[PATCH RFC 4/8] fs: Introduce FALLOC_FL_PROVISION

Sarthak Kukreti
2022-09-15T16:49:25Z

From: Sarthak Kukreti <sarthakkukreti@chromium.org>

FALLOC_FL_PROVISION is a new fallocate() allocation mode that
sends a hint to (supported) thinly provisioned block devices to
allocate space for the given range of sectors via REQ_OP_PROVISION.

Signed-off-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
---
block/fops.c | 7 ++++++-
include/linux/falloc.h | 3 ++-
include/uapi/linux/falloc.h | 8 ++++++++
3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/block/fops.c b/block/fops.c
index b90742595317..a436a7596508 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -605,7 +605,8 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)

#define BLKDEV_FALLOC_FL_SUPPORTED \
(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
- FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
+ FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE | \
+ FALLOC_FL_PROVISION)

static long blkdev_fallocate(struct file *file, int mode, loff_t start,
loff_t len)
@@ -661,6 +662,10 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start,
error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
len >> SECTOR_SHIFT, GFP_KERNEL);
break;
+ case FALLOC_FL_PROVISION:
+ error = blkdev_issue_provision(bdev, start >> SECTOR_SHIFT,
+ len >> SECTOR_SHIFT, GFP_KERNEL);
+ break;
default:
error = -EOPNOTSUPP;
}
diff --git a/include/linux/falloc.h b/include/linux/falloc.h
index f3f0b97b1675..a0e506255b20 100644
--- a/include/linux/falloc.h
+++ b/include/linux/falloc.h
@@ -30,7 +30,8 @@ struct space_resv {
FALLOC_FL_COLLAPSE_RANGE | \
FALLOC_FL_ZERO_RANGE | \
FALLOC_FL_INSERT_RANGE | \
- FALLOC_FL_UNSHARE_RANGE)
+ FALLOC_FL_UNSHARE_RANGE | \
+ FALLOC_FL_PROVISION)

/* on ia32 l_start is on a 32-bit boundary */
#if defined(CONFIG_X86_64)
diff --git a/include/uapi/linux/falloc.h b/include/uapi/linux/falloc.h
index 51398fa57f6c..2d323d113eed 100644
--- a/include/uapi/linux/falloc.h
+++ b/include/uapi/linux/falloc.h
@@ -77,4 +77,12 @@
*/
#define FALLOC_FL_UNSHARE_RANGE 0x40

+/*
+ * FALLOC_FL_PROVISION acts as a hint for thinly provisioned devices to allocate
+ * blocks for the range/EOF.
+ *
+ * FALLOC_FL_PROVISION can only be used with allocate-mode fallocate.
+ */
+#define FALLOC_FL_PROVISION 0x80
+
#endif /* _UAPI_FALLOC_H_ */
--
2.31.0