[Linux-cachefs] [PATCH] cachefiles: revert inode in use in error path

[Jeffle Xu]

Unmark inode in use if error encountered. Or Cachefiles will complain
"Inode already in use" when the cookie with the same index key is looked
up for the second time.

Reported-by: Gao Xiang <hsiangkao at linux.alibaba.com>
Fixes: 1f08c925e7a3 ("cachefiles: Implement backing file wrangling")
Signed-off-by: Jeffle Xu <jefflexu at linux.alibaba.com>
---
 fs/cachefiles/namei.c | 44 ++++++++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 15 deletions(-)

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index f256c8aff7bb..69ef0620009d 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -57,6 +57,16 @@ static void __cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
 	trace_cachefiles_mark_inactive(object, inode);
 }
 
+static void cachefiles_do_unmark_inode_in_use(struct cachefiles_object *object,
+				       struct dentry *dentry)
+{
+	struct inode *inode = d_backing_inode(dentry);
+
+	inode_lock(inode);
+	__cachefiles_unmark_inode_in_use(object, dentry);
+	inode_unlock(inode);
+}
+
 /*
  * Unmark a backing inode and tell cachefilesd that there's something that can
  * be culled.
@@ -68,9 +78,7 @@ void cachefiles_unmark_inode_in_use(struct cachefiles_object *object,
 	struct inode *inode = file_inode(file);
 
 	if (inode) {
-		inode_lock(inode);
-		__cachefiles_unmark_inode_in_use(object, file->f_path.dentry);
-		inode_unlock(inode);
+		cachefiles_do_unmark_inode_in_use(object, file->f_path.dentry);
 
 		if (!test_bit(CACHEFILES_OBJECT_USING_TMPFILE, &object->flags)) {
 			atomic_long_add(inode->i_blocks, &cache->b_released);
@@ -484,7 +492,7 @@ struct file *cachefiles_create_tmpfile(struct cachefiles_object *object)
 				object, d_backing_inode(path.dentry), ret,
 				cachefiles_trace_trunc_error);
 			file = ERR_PTR(ret);
-			goto out_dput;
+			goto out_unuse;
 		}
 	}
 
@@ -494,15 +502,20 @@ struct file *cachefiles_create_tmpfile(struct cachefiles_object *object)
 		trace_cachefiles_vfs_error(object, d_backing_inode(path.dentry),
 					   PTR_ERR(file),
 					   cachefiles_trace_open_error);
-		goto out_dput;
+		goto out_unuse;
 	}
 	if (unlikely(!file->f_op->read_iter) ||
 	    unlikely(!file->f_op->write_iter)) {
 		fput(file);
 		pr_notice("Cache does not support read_iter and write_iter\n");
 		file = ERR_PTR(-EINVAL);
+		goto out_unuse;
 	}
 
+	goto out_dput;
+
+out_unuse:
+	cachefiles_do_unmark_inode_in_use(object, path.dentry);
 out_dput:
 	dput(path.dentry);
 out:
@@ -574,8 +587,16 @@ static bool cachefiles_open_file(struct cachefiles_object *object,
 	_debug("file -> %pd positive", dentry);
 
 	ret = cachefiles_check_auxdata(object, file);
-	if (ret < 0)
-		goto check_failed;
+	if (ret < 0) {
+		fscache_cookie_lookup_negative(object->cookie);
+		cachefiles_unmark_inode_in_use(object, file);
+		fput(file);
+		dput(dentry);
+
+		if (ret == -ESTALE)
+			return cachefiles_create_file(object);
+		return false;
+	}
 
 	object->file = file;
 
@@ -587,17 +608,10 @@ static bool cachefiles_open_file(struct cachefiles_object *object,
 	dput(dentry);
 	return true;
 
-check_failed:
-	fscache_cookie_lookup_negative(object->cookie);
-	cachefiles_unmark_inode_in_use(object, file);
-	if (ret == -ESTALE) {
-		fput(file);
-		dput(dentry);
-		return cachefiles_create_file(object);
-	}
 error_fput:
 	fput(file);
 error:
+	cachefiles_do_unmark_inode_in_use(object, dentry);
 	dput(dentry);
 	return false;
 }
-- 
2.27.0