Merge tag 'for-3.14-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs

Pull 9p changes from Eric Van Hensbergen:
 "Included are a new cache model for support of mmap, and several
  cleanups across the filesystem and networking portions of the code"

* tag 'for-3.14-merge-window' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  9p: update documentation
  9P: introduction of a new cache=mmap model.
  net/9p: remove virtio default hack and set appropriate bits instead
  9p: remove useless 'name' variable and assignment
  9p: fix return value in case in v9fs_fid_xattr_set()
  9p: remove useless variable and assignment
  9p: remove useless assignment
  9p: remove unused 'super_block' struct pointer
  9p: remove never used return variable
  9p: remove unused 'p9_fid' struct pointer
  9p: remove unused 'p9_client' struct pointer

Documentation/filesystems/9p.txt

@@ -69,10 +69,14 @@ OPTIONS
   		offering several exported file systems.
 
   cache=mode	specifies a caching policy.  By default, no caches are used.
+                        none = default no cache policy, metadata and data
+                                alike are synchronous.
 			loose = no attempts are made at consistency,
                                 intended for exclusive, read-only mounts
-			fscache = use FS-Cache for a persistent, read-only
+                        fscache = use FS-Cache for a persistent, read-only
 				cache backend.
+                        mmap = minimal cache that is only used for read-write
+                                mmap.  Northing else is cached, like cache=none
 
   debug=n	specifies debug level.  The debug level is a bitmask.
 			0x01  = display verbose error messages
@@ -147,8 +151,7 @@ on sourceforge (http://sourceforge.net/projects/v9fs).
 News and other information is maintained on a Wiki.
 (http://sf.net/apps/mediawiki/v9fs/index.php).
 
-Bug reports may be issued through the kernel.org bugzilla 
-(http://bugzilla.kernel.org)
+Bug reports are best issued via the mailing list.
 
 For more information on the Plan 9 Operating System check out
 http://plan9.bell-labs.com/plan9
@@ -156,11 +159,3 @@ http://plan9.bell-labs.com/plan9
 For information on Plan 9 from User Space (Plan 9 applications and libraries
 ported to Linux/BSD/OSX/etc) check out http://swtch.com/plan9
 
-
-STATUS
-======
-
-The 2.6 kernel support is working on PPC and x86.
-
-PLEASE USE THE KERNEL BUGZILLA TO REPORT PROBLEMS. (http://bugzilla.kernel.org)
-

fs/9p/cache.c

@@ -239,13 +239,12 @@ void v9fs_cache_inode_flush_cookie(struct inode *inode)
 void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp)
 {
 	struct v9fs_inode *v9inode = V9FS_I(inode);
-	struct p9_fid *fid;
 
 	if (!v9inode->fscache)
 		return;
 
 	spin_lock(&v9inode->fscache_lock);
-	fid = filp->private_data;
+
 	if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
 		v9fs_cache_inode_flush_cookie(inode);
 	else

fs/9p/v9fs.c

@@ -56,7 +56,7 @@ enum {
 	/* Options that take no arguments */
 	Opt_nodevmap,
 	/* Cache options */
-	Opt_cache_loose, Opt_fscache,
+	Opt_cache_loose, Opt_fscache, Opt_mmap,
 	/* Access options */
 	Opt_access, Opt_posixacl,
 	/* Error token */
@@ -74,6 +74,7 @@ static const match_table_t tokens = {
 	{Opt_cache, "cache=%s"},
 	{Opt_cache_loose, "loose"},
 	{Opt_fscache, "fscache"},
+	{Opt_mmap, "mmap"},
 	{Opt_cachetag, "cachetag=%s"},
 	{Opt_access, "access=%s"},
 	{Opt_posixacl, "posixacl"},
@@ -91,6 +92,9 @@ static int get_cache_mode(char *s)
 	} else if (!strcmp(s, "fscache")) {
 		version = CACHE_FSCACHE;
 		p9_debug(P9_DEBUG_9P, "Cache mode: fscache\n");
+	} else if (!strcmp(s, "mmap")) {
+		version = CACHE_MMAP;
+		p9_debug(P9_DEBUG_9P, "Cache mode: mmap\n");
 	} else if (!strcmp(s, "none")) {
 		version = CACHE_NONE;
 		p9_debug(P9_DEBUG_9P, "Cache mode: none\n");
@@ -220,6 +224,9 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 		case Opt_fscache:
 			v9ses->cache = CACHE_FSCACHE;
 			break;
+		case Opt_mmap:
+			v9ses->cache = CACHE_MMAP;
+			break;
 		case Opt_cachetag:
 #ifdef CONFIG_9P_FSCACHE
 			v9ses->cachetag = match_strdup(&args[0]);

fs/9p/v9fs.h

@@ -64,6 +64,7 @@ enum p9_session_flags {
 
 enum p9_cache_modes {
 	CACHE_NONE,
+	CACHE_MMAP,
 	CACHE_LOOSE,
 	CACHE_FSCACHE,
 };

fs/9p/v9fs_vfs.h

@@ -50,6 +50,8 @@ extern const struct dentry_operations v9fs_dentry_operations;
 extern const struct dentry_operations v9fs_cached_dentry_operations;
 extern const struct file_operations v9fs_cached_file_operations;
 extern const struct file_operations v9fs_cached_file_operations_dotl;
+extern const struct file_operations v9fs_mmap_file_operations;
+extern const struct file_operations v9fs_mmap_file_operations_dotl;
 extern struct kmem_cache *v9fs_inode_cache;
 
 struct inode *v9fs_alloc_inode(struct super_block *sb);

fs/9p/vfs_addr.c

@@ -202,6 +202,8 @@ static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
 {
 	int retval;
 
+	p9_debug(P9_DEBUG_VFS, "page %p\n", page);
+
 	retval = v9fs_vfs_writepage_locked(page);
 	if (retval < 0) {
 		if (retval == -EAGAIN) {
@@ -282,6 +284,9 @@ static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
 	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
 	struct inode *inode = mapping->host;
 
+
+	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
+
 	v9inode = V9FS_I(inode);
 start:
 	page = grab_cache_page_write_begin(mapping, index, flags);
@@ -312,6 +317,8 @@ static int v9fs_write_end(struct file *filp, struct address_space *mapping,
 	loff_t last_pos = pos + copied;
 	struct inode *inode = page->mapping->host;
 
+	p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
+
 	if (unlikely(copied < len)) {
 		/*
 		 * zero out the rest of the area

fs/9p/vfs_file.c

@@ -45,6 +45,7 @@
 #include "cache.h"
 
 static const struct vm_operations_struct v9fs_file_vm_ops;
+static const struct vm_operations_struct v9fs_mmap_file_vm_ops;
 
 /**
  * v9fs_file_open - open a file (or directory)
@@ -87,7 +88,8 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 
 	file->private_data = fid;
 	mutex_lock(&v9inode->v_mutex);
-	if (v9ses->cache && !v9inode->writeback_fid &&
+	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
+	    !v9inode->writeback_fid &&
 	    ((file->f_flags & O_ACCMODE) != O_RDONLY)) {
 		/*
 		 * clone a fid and add it to writeback_fid
@@ -105,7 +107,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 		v9inode->writeback_fid = (void *) fid;
 	}
 	mutex_unlock(&v9inode->v_mutex);
-	if (v9ses->cache)
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 		v9fs_cache_inode_set_cookie(inode, file);
 	return 0;
 out_error:
@@ -461,14 +463,12 @@ v9fs_file_write_internal(struct inode *inode, struct p9_fid *fid,
 	int n;
 	loff_t i_size;
 	size_t total = 0;
-	struct p9_client *clnt;
 	loff_t origin = *offset;
 	unsigned long pg_start, pg_end;
 
 	p9_debug(P9_DEBUG_VFS, "data %p count %d offset %x\n",
 		 data, (int)count, (int)*offset);
 
-	clnt = fid->clnt;
 	do {
 		n = p9_client_write(fid, NULL, data+total, origin+total, count);
 		if (n <= 0)
@@ -581,17 +581,55 @@ int v9fs_file_fsync_dotl(struct file *filp, loff_t start, loff_t end,
 }
 
 static int
-v9fs_file_mmap(struct file *file, struct vm_area_struct *vma)
+v9fs_file_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	int retval;
 
-	retval = generic_file_mmap(file, vma);
+
+	retval = generic_file_mmap(filp, vma);
 	if (!retval)
 		vma->vm_ops = &v9fs_file_vm_ops;
 
 	return retval;
 }
 
+static int
+v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	int retval;
+	struct inode *inode;
+	struct v9fs_inode *v9inode;
+	struct p9_fid *fid;
+
+	inode = file_inode(filp);
+	v9inode = V9FS_I(inode);
+	mutex_lock(&v9inode->v_mutex);
+	if (!v9inode->writeback_fid &&
+	    (vma->vm_flags & VM_WRITE)) {
+		/*
+		 * clone a fid and add it to writeback_fid
+		 * we do it during mmap instead of
+		 * page dirty time via write_begin/page_mkwrite
+		 * because we want write after unlink usecase
+		 * to work.
+		 */
+		fid = v9fs_writeback_fid(filp->f_path.dentry);
+		if (IS_ERR(fid)) {
+			retval = PTR_ERR(fid);
+			mutex_unlock(&v9inode->v_mutex);
+			return retval;
+		}
+		v9inode->writeback_fid = (void *) fid;
+	}
+	mutex_unlock(&v9inode->v_mutex);
+
+	retval = generic_file_mmap(filp, vma);
+	if (!retval)
+		vma->vm_ops = &v9fs_mmap_file_vm_ops;
+
+	return retval;
+}
+
 static int
 v9fs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
@@ -660,6 +698,22 @@ v9fs_cached_file_read(struct file *filp, char __user *data, size_t count,
 	return do_sync_read(filp, data, count, offset);
 }
 
+/**
+ * v9fs_mmap_file_read - read from a file
+ * @filp: file pointer to read
+ * @udata: user data buffer to read data into
+ * @count: size of buffer
+ * @offset: offset at which to read data
+ *
+ */
+static ssize_t
+v9fs_mmap_file_read(struct file *filp, char __user *data, size_t count,
+		      loff_t *offset)
+{
+	/* TODO: Check if there are dirty pages */
+	return v9fs_file_read(filp, data, count, offset);
+}
+
 static ssize_t
 v9fs_direct_write(struct file *filp, const char __user * data,
 		  size_t count, loff_t *offsetp)
@@ -730,12 +784,65 @@ v9fs_cached_file_write(struct file *filp, const char __user * data,
 	return do_sync_write(filp, data, count, offset);
 }
 
+
+/**
+ * v9fs_mmap_file_write - write to a file
+ * @filp: file pointer to write
+ * @data: data buffer to write data from
+ * @count: size of buffer
+ * @offset: offset at which to write data
+ *
+ */
+static ssize_t
+v9fs_mmap_file_write(struct file *filp, const char __user *data,
+		       size_t count, loff_t *offset)
+{
+	/*
+	 * TODO: invalidate mmaps on filp's inode between
+	 * offset and offset+count
+	 */
+	return v9fs_file_write(filp, data, count, offset);
+}
+
+static void v9fs_mmap_vm_close(struct vm_area_struct *vma)
+{
+	struct inode *inode;
+
+	struct writeback_control wbc = {
+		.nr_to_write = LONG_MAX,
+		.sync_mode = WB_SYNC_ALL,
+		.range_start = vma->vm_pgoff * PAGE_SIZE,
+		 /* absolute end, byte at end included */
+		.range_end = vma->vm_pgoff * PAGE_SIZE +
+			(vma->vm_end - vma->vm_start - 1),
+	};
+
+
+	p9_debug(P9_DEBUG_VFS, "9p VMA close, %p, flushing", vma);
+
+	inode = file_inode(vma->vm_file);
+
+	if (!mapping_cap_writeback_dirty(inode->i_mapping))
+		wbc.nr_to_write = 0;
+
+	might_sleep();
+	sync_inode(inode, &wbc);
+}
+
+
 static const struct vm_operations_struct v9fs_file_vm_ops = {
 	.fault = filemap_fault,
 	.page_mkwrite = v9fs_vm_page_mkwrite,
 	.remap_pages = generic_file_remap_pages,
 };
 
+static const struct vm_operations_struct v9fs_mmap_file_vm_ops = {
+	.close = v9fs_mmap_vm_close,
+	.fault = filemap_fault,
+	.page_mkwrite = v9fs_vm_page_mkwrite,
+	.remap_pages = generic_file_remap_pages,
+};
+
 
 const struct file_operations v9fs_cached_file_operations = {
 	.llseek = generic_file_llseek,
@@ -786,3 +893,26 @@ const struct file_operations v9fs_file_operations_dotl = {
 	.mmap = generic_file_readonly_mmap,
 	.fsync = v9fs_file_fsync_dotl,
 };
+
+const struct file_operations v9fs_mmap_file_operations = {
+	.llseek = generic_file_llseek,
+	.read = v9fs_mmap_file_read,
+	.write = v9fs_mmap_file_write,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.lock = v9fs_file_lock,
+	.mmap = v9fs_mmap_file_mmap,
+	.fsync = v9fs_file_fsync,
+};
+
+const struct file_operations v9fs_mmap_file_operations_dotl = {
+	.llseek = generic_file_llseek,
+	.read = v9fs_mmap_file_read,
+	.write = v9fs_mmap_file_write,
+	.open = v9fs_file_open,
+	.release = v9fs_dir_release,
+	.lock = v9fs_file_lock_dotl,
+	.flock = v9fs_file_flock_dotl,
+	.mmap = v9fs_mmap_file_mmap,
+	.fsync = v9fs_file_fsync_dotl,
+};

fs/9p/vfs_inode.c

@@ -299,15 +299,22 @@ int v9fs_init_inode(struct v9fs_session_info *v9ses,
 	case S_IFREG:
 		if (v9fs_proto_dotl(v9ses)) {
 			inode->i_op = &v9fs_file_inode_operations_dotl;
-			if (v9ses->cache)
+			if (v9ses->cache == CACHE_LOOSE ||
+			    v9ses->cache == CACHE_FSCACHE)
 				inode->i_fop =
 					&v9fs_cached_file_operations_dotl;
+			else if (v9ses->cache == CACHE_MMAP)
+				inode->i_fop = &v9fs_mmap_file_operations_dotl;
 			else
 				inode->i_fop = &v9fs_file_operations_dotl;
 		} else {
 			inode->i_op = &v9fs_file_inode_operations;
-			if (v9ses->cache)
-				inode->i_fop = &v9fs_cached_file_operations;
+			if (v9ses->cache == CACHE_LOOSE ||
+			    v9ses->cache == CACHE_FSCACHE)
+				inode->i_fop =
+					&v9fs_cached_file_operations;
+			else if (v9ses->cache == CACHE_MMAP)
+				inode->i_fop = &v9fs_mmap_file_operations;
 			else
 				inode->i_fop = &v9fs_file_operations;
 		}
@@ -779,7 +786,6 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 				      unsigned int flags)
 {
 	struct dentry *res;
-	struct super_block *sb;
 	struct v9fs_session_info *v9ses;
 	struct p9_fid *dfid, *fid;
 	struct inode *inode;
@@ -791,7 +797,6 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 	if (dentry->d_name.len > NAME_MAX)
 		return ERR_PTR(-ENAMETOOLONG);
 
-	sb = dir->i_sb;
 	v9ses = v9fs_inode2v9ses(dir);
 	/* We can walk d_parent because we hold the dir->i_mutex */
 	dfid = v9fs_fid_lookup(dentry->d_parent);
@@ -812,7 +817,7 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
 	 * unlink. For cached mode create calls request for new
 	 * inode. But with cache disabled, lookup should do this.
 	 */
-	if (v9ses->cache)
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 		inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
 	else
 		inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
@@ -863,7 +868,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 		return finish_no_open(file, res);
 
 	err = 0;
-	fid = NULL;
+
 	v9ses = v9fs_inode2v9ses(dir);
 	perm = unixmode2p9mode(v9ses, mode);
 	fid = v9fs_create(v9ses, dir, dentry, NULL, perm,
@@ -878,7 +883,8 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 	v9fs_invalidate_inode_attr(dir);
 	v9inode = V9FS_I(dentry->d_inode);
 	mutex_lock(&v9inode->v_mutex);
-	if (v9ses->cache && !v9inode->writeback_fid &&
+	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
+	    !v9inode->writeback_fid &&
 	    ((flags & O_ACCMODE) != O_RDONLY)) {
 		/*
 		 * clone a fid and add it to writeback_fid
@@ -901,7 +907,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 		goto error;
 
 	file->private_data = fid;
-	if (v9ses->cache)
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 		v9fs_cache_inode_set_cookie(dentry->d_inode, file);
 
 	*opened |= FILE_CREATED;
@@ -1479,7 +1485,7 @@ int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
 	 */
 	i_size = inode->i_size;
 	v9fs_stat2inode(st, inode, inode->i_sb);
-	if (v9ses->cache)
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 		inode->i_size = i_size;
 	spin_unlock(&inode->i_lock);
 out:

fs/9p/vfs_inode_dotl.c

@@ -330,7 +330,8 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
 
 	v9inode = V9FS_I(inode);
 	mutex_lock(&v9inode->v_mutex);
-	if (v9ses->cache && !v9inode->writeback_fid &&
+	if ((v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) &&
+	    !v9inode->writeback_fid &&
 	    ((flags & O_ACCMODE) != O_RDONLY)) {
 		/*
 		 * clone a fid and add it to writeback_fid
@@ -353,7 +354,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
 	if (err)
 		goto err_clunk_old_fid;
 	file->private_data = ofid;
-	if (v9ses->cache)
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 		v9fs_cache_inode_set_cookie(inode, file);
 	*opened |= FILE_CREATED;
 out:
@@ -473,13 +474,11 @@ static int
 v9fs_vfs_getattr_dotl(struct vfsmount *mnt, struct dentry *dentry,
 		 struct kstat *stat)
 {
-	int err;
 	struct v9fs_session_info *v9ses;
 	struct p9_fid *fid;
 	struct p9_stat_dotl *st;
 
 	p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
-	err = -EPERM;
 	v9ses = v9fs_dentry2v9ses(dentry);
 	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
 		generic_fillattr(dentry->d_inode, stat);
@@ -556,7 +555,6 @@ static int v9fs_mapped_iattr_valid(int iattr_valid)
 int v9fs_vfs_setattr_dotl(struct dentry *dentry, struct iattr *iattr)
 {
 	int retval;
-	struct v9fs_session_info *v9ses;
 	struct p9_fid *fid;
 	struct p9_iattr_dotl p9attr;
 	struct inode *inode = dentry->d_inode;
@@ -577,8 +575,6 @@ int v9fs_vfs_setattr_dotl(struct dentry *dentry, struct iattr *iattr)
 	p9attr.mtime_sec = iattr->ia_mtime.tv_sec;
 	p9attr.mtime_nsec = iattr->ia_mtime.tv_nsec;
 
-	retval = -EPERM;
-	v9ses = v9fs_dentry2v9ses(dentry);
 	fid = v9fs_fid_lookup(dentry);
 	if (IS_ERR(fid))
 		return PTR_ERR(fid);
@@ -715,7 +711,7 @@ v9fs_vfs_symlink_dotl(struct inode *dir, struct dentry *dentry,
 	}
 
 	v9fs_invalidate_inode_attr(dir);
-	if (v9ses->cache) {
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE) {
 		/* Now walk from the parent so we can get an unopened fid. */
 		fid = p9_client_walk(dfid, 1, &name, 1);
 		if (IS_ERR(fid)) {
@@ -768,7 +764,6 @@ v9fs_vfs_link_dotl(struct dentry *old_dentry, struct inode *dir,
 		struct dentry *dentry)
 {
 	int err;
-	char *name;
 	struct dentry *dir_dentry;
 	struct p9_fid *dfid, *oldfid;
 	struct v9fs_session_info *v9ses;
@@ -786,8 +781,6 @@ v9fs_vfs_link_dotl(struct dentry *old_dentry, struct inode *dir,
 	if (IS_ERR(oldfid))
 		return PTR_ERR(oldfid);
 
-	name = (char *) dentry->d_name.name;
-
 	err = p9_client_link(dfid, oldfid, (char *)dentry->d_name.name);
 
 	if (err < 0) {
@@ -973,7 +966,7 @@ int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode)
 	 */
 	i_size = inode->i_size;
 	v9fs_stat2inode_dotl(st, inode);
-	if (v9ses->cache)
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 		inode->i_size = i_size;
 	spin_unlock(&inode->i_lock);
 out:

fs/9p/vfs_super.c

@@ -144,7 +144,7 @@ static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
 	}
 	v9fs_fill_super(sb, v9ses, flags, data);
 
-	if (v9ses->cache)
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 		sb->s_d_op = &v9fs_cached_dentry_operations;
 	else
 		sb->s_d_op = &v9fs_dentry_operations;
@@ -282,7 +282,7 @@ static int v9fs_drop_inode(struct inode *inode)
 {
 	struct v9fs_session_info *v9ses;
 	v9ses = v9fs_inode2v9ses(inode);
-	if (v9ses->cache)
+	if (v9ses->cache == CACHE_LOOSE || v9ses->cache == CACHE_FSCACHE)
 		return generic_drop_inode(inode);
 	/*
 	 * in case of non cached mode always drop the
@@ -325,10 +325,12 @@ static int v9fs_write_inode_dotl(struct inode *inode,
 	 * send an fsync request to server irrespective of
 	 * wbc->sync_mode.
 	 */
-	p9_debug(P9_DEBUG_VFS, "%s: inode %p\n", __func__, inode);
 	v9inode = V9FS_I(inode);
+	p9_debug(P9_DEBUG_VFS, "%s: inode %p, writeback_fid %p\n",
+		 __func__, inode, v9inode->writeback_fid);
 	if (!v9inode->writeback_fid)
 		return 0;
+
 	ret = p9_client_fsync(v9inode->writeback_fid, 0);
 	if (ret < 0) {
 		__mark_inode_dirty(inode, I_DIRTY_DATASYNC);

fs/9p/xattr.c

@@ -138,8 +138,7 @@ int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
 	if (retval < 0) {
 		p9_debug(P9_DEBUG_VFS, "p9_client_xattrcreate failed %d\n",
 			 retval);
-		p9_client_clunk(fid);
-		return retval;
+		goto err;
 	}
 	msize = fid->clnt->msize;
 	while (value_len) {
@@ -152,12 +151,15 @@ int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
 		if (write_count < 0) {
 			/* error in xattr write */
 			retval = write_count;
-			break;
+			goto err;
 		}
 		offset += write_count;
 		value_len -= write_count;
 	}
-	return p9_client_clunk(fid);
+	retval = offset;
+err:
+	p9_client_clunk(fid);
+	return retval;
 }
 
 ssize_t v9fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)

net/9p/client.c

@@ -1011,9 +1011,6 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
 	if (err < 0)
 		goto destroy_tagpool;
 
-	if (!clnt->trans_mod)
-		clnt->trans_mod = v9fs_get_trans_by_name("virtio");
-
 	if (!clnt->trans_mod)
 		clnt->trans_mod = v9fs_get_default_trans();
 

net/9p/trans_fd.c

@@ -1048,7 +1048,7 @@ p9_fd_create(struct p9_client *client, const char *addr, char *args)
 static struct p9_trans_module p9_tcp_trans = {
 	.name = "tcp",
 	.maxsize = MAX_SOCK_BUF,
-	.def = 1,
+	.def = 0,
 	.create = p9_fd_create_tcp,
 	.close = p9_fd_close,
 	.request = p9_fd_request,

net/9p/trans_virtio.c

@@ -698,7 +698,7 @@ static struct p9_trans_module p9_virtio_trans = {
 	 * page in zero copy.
 	 */
 	.maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3),
-	.def = 0,
+	.def = 1,
 	.owner = THIS_MODULE,
 };