Unverified Commit d8e1e0d3 authored by Konstantin Komarov's avatar Konstantin Komarov
Browse files

fs/ntfs3: check minimum alignment for direct I/O 



Add a check for minimum alignment when performing direct I/O reads. If the
file offset or user buffer is not aligned to the device's logical block
size, fall back to buffered I/O instead of continuing with unaligned direct I/O.

Signed-off-by: default avatarKonstantin Komarov <almaz.alexandrovich@paragon-software.com>
parent ae91dfe3

fs/ntfs3/file.c

+10 −0
Original line number Diff line number Diff line
@@ -941,6 +941,16 @@ static ssize_t ntfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) 
		file->f_ra.ra_pages = 0;

	}



	/* Check minimum alignment for dio. */

	if (iocb->ki_flags & IOCB_DIRECT) {

		struct super_block *sb = inode->i_sb;

		struct ntfs_sb_info *sbi = sb->s_fs_info;

		if ((iocb->ki_pos | iov_iter_alignment(iter)) &

		    sbi->bdev_blocksize_mask) {

			iocb->ki_flags &= ~IOCB_DIRECT;

		}

	}



	return generic_file_read_iter(iocb, iter);

}

fs/ntfs3/ntfs_fs.h

+1 −0
Original line number Diff line number Diff line
@@ -212,6 +212,7 @@ struct ntfs_sb_info { 


	u32 discard_granularity;

	u64 discard_granularity_mask_inv; // ~(discard_granularity_mask_inv-1)

	u32 bdev_blocksize_mask; // bdev_logical_block_size(bdev) - 1;



	u32 cluster_size; // bytes per cluster

	u32 cluster_mask; // == cluster_size - 1

fs/ntfs3/super.c

+1 −0
Original line number Diff line number Diff line
@@ -1075,6 +1075,7 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size, 
		dev_size += sector_size - 1;

	}



	sbi->bdev_blocksize_mask = max(boot_sector_size, sector_size) - 1;

	sbi->mft.lbo = mlcn << cluster_bits;

	sbi->mft.lbo2 = mlcn2 << cluster_bits;