smb: client: add support for O_TMPFILE

Implement O_TMPFILE support for SMB2+ in the CIFS client.

Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>

Author: pcacjr

fs/smb/client/cifsfs.c

@@ -124,6 +124,9 @@ MODULE_PARM_DESC(dir_cache_timeout, "Number of seconds to cache directory conten
 /* Module-wide total cached dirents (in bytes) across all tcons */
 atomic64_t cifs_dircache_bytes_used = ATOMIC64_INIT(0);
 
+atomic_t cifs_sillycounter;
+atomic_t cifs_tmpcounter;
+
 /*
  * Write-only module parameter to drop all cached directory entries across
  * all CIFS mounts. Echo a non-zero value to trigger.
@@ -1199,6 +1202,7 @@ MODULE_ALIAS("smb3");
 const struct inode_operations cifs_dir_inode_ops = {
 	.create = cifs_create,
 	.atomic_open = cifs_atomic_open,
+	.tmpfile = cifs_tmpfile,
 	.lookup = cifs_lookup,
 	.getattr = cifs_getattr,
 	.unlink = cifs_unlink,

fs/smb/client/cifsfs.h

@@ -13,6 +13,9 @@
 
 #define ROOT_I 2
 
+extern atomic_t cifs_sillycounter;
+extern atomic_t cifs_tmpcounter;
+
 /*
  * ino_t is 32-bits on 32-bit arch. We have to squash the 64-bit value down
  * so that it will fit. We use hash_64 to convert the value to 31 bits, and
@@ -53,6 +56,8 @@ int cifs_create(struct mnt_idmap *idmap, struct inode *inode,
 		struct dentry *direntry, umode_t mode, bool excl);
 int cifs_atomic_open(struct inode *inode, struct dentry *direntry,
 		     struct file *file, unsigned int oflags, umode_t mode);
+int cifs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
+		 struct file *file, umode_t mode);
 struct dentry *cifs_lookup(struct inode *parent_dir_inode,
 			   struct dentry *direntry, unsigned int flags);
 int cifs_unlink(struct inode *dir, struct dentry *dentry);
@@ -142,6 +147,20 @@ struct smb3_fs_context;
 struct dentry *cifs_smb3_do_mount(struct file_system_type *fs_type, int flags,
 				  struct smb3_fs_context *old_ctx);
 
+char *cifs_silly_fullpath(struct dentry *dentry);
+
+#define CIFS_TMPNAME_PREFIX        ".__smbfile_tmp"
+#define CIFS_TMPNAME_PREFIX_LEN    ((int)sizeof(CIFS_TMPNAME_PREFIX) - 1)
+#define CIFS_TMPNAME_COUNTER_LEN   ((int)sizeof(cifs_tmpcounter) * 2)
+#define CIFS_TMPNAME_LEN \
+	(CIFS_TMPNAME_PREFIX_LEN + CIFS_TMPNAME_COUNTER_LEN)
+
+#define CIFS_SILLYNAME_PREFIX	    ".__smbfile_silly"
+#define CIFS_SILLYNAME_PREFIX_LEN  ((int)sizeof(CIFS_SILLYNAME_PREFIX) - 1)
+#define CIFS_SILLYNAME_COUNTER_LEN ((int)sizeof(cifs_sillycounter) * 2)
+#define CIFS_SILLYNAME_LEN \
+	(CIFS_SILLYNAME_PREFIX_LEN + CIFS_SILLYNAME_COUNTER_LEN)
+
 #ifdef CONFIG_CIFS_NFSD_EXPORT
 extern const struct export_operations cifs_export_ops;
 #endif /* CONFIG_CIFS_NFSD_EXPORT */

fs/smb/client/cifsglob.h

@@ -1534,9 +1534,16 @@ int cifs_file_set_size(const unsigned int xid, struct dentry *dentry,
 #define CIFS_CACHE_RW_FLG	(CIFS_CACHE_READ_FLG | CIFS_CACHE_WRITE_FLG)
 #define CIFS_CACHE_RHW_FLG	(CIFS_CACHE_RW_FLG | CIFS_CACHE_HANDLE_FLG)
 
-/*
- * One of these for each file inode
- */
+enum cifs_inode_flags {
+	CIFS_INODE_PENDING_OPLOCK_BREAK,	/* oplock break in progress */
+	CIFS_INODE_PENDING_WRITERS,		/* Writes in progress */
+	CIFS_INODE_FLAG_UNUSED,			/* Unused flag */
+	CIFS_INO_DELETE_PENDING,		/* delete pending on server */
+	CIFS_INO_INVALID_MAPPING,		/* pagecache is invalid */
+	CIFS_INO_LOCK,				/* lock bit for synchronization */
+	CIFS_INO_TMPFILE,			/* for O_TMPFILE inodes */
+	CIFS_INO_CLOSE_ON_LOCK,			/* Not to defer the close when lock is set */
+};
 
 struct cifsInodeInfo {
 	struct netfs_inode netfs; /* Netfslib context and vfs inode */
@@ -1554,13 +1561,6 @@ struct cifsInodeInfo {
 	__u32 cifsAttrs; /* e.g. DOS archive bit, sparse, compressed, system */
 	unsigned int oplock;		/* oplock/lease level we have */
 	__u16 epoch;		/* used to track lease state changes */
-#define CIFS_INODE_PENDING_OPLOCK_BREAK   (0) /* oplock break in progress */
-#define CIFS_INODE_PENDING_WRITERS	  (1) /* Writes in progress */
-#define CIFS_INODE_FLAG_UNUSED		  (2) /* Unused flag */
-#define CIFS_INO_DELETE_PENDING		  (3) /* delete pending on server */
-#define CIFS_INO_INVALID_MAPPING	  (4) /* pagecache is invalid */
-#define CIFS_INO_LOCK			  (5) /* lock bit for synchronization */
-#define CIFS_INO_CLOSE_ON_LOCK            (7) /* Not to defer the close when lock is set */
 	unsigned long flags;
 	spinlock_t writers_lock;
 	unsigned int writers;		/* Number of writers on this inode */
@@ -2259,6 +2259,7 @@ struct smb2_compound_vars {
 	struct kvec qi_iov;
 	struct kvec io_iov[SMB2_IOCTL_IOV_SIZE];
 	struct kvec si_iov[SMB2_SET_INFO_IOV_SIZE];
+	struct kvec hl_iov[SMB2_SET_INFO_IOV_SIZE];
 	struct kvec unlink_iov[SMB2_SET_INFO_IOV_SIZE];
 	struct kvec rename_iov[SMB2_SET_INFO_IOV_SIZE];
 	struct kvec close_iov;
@@ -2383,6 +2384,8 @@ static inline int cifs_open_create_options(unsigned int oflags, int opts)
 		opts |= CREATE_WRITE_THROUGH;
 	if (oflags & O_DIRECT)
 		opts |= CREATE_NO_BUFFER;
+	if (oflags & O_TMPFILE)
+		opts |= CREATE_DELETE_ON_CLOSE;
 	return opts;
 }
 

fs/smb/client/cifsproto.h

@@ -141,7 +141,8 @@ struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *cifs_inode,
 int __cifs_get_writable_file(struct cifsInodeInfo *cifs_inode,
 			     unsigned int find_flags, unsigned int open_flags,
 			     struct cifsFileInfo **ret_file);
-int cifs_get_writable_path(struct cifs_tcon *tcon, const char *name, int flags,
+int cifs_get_writable_path(struct cifs_tcon *tcon, const char *name,
+			   struct inode *inode, int flags,
 			   struct cifsFileInfo **ret_file);
 struct cifsFileInfo *__find_readable_file(struct cifsInodeInfo *cifs_inode,
 					  unsigned int find_flags,