| Message ID | 20240307151157.466013-3-hch@lst.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/10] block: remove the discard_granularity check in __blkdev_issue_discard | expand |
On Thu, Mar 07, 2024 at 08:11:49AM -0700, Christoph Hellwig wrote: > Most bio operations get basic sanity checking in submit_bio and anything > more complicated than that is done in the callers. Discards are a bit > different from that in that a lot of checking is done in > __blkdev_issue_discard, and the specific errnos for that are returned > to userspace. Move the checks that require specific errnos to the ioctl > handler instead, and just leave the basic sanity checking in submit_bio > for the other handlers. This introduces two changes in behavior: > > 1) the logical block size alignment check of the start and len is lost > for non-ioctl callers. > This matches what is done for other operations including reads and > writes. We should probably verify this for all bios, but for now > make discards match the normal flow. > 2) for non-ioctl callers all errors are reported on I/O completion now > instead of synchronously. Callers in general mostly ignore or log > errors so this will actually simplify the code once cleaned up > > Signed-off-by: Christoph Hellwig <hch@lst.de> OK. > --- > block/blk-lib.c | 13 ------------- > block/ioctl.c | 13 +++++++++---- > 2 files changed, 9 insertions(+), 17 deletions(-) > > diff --git a/block/blk-lib.c b/block/blk-lib.c > index f873eb9a886f63..50923508a32466 100644 > --- a/block/blk-lib.c > +++ b/block/blk-lib.c > @@ -59,19 +59,6 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, > sector_t nr_sects, gfp_t gfp_mask, struct bio **biop) > { > struct bio *bio = *biop; > - sector_t bs_mask; > - > - if (bdev_read_only(bdev)) > - return -EPERM; > - if (!bdev_max_discard_sectors(bdev)) > - return -EOPNOTSUPP; > - > - bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; > - if ((sector | nr_sects) & bs_mask) > - return -EINVAL; > - > - if (!nr_sects) > - return -EINVAL; > > while (nr_sects) { > sector_t req_sects = > diff --git a/block/ioctl.c b/block/ioctl.c > index de0cc0d215c633..1d5de0a890c5e8 100644 > --- a/block/ioctl.c > +++ b/block/ioctl.c > @@ -95,6 +95,8 @@ static int compat_blkpg_ioctl(struct block_device *bdev, > static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode, > unsigned long arg) > { > + sector_t bs_mask = (bdev_logical_block_size(bdev) >> SECTOR_SHIFT) - 1; > + sector_t sector, nr_sects; This changes the alignment checks from a hard coded 512 byte sector to the logical block size of the device. I don't see a problem with this (it fixes a bug) but it should at least be mentioned in the commit message. -Dave.
On Fri, Mar 08, 2024 at 08:33:08AM +1100, Dave Chinner wrote: > > static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode, > > unsigned long arg) > > { > > + sector_t bs_mask = (bdev_logical_block_size(bdev) >> SECTOR_SHIFT) - 1; > > + sector_t sector, nr_sects; > > This changes the alignment checks from a hard coded 512 byte sector > to the logical block size of the device. I don't see a problem with > this (it fixes a bug) but it should at least be mentioned in the > commit message. Before the exact block size alignment check as done down in __blkdev_issue_discard, it just moves up here now. I guess I need to make that more clear in the commit message.
On Fri, Mar 08, 2024 at 04:22:44PM +0100, Christoph Hellwig wrote: > On Fri, Mar 08, 2024 at 08:33:08AM +1100, Dave Chinner wrote: > > > static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode, > > > unsigned long arg) > > > { > > > + sector_t bs_mask = (bdev_logical_block_size(bdev) >> SECTOR_SHIFT) - 1; > > > + sector_t sector, nr_sects; > > > > This changes the alignment checks from a hard coded 512 byte sector > > to the logical block size of the device. I don't see a problem with > > this (it fixes a bug) but it should at least be mentioned in the > > commit message. > > Before the exact block size alignment check as done down in > __blkdev_issue_discard, it just moves up here now. I guess I need to > make that more clear in the commit message. Ah, eyeball pattern matching fail on my part - you changed it from a hard coded '9' to SECTOR_SHIFT as it moved (which is fine!), I just missed that. All good! -Dave.
diff --git a/block/blk-lib.c b/block/blk-lib.c index f873eb9a886f63..50923508a32466 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -59,19 +59,6 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, sector_t nr_sects, gfp_t gfp_mask, struct bio **biop) { struct bio *bio = *biop; - sector_t bs_mask; - - if (bdev_read_only(bdev)) - return -EPERM; - if (!bdev_max_discard_sectors(bdev)) - return -EOPNOTSUPP; - - bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; - if ((sector | nr_sects) & bs_mask) - return -EINVAL; - - if (!nr_sects) - return -EINVAL; while (nr_sects) { sector_t req_sects = diff --git a/block/ioctl.c b/block/ioctl.c index de0cc0d215c633..1d5de0a890c5e8 100644 --- a/block/ioctl.c +++ b/block/ioctl.c @@ -95,6 +95,8 @@ static int compat_blkpg_ioctl(struct block_device *bdev, static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode, unsigned long arg) { + sector_t bs_mask = (bdev_logical_block_size(bdev) >> SECTOR_SHIFT) - 1; + sector_t sector, nr_sects; uint64_t range[2]; uint64_t start, len; struct inode *inode = bdev->bd_inode; @@ -105,18 +107,21 @@ static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode, if (!bdev_max_discard_sectors(bdev)) return -EOPNOTSUPP; + if (bdev_read_only(bdev)) + return -EPERM; if (copy_from_user(range, (void __user *)arg, sizeof(range))) return -EFAULT; start = range[0]; len = range[1]; + sector = start >> SECTOR_SHIFT; + nr_sects = len >> SECTOR_SHIFT; - if (start & 511) + if (!nr_sects) return -EINVAL; - if (len & 511) + if ((sector | nr_sects) & bs_mask) return -EINVAL; - if (start + len > bdev_nr_bytes(bdev)) return -EINVAL; @@ -124,7 +129,7 @@ static int blk_ioctl_discard(struct block_device *bdev, blk_mode_t mode, err = truncate_bdev_range(bdev, mode, start, start + len - 1); if (err) goto fail; - err = blkdev_issue_discard(bdev, start >> 9, len >> 9, GFP_KERNEL); + err = blkdev_issue_discard(bdev, sector, nr_sects, GFP_KERNEL); fail: filemap_invalidate_unlock(inode->i_mapping); return err;
Most bio operations get basic sanity checking in submit_bio and anything more complicated than that is done in the callers. Discards are a bit different from that in that a lot of checking is done in __blkdev_issue_discard, and the specific errnos for that are returned to userspace. Move the checks that require specific errnos to the ioctl handler instead, and just leave the basic sanity checking in submit_bio for the other handlers. This introduces two changes in behavior: 1) the logical block size alignment check of the start and len is lost for non-ioctl callers. This matches what is done for other operations including reads and writes. We should probably verify this for all bios, but for now make discards match the normal flow. 2) for non-ioctl callers all errors are reported on I/O completion now instead of synchronously. Callers in general mostly ignore or log errors so this will actually simplify the code once cleaned up Signed-off-by: Christoph Hellwig <hch@lst.de> --- block/blk-lib.c | 13 ------------- block/ioctl.c | 13 +++++++++---- 2 files changed, 9 insertions(+), 17 deletions(-)