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Code Issues Releases Wiki Activity

namei: Standardize callers of filename_lookup() 

filename_lookup() has two variants, one which drops the caller's
reference to filename (filename_lookup), and one which does
not (__filename_lookup). This can be confusing as it's unusual to drop a
caller's reference. Remove filename_lookup, rename __filename_lookup
to filename_lookup, and convert all callers. The cost is a few slightly
longer functions, but the clarity is greater.

[AV: consuming a reference is not at all unusual, actually; look at
e.g. do_mkdirat(), for example.  It's more that we want non-consuming
variant for close relative of that function...]

Link: https://lore.kernel.org/linux-fsdevel/YS+dstZ3xfcLxhoB@zeniv-ca.linux.org.uk/
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Stephen Brennan 2021-09-01 10:51:42 -07:00 committed by Al Viro
parent c5f563f9e9
commit 794ebcea86
2 changed files with 20 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/fs_parser.c
View File

@ -165,7 +165,6 @@ int fs_lookup_param(struct fs_context *fc,
return invalf(fc, "%s: not usable as path", param->key);
}
f->refcnt++; /* filename_lookup() drops our ref. */
ret = filename_lookup(param->dirfd, f, flags, _path, NULL);
if (ret < 0) {
errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);

37
fs/namei.c
View File

@ -2467,7 +2467,7 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path
return err;
}
static int __filename_lookup(int dfd, struct filename *name, unsigned flags,
int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct path *path, struct path *root)
{
int retval;
@ -2488,15 +2488,6 @@ static int __filename_lookup(int dfd, struct filename *name, unsigned flags,
return retval;
}
int filename_lookup(int dfd, struct filename *name, unsigned flags,
struct path *path, struct path *root)
{
int retval = __filename_lookup(dfd, name, flags, path, root);
putname(name);
return retval;
}
/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */
static int path_parentat(struct nameidata *nd, unsigned flags,
struct path *parent)
@ -2573,8 +2564,12 @@ struct dentry *kern_path_locked(const char *name, struct path *path)
int kern_path(const char *name, unsigned int flags, struct path *path)
{
return filename_lookup(AT_FDCWD, getname_kernel(name),
flags, path, NULL);
struct filename *filename = getname_kernel(name);
int ret = filename_lookup(AT_FDCWD, filename, flags, path, NULL);
putname(filename);
return ret;
}
EXPORT_SYMBOL(kern_path);
@ -2590,10 +2585,15 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
const char *name, unsigned int flags,
struct path *path)
{
struct filename *filename;
struct path root = {.mnt = mnt, .dentry = dentry};
int ret;
filename = getname_kernel(name);
/* the first argument of filename_lookup() is ignored with root */
return filename_lookup(AT_FDCWD, getname_kernel(name),
flags , path, &root);
ret = filename_lookup(AT_FDCWD, filename, flags, path, &root);
putname(filename);
return ret;
}
EXPORT_SYMBOL(vfs_path_lookup);
@ -2797,8 +2797,11 @@ int path_pts(struct path *path)
int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
struct path *path, int *empty)
{
return filename_lookup(dfd, getname_flags(name, flags, empty),
flags, path, NULL);
struct filename *filename = getname_flags(name, flags, empty);
int ret = filename_lookup(dfd, filename, flags, path, NULL);
putname(filename);
return ret;
}
EXPORT_SYMBOL(user_path_at_empty);
@ -4425,7 +4428,7 @@ int do_linkat(int olddfd, struct filename *old, int newdfd,
if (flags & AT_SYMLINK_FOLLOW)
how |= LOOKUP_FOLLOW;
retry:
error = __filename_lookup(olddfd, old, how, &old_path, NULL);
error = filename_lookup(olddfd, old, how, &old_path, NULL);
if (error)
goto out_putnames;