On Tue, Apr 12, 2016 at 04:04:59PM -0400, Mike Snitzer wrote: > On Tue, Apr 12 2016 at 12:42P -0400, > Brian Foster <bfoster@xxxxxxxxxx> wrote: > > > Hi all, > > > > This is v2 of the XFS and block device reservation experiment. The > > significant changes in v2 are that the bdev interface has been condensed > > to a single callback function, the XFS transaction reservation > > management has been reworked to make transactions responsible for > > tracking and releasing excess reservation (for non-delalloc cases) and a > > workaround for the fallocate over-reservation issue is included. Beyond > > that, this version adds a bunch of miscellaneous cleanups and fixes some > > of the nastier locking/leak issues present in the first rfc. > > > > Patches 1-2 refactor some XFS reserve pool and block accounting code in > > preparation for subsequent patches. Patches 3-5 add block/device-mapper > > reservation support. Patches 6-10 add the core reservation > > infrastructure and management bits to XFS. See the link to the original > > rfc below for instructions and further details around the purpose of > > this series. > > > > Finally, note that this is still highly experimental/theoretical and > > should not be used on production systems. Thoughts, reviews, flames > > appreciated. > > Thanks for carrying on with this work Brian. > > I've started to review your patchset and Darrick's fallocate patchset. > I've pushed a branch to linux-dm.git that combines the 2, see: > https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/log/?h=dm-fallocate > > and then added this RFC patch, at the end, which relies on both of your > patchsets -- you'll see blkdev_ensure_space_exists() has a FIXME which > implies it isn't much more than simply stubbed out at this point > (completely untested): Hmm, ok, but -rc3 broke a bunch of stuff. Guess I should repost with all the PAGE_CACHE_ -> PAGE_ stuff fixed. :) > From: Mike Snitzer <snitzer@xxxxxxxxxx> > Date: Tue, 12 Apr 2016 15:54:31 -0400 > Subject: [RFC PATCH] block: wire blkdev_fallocate() to block_device_operations' reserve_space > > This effectively exposes the primitive for "ensure space exists". It > relies on block_device_operations' reserve_space method. > > Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> > --- > block/blk-lib.c | 26 ++++++++++++++++++++++++++ > fs/block_dev.c | 20 +++++++++++--------- > include/linux/blkdev.h | 2 ++ > 3 files changed, 39 insertions(+), 9 deletions(-) > > diff --git a/block/blk-lib.c b/block/blk-lib.c > index 9dca6bb..5042a84 100644 > --- a/block/blk-lib.c > +++ b/block/blk-lib.c > @@ -314,3 +314,29 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, > return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask); > } > EXPORT_SYMBOL(blkdev_issue_zeroout); > + > +/** > + * blkdev_ensure_space_exists - preallocate a block range > + * @bdev: blockdev to preallocate space for > + * @sector: start sector > + * @nr_sects: number of sectors to preallocate > + * @gfp_mask: memory allocation flags (for bio_alloc) > + * @flags: FALLOC_FL_* to control behaviour > + * > + * Description: > + * Ensure space exists, or is preallocated, for the sectors in question. > + */ > +int blkdev_ensure_space_exists(struct block_device *bdev, sector_t sector, > + sector_t nr_sects, unsigned long flags) > +{ > + sector_t res; > + const struct block_device_operations *ops = bdev->bd_disk->fops; > + > + if (!ops->reserve_space) > + return -EOPNOTSUPP; > + > + // FIXME: check with Brian Foster on whether it makes sense to > + // use BDEV_RES_GET/BDEV_RES_MOD instead of BDEV_RES_PROVISION? > + return ops->reserve_space(bdev, BDEV_RES_PROVISION, sector, nr_sects, &res); /me thinks BDEV_RES_PROVISION is correct here, because regular-mode file fallocate (for ext4/xfs anyway) allocates blocks and maps them to specific file offsets as unwritten extents. afaict RES_PROVISION -> thin_provision_space() and thin_provision_space() seems to allocate blocks and map them to the device's LBAs. If I'm reading the patches correctly, RES_GET/RES_MOD seem to reserve N blocks but doesn't map them to any specific LBA. > +} > +EXPORT_SYMBOL(blkdev_ensure_space_exists); > diff --git a/fs/block_dev.c b/fs/block_dev.c > index 5a2c3ab..b34c07b 100644 > --- a/fs/block_dev.c > +++ b/fs/block_dev.c > @@ -1801,17 +1801,13 @@ long blkdev_fallocate(struct file *file, int mode, loff_t start, loff_t len) > struct request_queue *q = bdev_get_queue(bdev); > struct address_space *mapping; > loff_t end = start + len - 1; > - loff_t bs_mask, isize; > + loff_t isize; > int error; > > /* We only support zero range and punch hole. */ > if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) > return -EOPNOTSUPP; > > - /* We haven't a primitive for "ensure space exists" right now. */ > - if (!(mode & ~FALLOC_FL_KEEP_SIZE)) > - return -EOPNOTSUPP; > - > /* Only punch if the device can do zeroing discard. */ > if ((mode & FALLOC_FL_PUNCH_HOLE) && > (!blk_queue_discard(q) || !q->limits.discard_zeroes_data)) > @@ -1829,9 +1825,12 @@ long blkdev_fallocate(struct file *file, int mode, loff_t start, loff_t len) > return -EINVAL; > } > > - /* Don't allow IO that isn't aligned to logical block size */ > - bs_mask = bdev_logical_block_size(bdev) - 1; > - if ((start | len) & bs_mask) > + /* > + * Don't allow IO that isn't aligned to minimum IO size (io_min) > + * - for normal device's io_min is usually logical block size > + * - but for more exotic devices (e.g. DM thinp) it may be larger > + */ > + if ((start | len) % bdev_io_min(bdev)) > return -EINVAL; Noted. Will update the original patch. > /* Invalidate the page cache, including dirty pages. */ > @@ -1839,7 +1838,10 @@ long blkdev_fallocate(struct file *file, int mode, loff_t start, loff_t len) > truncate_inode_pages_range(mapping, start, end); > > error = -EINVAL; > - if (mode & FALLOC_FL_ZERO_RANGE) > + if (!(mode & ~FALLOC_FL_KEEP_SIZE)) > + error = blkdev_ensure_space_exists(bdev, start >> 9, len >> 9, > + mode); > + else if (mode & FALLOC_FL_ZERO_RANGE) This whole thing got converted to a switch statement due to some feedback from hch. Anyway, will try to have a new blockdev fallocate patchset done by the end of the day. (Is there a test case for this?) --D > error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, > GFP_KERNEL, false); > else if (mode & FALLOC_FL_PUNCH_HOLE) > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index 6c6ea96..4147af2 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -1132,6 +1132,8 @@ extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector, > sector_t nr_sects, gfp_t gfp_mask, struct page *page); > extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, > sector_t nr_sects, gfp_t gfp_mask, bool discard); > +extern int blkdev_ensure_space_exists(struct block_device *bdev, sector_t sector, > + sector_t nr_sects, unsigned long flags); > static inline int sb_issue_discard(struct super_block *sb, sector_t block, > sector_t nr_blocks, gfp_t gfp_mask, unsigned long flags) > { > -- > 2.6.4 (Apple Git-63) > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
