From 4b0228fa1d753f77fe0e6cf4c41398ec77dfbd2a Mon Sep 17 00:00:00 2001 From: Vishal Verma Date: Thu, 21 Apr 2016 15:13:46 -0400 Subject: dax: for truncate/hole-punch, do zeroing through the driver if possible In the truncate or hole-punch path in dax, we clear out sub-page ranges. If these sub-page ranges are sector aligned and sized, we can do the zeroing through the driver instead so that error-clearing is handled automatically. For sub-sector ranges, we still have to rely on clear_pmem and have the possibility of tripping over errors. Cc: Dan Williams Cc: Ross Zwisler Cc: Jeff Moyer Cc: Christoph Hellwig Cc: Dave Chinner Cc: Jan Kara Reviewed-by: Christoph Hellwig Reviewed-by: Jan Kara Signed-off-by: Vishal Verma --- fs/dax.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) (limited to 'fs/dax.c') diff --git a/fs/dax.c b/fs/dax.c index 651d4b18ac29..0b9a16934017 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -947,6 +947,19 @@ int dax_pfn_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) } EXPORT_SYMBOL_GPL(dax_pfn_mkwrite); +static bool dax_range_is_aligned(struct block_device *bdev, + unsigned int offset, unsigned int length) +{ + unsigned short sector_size = bdev_logical_block_size(bdev); + + if (!IS_ALIGNED(offset, sector_size)) + return false; + if (!IS_ALIGNED(length, sector_size)) + return false; + + return true; +} + int __dax_zero_page_range(struct block_device *bdev, sector_t sector, unsigned int offset, unsigned int length) { @@ -955,11 +968,18 @@ int __dax_zero_page_range(struct block_device *bdev, sector_t sector, .size = PAGE_SIZE, }; - if (dax_map_atomic(bdev, &dax) < 0) - return PTR_ERR(dax.addr); - clear_pmem(dax.addr + offset, length); - wmb_pmem(); - dax_unmap_atomic(bdev, &dax); + if (dax_range_is_aligned(bdev, offset, length)) { + sector_t start_sector = dax.sector + (offset >> 9); + + return blkdev_issue_zeroout(bdev, start_sector, + length >> 9, GFP_NOFS, true); + } else { + if (dax_map_atomic(bdev, &dax) < 0) + return PTR_ERR(dax.addr); + clear_pmem(dax.addr + offset, length); + wmb_pmem(); + dax_unmap_atomic(bdev, &dax); + } return 0; } EXPORT_SYMBOL_GPL(__dax_zero_page_range); -- cgit v1.2.3