From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx> Subject: 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@xxxxxxxxxxxxxxxx Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Reviewed-by: Hannes Reinecke <hare@xxxxxxxx> Reviewed-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> Cc: Theodore Ts'o <tytso@xxxxxxx> Cc: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Cc: Mike Snitzer <snitzer@xxxxxxxxxx> # tweaked header Cc: Brian Foster <bfoster@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Hannes Reinecke <hare@xxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/block_dev.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++ fs/open.c | 3 + 2 files changed, 79 insertions(+), 1 deletion(-) diff -puN fs/block_dev.c~block-implement-some-of-fallocate-for-block-devices fs/block_dev.c --- a/fs/block_dev.c~block-implement-some-of-fallocate-for-block-devices +++ a/fs/block_dev.c @@ -30,6 +30,7 @@ #include <linux/cleancache.h> #include <linux/dax.h> #include <linux/badblocks.h> +#include <linux/falloc.h> #include <asm/uaccess.h> #include "internal.h" @@ -1775,6 +1776,81 @@ static const struct address_space_operat .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_fop #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 -puN fs/open.c~block-implement-some-of-fallocate-for-block-devices fs/open.c --- a/fs/open.c~block-implement-some-of-fallocate-for-block-devices +++ a/fs/open.c @@ -300,7 +300,8 @@ int vfs_fallocate(struct file *file, int * 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 */ _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
