vfs: update d_make_root() description

Clearify d_make_root() usage, error handling and cleanup
requirements.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Ian Kent 2019-04-11 12:28:02 +08:00 committed by Al Viro
parent a188339ca5
commit 8811249f0c
1 changed files with 13 additions and 2 deletions

View File

@ -428,8 +428,19 @@ release it yourself.
--
[mandatory]
d_alloc_root() is gone, along with a lot of bugs caused by code
misusing it. Replacement: d_make_root(inode). The difference is,
d_make_root() drops the reference to inode if dentry allocation fails.
misusing it. Replacement: d_make_root(inode). On success d_make_root(inode)
allocates and returns a new dentry instantiated with the passed in inode.
On failure NULL is returned and the passed in inode is dropped so the reference
to inode is consumed in all cases and failure handling need not do any cleanup
for the inode. If d_make_root(inode) is passed a NULL inode it returns NULL
and also requires no further error handling. Typical usage is:
inode = foofs_new_inode(....);
s->s_root = d_make_inode(inode);
if (!s->s_root)
/* Nothing needed for the inode cleanup */
return -ENOMEM;
...
--
[mandatory]