Commit 1383a7ed authored by Darrick J. Wong's avatar Darrick J. Wong Committed by Dave Chinner
Browse files

vfs: check file ranges before cloning files 



Move the file range checks from vfs_clone_file_prep into a separate
generic_remap_checks function so that all the checks are collected in a
central location.  This forms the basis for adding more checks from
generic_write_checks that will make cloning's input checking more
consistent with write input checking.

Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent 5b49f64d

fs/ocfs2/refcounttree.c

+1 −1
Original line number Diff line number Diff line
@@ -4850,7 +4850,7 @@ int ocfs2_reflink_remap_range(struct file *file_in, 
	    (OCFS2_I(inode_out)->ip_flags & OCFS2_INODE_SYSTEM_FILE))

		goto out_unlock;



	ret = vfs_clone_file_prep_inodes(inode_in, pos_in, inode_out, pos_out,

	ret = vfs_clone_file_prep(file_in, pos_in, file_out, pos_out,

			&len, is_dedupe);

	if (ret <= 0)

		goto out_unlock;

fs/read_write.c

+13 −42
Original line number Diff line number Diff line
@@ -1717,13 +1717,12 @@ static int clone_verify_area(struct file *file, loff_t pos, u64 len, bool write) 
 * Returns: 0 for "nothing to clone", 1 for "something to clone", or

 * the usual negative error code.

 */

int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,

			       struct inode *inode_out, loff_t pos_out,

int vfs_clone_file_prep(struct file *file_in, loff_t pos_in,

			struct file *file_out, loff_t pos_out,

			u64 *len, bool is_dedupe)

{

	loff_t bs = inode_out->i_sb->s_blocksize;

	loff_t blen;

	loff_t isize;

	struct inode *inode_in = file_inode(file_in);

	struct inode *inode_out = file_inode(file_out);

	bool same_inode = (inode_in == inode_out);

	int ret;
@@ -1740,10 +1739,10 @@ int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in, 
	if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))

		return -EINVAL;



	isize = i_size_read(inode_in);



	/* Zero length dedupe exits immediately; reflink goes to EOF. */

	if (*len == 0) {

		loff_t isize = i_size_read(inode_in);



		if (is_dedupe || pos_in == isize)

			return 0;

		if (pos_in > isize)
@@ -1751,36 +1750,11 @@ int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in, 
		*len = isize - pos_in;

	}



	/* Ensure offsets don't wrap and the input is inside i_size */

	if (pos_in + *len < pos_in || pos_out + *len < pos_out ||

	    pos_in + *len > isize)

		return -EINVAL;



	/* Don't allow dedupe past EOF in the dest file */

	if (is_dedupe) {

		loff_t	disize;



		disize = i_size_read(inode_out);

		if (pos_out >= disize || pos_out + *len > disize)

			return -EINVAL;

	}



	/* If we're linking to EOF, continue to the block boundary. */

	if (pos_in + *len == isize)

		blen = ALIGN(isize, bs) - pos_in;

	else

		blen = *len;



	/* Only reflink if we're aligned to block boundaries */

	if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_in + blen, bs) ||

	    !IS_ALIGNED(pos_out, bs) || !IS_ALIGNED(pos_out + blen, bs))

		return -EINVAL;



	/* Don't allow overlapped reflink within the same file */

	if (same_inode) {

		if (pos_out + blen > pos_in && pos_out < pos_in + blen)

			return -EINVAL;

	}

	/* Check that we don't violate system file offset limits. */

	ret = generic_remap_checks(file_in, pos_in, file_out, pos_out, len,

			is_dedupe);

	if (ret)

		return ret;



	/* Wait for the completion of any pending IOs on both files */

	inode_dio_wait(inode_in);
@@ -1813,7 +1787,7 @@ int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in, 


	return 1;

}

EXPORT_SYMBOL(vfs_clone_file_prep_inodes);

EXPORT_SYMBOL(vfs_clone_file_prep);



int do_clone_file_range(struct file *file_in, loff_t pos_in,

			struct file *file_out, loff_t pos_out, u64 len)
@@ -1851,9 +1825,6 @@ int do_clone_file_range(struct file *file_in, loff_t pos_in, 
	if (ret)

		return ret;



	if (pos_in + len > i_size_read(inode_in))

		return -EINVAL;



	ret = file_in->f_op->clone_file_range(file_in, pos_in,

			file_out, pos_out, len);

	if (!ret) {

fs/xfs/xfs_reflink.c

+1 −1
Original line number Diff line number Diff line
@@ -1326,7 +1326,7 @@ xfs_reflink_remap_prep( 
	if (IS_DAX(inode_in) || IS_DAX(inode_out))

		goto out_unlock;



	ret = vfs_clone_file_prep_inodes(inode_in, pos_in, inode_out, pos_out,

	ret = vfs_clone_file_prep(file_in, pos_in, file_out, pos_out,

			len, is_dedupe);

	if (ret <= 0)

		goto out_unlock;

include/linux/fs.h

+6 −3
Original line number Diff line number Diff line
@@ -1825,9 +1825,9 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *, 
		unsigned long, loff_t *, rwf_t);

extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *,

				   loff_t, size_t, unsigned int);

extern int vfs_clone_file_prep_inodes(struct inode *inode_in, loff_t pos_in,

				      struct inode *inode_out, loff_t pos_out,

				      u64 *len, bool is_dedupe);

extern int vfs_clone_file_prep(struct file *file_in, loff_t pos_in,

			       struct file *file_out, loff_t pos_out,

			       u64 *count, bool is_dedupe);

extern int do_clone_file_range(struct file *file_in, loff_t pos_in,

			       struct file *file_out, loff_t pos_out, u64 len);

extern int vfs_clone_file_range(struct file *file_in, loff_t pos_in,
@@ -2967,6 +2967,9 @@ extern int sb_min_blocksize(struct super_block *, int); 
extern int generic_file_mmap(struct file *, struct vm_area_struct *);

extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);

extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);

extern int generic_remap_checks(struct file *file_in, loff_t pos_in,

				struct file *file_out, loff_t pos_out,

				uint64_t *count, bool is_dedupe);

extern ssize_t generic_file_read_iter(struct kiocb *, struct iov_iter *);

extern ssize_t __generic_file_write_iter(struct kiocb *, struct iov_iter *);

extern ssize_t generic_file_write_iter(struct kiocb *, struct iov_iter *);

mm/filemap.c

+69 −0
Original line number Diff line number Diff line
@@ -2974,6 +2974,75 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) 
}

EXPORT_SYMBOL(generic_write_checks);



/*

 * Performs necessary checks before doing a clone.

 *

 * Can adjust amount of bytes to clone.

 * Returns appropriate error code that caller should return or

 * zero in case the clone should be allowed.

 */

int generic_remap_checks(struct file *file_in, loff_t pos_in,

			 struct file *file_out, loff_t pos_out,

			 uint64_t *req_count, bool is_dedupe)

{

	struct inode *inode_in = file_in->f_mapping->host;

	struct inode *inode_out = file_out->f_mapping->host;

	uint64_t count = *req_count;

	uint64_t bcount;

	loff_t size_in, size_out;

	loff_t bs = inode_out->i_sb->s_blocksize;



	/* The start of both ranges must be aligned to an fs block. */

	if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_out, bs))

		return -EINVAL;



	/* Ensure offsets don't wrap. */

	if (pos_in + count < pos_in || pos_out + count < pos_out)

		return -EINVAL;



	size_in = i_size_read(inode_in);

	size_out = i_size_read(inode_out);



	/* Dedupe requires both ranges to be within EOF. */

	if (is_dedupe &&

	    (pos_in >= size_in || pos_in + count > size_in ||

	     pos_out >= size_out || pos_out + count > size_out))

		return -EINVAL;



	/* Ensure the infile range is within the infile. */

	if (pos_in >= size_in)

		return -EINVAL;

	count = min(count, size_in - (uint64_t)pos_in);



	/*

	 * If the user wanted us to link to the infile's EOF, round up to the

	 * next block boundary for this check.

	 *

	 * Otherwise, make sure the count is also block-aligned, having

	 * already confirmed the starting offsets' block alignment.

	 */

	if (pos_in + count == size_in) {

		bcount = ALIGN(size_in, bs) - pos_in;

	} else {

		if (!IS_ALIGNED(count, bs))

			return -EINVAL;



		bcount = count;

	}



	/* Don't allow overlapped cloning within the same file. */

	if (inode_in == inode_out &&

	    pos_out + bcount > pos_in &&

	    pos_out < pos_in + bcount)

		return -EINVAL;



	/* For now we don't support changing the length. */

	if (*req_count != count)

		return -EINVAL;



	return 0;

}



int pagecache_write_begin(struct file *file, struct address_space *mapping,

				loff_t pos, unsigned len, unsigned flags,

				struct page **pagep, void **fsdata)

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