Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
libfs: massage path_from_stashed() to allow custom stashing behavior
* Add a callback to struct stashed_operations so it's possible to
implement custom behavior for pidfs and allow for it to return errors.
* Teach stashed_dentry_get() to handle error pointers.
Link: https://lore.kernel.org/20250618-work-pidfs-persistent-v2-2-98f3456fd552@kernel.org
Reviewed-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
+23
-7
+3
fs/internal.h
+3
fs/internal.h
···
322
322
struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap);
323
323
void mnt_idmap_put(struct mnt_idmap *idmap);
324
324
struct stashed_operations {
325
+
struct dentry *(*stash_dentry)(struct dentry **stashed,
326
+
struct dentry *dentry);
325
327
void (*put_data)(void *data);
326
328
int (*init_inode)(struct inode *inode, void *data);
327
329
};
328
330
int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data,
329
331
struct path *path);
330
332
void stashed_dentry_prune(struct dentry *dentry);
333
+
struct dentry *stash_dentry(struct dentry **stashed, struct dentry *dentry);
331
334
struct dentry *stashed_dentry_get(struct dentry **stashed);
332
335
/**
333
336
* path_mounted - check whether path is mounted
+20
-7
fs/libfs.c
+20
-7
fs/libfs.c
···
2128
2128
dentry = rcu_dereference(*stashed);
2129
2129
if (!dentry)
2130
2130
return NULL;
2131
+
if (IS_ERR(dentry))
2132
+
return dentry;
2131
2133
if (!lockref_get_not_dead(&dentry->d_lockref))
2132
2134
return NULL;
2133
2135
return dentry;
···
2178
2176
return dentry;
2179
2177
}
2180
2178
2181
-
static struct dentry *stash_dentry(struct dentry **stashed,
2182
-
struct dentry *dentry)
2179
+
struct dentry *stash_dentry(struct dentry **stashed, struct dentry *dentry)
2183
2180
{
2184
2181
guard(rcu)();
2185
2182
for (;;) {
···
2219
2218
int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data,
2220
2219
struct path *path)
2221
2220
{
2222
-
struct dentry *dentry;
2221
+
struct dentry *dentry, *res;
2223
2222
const struct stashed_operations *sops = mnt->mnt_sb->s_fs_info;
2224
2223
2225
2224
/* See if dentry can be reused. */
2226
-
path->dentry = stashed_dentry_get(stashed);
2227
-
if (path->dentry) {
2225
+
res = stashed_dentry_get(stashed);
2226
+
if (IS_ERR(res))
2227
+
return PTR_ERR(res);
2228
+
if (res) {
2229
+
path->dentry = res;
2228
2230
sops->put_data(data);
2229
2231
goto out_path;
2230
2232
}
···
2238
2234
return PTR_ERR(dentry);
2239
2235
2240
2236
/* Added a new dentry. @data is now owned by the filesystem. */
2241
-
path->dentry = stash_dentry(stashed, dentry);
2242
-
if (path->dentry != dentry)
2237
+
if (sops->stash_dentry)
2238
+
res = sops->stash_dentry(stashed, dentry);
2239
+
else
2240
+
res = stash_dentry(stashed, dentry);
2241
+
if (IS_ERR(res)) {
2242
+
dput(dentry);
2243
+
return PTR_ERR(res);
2244
+
}
2245
+
path->dentry = res;
2246
+
/* A dentry was reused. */
2247
+
if (res != dentry)
2243
2248
dput(dentry);
2244
2249
2245
2250
out_path: