From: Steve French <stfrench@microsoft.com>
Date: Thu, 29 Apr 2021 00:18:43 -0500
Subject: [PATCH] cifs: add shutdown support
Git-commit: 087f757b0129850c99cc9116df4909dac1bce871
References: bsc#1190317
Patch-mainline: v5.13-rc1

Various filesystem support the shutdown ioctl which is used by various
xfstests. The shutdown ioctl sets a flag on the superblock which
prevents open, unlink, symlink, hardlink, rmdir, create etc.
on the file system until unmount and remounted. The two flags supported
in this patch are:

  FSOP_GOING_FLAGS_LOGFLUSH and FSOP_GOING_FLAGS_NOLOGFLUSH

which require very little other than blocking new operations (since
we do not cache writes to metadata on the client with cifs.ko).
FSOP_GOING_FLAGS_DEFAULT is not supported yet, but could be added in
the future but would need to call syncfs or equivalent to write out
pending data on the mount.

With this patch various xfstests now work including tests 043 through
046 for example.

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
 fs/cifs/cifs_fs_sb.h |  1 +
 fs/cifs/cifs_ioctl.h | 16 +++++++++++++
 fs/cifs/dir.c        | 10 +++++++++
 fs/cifs/file.c       |  6 +++++
 fs/cifs/fs_context.c |  1 +
 fs/cifs/inode.c      | 25 +++++++++++++++++++--
 fs/cifs/ioctl.c      | 53 ++++++++++++++++++++++++++++++++++++++++++++
 fs/cifs/link.c       |  7 ++++++
 fs/cifs/xattr.c      |  4 ++++
 9 files changed, 121 insertions(+), 2 deletions(-)

--- a/fs/cifs/cifs_fs_sb.h
+++ b/fs/cifs/cifs_fs_sb.h
@@ -55,6 +55,7 @@
 #define CIFS_MOUNT_MODE_FROM_SID 0x10000000 /* retrieve mode from special ACE */
 #define CIFS_MOUNT_RO_CACHE	0x20000000  /* assumes share will not change */
 #define CIFS_MOUNT_RW_CACHE	0x40000000  /* assumes only client accessing */
+#define CIFS_MOUNT_SHUTDOWN	0x80000000
 
 struct cifs_sb_info {
 	struct rb_root tlink_tree;
--- a/fs/cifs/cifs_ioctl.h
+++ b/fs/cifs/cifs_ioctl.h
@@ -78,3 +78,19 @@ struct smb3_notify {
 #define CIFS_QUERY_INFO _IOWR(CIFS_IOCTL_MAGIC, 7, struct smb_query_info)
 #define CIFS_DUMP_KEY _IOWR(CIFS_IOCTL_MAGIC, 8, struct smb3_key_debug_info)
 #define CIFS_IOC_NOTIFY _IOW(CIFS_IOCTL_MAGIC, 9, struct smb3_notify)
+#define CIFS_IOC_SHUTDOWN _IOR ('X', 125, __u32)
+
+/*
+ * Flags for going down operation
+ */
+#define CIFS_GOING_FLAGS_DEFAULT                0x0     /* going down */
+#define CIFS_GOING_FLAGS_LOGFLUSH               0x1     /* flush log but not data */
+#define CIFS_GOING_FLAGS_NOLOGFLUSH             0x2     /* don't flush log nor data */
+
+static inline bool cifs_forced_shutdown(struct cifs_sb_info *sbi)
+{
+	if (CIFS_MOUNT_SHUTDOWN & sbi->mnt_cifs_flags)
+		return true;
+	else
+		return false;
+}
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -33,6 +33,7 @@
 #include "cifs_debug.h"
 #include "cifs_fs_sb.h"
 #include "cifs_unicode.h"
+#include "cifs_ioctl.h"
 
 static void
 renew_parental_timestamps(struct dentry *direntry)
@@ -473,6 +474,9 @@ cifs_atomic_open(struct inode *inode, st
 	__u32 oplock;
 	struct cifsFileInfo *file_info;
 
+	if (unlikely(cifs_forced_shutdown(CIFS_SB(inode->i_sb))))
+		return -EIO;
+
 	/*
 	 * Posix open is only called (at lookup time) for file create now. For
 	 * opens (rather than creates), because we do not know if it is a file
@@ -590,6 +594,9 @@ int cifs_create(struct inode *inode, str
 	cifs_dbg(FYI, "cifs_create parent inode = 0x%p name is: %pd and dentry = 0x%p\n",
 		 inode, direntry, direntry);
 
+	if (unlikely(cifs_forced_shutdown(CIFS_SB(inode->i_sb))))
+		return -EIO;
+
 	tlink = cifs_sb_tlink(CIFS_SB(inode->i_sb));
 	rc = PTR_ERR(tlink);
 	if (IS_ERR(tlink))
@@ -626,6 +633,9 @@ int cifs_mknod(struct inode *inode, stru
 		return -EINVAL;
 
 	cifs_sb = CIFS_SB(inode->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -43,6 +43,7 @@
 #include "cifs_fs_sb.h"
 #include "fscache.h"
 #include "smbdirect.h"
+#include "cifs_ioctl.h"
 
 static inline int cifs_convert_flags(unsigned int flags)
 {
@@ -535,6 +536,11 @@ int cifs_open(struct inode *inode, struc
 	xid = get_xid();
 
 	cifs_sb = CIFS_SB(inode->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb))) {
+		free_xid(xid);
+		return -EIO;
+	}
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink)) {
 		free_xid(xid);
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -36,7 +36,7 @@
 #include "cifs_fs_sb.h"
 #include "cifs_unicode.h"
 #include "fscache.h"
-
+#include "cifs_ioctl.h"
 
 static void cifs_set_ops(struct inode *inode)
 {
@@ -1418,6 +1418,9 @@ int cifs_unlink(struct inode *dir, struc
 
 	cifs_dbg(FYI, "cifs_unlink, dir=0x%p, dentry=0x%p\n", dir, dentry);
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
@@ -1675,6 +1678,8 @@ int cifs_mkdir(struct inode *inode, stru
 		 mode, inode);
 
 	cifs_sb = CIFS_SB(inode->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
@@ -1755,6 +1760,11 @@ int cifs_rmdir(struct inode *inode, stru
 	}
 
 	cifs_sb = CIFS_SB(inode->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb))) {
+		rc = -EIO;
+		goto rmdir_exit;
+	}
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink)) {
 		rc = PTR_ERR(tlink);
@@ -1889,6 +1899,9 @@ cifs_rename2(struct inode *source_dir, s
 		return -EINVAL;
 
 	cifs_sb = CIFS_SB(source_dir->i_sb);
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
@@ -2195,6 +2208,9 @@ int cifs_getattr(const struct path *path
 	struct inode *inode = d_inode(dentry);
 	int rc;
 
+	if (unlikely(cifs_forced_shutdown(CIFS_SB(inode->i_sb))))
+		return -EIO;
+
 	/*
 	 * We need to be sure that all dirty pages are written and the server
 	 * has actual ctime, mtime and file length.
@@ -2267,6 +2283,9 @@ int cifs_fiemap(struct inode *inode, str
 	struct cifsFileInfo *cfile;
 	int rc;
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	/*
 	 * We need to be sure that all dirty pages are written as they
 	 * might fill holes on the server.
@@ -2753,6 +2772,9 @@ cifs_setattr(struct dentry *direntry, st
 	struct cifs_tcon *pTcon = cifs_sb_master_tcon(cifs_sb);
 	int rc, retries = 0;
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	do {
 		if (pTcon->unix_ext)
 			rc = cifs_setattr_unix(direntry, attrs);
--- a/fs/cifs/ioctl.c
+++ b/fs/cifs/ioctl.c
@@ -161,6 +161,56 @@ static long smb_mnt_get_fsinfo(unsigned
 	return rc;
 }
 
+static int cifs_shutdown(struct super_block *sb, unsigned long arg)
+{
+	struct cifs_sb_info *sbi = CIFS_SB(sb);
+	__u32 flags;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (get_user(flags, (__u32 __user *)arg))
+		return -EFAULT;
+
+	if (flags > CIFS_GOING_FLAGS_NOLOGFLUSH)
+		return -EINVAL;
+
+	if (cifs_forced_shutdown(sbi))
+		return 0;
+
+	cifs_dbg(VFS, "shut down requested (%d)", flags);
+/*	trace_cifs_shutdown(sb, flags);*/
+
+	/*
+	 * see:
+	 *   https://man7.org/linux/man-pages/man2/ioctl_xfs_goingdown.2.html
+	 * for more information and description of original intent of the flags
+	 */
+	switch (flags) {
+	/*
+	 * We could add support later for default flag which requires:
+	 *     "Flush all dirty data and metadata to disk"
+	 * would need to call syncfs or equivalent to flush page cache for
+	 * the mount and then issue fsync to server (if nostrictsync not set)
+	 */
+	case CIFS_GOING_FLAGS_DEFAULT:
+		cifs_dbg(FYI, "shutdown with default flag not supported\n");
+		return -EINVAL;
+	/*
+	 * FLAGS_LOGFLUSH is easy since it asks to write out metadata (not
+	 * data) but metadata writes are not cached on the client, so can treat
+	 * it similarly to NOLOGFLUSH
+	 */
+	case CIFS_GOING_FLAGS_LOGFLUSH:
+	case CIFS_GOING_FLAGS_NOLOGFLUSH:
+		sbi->mnt_cifs_flags |= CIFS_MOUNT_SHUTDOWN;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
 long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
 {
 	struct inode *inode = file_inode(filep);
@@ -322,6 +372,9 @@ long cifs_ioctl(struct file *filep, unsi
 				rc = -EOPNOTSUPP;
 			cifs_put_tlink(tlink);
 			break;
+		case CIFS_IOC_SHUTDOWN:
+			rc = cifs_shutdown(inode->i_sb, arg);
+			break;
 		default:
 			cifs_dbg(FYI, "unsupported ioctl\n");
 			break;
--- a/fs/cifs/link.c
+++ b/fs/cifs/link.c
@@ -30,6 +30,7 @@
 #include "cifs_fs_sb.h"
 #include "cifs_unicode.h"
 #include "smb2proto.h"
+#include "cifs_ioctl.h"
 
 /*
  * M-F Symlink Functions - Begin
@@ -518,6 +519,9 @@ cifs_hardlink(struct dentry *old_file, s
 	struct TCP_Server_Info *server;
 	struct cifsInodeInfo *cifsInode;
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
--- a/fs/cifs/xattr.c
+++ b/fs/cifs/xattr.c
@@ -30,6 +30,7 @@
 #include "cifs_debug.h"
 #include "cifs_fs_sb.h"
 #include "cifs_unicode.h"
+#include "cifs_ioctl.h"
 
 #define MAX_EA_VALUE_SIZE CIFSMaxBufSize
 #define CIFS_XATTR_CIFS_ACL "system.cifs_acl" /* DACL only */
@@ -415,6 +416,9 @@ ssize_t cifs_listxattr(struct dentry *di
 	struct cifs_tcon *pTcon;
 	const char *full_path;
 
+	if (unlikely(cifs_forced_shutdown(cifs_sb)))
+		return -EIO;
+
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 		return -EOPNOTSUPP;