long dev);
extern unsigned long long os_makedev(unsigned major, unsigned minor);
extern int os_falloc_punch(int fd, unsigned long long offset, int count);
/* start_up.c */
extern void os_early_checks(void);

10
arch/um/os-Linux/file.c
View File

@ -610,3 +610,13 @@ unsigned long long os_makedev(unsigned major, unsigned minor)
{
return makedev(major, minor);
}
int os_falloc_punch(int fd, unsigned long long offset, int len)
{
int n = fallocate(fd, FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE, offset, len);
if (n < 0)
return -errno;
return n;
}