github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-28 01:55:51 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

alloc_path_pseudo(): make sure we don't end up with NORCU dentries for directories

Browse Source 
A lot of places relies upon directories never having NORCU dentries;
currently that property holds, but the proof is not straightforward
and rather brittle.

It's better to have that verified in the sole caller of d_alloc_pseudo(),
so that any future bugs in that direction were caught early.

That way we can be sure that
	* current directory of any process is not NORCU
	* root directory of any process is not NORCU
	* starting point of any LOOKUP_RCU pathwalk is not NORCU
	* dget_parent() can rely upon ->d_parent not being NORCU
	* d_walk() and is_subdir() can rely upon the same
	* alloc_file_pseudo() won't create multiple aliases for a directory
without having to go through a convoluted audit.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2026-04-27 14:19:28 -04:00
parent 0e0e490f5d
commit 4a810147a0
1 changed files with 2 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/file_table.c
View File

@ -402,6 +402,8 @@ static struct file *alloc_file(const struct path *path, int flags,
static inline int alloc_path_pseudo(const char *name, struct inode *inode,
struct vfsmount *mnt, struct path *path)
{
if (WARN_ON_ONCE(S_ISDIR(inode->i_mode)))
return -EINVAL;
path->dentry = d_alloc_pseudo(mnt->mnt_sb, &QSTR(name));
if (!path->dentry)
return -ENOMEM;