From fa6fe07d1536361a227d655e69ca270faf28fdbe Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 19 Mar 2025 14:01:35 +1100 Subject: VFS: rename lookup_one_len family to lookup_noperm and remove permission check The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner --- fs/debugfs/inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/debugfs/inode.c') diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c index 75715d8877ee..30c4944e1862 100644 --- a/fs/debugfs/inode.c +++ b/fs/debugfs/inode.c @@ -346,7 +346,7 @@ struct dentry *debugfs_lookup(const char *name, struct dentry *parent) if (!parent) parent = debugfs_mount->mnt_root; - dentry = lookup_positive_unlocked(name, parent, strlen(name)); + dentry = lookup_noperm_positive_unlocked(&QSTR(name), parent); if (IS_ERR(dentry)) return NULL; return dentry; @@ -388,7 +388,7 @@ static struct dentry *start_creating(const char *name, struct dentry *parent) if (unlikely(IS_DEADDIR(d_inode(parent)))) dentry = ERR_PTR(-ENOENT); else - dentry = lookup_one_len(name, parent, strlen(name)); + dentry = lookup_noperm(&QSTR(name), parent); if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { if (d_is_dir(dentry)) pr_err("Directory '%s' with parent '%s' already present!\n", @@ -872,7 +872,7 @@ int __printf(2, 3) debugfs_change_name(struct dentry *dentry, const char *fmt, . } if (strcmp(old_name.name.name, new_name) == 0) goto out; - target = lookup_one_len(new_name, parent, strlen(new_name)); + target = lookup_noperm(&QSTR(new_name), parent); if (IS_ERR(target)) { error = PTR_ERR(target); goto out; -- cgit v1.2.3