Commit 9ccf3216 authored by Steve French's avatar Steve French Committed by Steve French
Browse files

Add support for original fallocate 



In many cases the simple fallocate call is
a no op (since the file is already not sparse) or
can simply be converted from a sparse to a non-sparse
file if we are fallocating the whole file and keeping
the size.

Signed-off-by: default avatarSteven French <smfrench@gmail.com>
parent b2776bf7

fs/cifs/smb2ops.c

+62 −1
Original line number Diff line number Diff line
@@ -1102,6 +1102,64 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon, 
	return rc;

}



static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,

			    loff_t off, loff_t len, bool keep_size)

{

	struct inode *inode;

	struct cifsInodeInfo *cifsi;

	struct cifsFileInfo *cfile = file->private_data;

	long rc = -EOPNOTSUPP;

	unsigned int xid;



	xid = get_xid();



	inode = cfile->dentry->d_inode;

	cifsi = CIFS_I(inode);



	/* if file not oplocked can't be sure whether asking to extend size */

	if (!CIFS_CACHE_READ(cifsi))

		if (keep_size == false)

			return -EOPNOTSUPP;



	/*

	 * Files are non-sparse by default so falloc may be a no-op

	 * Must check if file sparse. If not sparse, and not extending

	 * then no need to do anything since file already allocated

	 */

	if ((cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE) == 0) {

		if (keep_size == true)

			return 0;

		/* check if extending file */

		else if (i_size_read(inode) >= off + len)

			/* not extending file and already not sparse */

			return 0;

		/* BB: in future add else clause to extend file */

		else

			return -EOPNOTSUPP;

	}



	if ((keep_size == true) || (i_size_read(inode) >= off + len)) {

		/*

		 * Check if falloc starts within first few pages of file

		 * and ends within a few pages of the end of file to

		 * ensure that most of file is being forced to be

		 * fallocated now. If so then setting whole file sparse

		 * ie potentially making a few extra pages at the beginning

		 * or end of the file non-sparse via set_sparse is harmless.

		 */

		if ((off > 8192) || (off + len + 8192 < i_size_read(inode)))

			return -EOPNOTSUPP;



		rc = smb2_set_sparse(xid, tcon, cfile, inode, false);

	}

	/* BB: else ... in future add code to extend file and set sparse */





	free_xid(xid);

	return rc;

}





static long smb3_fallocate(struct file *file, struct cifs_tcon *tcon, int mode,

			   loff_t off, loff_t len)

{
@@ -1112,7 +1170,10 @@ static long smb3_fallocate(struct file *file, struct cifs_tcon *tcon, int mode, 
		if (mode & FALLOC_FL_KEEP_SIZE)

			return smb3_zero_range(file, tcon, off, len, true);

		return smb3_zero_range(file, tcon, off, len, false);

	}

	} else if (mode == FALLOC_FL_KEEP_SIZE)

		return smb3_simple_falloc(file, tcon, off, len, true);

	else if (mode == 0)

		return smb3_simple_falloc(file, tcon, off, len, false);



	return -EOPNOTSUPP;

}