cifs: add fiemap support

Useful for improved copy performance as well as for
applications which query allocated ranges of sparse
files.
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsfs.c

@@ -986,6 +986,7 @@ const struct inode_operations cifs_file_inode_ops = {
 	.getattr = cifs_getattr,
 	.permission = cifs_permission,
 	.listxattr = cifs_listxattr,
+	.fiemap = cifs_fiemap,
 };
 
 const struct inode_operations cifs_symlink_inode_ops = {

fs/cifs/cifsfs.h

@@ -84,6 +84,8 @@ extern int cifs_revalidate_mapping(struct inode *inode);
 extern int cifs_zap_mapping(struct inode *inode);
 extern int cifs_getattr(const struct path *, struct kstat *, u32, unsigned int);
 extern int cifs_setattr(struct dentry *, struct iattr *);
+extern int cifs_fiemap(struct inode *, struct fiemap_extent_info *, u64 start,
+		       u64 len);
 
 extern const struct inode_operations cifs_file_inode_ops;
 extern const struct inode_operations cifs_symlink_inode_ops;

fs/cifs/cifsglob.h

@@ -493,6 +493,9 @@ struct smb_version_operations {
 			 char *full_path,
 			 umode_t mode,
 			 dev_t device_number);
+	/* version specific fiemap implementation */
+	int (*fiemap)(struct cifs_tcon *tcon, struct cifsFileInfo *,
+		      struct fiemap_extent_info *, u64, u64);
 };
 
 struct smb_version_values {

fs/cifs/inode.c

@@ -2116,6 +2116,43 @@ int cifs_getattr(const struct path *path, struct kstat *stat,
 	return rc;
 }
 
+int cifs_fiemap(struct inode *inode, struct fiemap_extent_info *fei, u64 start,
+		u64 len)
+{
+	struct cifsInodeInfo *cifs_i = CIFS_I(inode);
+	struct cifs_sb_info *cifs_sb = CIFS_SB(cifs_i->vfs_inode.i_sb);
+	struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+	struct TCP_Server_Info *server = tcon->ses->server;
+	struct cifsFileInfo *cfile;
+	int rc;
+
+	/*
+	 * We need to be sure that all dirty pages are written as they
+	 * might fill holes on the server.
+	 */
+	if (!CIFS_CACHE_READ(CIFS_I(inode)) && inode->i_mapping &&
+	    inode->i_mapping->nrpages != 0) {
+		rc = filemap_fdatawait(inode->i_mapping);
+		if (rc) {
+			mapping_set_error(inode->i_mapping, rc);
+			return rc;
+		}
+	}
+
+	cfile = find_readable_file(cifs_i, false);
+	if (cfile == NULL)
+		return -EINVAL;
+
+	if (server->ops->fiemap) {
+		rc = server->ops->fiemap(tcon, cfile, fei, start, len);
+		cifsFileInfo_put(cfile);
+		return rc;
+	}
+
+	cifsFileInfo_put(cfile);
+	return -ENOTSUPP;
+}
+
 static int cifs_truncate_page(struct address_space *mapping, loff_t from)
 {
 	pgoff_t index = from >> PAGE_SHIFT;

fs/cifs/smb2ops.c

@@ -2886,6 +2886,79 @@ static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
 	return rc;
 }
 
+static int smb3_fiemap(struct cifs_tcon *tcon,
+		       struct cifsFileInfo *cfile,
+		       struct fiemap_extent_info *fei, u64 start, u64 len)
+{
+	unsigned int xid;
+	struct file_allocated_range_buffer in_data, *out_data;
+	u32 out_data_len;
+	int i, num, rc, flags, last_blob;
+	u64 next;
+
+	if (fiemap_check_flags(fei, FIEMAP_FLAG_SYNC))
+		return -EBADR;
+
+	xid = get_xid();
+ again:
+	in_data.file_offset = cpu_to_le64(start);
+	in_data.length = cpu_to_le64(len);
+
+	rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
+			cfile->fid.volatile_fid,
+			FSCTL_QUERY_ALLOCATED_RANGES, true,
+			(char *)&in_data, sizeof(in_data),
+			1024 * sizeof(struct file_allocated_range_buffer),
+			(char **)&out_data, &out_data_len);
+	if (rc == -E2BIG) {
+		last_blob = 0;
+		rc = 0;
+	} else
+		last_blob = 1;
+	if (rc)
+		goto out;
+
+	if (out_data_len < sizeof(struct file_allocated_range_buffer)) {
+		rc = -EINVAL;
+		goto out;
+	}
+	if (out_data_len % sizeof(struct file_allocated_range_buffer)) {
+		rc = -EINVAL;
+		goto out;
+	}
+
+	num = out_data_len / sizeof(struct file_allocated_range_buffer);
+	for (i = 0; i < num; i++) {
+		flags = 0;
+		if (i == num - 1 && last_blob)
+			flags |= FIEMAP_EXTENT_LAST;
+
+		rc = fiemap_fill_next_extent(fei,
+				le64_to_cpu(out_data[i].file_offset),
+				le64_to_cpu(out_data[i].file_offset),
+				le64_to_cpu(out_data[i].length),
+				flags);
+		if (rc < 0)
+			goto out;
+		if (rc == 1) {
+			rc = 0;
+			goto out;
+		}
+	}
+
+	if (!last_blob) {
+		next = le64_to_cpu(out_data[num - 1].file_offset) +
+		  le64_to_cpu(out_data[num - 1].length);
+		len = len - (next - start);
+		start = next;
+		goto again;
+	}
+
+ out:
+	free_xid(xid);
+	kfree(out_data);
+	return rc;
+}
 
 static long smb3_fallocate(struct file *file, struct cifs_tcon *tcon, int mode,
 			   loff_t off, loff_t len)
@@ -4054,6 +4127,7 @@ struct smb_version_operations smb20_operations = {
 	.next_header = smb2_next_header,
 	.ioctl_query_info = smb2_ioctl_query_info,
 	.make_node = smb2_make_node,
+	.fiemap = smb3_fiemap,
 };
 
 struct smb_version_operations smb21_operations = {
@@ -4153,6 +4227,7 @@ struct smb_version_operations smb21_operations = {
 	.next_header = smb2_next_header,
 	.ioctl_query_info = smb2_ioctl_query_info,
 	.make_node = smb2_make_node,
+	.fiemap = smb3_fiemap,
 };
 
 struct smb_version_operations smb30_operations = {
@@ -4261,6 +4336,7 @@ struct smb_version_operations smb30_operations = {
 	.next_header = smb2_next_header,
 	.ioctl_query_info = smb2_ioctl_query_info,
 	.make_node = smb2_make_node,
+	.fiemap = smb3_fiemap,
 };
 
 struct smb_version_operations smb311_operations = {
@@ -4370,6 +4446,7 @@ struct smb_version_operations smb311_operations = {
 	.next_header = smb2_next_header,
 	.ioctl_query_info = smb2_ioctl_query_info,
 	.make_node = smb2_make_node,
+	.fiemap = smb3_fiemap,
 };
 
 struct smb_version_values smb20_values = {

fs/cifs/smb2pdu.c

@@ -2622,7 +2622,7 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 		trace_smb3_fsctl_err(xid, persistent_fid, tcon->tid,
 				ses->Suid, 0, opcode, rc);
 
-	if ((rc != 0) && (rc != -EINVAL)) {
+	if ((rc != 0) && (rc != -EINVAL) && (rc != -E2BIG)) {
 		cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
 		goto ioctl_exit;
 	} else if (rc == -EINVAL) {
@@ -2631,6 +2631,11 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 			cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
 			goto ioctl_exit;
 		}
+	} else if (rc == -E2BIG) {
+		if (opcode != FSCTL_QUERY_ALLOCATED_RANGES) {
+			cifs_stats_fail_inc(tcon, SMB2_IOCTL_HE);
+			goto ioctl_exit;
+		}
 	}
 
 	/* check if caller wants to look at return data or just return rc */

fs/cifs/smb2pdu.h

@@ -868,6 +868,11 @@ struct fsctl_get_integrity_information_rsp {
 	__le32	ClusterSizeInBytes;
 } __packed;
 
+struct file_allocated_range_buffer {
+	__le64	file_offset;
+	__le64	length;
+} __packed;
+
 /* Integrity ChecksumAlgorithm choices for above */
 #define	CHECKSUM_TYPE_NONE	0x0000
 #define	CHECKSUM_TYPE_CRC64	0x0002

fs/cifs/smbfsctl.h

@@ -103,7 +103,7 @@
 #define FSCTL_SET_ZERO_ON_DEALLOC    0x00090194 /* BB add struct */
 #define FSCTL_SET_SHORT_NAME_BEHAVIOR 0x000901B4 /* BB add struct */
 #define FSCTL_GET_INTEGRITY_INFORMATION 0x0009027C
-#define FSCTL_QUERY_ALLOCATED_RANGES 0x000940CF /* BB add struct */
+#define FSCTL_QUERY_ALLOCATED_RANGES 0x000940CF
 #define FSCTL_SET_DEFECT_MANAGEMENT  0x00098134 /* BB add struct */
 #define FSCTL_FILE_LEVEL_TRIM        0x00098208 /* BB add struct */
 #define FSCTL_DUPLICATE_EXTENTS_TO_FILE 0x00098344