Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
new helper: simple_start_creating()
Set the things up for kernel-initiated creation of object in
a tree-in-dcache filesystem. With respect to locking it's
an equivalent of filename_create() - we either get a negative
dentry with locked parent, or ERR_PTR() and no locks taken.
tracefs and debugfs had that open-coded as part of their
object creation machinery; switched to calling new helper.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
+31
-31
+3
-18
fs/debugfs/inode.c
+3
-18
fs/debugfs/inode.c
···
384
384
if (!parent)
385
385
parent = debugfs_mount->mnt_root;
386
386
387
-
inode_lock(d_inode(parent));
388
-
if (unlikely(IS_DEADDIR(d_inode(parent))))
389
-
dentry = ERR_PTR(-ENOENT);
390
-
else
391
-
dentry = lookup_noperm(&QSTR(name), parent);
392
-
if (!IS_ERR(dentry) && d_really_is_positive(dentry)) {
393
-
if (d_is_dir(dentry))
394
-
pr_err("Directory '%s' with parent '%s' already present!\n",
395
-
name, parent->d_name.name);
396
-
else
397
-
pr_err("File '%s' in directory '%s' already present!\n",
398
-
name, parent->d_name.name);
399
-
dput(dentry);
400
-
dentry = ERR_PTR(-EEXIST);
401
-
}
402
-
387
+
dentry = simple_start_creating(parent, name);
403
388
if (IS_ERR(dentry)) {
404
-
inode_unlock(d_inode(parent));
389
+
if (dentry == ERR_PTR(-EEXIST))
390
+
pr_err("'%s' already exists in '%pd'\n", name, parent);
405
391
simple_release_fs(&debugfs_mount, &debugfs_mount_count);
406
392
}
407
-
408
393
return dentry;
409
394
}
410
395
+25
fs/libfs.c
+25
fs/libfs.c
···
2260
2260
*/
2261
2261
cmpxchg(stashed, dentry, NULL);
2262
2262
}
2263
+
2264
+
/* parent must be held exclusive */
2265
+
struct dentry *simple_start_creating(struct dentry *parent, const char *name)
2266
+
{
2267
+
struct dentry *dentry;
2268
+
struct inode *dir = d_inode(parent);
2269
+
2270
+
inode_lock(dir);
2271
+
if (unlikely(IS_DEADDIR(dir))) {
2272
+
inode_unlock(dir);
2273
+
return ERR_PTR(-ENOENT);
2274
+
}
2275
+
dentry = lookup_noperm(&QSTR(name), parent);
2276
+
if (IS_ERR(dentry)) {
2277
+
inode_unlock(dir);
2278
+
return dentry;
2279
+
}
2280
+
if (dentry->d_inode) {
2281
+
dput(dentry);
2282
+
inode_unlock(dir);
2283
+
return ERR_PTR(-EEXIST);
2284
+
}
2285
+
return dentry;
2286
+
}
2287
+
EXPORT_SYMBOL(simple_start_creating);
+2
-13
fs/tracefs/inode.c
+2
-13
fs/tracefs/inode.c
···
551
551
if (!parent)
552
552
parent = tracefs_mount->mnt_root;
553
553
554
-
inode_lock(d_inode(parent));
555
-
if (unlikely(IS_DEADDIR(d_inode(parent))))
556
-
dentry = ERR_PTR(-ENOENT);
557
-
else
558
-
dentry = lookup_noperm(&QSTR(name), parent);
559
-
if (!IS_ERR(dentry) && d_inode(dentry)) {
560
-
dput(dentry);
561
-
dentry = ERR_PTR(-EEXIST);
562
-
}
563
-
564
-
if (IS_ERR(dentry)) {
565
-
inode_unlock(d_inode(parent));
554
+
dentry = simple_start_creating(parent, name);
555
+
if (IS_ERR(dentry))
566
556
simple_release_fs(&tracefs_mount, &tracefs_mount_count);
567
-
}
568
557
569
558
return dentry;
570
559
}
+1
include/linux/fs.h
+1
include/linux/fs.h
···
3619
3619
const struct tree_descr *);
3620
3620
extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int *count);
3621
3621
extern void simple_release_fs(struct vfsmount **mount, int *count);
3622
+
struct dentry *simple_start_creating(struct dentry *, const char *);
3622
3623
3623
3624
extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
3624
3625
loff_t *ppos, const void *from, size_t available);