diff options
| author | Christian Brauner <brauner@kernel.org> | 2025-06-18 22:53:36 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2025-06-19 14:28:24 +0200 |
| commit | bda3f1608d993419fa247dc11263fc931ceca58a (patch) | |
| tree | dd125c788bb4a1b8b322d60ac6b0687ed5b5a452 /fs | |
| parent | 1a1ad73aa1a66787f05f7f10f686b74bab77be72 (diff) | |
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>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/internal.h | 3 | ||||
| -rw-r--r-- | fs/libfs.c | 27 |
2 files changed, 23 insertions, 7 deletions
diff --git a/fs/internal.h b/fs/internal.h index 393f6c5c24f6b..22ba066d1dbaf 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -322,12 +322,15 @@ struct mnt_idmap *alloc_mnt_idmap(struct user_namespace *mnt_userns); struct mnt_idmap *mnt_idmap_get(struct mnt_idmap *idmap); void mnt_idmap_put(struct mnt_idmap *idmap); struct stashed_operations { + struct dentry *(*stash_dentry)(struct dentry **stashed, + struct dentry *dentry); void (*put_data)(void *data); int (*init_inode)(struct inode *inode, void *data); }; int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data, struct path *path); void stashed_dentry_prune(struct dentry *dentry); +struct dentry *stash_dentry(struct dentry **stashed, struct dentry *dentry); struct dentry *stashed_dentry_get(struct dentry **stashed); /** * path_mounted - check whether path is mounted diff --git a/fs/libfs.c b/fs/libfs.c index 9ea0ecc325a81..3541e22c87b5d 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -2128,6 +2128,8 @@ struct dentry *stashed_dentry_get(struct dentry **stashed) dentry = rcu_dereference(*stashed); if (!dentry) return NULL; + if (IS_ERR(dentry)) + return dentry; if (!lockref_get_not_dead(&dentry->d_lockref)) return NULL; return dentry; @@ -2176,8 +2178,7 @@ static struct dentry *prepare_anon_dentry(struct dentry **stashed, return dentry; } -static struct dentry *stash_dentry(struct dentry **stashed, - struct dentry *dentry) +struct dentry *stash_dentry(struct dentry **stashed, struct dentry *dentry) { guard(rcu)(); for (;;) { @@ -2218,12 +2219,15 @@ static struct dentry *stash_dentry(struct dentry **stashed, int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data, struct path *path) { - struct dentry *dentry; + struct dentry *dentry, *res; const struct stashed_operations *sops = mnt->mnt_sb->s_fs_info; /* See if dentry can be reused. */ - path->dentry = stashed_dentry_get(stashed); - if (path->dentry) { + res = stashed_dentry_get(stashed); + if (IS_ERR(res)) + return PTR_ERR(res); + if (res) { + path->dentry = res; sops->put_data(data); goto out_path; } @@ -2234,8 +2238,17 @@ int path_from_stashed(struct dentry **stashed, struct vfsmount *mnt, void *data, return PTR_ERR(dentry); /* Added a new dentry. @data is now owned by the filesystem. */ - path->dentry = stash_dentry(stashed, dentry); - if (path->dentry != dentry) + if (sops->stash_dentry) + res = sops->stash_dentry(stashed, dentry); + else + res = stash_dentry(stashed, dentry); + if (IS_ERR(res)) { + dput(dentry); + return PTR_ERR(res); + } + path->dentry = res; + /* A dentry was reused. */ + if (res != dentry) dput(dentry); out_path: |