Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse

Pull fuse bugfixes from Miklos Szeredi:
 "This contains two more fixes by Maxim for writeback/truncate races and
  fixes for RCU walk in fuse_dentry_revalidate()"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
  fuse: no RCU mode in fuse_access()
  fuse: readdirplus: fix RCU walk
  fuse: don't check_submounts_and_drop() in RCU walk
  fuse: fix fallocate vs. ftruncate race
  fuse: wait for writeback in fuse_file_fallocate()

Author: torvalds

fs/fuse/dir.c

@@ -182,6 +182,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 	struct inode *inode;
 	struct dentry *parent;
 	struct fuse_conn *fc;
+	struct fuse_inode *fi;
 	int ret;
 
 	inode = ACCESS_ONCE(entry->d_inode);
@@ -228,7 +229,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 		if (!err && !outarg.nodeid)
 			err = -ENOENT;
 		if (!err) {
-			struct fuse_inode *fi = get_fuse_inode(inode);
+			fi = get_fuse_inode(inode);
 			if (outarg.nodeid != get_node_id(inode)) {
 				fuse_queue_forget(fc, forget, outarg.nodeid, 1);
 				goto invalid;
@@ -246,8 +247,11 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 				       attr_version);
 		fuse_change_entry_timeout(entry, &outarg);
 	} else if (inode) {
-		fc = get_fuse_conn(inode);
-		if (fc->readdirplus_auto) {
+		fi = get_fuse_inode(inode);
+		if (flags & LOOKUP_RCU) {
+			if (test_bit(FUSE_I_INIT_RDPLUS, &fi->state))
+				return -ECHILD;
+		} else if (test_and_clear_bit(FUSE_I_INIT_RDPLUS, &fi->state)) {
 			parent = dget_parent(entry);
 			fuse_advise_use_readdirplus(parent->d_inode);
 			dput(parent);
@@ -259,7 +263,8 @@ static int fuse_dentry_revalidate(struct dentry *entry, unsigned int flags)
 
 invalid:
 	ret = 0;
-	if (check_submounts_and_drop(entry) != 0)
+
+	if (!(flags & LOOKUP_RCU) && check_submounts_and_drop(entry) != 0)
 		ret = 1;
 	goto out;
 }
@@ -1063,6 +1068,8 @@ static int fuse_access(struct inode *inode, int mask)
 	struct fuse_access_in inarg;
 	int err;
 
+	BUG_ON(mask & MAY_NOT_BLOCK);
+
 	if (fc->no_access)
 		return 0;
 
@@ -1150,9 +1157,6 @@ static int fuse_permission(struct inode *inode, int mask)
 		   noticed immediately, only after the attribute
 		   timeout has expired */
 	} else if (mask & (MAY_ACCESS | MAY_CHDIR)) {
-		if (mask & MAY_NOT_BLOCK)
-			return -ECHILD;
-
 		err = fuse_access(inode, mask);
 	} else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {
 		if (!(inode->i_mode & S_IXUGO)) {
@@ -1291,6 +1295,8 @@ static int fuse_direntplus_link(struct file *file,
 	}
 
 found:
+	if (fc->readdirplus_auto)
+		set_bit(FUSE_I_INIT_RDPLUS, &get_fuse_inode(inode)->state);
 	fuse_change_entry_timeout(dentry, o);
 
 	err = 0;

fs/fuse/file.c

@@ -2467,6 +2467,7 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 {
 	struct fuse_file *ff = file->private_data;
 	struct inode *inode = file->f_inode;
+	struct fuse_inode *fi = get_fuse_inode(inode);
 	struct fuse_conn *fc = ff->fc;
 	struct fuse_req *req;
 	struct fuse_fallocate_in inarg = {
@@ -2484,10 +2485,20 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 
 	if (lock_inode) {
 		mutex_lock(&inode->i_mutex);
-		if (mode & FALLOC_FL_PUNCH_HOLE)
-			fuse_set_nowrite(inode);
+		if (mode & FALLOC_FL_PUNCH_HOLE) {
+			loff_t endbyte = offset + length - 1;
+			err = filemap_write_and_wait_range(inode->i_mapping,
+							   offset, endbyte);
+			if (err)
+				goto out;
+
+			fuse_sync_writes(inode);
+		}
 	}
 
+	if (!(mode & FALLOC_FL_KEEP_SIZE))
+		set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
+
 	req = fuse_get_req_nopages(fc);
 	if (IS_ERR(req)) {
 		err = PTR_ERR(req);
@@ -2520,11 +2531,11 @@ static long fuse_file_fallocate(struct file *file, int mode, loff_t offset,
 	fuse_invalidate_attr(inode);
 
 out:
-	if (lock_inode) {
-		if (mode & FALLOC_FL_PUNCH_HOLE)
-			fuse_release_nowrite(inode);
+	if (!(mode & FALLOC_FL_KEEP_SIZE))
+		clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state);
+
+	if (lock_inode)
 		mutex_unlock(&inode->i_mutex);
-	}
 
 	return err;
 }

fs/fuse/fuse_i.h

@@ -115,6 +115,8 @@ struct fuse_inode {
 enum {
 	/** Advise readdirplus  */
 	FUSE_I_ADVISE_RDPLUS,
+	/** Initialized with readdirplus */
+	FUSE_I_INIT_RDPLUS,
 	/** An operation changing file size is in progress  */
 	FUSE_I_SIZE_UNSTABLE,
 };