[PATCH] v9fs: fix atomic create open

In order to assure atomic create+open v9fs stores the open fid produced by
v9fs_vfs_create in the dentry, from where v9fs_file_open retrieves it and
associates it with the open file.

This patch modifies v9fs to use nameidata.intent.open values to do the atomic
create+open.
Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/9p/fid.c

@@ -40,7 +40,7 @@
  *
  */
 
-static int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
+int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
 {
 	struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
 	dprintk(DEBUG_9P, "fid %d (%p) dentry %s (%p)\n", fid->fid, fid,
@@ -68,14 +68,11 @@ static int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry)
  *
  */
 
-struct v9fs_fid *v9fs_fid_create(struct dentry *dentry,
-	struct v9fs_session_info *v9ses, int fid, int create)
+struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *v9ses, int fid)
 {
 	struct v9fs_fid *new;
 
-	dprintk(DEBUG_9P, "fid create dentry %p, fid %d, create %d\n",
-		dentry, fid, create);
-
+	dprintk(DEBUG_9P, "fid create fid %d\n", fid);
 	new = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
 	if (new == NULL) {
 		dprintk(DEBUG_ERROR, "Out of Memory\n");
@@ -85,19 +82,13 @@ struct v9fs_fid *v9fs_fid_create(struct dentry *dentry,
 	new->fid = fid;
 	new->v9ses = v9ses;
 	new->fidopen = 0;
-	new->fidcreate = create;
 	new->fidclunked = 0;
 	new->iounit = 0;
 	new->rdir_pos = 0;
 	new->rdir_fcall = NULL;
+	INIT_LIST_HEAD(&new->list);
 
-	if (v9fs_fid_insert(new, dentry) == 0)
 		return new;
-	else {
-		dprintk(DEBUG_ERROR, "Problems inserting to dentry\n");
-		kfree(new);
-		return NULL;
-	}
 }
 
 /**
@@ -119,7 +110,7 @@ void v9fs_fid_destroy(struct v9fs_fid *fid)
 static struct v9fs_fid *v9fs_fid_walk_up(struct dentry *dentry)
 {
 	int fidnum, cfidnum, err;
-	struct v9fs_fid *cfid;
+	struct v9fs_fid *cfid, *fid;
 	struct dentry *cde;
 	struct v9fs_session_info *v9ses;
 
@@ -158,7 +149,16 @@ static struct v9fs_fid *v9fs_fid_walk_up(struct dentry *dentry)
 		cde = cde->d_parent;
 	}
 
-	return v9fs_fid_create(dentry, v9ses, fidnum, 0);
+	fid = v9fs_fid_create(v9ses, fidnum);
+	if (fid) {
+		err = v9fs_fid_insert(fid, dentry);
+		if (err < 0) {
+			kfree(fid);
+			goto clunk_fid;
+		}
+	}
+
+	return fid;
 
 clunk_fid:
 	v9fs_t_clunk(v9ses, fidnum);
@@ -179,29 +179,12 @@ clunk_fid:
 struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
 {
 	struct list_head *fid_list = (struct list_head *)dentry->d_fsdata;
-	struct v9fs_fid *current_fid = NULL;
-	struct v9fs_fid *temp = NULL;
 	struct v9fs_fid *return_fid = NULL;
 
 	dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
 
-	if (fid_list) {
-		list_for_each_entry_safe(current_fid, temp, fid_list, list) {
-			if (!current_fid->fidcreate) {
-				return_fid = current_fid;
-				break;
-			}
-		}
-
-		if (!return_fid)
-			return_fid = current_fid;
-	}
-
-	/* we are at the root but didn't match */
-	if ((!return_fid) && (dentry->d_parent == dentry)) {
-		/* TODO: clone attach with new uid */
-		return_fid = current_fid;
-	}
+	if (fid_list)
+		return_fid = list_entry(fid_list->next, struct v9fs_fid, list);
 
 	if (!return_fid) {
 		struct dentry *par = current->fs->pwd->d_parent;
@@ -228,25 +211,3 @@ struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry)
 
 	return return_fid;
 }
-
-struct v9fs_fid *v9fs_fid_get_created(struct dentry *dentry)
-{
-	struct list_head *fid_list;
-	struct v9fs_fid *fid, *ftmp, *ret;
-
-	dprintk(DEBUG_9P, " dentry: %s (%p)\n", dentry->d_iname, dentry);
-	fid_list = (struct list_head *)dentry->d_fsdata;
-	ret = NULL;
-	if (fid_list) {
-		list_for_each_entry_safe(fid, ftmp, fid_list, list) {
-			if (fid->fidcreate && fid->pid == current->pid) {
-				list_del(&fid->list);
-				ret = fid;
-				break;
-			}
-		}
-	}
-
-	dprintk(DEBUG_9P, "return %p\n", ret);
-	return ret;
-}

fs/9p/fid.h

@@ -33,7 +33,6 @@ struct v9fs_fid {
 
 	u32 fid;
 	unsigned char fidopen;	  /* set when fid is opened */
-	unsigned char fidcreate;  /* set when fid was just created */
 	unsigned char fidclunked; /* set when fid has already been clunked */
 
 	struct v9fs_qid qid;
@@ -56,5 +55,5 @@ struct v9fs_fid {
 struct v9fs_fid *v9fs_fid_lookup(struct dentry *dentry);
 struct v9fs_fid *v9fs_fid_get_created(struct dentry *);
 void v9fs_fid_destroy(struct v9fs_fid *fid);
-struct v9fs_fid *v9fs_fid_create(struct dentry *,
-	struct v9fs_session_info *v9ses, int fid, int create);
+struct v9fs_fid *v9fs_fid_create(struct v9fs_session_info *, int fid);
+int v9fs_fid_insert(struct v9fs_fid *fid, struct dentry *dentry);

fs/9p/v9fs_vfs.h

@@ -51,3 +51,4 @@ int v9fs_dir_release(struct inode *inode, struct file *filp);
 int v9fs_file_open(struct inode *inode, struct file *file);
 void v9fs_inode2stat(struct inode *inode, struct v9fs_stat *stat);
 void v9fs_dentry_release(struct dentry *);
+int v9fs_uflags2omode(int uflags);

fs/9p/vfs_file.c

@@ -53,94 +53,70 @@
 int v9fs_file_open(struct inode *inode, struct file *file)
 {
 	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
-	struct v9fs_fid *v9fid, *fid;
+	struct v9fs_fid *vfid;
 	struct v9fs_fcall *fcall = NULL;
-	int open_mode = 0;
-	unsigned int iounit = 0;
-	int newfid = -1;
-	long result = -1;
+	int omode;
+	int fid = V9FS_NOFID;
+	int err;
 
 	dprintk(DEBUG_VFS, "inode: %p file: %p \n", inode, file);
 
-	v9fid = v9fs_fid_get_created(file->f_dentry);
-	if (!v9fid)
-		v9fid = v9fs_fid_lookup(file->f_dentry);
-
-	if (!v9fid) {
+	vfid = v9fs_fid_lookup(file->f_dentry);
+	if (!vfid) {
 		dprintk(DEBUG_ERROR, "Couldn't resolve fid from dentry\n");
 		return -EBADF;
 	}
 
-	if (!v9fid->fidcreate) {
-		fid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
-		if (fid == NULL) {
-			dprintk(DEBUG_ERROR, "Out of Memory\n");
-			return -ENOMEM;
-		}
-
-		fid->fidopen = 0;
-		fid->fidcreate = 0;
-		fid->fidclunked = 0;
-		fid->iounit = 0;
-		fid->v9ses = v9ses;
-
-		newfid = v9fs_get_idpool(&v9ses->fidpool);
-		if (newfid < 0) {
+	fid = v9fs_get_idpool(&v9ses->fidpool);
+	if (fid < 0) {
 			eprintk(KERN_WARNING, "newfid fails!\n");
 			return -ENOSPC;
 		}
 
-		result =
-		    v9fs_t_walk(v9ses, v9fid->fid, newfid, NULL, NULL);
-
-		if (result < 0) {
-			v9fs_put_idpool(newfid, &v9ses->fidpool);
+	err = v9fs_t_walk(v9ses, vfid->fid, fid, NULL, NULL);
+	if (err < 0) {
 			dprintk(DEBUG_ERROR, "rewalk didn't work\n");
-			return -EBADF;
+		goto put_fid;
+	}
+
+	vfid = kmalloc(sizeof(struct v9fs_fid), GFP_KERNEL);
+	if (vfid == NULL) {
+		dprintk(DEBUG_ERROR, "out of memory\n");
+		goto clunk_fid;
 		}
 
-		fid->fid = newfid;
-		v9fid = fid;
 		/* TODO: do special things for O_EXCL, O_NOFOLLOW, O_SYNC */
 		/* translate open mode appropriately */
-		open_mode = file->f_flags & 0x3;
+	omode = v9fs_uflags2omode(file->f_flags);
+	err = v9fs_t_open(v9ses, fid, omode, &fcall);
+	if (err < 0) {
+		PRINT_FCALL_ERROR("open failed", fcall);
+		goto destroy_vfid;
+	}
 
-		if (file->f_flags & O_EXCL)
-			open_mode |= V9FS_OEXCL;
+	file->private_data = vfid;
+	vfid->fid = fid;
+	vfid->fidopen = 1;
+	vfid->fidclunked = 0;
+	vfid->iounit = fcall->params.ropen.iounit;
+	vfid->rdir_pos = 0;
+	vfid->rdir_fcall = NULL;
+	vfid->filp = file;
+	kfree(fcall);
 
-		if (v9ses->extended) {
-			if (file->f_flags & O_TRUNC)
-				open_mode |= V9FS_OTRUNC;
+	return 0;
 
-			if (file->f_flags & O_APPEND)
-				open_mode |= V9FS_OAPPEND;
-		}
+destroy_vfid:
+	v9fs_fid_destroy(vfid);
 
-		result = v9fs_t_open(v9ses, newfid, open_mode, &fcall);
-		if (result < 0) {
-			PRINT_FCALL_ERROR("open failed", fcall);
-			kfree(fcall);
-			return result;
-		}
+clunk_fid:
+	v9fs_t_clunk(v9ses, fid);
 
-		iounit = fcall->params.ropen.iounit;
+put_fid:
+	v9fs_put_idpool(fid, &v9ses->fidpool);
 		kfree(fcall);
-	} else {
-		/* create case */
-		newfid = v9fid->fid;
-		iounit = v9fid->iounit;
-		v9fid->fidcreate = 0;
-	}
-
-	file->private_data = v9fid;
-
-	v9fid->rdir_pos = 0;
-	v9fid->rdir_fcall = NULL;
-	v9fid->fidopen = 1;
-	v9fid->filp = file;
-	v9fid->iounit = iounit;
 
-	return 0;
+	return err;
 }
 
 /**
@@ -289,9 +265,7 @@ v9fs_file_write(struct file *filp, const char __user * data,
 		total += result;
 	} while (count);
 
-	if(inode->i_mapping->nrpages)
 		invalidate_inode_pages2(inode->i_mapping);
-
 	return total;
 }
 

fs/9p/vfs_super.c

@@ -146,7 +146,6 @@ static struct super_block *v9fs_get_sb(struct file_system_type
 	inode->i_gid = gid;
 
 	root = d_alloc_root(inode);
-
 	if (!root) {
 		retval = -ENOMEM;
 		goto put_back_sb;
@@ -157,24 +156,27 @@ static struct super_block *v9fs_get_sb(struct file_system_type
 	stat_result = v9fs_t_stat(v9ses, newfid, &fcall);
 	if (stat_result < 0) {
 		dprintk(DEBUG_ERROR, "stat error\n");
+		kfree(fcall);
 		v9fs_t_clunk(v9ses, newfid);
-		v9fs_put_idpool(newfid, &v9ses->fidpool);
 	} else {
 		/* Setup the Root Inode */
-		root_fid = v9fs_fid_create(root, v9ses, newfid, 0);
+		kfree(fcall);
+		root_fid = v9fs_fid_create(v9ses, newfid);
 		if (root_fid == NULL) {
 			retval = -ENOMEM;
 			goto put_back_sb;
 		}
 
+		retval = v9fs_fid_insert(root_fid, root);
+		if (retval < 0)
+			goto put_back_sb;
+
 		root_fid->qid = fcall->params.rstat.stat.qid;
 		root->d_inode->i_ino =
 		    v9fs_qid2ino(&fcall->params.rstat.stat.qid);
 		v9fs_stat2inode(&fcall->params.rstat.stat, root->d_inode, sb);
 	}
 
-	kfree(fcall);
-
 	if (stat_result < 0) {
 		retval = stat_result;
 		goto put_back_sb;