vfs: refactor clone/dedupe_file_range common functions

Hoist both the XFS reflink inode state and preparation code and the XFS
file blocks compare functions into the VFS so that ocfs2 can take
advantage of it for reflink and dedupe.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

1 files changed, 9 insertions, 204 deletions

diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index a279b4e..95d6828 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1165,111 +1165,6 @@ err:
 }
 
 /*
- * Read a page's worth of file data into the page cache.  Return the page
- * locked.
- */
-static struct page *
-xfs_get_page(
-	struct inode	*inode,
-	xfs_off_t	offset)
-{
-	struct address_space	*mapping;
-	struct page		*page;
-	pgoff_t			n;
-
-	n = offset >> PAGE_SHIFT;
-	mapping = inode->i_mapping;
-	page = read_mapping_page(mapping, n, NULL);
-	if (IS_ERR(page))
-		return page;
-	if (!PageUptodate(page)) {
-		put_page(page);
-		return ERR_PTR(-EIO);
-	}
-	lock_page(page);
-	return page;
-}
-
-/*
- * Compare extents of two files to see if they are the same.
- */
-static int
-xfs_compare_extents(
-	struct inode	*src,
-	xfs_off_t	srcoff,
-	struct inode	*dest,
-	xfs_off_t	destoff,
-	xfs_off_t	len,
-	bool		*is_same)
-{
-	xfs_off_t	src_poff;
-	xfs_off_t	dest_poff;
-	void		*src_addr;
-	void		*dest_addr;
-	struct page	*src_page;
-	struct page	*dest_page;
-	xfs_off_t	cmp_len;
-	bool		same;
-	int		error;
-
-	error = -EINVAL;
-	same = true;
-	while (len) {
-		src_poff = srcoff & (PAGE_SIZE - 1);
-		dest_poff = destoff & (PAGE_SIZE - 1);
-		cmp_len = min(PAGE_SIZE - src_poff,
-			      PAGE_SIZE - dest_poff);
-		cmp_len = min(cmp_len, len);
-		ASSERT(cmp_len > 0);
-
-		trace_xfs_reflink_compare_extents(XFS_I(src), srcoff, cmp_len,
-				XFS_I(dest), destoff);
-
-		src_page = xfs_get_page(src, srcoff);
-		if (IS_ERR(src_page)) {
-			error = PTR_ERR(src_page);
-			goto out_error;
-		}
-		dest_page = xfs_get_page(dest, destoff);
-		if (IS_ERR(dest_page)) {
-			error = PTR_ERR(dest_page);
-			unlock_page(src_page);
-			put_page(src_page);
-			goto out_error;
-		}
-		src_addr = kmap_atomic(src_page);
-		dest_addr = kmap_atomic(dest_page);
-
-		flush_dcache_page(src_page);
-		flush_dcache_page(dest_page);
-
-		if (memcmp(src_addr + src_poff, dest_addr + dest_poff, cmp_len))
-			same = false;
-
-		kunmap_atomic(dest_addr);
-		kunmap_atomic(src_addr);
-		unlock_page(dest_page);
-		unlock_page(src_page);
-		put_page(dest_page);
-		put_page(src_page);
-
-		if (!same)
-			break;
-
-		srcoff += cmp_len;
-		destoff += cmp_len;
-		len -= cmp_len;
-	}
-
-	*is_same = same;
-	return 0;
-
-out_error:
-	trace_xfs_reflink_compare_extents_error(XFS_I(dest), error, _RET_IP_);
-	return error;
-}
-
-/*
  * Link a range of blocks from one file to another.
  */
 int
@@ -1286,14 +1181,11 @@ xfs_reflink_remap_range(
 	struct inode		*inode_out = file_inode(file_out);
 	struct xfs_inode	*dest = XFS_I(inode_out);
 	struct xfs_mount	*mp = src->i_mount;
-	loff_t			bs = inode_out->i_sb->s_blocksize;
 	bool			same_inode = (inode_in == inode_out);
 	xfs_fileoff_t		sfsbno, dfsbno;
 	xfs_filblks_t		fsblen;
 	xfs_extlen_t		cowextsize;
-	loff_t			isize;
 	ssize_t			ret;
-	loff_t			blen;
 
 	if (!xfs_sb_version_hasreflink(&mp->m_sb))
 		return -EOPNOTSUPP;
@@ -1310,26 +1202,8 @@ xfs_reflink_remap_range(
 		xfs_lock_two_inodes(src, dest, XFS_MMAPLOCK_EXCL);
 	}
 
-	/* Don't touch certain kinds of inodes */
-	ret = -EPERM;
-	if (IS_IMMUTABLE(inode_out))
-		goto out_unlock;
-
-	ret = -ETXTBSY;
-	if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))
-		goto out_unlock;
-
-
-	/* Don't reflink dirs, pipes, sockets... */
-	ret = -EISDIR;
-	if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
-		goto out_unlock;
+	/* Check file eligibility and prepare for block sharing. */
 	ret = -EINVAL;
-	if (S_ISFIFO(inode_in->i_mode) || S_ISFIFO(inode_out->i_mode))
-		goto out_unlock;
-	if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
-		goto out_unlock;
-
 	/* Don't reflink realtime inodes */
 	if (XFS_IS_REALTIME_INODE(src) || XFS_IS_REALTIME_INODE(dest))
 		goto out_unlock;
@@ -1338,91 +1212,18 @@ xfs_reflink_remap_range(
 	if (IS_DAX(inode_in) || IS_DAX(inode_out))
 		goto out_unlock;
 
-	/* Are we going all the way to the end? */
-	isize = i_size_read(inode_in);
-	if (isize == 0) {
-		ret = 0;
-		goto out_unlock;
-	}
-
-	if (len == 0)
-		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)
-		goto out_unlock;
-
-	/* 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)
-			goto out_unlock;
-	}
-
-	/* 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))
-		goto out_unlock;
-
-	/* Don't allow overlapped reflink within the same file */
-	if (same_inode) {
-		if (pos_out + blen > pos_in && pos_out < pos_in + blen)
-			goto out_unlock;
-	}
-
-	/* Wait for the completion of any pending IOs on both files */
-	inode_dio_wait(inode_in);
-	if (!same_inode)
-		inode_dio_wait(inode_out);
-
-	ret = filemap_write_and_wait_range(inode_in->i_mapping,
-			pos_in, pos_in + len - 1);
-	if (ret)
-		goto out_unlock;
-
-	ret = filemap_write_and_wait_range(inode_out->i_mapping,
-			pos_out, pos_out + len - 1);
-	if (ret)
+	ret = vfs_clone_file_prep_inodes(inode_in, pos_in, inode_out, pos_out,
+			&len, is_dedupe);
+	if (ret || len == 0)
 		goto out_unlock;
 
 	trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);
 
-	/*
-	 * Check that the extents are the same.
-	 */
-	if (is_dedupe) {
-		bool		is_same = false;
-
-		ret = xfs_compare_extents(inode_in, pos_in, inode_out, pos_out,
-				len, &is_same);
-		if (ret)
-			goto out_unlock;
-		if (!is_same) {
-			ret = -EBADE;
-			goto out_unlock;
-		}
-	}
-
+	/* Set flags and remap blocks. */
 	ret = xfs_reflink_set_inode_flag(src, dest);
 	if (ret)
 		goto out_unlock;
 
-	/*
-	 * Invalidate the page cache so that we can clear any CoW mappings
-	 * in the destination file.
-	 */
-	truncate_inode_pages_range(&inode_out->i_data, pos_out,
-				   PAGE_ALIGN(pos_out + len) - 1);
-
 	dfsbno = XFS_B_TO_FSBT(mp, pos_out);
 	sfsbno = XFS_B_TO_FSBT(mp, pos_in);
 	fsblen = XFS_B_TO_FSB(mp, len);
@@ -1431,6 +1232,10 @@ xfs_reflink_remap_range(
 	if (ret)
 		goto out_unlock;
 
+	/* Zap any page cache for the destination file's range. */
+	truncate_inode_pages_range(&inode_out->i_data, pos_out,
+				   PAGE_ALIGN(pos_out + len) - 1);
+
 	/*
 	 * Carry the cowextsize hint from src to dest if we're sharing the
 	 * entire source file to the entire destination file, the source file