From 25f4c41415e513f0e9fb1f3fce2ce98fcba8d263 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 11 Oct 2016 13:51:11 -0700 Subject: [PATCH] block: implement (some of) fallocate for block devices After much discussion, it seems that the fallocate feature flag FALLOC_FL_ZERO_RANGE maps nicely to SCSI WRITE SAME; and the feature FALLOC_FL_PUNCH_HOLE maps nicely to the devices that have been whitelisted for zeroing SCSI UNMAP. Punch still requires that FALLOC_FL_KEEP_SIZE is set. A length that goes past the end of the device will be clamped to the device size if KEEP_SIZE is set; or will return -EINVAL if not. Both start and length must be aligned to the device's logical block size. Since the semantics of fallocate are fairly well established already, wire up the two pieces. The other fallocate variants (collapse range, insert range, and allocate blocks) are not supported. Link: http://lkml.kernel.org/r/147518379992.22791.8849838163218235007.stgit@birch.djwong.org Signed-off-by: Darrick J. Wong Reviewed-by: Hannes Reinecke Reviewed-by: Bart Van Assche Cc: Theodore Ts'o Cc: Martin K. Petersen Cc: Mike Snitzer # tweaked header Cc: Brian Foster Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Jens Axboe Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/block_dev.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/open.c | 3 ++- 2 files changed, 79 insertions(+), 1 deletion(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index 376e4e4..05b55336 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include "internal.h" @@ -1775,6 +1776,81 @@ static const struct address_space_operations def_blk_aops = { .is_dirty_writeback = buffer_check_dirty_writeback, }; +#define BLKDEV_FALLOC_FL_SUPPORTED \ + (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ + FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE) + +static long blkdev_fallocate(struct file *file, int mode, loff_t start, + loff_t len) +{ + struct block_device *bdev = I_BDEV(bdev_file_inode(file)); + struct request_queue *q = bdev_get_queue(bdev); + struct address_space *mapping; + loff_t end = start + len - 1; + loff_t isize; + int error; + + /* Fail if we don't recognize the flags. */ + if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) + return -EOPNOTSUPP; + + /* Don't go off the end of the device. */ + isize = i_size_read(bdev->bd_inode); + if (start >= isize) + return -EINVAL; + if (end >= isize) { + if (mode & FALLOC_FL_KEEP_SIZE) { + len = isize - start; + end = start + len - 1; + } else + return -EINVAL; + } + + /* + * Don't allow IO that isn't aligned to logical block size. + */ + if ((start | len) & (bdev_logical_block_size(bdev) - 1)) + return -EINVAL; + + /* Invalidate the page cache, including dirty pages. */ + mapping = bdev->bd_inode->i_mapping; + truncate_inode_pages_range(mapping, start, end); + + switch (mode) { + case FALLOC_FL_ZERO_RANGE: + case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: + error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, + GFP_KERNEL, false); + break; + case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: + /* Only punch if the device can do zeroing discard. */ + if (!blk_queue_discard(q) || !q->limits.discard_zeroes_data) + return -EOPNOTSUPP; + error = blkdev_issue_discard(bdev, start >> 9, len >> 9, + GFP_KERNEL, 0); + break; + case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: + if (!blk_queue_discard(q)) + return -EOPNOTSUPP; + error = blkdev_issue_discard(bdev, start >> 9, len >> 9, + GFP_KERNEL, 0); + break; + default: + return -EOPNOTSUPP; + } + if (error) + return error; + + /* + * Invalidate again; if someone wandered in and dirtied a page, + * the caller will be given -EBUSY. The third argument is + * inclusive, so the rounding here is safe. + */ + return invalidate_inode_pages2_range(mapping, + start >> PAGE_SHIFT, + end >> PAGE_SHIFT); +} + const struct file_operations def_blk_fops = { .open = blkdev_open, .release = blkdev_close, @@ -1789,6 +1865,7 @@ const struct file_operations def_blk_fops = { #endif .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, + .fallocate = blkdev_fallocate, }; int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) diff --git a/fs/open.c b/fs/open.c index 8aeb08b..a7719cf 100644 --- a/fs/open.c +++ b/fs/open.c @@ -300,7 +300,8 @@ int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len) * Let individual file system decide if it supports preallocation * for directories or not. */ - if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) + if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode) && + !S_ISBLK(inode->i_mode)) return -ENODEV; /* Check for wrap through zero too */ -- 2.7.4