Add way to query server fs info for smb3

The server exports information about the share and underlying
device under an SMB3 export, including its attributes and
capabilities, which is stored by cifs.ko when first connecting
to the share.

Add ioctl to cifs.ko to allow user space smb3 helper utilities
(in cifs-utils) to display this (e.g. via smb3util).

This information is also useful for debugging and for
resolving configuration errors.

Signed-off-by: Steve French <steve.french@primarydata.com>

1 files changed, 42 insertions, 6 deletions

diff --git a/fs/cifs/ioctl.c b/fs/cifs/ioctl.c
index 49b8b6e41a18..c63f5227b681 100644
--- a/fs/cifs/ioctl.c
+++ b/fs/cifs/ioctl.c
@@ -31,12 +31,9 @@
 #include "cifsproto.h"
 #include "cifs_debug.h"
 #include "cifsfs.h"
+#include "cifs_ioctl.h"
 #include <linux/btrfs.h>
 
-#define CIFS_IOCTL_MAGIC	0xCF
-#define CIFS_IOC_COPYCHUNK_FILE	_IOW(CIFS_IOCTL_MAGIC, 3, int)
-#define CIFS_IOC_SET_INTEGRITY  _IO(CIFS_IOCTL_MAGIC, 4)
-
 static long cifs_ioctl_clone(unsigned int xid, struct file *dst_file,
 			unsigned long srcfd, u64 off, u64 len, u64 destoff,
 			bool dup_extents)
@@ -135,6 +132,43 @@ out_drop_write:
 	return rc;
 }
 
+static long smb_mnt_get_fsinfo(unsigned int xid, struct cifs_tcon *tcon,
+				void __user *arg)
+{
+	int rc = 0;
+	struct smb_mnt_fs_info *fsinf;
+
+	fsinf = kzalloc(sizeof(struct smb_mnt_fs_info), GFP_KERNEL);
+	if (fsinf == NULL)
+		return -ENOMEM;
+
+	fsinf->version = 1;
+	fsinf->protocol_id = tcon->ses->server->vals->protocol_id;
+	fsinf->device_characteristics =
+			le32_to_cpu(tcon->fsDevInfo.DeviceCharacteristics);
+	fsinf->device_type = le32_to_cpu(tcon->fsDevInfo.DeviceType);
+	fsinf->fs_attributes = le32_to_cpu(tcon->fsAttrInfo.Attributes);
+	fsinf->max_path_component =
+		le32_to_cpu(tcon->fsAttrInfo.MaxPathNameComponentLength);
+#ifdef CONFIG_CIFS_SMB2
+	fsinf->vol_serial_number = tcon->vol_serial_number;
+	fsinf->vol_create_time = le64_to_cpu(tcon->vol_create_time);
+	fsinf->share_flags = tcon->share_flags;
+	fsinf->share_caps = le32_to_cpu(tcon->capabilities);
+	fsinf->sector_flags = tcon->ss_flags;
+	fsinf->optimal_sector_size = tcon->perf_sector_size;
+	fsinf->max_bytes_chunk = tcon->max_bytes_chunk;
+	fsinf->maximal_access = tcon->maximal_access;
+#endif /* SMB2 */
+	fsinf->cifs_posix_caps = le64_to_cpu(tcon->fsUnixInfo.Capability);
+
+	if (copy_to_user(arg, fsinf, sizeof(struct smb_mnt_fs_info)))
+		rc = -EFAULT;
+
+	kfree(fsinf);
+	return rc;
+}
+
 long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
 {
 	struct inode *inode = file_inode(filep);
@@ -148,8 +182,6 @@ long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
 
 	xid = get_xid();
 
-	cifs_dbg(FYI, "ioctl file %p  cmd %u  arg %lu\n", filep, command, arg);
-
 	cifs_sb = CIFS_SB(inode->i_sb);
 
 	switch (command) {
@@ -228,6 +260,10 @@ long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
 			else
 				rc = -EOPNOTSUPP;
 			break;
+		case CIFS_IOC_GET_MNT_INFO:
+			tcon = tlink_tcon(pSMBFile->tlink);
+			rc = smb_mnt_get_fsinfo(xid, tcon, (void __user *)arg);
+			break;
 		default:
 			cifs_dbg(FYI, "unsupported ioctl\n");
 			break;