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authorLinus Torvalds <torvalds@linux-foundation.org>2022-05-30 11:19:16 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-05-30 11:19:16 -0700
commit2c5ca23f7414eb2c782f945aa417cfab7b5c88dd (patch)
tree97e60152455347a36ed571da6b417a1daa4a6352 /fs/namei.c
parent73d15ba6ba390caed47aa8885811d1cd7b4477f3 (diff)
parentbc70682a497c4f3c968c552e465d1d9948b1ff4c (diff)
Merge tag 'ovl-update-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi: - Support idmapped layers in overlayfs (Christian Brauner) - Add a fix to exportfs that is relevant to open_by_handle_at(2) as well - Introduce new lookup helpers that allow passing mnt_userns into inode_permission() * tag 'ovl-update-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: support idmapped layers ovl: handle idmappings in ovl_xattr_{g,s}et() ovl: handle idmappings in layer open helpers ovl: handle idmappings in ovl_permission() ovl: use ovl_copy_{real,upper}attr() wrappers ovl: store lower path in ovl_inode ovl: handle idmappings for layer lookup ovl: handle idmappings for layer fileattrs ovl: use ovl_path_getxattr() wrapper ovl: use ovl_lookup_upper() wrapper ovl: use ovl_do_notify_change() wrapper ovl: pass layer mnt to ovl_open_realfile() ovl: pass ofs to setattr operations ovl: handle idmappings in creation operations ovl: add ovl_upper_mnt_userns() wrapper ovl: pass ofs to creation operations ovl: use wrappers to all vfs_*xattr() calls exportfs: support idmapped mounts fs: add two trivial lookup helpers
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c70
1 files changed, 60 insertions, 10 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 3dc0db2df561..776ecf679965 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2769,7 +2769,8 @@ struct dentry *lookup_one(struct user_namespace *mnt_userns, const char *name,
EXPORT_SYMBOL(lookup_one);
/**
- * lookup_one_len_unlocked - filesystem helper to lookup single pathname component
+ * lookup_one_unlocked - filesystem helper to lookup single pathname component
+ * @mnt_userns: idmapping of the mount the lookup is performed from
* @name: pathname component to lookup
* @base: base directory to lookup from
* @len: maximum length @len should be interpreted to
@@ -2780,14 +2781,15 @@ EXPORT_SYMBOL(lookup_one);
* Unlike lookup_one_len, it should be called without the parent
* i_mutex held, and will take the i_mutex itself if necessary.
*/
-struct dentry *lookup_one_len_unlocked(const char *name,
- struct dentry *base, int len)
+struct dentry *lookup_one_unlocked(struct user_namespace *mnt_userns,
+ const char *name, struct dentry *base,
+ int len)
{
struct qstr this;
int err;
struct dentry *ret;
- err = lookup_one_common(&init_user_ns, name, base, len, &this);
+ err = lookup_one_common(mnt_userns, name, base, len, &this);
if (err)
return ERR_PTR(err);
@@ -2796,6 +2798,59 @@ struct dentry *lookup_one_len_unlocked(const char *name,
ret = lookup_slow(&this, base, 0);
return ret;
}
+EXPORT_SYMBOL(lookup_one_unlocked);
+
+/**
+ * lookup_one_positive_unlocked - filesystem helper to lookup single
+ * pathname component
+ * @mnt_userns: idmapping of the mount the lookup is performed from
+ * @name: pathname component to lookup
+ * @base: base directory to lookup from
+ * @len: maximum length @len should be interpreted to
+ *
+ * This helper will yield ERR_PTR(-ENOENT) on negatives. The helper returns
+ * known positive or ERR_PTR(). This is what most of the users want.
+ *
+ * Note that pinned negative with unlocked parent _can_ become positive at any
+ * time, so callers of lookup_one_unlocked() need to be very careful; pinned
+ * positives have >d_inode stable, so this one avoids such problems.
+ *
+ * Note that this routine is purely a helper for filesystem usage and should
+ * not be called by generic code.
+ *
+ * The helper should be called without i_mutex held.
+ */
+struct dentry *lookup_one_positive_unlocked(struct user_namespace *mnt_userns,
+ const char *name,
+ struct dentry *base, int len)
+{
+ struct dentry *ret = lookup_one_unlocked(mnt_userns, name, base, len);
+
+ if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) {
+ dput(ret);
+ ret = ERR_PTR(-ENOENT);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(lookup_one_positive_unlocked);
+
+/**
+ * lookup_one_len_unlocked - filesystem helper to lookup single pathname component
+ * @name: pathname component to lookup
+ * @base: base directory to lookup from
+ * @len: maximum length @len should be interpreted to
+ *
+ * Note that this routine is purely a helper for filesystem usage and should
+ * not be called by generic code.
+ *
+ * Unlike lookup_one_len, it should be called without the parent
+ * i_mutex held, and will take the i_mutex itself if necessary.
+ */
+struct dentry *lookup_one_len_unlocked(const char *name,
+ struct dentry *base, int len)
+{
+ return lookup_one_unlocked(&init_user_ns, name, base, len);
+}
EXPORT_SYMBOL(lookup_one_len_unlocked);
/*
@@ -2809,12 +2864,7 @@ EXPORT_SYMBOL(lookup_one_len_unlocked);
struct dentry *lookup_positive_unlocked(const char *name,
struct dentry *base, int len)
{
- struct dentry *ret = lookup_one_len_unlocked(name, base, len);
- if (!IS_ERR(ret) && d_flags_negative(smp_load_acquire(&ret->d_flags))) {
- dput(ret);
- ret = ERR_PTR(-ENOENT);
- }
- return ret;
+ return lookup_one_positive_unlocked(&init_user_ns, name, base, len);
}
EXPORT_SYMBOL(lookup_positive_unlocked);