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Commit 30175628 authored by Steve French's avatar Steve French
Browse files

[SMB3] Enable fallocate -z support for SMB3 mounts 



fallocate -z (FALLOC_FL_ZERO_RANGE) can map to SMB3
FSCTL_SET_ZERO_DATA SMB3 FSCTL but FALLOC_FL_ZERO_RANGE
when called without the FALLOC_FL_KEEPSIZE flag set could want
the file size changed so we can not support that subcase unless
the file is cached (and thus we know the file size).

Signed-off-by: default avatarSteve French <smfrench@gmail.com>
Reviewed-by: default avatarPavel Shilovsky <pshilovsky@samba.org>
parent 31742c5a

fs/cifs/smb2ops.c

+55 −0
Original line number Diff line number Diff line
@@ -1015,6 +1015,56 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon, 
	return rc;

}



static long smb3_zero_range(struct file *file, struct cifs_tcon *tcon,

			    loff_t offset, loff_t len, bool keep_size)

{

	struct inode *inode;

	struct cifsInodeInfo *cifsi;

	struct cifsFileInfo *cfile = file->private_data;

	struct file_zero_data_information fsctl_buf;

	long rc;

	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;



	/* 

	 * Must check if file sparse since fallocate -z (zero range) assumes

	 * non-sparse allocation

	 */

	if (!(cifsi->cifsAttrs & FILE_ATTRIBUTE_SPARSE_FILE))

		return -EOPNOTSUPP;



	/*

	 * need to make sure we are not asked to extend the file since the SMB3

	 * fsctl does not change the file size. In the future we could change

	 * this to zero the first part of the range then set the file size

	 * which for a non sparse file would zero the newly extended range

	 */

	if (keep_size == false)

		if (i_size_read(inode) < offset + len)

			return -EOPNOTSUPP;



	cifs_dbg(FYI, "offset %lld len %lld", offset, len);



	fsctl_buf.FileOffset = cpu_to_le64(offset);

	fsctl_buf.BeyondFinalZero = cpu_to_le64(offset + len);



	rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,

			cfile->fid.volatile_fid, FSCTL_SET_ZERO_DATA,

			true /* is_fctl */, (char *)&fsctl_buf,

			sizeof(struct file_zero_data_information), NULL, NULL);

	free_xid(xid);

	return rc;

}



static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,

			    loff_t offset, loff_t len)

{
@@ -1055,6 +1105,11 @@ static long smb3_fallocate(struct file *file, struct cifs_tcon *tcon, int mode, 
	/* KEEP_SIZE already checked for by do_fallocate */

	if (mode & FALLOC_FL_PUNCH_HOLE)

		return smb3_punch_hole(file, tcon, off, len);

	else if (mode & FALLOC_FL_ZERO_RANGE) {

		if (mode & FALLOC_FL_KEEP_SIZE)

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

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

	}



	return -EOPNOTSUPP;

}