obj-$(CONFIG_OVERLAY_FS) += overlay.o
-overlay-objs := super.o inode.o dir.o readdir.o copy_up.o
+overlay-objs := super.o namei.o util.o inode.o dir.o readdir.o copy_up.o
--- /dev/null
+/*
+ * Copyright (C) 2011 Novell Inc.
+ * Copyright (C) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/xattr.h>
+#include "overlayfs.h"
+#include "ovl_entry.h"
+
+static struct dentry *ovl_lookup_real(struct dentry *dir,
+ const struct qstr *name)
+{
+ struct dentry *dentry;
+
+ dentry = lookup_one_len_unlocked(name->name, dir, name->len);
+ if (IS_ERR(dentry)) {
+ if (PTR_ERR(dentry) == -ENOENT)
+ dentry = NULL;
+ } else if (!dentry->d_inode) {
+ dput(dentry);
+ dentry = NULL;
+ } else if (ovl_dentry_weird(dentry)) {
+ dput(dentry);
+ /* Don't support traversing automounts and other weirdness */
+ dentry = ERR_PTR(-EREMOTE);
+ }
+ return dentry;
+}
+
+static bool ovl_is_opaquedir(struct dentry *dentry)
+{
+ int res;
+ char val;
+
+ if (!d_is_dir(dentry))
+ return false;
+
+ res = vfs_getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1);
+ if (res == 1 && val == 'y')
+ return true;
+
+ return false;
+}
+
+/*
+ * Returns next layer in stack starting from top.
+ * Returns -1 if this is the last layer.
+ */
+int ovl_path_next(int idx, struct dentry *dentry, struct path *path)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ BUG_ON(idx < 0);
+ if (idx == 0) {
+ ovl_path_upper(dentry, path);
+ if (path->dentry)
+ return oe->numlower ? 1 : -1;
+ idx++;
+ }
+ BUG_ON(idx > oe->numlower);
+ *path = oe->lowerstack[idx - 1];
+
+ return (idx < oe->numlower) ? idx + 1 : -1;
+}
+
+struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
+ unsigned int flags)
+{
+ struct ovl_entry *oe;
+ const struct cred *old_cred;
+ struct ovl_entry *poe = dentry->d_parent->d_fsdata;
+ struct path *stack = NULL;
+ struct dentry *upperdir, *upperdentry = NULL;
+ unsigned int ctr = 0;
+ struct inode *inode = NULL;
+ bool upperopaque = false;
+ bool stop = false;
+ bool isdir = false;
+ struct dentry *this;
+ unsigned int i;
+ int err;
+
+ old_cred = ovl_override_creds(dentry->d_sb);
+ upperdir = ovl_upperdentry_dereference(poe);
+ if (upperdir) {
+ this = ovl_lookup_real(upperdir, &dentry->d_name);
+ err = PTR_ERR(this);
+ if (IS_ERR(this))
+ goto out;
+
+ if (this) {
+ if (unlikely(ovl_dentry_remote(this))) {
+ dput(this);
+ err = -EREMOTE;
+ goto out;
+ }
+ if (ovl_is_whiteout(this)) {
+ dput(this);
+ this = NULL;
+ stop = upperopaque = true;
+ } else if (!d_is_dir(this)) {
+ stop = true;
+ } else {
+ isdir = true;
+ if (poe->numlower && ovl_is_opaquedir(this))
+ stop = upperopaque = true;
+ }
+ }
+ upperdentry = this;
+ }
+
+ if (!stop && poe->numlower) {
+ err = -ENOMEM;
+ stack = kcalloc(poe->numlower, sizeof(struct path), GFP_KERNEL);
+ if (!stack)
+ goto out_put_upper;
+ }
+
+ for (i = 0; !stop && i < poe->numlower; i++) {
+ struct path lowerpath = poe->lowerstack[i];
+
+ this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name);
+ err = PTR_ERR(this);
+ if (IS_ERR(this)) {
+ /*
+ * If it's positive, then treat ENAMETOOLONG as ENOENT.
+ */
+ if (err == -ENAMETOOLONG && (upperdentry || ctr))
+ continue;
+ goto out_put;
+ }
+ if (!this)
+ continue;
+ if (ovl_is_whiteout(this)) {
+ dput(this);
+ break;
+ }
+ /*
+ * If this is a non-directory then stop here.
+ */
+ if (!d_is_dir(this)) {
+ if (isdir) {
+ dput(this);
+ break;
+ }
+ stop = true;
+ } else {
+ /*
+ * Only makes sense to check opaque dir if this is not
+ * the lowermost layer.
+ */
+ if (i < poe->numlower - 1 && ovl_is_opaquedir(this))
+ stop = true;
+ }
+
+ stack[ctr].dentry = this;
+ stack[ctr].mnt = lowerpath.mnt;
+ ctr++;
+ }
+
+ oe = ovl_alloc_entry(ctr);
+ err = -ENOMEM;
+ if (!oe)
+ goto out_put;
+
+ if (upperdentry || ctr) {
+ struct dentry *realdentry;
+ struct inode *realinode;
+
+ realdentry = upperdentry ? upperdentry : stack[0].dentry;
+ realinode = d_inode(realdentry);
+
+ err = -ENOMEM;
+ if (upperdentry && !d_is_dir(upperdentry)) {
+ inode = ovl_get_inode(dentry->d_sb, realinode);
+ } else {
+ inode = ovl_new_inode(dentry->d_sb, realinode->i_mode,
+ realinode->i_rdev);
+ if (inode)
+ ovl_inode_init(inode, realinode, !!upperdentry);
+ }
+ if (!inode)
+ goto out_free_oe;
+ ovl_copyattr(realdentry->d_inode, inode);
+ }
+
+ revert_creds(old_cred);
+ oe->opaque = upperopaque;
+ oe->__upperdentry = upperdentry;
+ memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
+ kfree(stack);
+ dentry->d_fsdata = oe;
+ d_add(dentry, inode);
+
+ return NULL;
+
+out_free_oe:
+ kfree(oe);
+out_put:
+ for (i = 0; i < ctr; i++)
+ dput(stack[i].dentry);
+ kfree(stack);
+out_put_upper:
+ dput(upperdentry);
+out:
+ revert_creds(old_cred);
+ return ERR_PTR(err);
+}
+
+bool ovl_lower_positive(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ struct ovl_entry *poe = dentry->d_parent->d_fsdata;
+ const struct qstr *name = &dentry->d_name;
+ unsigned int i;
+ bool positive = false;
+ bool done = false;
+
+ /*
+ * If dentry is negative, then lower is positive iff this is a
+ * whiteout.
+ */
+ if (!dentry->d_inode)
+ return oe->opaque;
+
+ /* Negative upper -> positive lower */
+ if (!oe->__upperdentry)
+ return true;
+
+ /* Positive upper -> have to look up lower to see whether it exists */
+ for (i = 0; !done && !positive && i < poe->numlower; i++) {
+ struct dentry *this;
+ struct dentry *lowerdir = poe->lowerstack[i].dentry;
+
+ this = lookup_one_len_unlocked(name->name, lowerdir,
+ name->len);
+ if (IS_ERR(this)) {
+ switch (PTR_ERR(this)) {
+ case -ENOENT:
+ case -ENAMETOOLONG:
+ break;
+
+ default:
+ /*
+ * Assume something is there, we just couldn't
+ * access it.
+ */
+ positive = true;
+ break;
+ }
+ } else {
+ if (this->d_inode) {
+ positive = !ovl_is_whiteout(this);
+ done = true;
+ }
+ dput(this);
+ }
+ }
+
+ return positive;
+}
#include <linux/kernel.h>
-struct ovl_entry;
-
enum ovl_path_type {
__OVL_PATH_UPPER = (1 << 0),
__OVL_PATH_MERGE = (1 << 1),
return (struct inode *) (x & ~OVL_ISUPPER_MASK);
}
+/* util.c */
+int ovl_want_write(struct dentry *dentry);
+void ovl_drop_write(struct dentry *dentry);
+struct dentry *ovl_workdir(struct dentry *dentry);
+const struct cred *ovl_override_creds(struct super_block *sb);
+struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
+bool ovl_dentry_remote(struct dentry *dentry);
+bool ovl_dentry_weird(struct dentry *dentry);
enum ovl_path_type ovl_path_type(struct dentry *dentry);
-u64 ovl_dentry_version_get(struct dentry *dentry);
-void ovl_dentry_version_inc(struct dentry *dentry);
void ovl_path_upper(struct dentry *dentry, struct path *path);
void ovl_path_lower(struct dentry *dentry, struct path *path);
enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
-int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
struct dentry *ovl_dentry_upper(struct dentry *dentry);
struct dentry *ovl_dentry_lower(struct dentry *dentry);
struct dentry *ovl_dentry_real(struct dentry *dentry);
-struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode,
- bool is_upper);
struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
-struct dentry *ovl_workdir(struct dentry *dentry);
-int ovl_want_write(struct dentry *dentry);
-void ovl_drop_write(struct dentry *dentry);
bool ovl_dentry_is_opaque(struct dentry *dentry);
-bool ovl_lower_positive(struct dentry *dentry);
bool ovl_dentry_is_whiteout(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque);
-bool ovl_is_whiteout(struct dentry *dentry);
-const struct cred *ovl_override_creds(struct super_block *sb);
void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
+void ovl_inode_init(struct inode *inode, struct inode *realinode,
+ bool is_upper);
void ovl_inode_update(struct inode *inode, struct inode *upperinode);
-struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
- unsigned int flags);
+void ovl_dentry_version_inc(struct dentry *dentry);
+u64 ovl_dentry_version_get(struct dentry *dentry);
+bool ovl_is_whiteout(struct dentry *dentry);
struct file *ovl_path_open(struct path *path, int flags);
-struct dentry *ovl_upper_create(struct dentry *upperdir, struct dentry *dentry,
- struct kstat *stat, const char *link);
+/* namei.c */
+int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
+struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags);
+bool ovl_lower_positive(struct dentry *dentry);
/* readdir.c */
extern const struct file_operations ovl_dir_operations;
--- /dev/null
+/*
+ *
+ * Copyright (C) 2011 Novell Inc.
+ * Copyright (C) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+struct ovl_config {
+ char *lowerdir;
+ char *upperdir;
+ char *workdir;
+ bool default_permissions;
+};
+
+/* private information held for overlayfs's superblock */
+struct ovl_fs {
+ struct vfsmount *upper_mnt;
+ unsigned numlower;
+ struct vfsmount **lower_mnt;
+ struct dentry *workdir;
+ long lower_namelen;
+ /* pathnames of lower and upper dirs, for show_options */
+ struct ovl_config config;
+ /* creds of process who forced instantiation of super block */
+ const struct cred *creator_cred;
+};
+
+/* private information held for every overlayfs dentry */
+struct ovl_entry {
+ struct dentry *__upperdentry;
+ struct ovl_dir_cache *cache;
+ union {
+ struct {
+ u64 version;
+ bool opaque;
+ };
+ struct rcu_head rcu;
+ };
+ unsigned numlower;
+ struct path lowerstack[];
+};
+
+struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
+
+static inline struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
+{
+ return lockless_dereference(oe->__upperdentry);
+}
#include <linux/fs.h>
#include <linux/namei.h>
-#include <linux/pagemap.h>
#include <linux/xattr.h>
-#include <linux/security.h>
#include <linux/mount.h>
-#include <linux/slab.h>
#include <linux/parser.h>
#include <linux/module.h>
-#include <linux/sched.h>
#include <linux/statfs.h>
#include <linux/seq_file.h>
#include <linux/posix_acl_xattr.h>
#include "overlayfs.h"
+#include "ovl_entry.h"
MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Overlay filesystem");
MODULE_LICENSE("GPL");
-struct ovl_config {
- char *lowerdir;
- char *upperdir;
- char *workdir;
- bool default_permissions;
-};
-
-/* private information held for overlayfs's superblock */
-struct ovl_fs {
- struct vfsmount *upper_mnt;
- unsigned numlower;
- struct vfsmount **lower_mnt;
- struct dentry *workdir;
- long lower_namelen;
- /* pathnames of lower and upper dirs, for show_options */
- struct ovl_config config;
- /* creds of process who forced instantiation of super block */
- const struct cred *creator_cred;
-};
struct ovl_dir_cache;
-/* private information held for every overlayfs dentry */
-struct ovl_entry {
- struct dentry *__upperdentry;
- struct ovl_dir_cache *cache;
- union {
- struct {
- u64 version;
- bool opaque;
- };
- struct rcu_head rcu;
- };
- unsigned numlower;
- struct path lowerstack[];
-};
-
#define OVL_MAX_STACK 500
-static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
-{
- return oe->numlower ? oe->lowerstack[0].dentry : NULL;
-}
-
-enum ovl_path_type ovl_path_type(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- enum ovl_path_type type = 0;
-
- if (oe->__upperdentry) {
- type = __OVL_PATH_UPPER;
-
- /*
- * Non-dir dentry can hold lower dentry from previous
- * location.
- */
- if (oe->numlower && d_is_dir(dentry))
- type |= __OVL_PATH_MERGE;
- } else {
- if (oe->numlower > 1)
- type |= __OVL_PATH_MERGE;
- }
- return type;
-}
-
-static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
-{
- return lockless_dereference(oe->__upperdentry);
-}
-
-void ovl_path_upper(struct dentry *dentry, struct path *path)
-{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- struct ovl_entry *oe = dentry->d_fsdata;
-
- path->mnt = ofs->upper_mnt;
- path->dentry = ovl_upperdentry_dereference(oe);
-}
-
-enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
-{
- enum ovl_path_type type = ovl_path_type(dentry);
-
- if (!OVL_TYPE_UPPER(type))
- ovl_path_lower(dentry, path);
- else
- ovl_path_upper(dentry, path);
-
- return type;
-}
-
-struct dentry *ovl_dentry_upper(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- return ovl_upperdentry_dereference(oe);
-}
-
-struct dentry *ovl_dentry_lower(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- return __ovl_dentry_lower(oe);
-}
-
-struct dentry *ovl_dentry_real(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- struct dentry *realdentry;
-
- realdentry = ovl_upperdentry_dereference(oe);
- if (!realdentry)
- realdentry = __ovl_dentry_lower(oe);
-
- return realdentry;
-}
-
-static void ovl_inode_init(struct inode *inode, struct inode *realinode,
- bool is_upper)
-{
- WRITE_ONCE(inode->i_private, (unsigned long) realinode |
- (is_upper ? OVL_ISUPPER_MASK : 0));
-}
-
-struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode,
- bool is_upper)
-{
- if (is_upper) {
- struct ovl_fs *ofs = inode->i_sb->s_fs_info;
-
- return ofs->upper_mnt;
- } else {
- return oe->numlower ? oe->lowerstack[0].mnt : NULL;
- }
-}
-
-struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- return oe->cache;
-}
-
-void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- oe->cache = cache;
-}
-
-void ovl_path_lower(struct dentry *dentry, struct path *path)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- *path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL };
-}
-
-int ovl_want_write(struct dentry *dentry)
-{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- return mnt_want_write(ofs->upper_mnt);
-}
-
-void ovl_drop_write(struct dentry *dentry)
-{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- mnt_drop_write(ofs->upper_mnt);
-}
-
-struct dentry *ovl_workdir(struct dentry *dentry)
-{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- return ofs->workdir;
-}
-
-bool ovl_dentry_is_opaque(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- return oe->opaque;
-}
-
-bool ovl_dentry_is_whiteout(struct dentry *dentry)
-{
- return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
-}
-
-void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- oe->opaque = opaque;
-}
-
-void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
- WARN_ON(oe->__upperdentry);
- /*
- * Make sure upperdentry is consistent before making it visible to
- * ovl_upperdentry_dereference().
- */
- smp_wmb();
- oe->__upperdentry = upperdentry;
-}
-
-void ovl_inode_update(struct inode *inode, struct inode *upperinode)
-{
- WARN_ON(!upperinode);
- WARN_ON(!inode_unhashed(inode));
- WRITE_ONCE(inode->i_private,
- (unsigned long) upperinode | OVL_ISUPPER_MASK);
- if (!S_ISDIR(upperinode->i_mode))
- __insert_inode_hash(inode, (unsigned long) upperinode);
-}
-
-void ovl_dentry_version_inc(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- WARN_ON(!inode_is_locked(dentry->d_inode));
- oe->version++;
-}
-
-u64 ovl_dentry_version_get(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- WARN_ON(!inode_is_locked(dentry->d_inode));
- return oe->version;
-}
-
-bool ovl_is_whiteout(struct dentry *dentry)
-{
- struct inode *inode = dentry->d_inode;
-
- return inode && IS_WHITEOUT(inode);
-}
-
-const struct cred *ovl_override_creds(struct super_block *sb)
-{
- struct ovl_fs *ofs = sb->s_fs_info;
-
- return override_creds(ofs->creator_cred);
-}
-
-static bool ovl_is_opaquedir(struct dentry *dentry)
-{
- int res;
- char val;
-
- if (!d_is_dir(dentry))
- return false;
-
- res = vfs_getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1);
- if (res == 1 && val == 'y')
- return true;
-
- return false;
-}
static void ovl_dentry_release(struct dentry *dentry)
{
.d_weak_revalidate = ovl_dentry_weak_revalidate,
};
-static struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
-{
- size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
- struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
-
- if (oe)
- oe->numlower = numlower;
-
- return oe;
-}
-
-static bool ovl_dentry_remote(struct dentry *dentry)
-{
- return dentry->d_flags &
- (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
- DCACHE_OP_REAL);
-}
-
-static bool ovl_dentry_weird(struct dentry *dentry)
-{
- return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
- DCACHE_MANAGE_TRANSIT |
- DCACHE_OP_HASH |
- DCACHE_OP_COMPARE);
-}
-
-static inline struct dentry *ovl_lookup_real(struct dentry *dir,
- const struct qstr *name)
-{
- struct dentry *dentry;
-
- dentry = lookup_one_len_unlocked(name->name, dir, name->len);
- if (IS_ERR(dentry)) {
- if (PTR_ERR(dentry) == -ENOENT)
- dentry = NULL;
- } else if (!dentry->d_inode) {
- dput(dentry);
- dentry = NULL;
- } else if (ovl_dentry_weird(dentry)) {
- dput(dentry);
- /* Don't support traversing automounts and other weirdness */
- dentry = ERR_PTR(-EREMOTE);
- }
- return dentry;
-}
-
-/*
- * Returns next layer in stack starting from top.
- * Returns -1 if this is the last layer.
- */
-int ovl_path_next(int idx, struct dentry *dentry, struct path *path)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- BUG_ON(idx < 0);
- if (idx == 0) {
- ovl_path_upper(dentry, path);
- if (path->dentry)
- return oe->numlower ? 1 : -1;
- idx++;
- }
- BUG_ON(idx > oe->numlower);
- *path = oe->lowerstack[idx - 1];
-
- return (idx < oe->numlower) ? idx + 1 : -1;
-}
-
-struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
- unsigned int flags)
-{
- struct ovl_entry *oe;
- const struct cred *old_cred;
- struct ovl_entry *poe = dentry->d_parent->d_fsdata;
- struct path *stack = NULL;
- struct dentry *upperdir, *upperdentry = NULL;
- unsigned int ctr = 0;
- struct inode *inode = NULL;
- bool upperopaque = false;
- bool stop = false;
- bool isdir = false;
- struct dentry *this;
- unsigned int i;
- int err;
-
- old_cred = ovl_override_creds(dentry->d_sb);
- upperdir = ovl_upperdentry_dereference(poe);
- if (upperdir) {
- this = ovl_lookup_real(upperdir, &dentry->d_name);
- err = PTR_ERR(this);
- if (IS_ERR(this))
- goto out;
-
- if (this) {
- if (unlikely(ovl_dentry_remote(this))) {
- dput(this);
- err = -EREMOTE;
- goto out;
- }
- if (ovl_is_whiteout(this)) {
- dput(this);
- this = NULL;
- stop = upperopaque = true;
- } else if (!d_is_dir(this)) {
- stop = true;
- } else {
- isdir = true;
- if (poe->numlower && ovl_is_opaquedir(this))
- stop = upperopaque = true;
- }
- }
- upperdentry = this;
- }
-
- if (!stop && poe->numlower) {
- err = -ENOMEM;
- stack = kcalloc(poe->numlower, sizeof(struct path), GFP_KERNEL);
- if (!stack)
- goto out_put_upper;
- }
-
- for (i = 0; !stop && i < poe->numlower; i++) {
- struct path lowerpath = poe->lowerstack[i];
-
- this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name);
- err = PTR_ERR(this);
- if (IS_ERR(this)) {
- /*
- * If it's positive, then treat ENAMETOOLONG as ENOENT.
- */
- if (err == -ENAMETOOLONG && (upperdentry || ctr))
- continue;
- goto out_put;
- }
- if (!this)
- continue;
- if (ovl_is_whiteout(this)) {
- dput(this);
- break;
- }
- /*
- * If this is a non-directory then stop here.
- */
- if (!d_is_dir(this)) {
- if (isdir) {
- dput(this);
- break;
- }
- stop = true;
- } else {
- /*
- * Only makes sense to check opaque dir if this is not
- * the lowermost layer.
- */
- if (i < poe->numlower - 1 && ovl_is_opaquedir(this))
- stop = true;
- }
-
- stack[ctr].dentry = this;
- stack[ctr].mnt = lowerpath.mnt;
- ctr++;
- }
-
- oe = ovl_alloc_entry(ctr);
- err = -ENOMEM;
- if (!oe)
- goto out_put;
-
- if (upperdentry || ctr) {
- struct dentry *realdentry;
- struct inode *realinode;
-
- realdentry = upperdentry ? upperdentry : stack[0].dentry;
- realinode = d_inode(realdentry);
-
- err = -ENOMEM;
- if (upperdentry && !d_is_dir(upperdentry)) {
- inode = ovl_get_inode(dentry->d_sb, realinode);
- } else {
- inode = ovl_new_inode(dentry->d_sb, realinode->i_mode,
- realinode->i_rdev);
- if (inode)
- ovl_inode_init(inode, realinode, !!upperdentry);
- }
- if (!inode)
- goto out_free_oe;
- ovl_copyattr(realdentry->d_inode, inode);
- }
-
- revert_creds(old_cred);
- oe->opaque = upperopaque;
- oe->__upperdentry = upperdentry;
- memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr);
- kfree(stack);
- dentry->d_fsdata = oe;
- d_add(dentry, inode);
-
- return NULL;
-
-out_free_oe:
- kfree(oe);
-out_put:
- for (i = 0; i < ctr; i++)
- dput(stack[i].dentry);
- kfree(stack);
-out_put_upper:
- dput(upperdentry);
-out:
- revert_creds(old_cred);
- return ERR_PTR(err);
-}
-
-bool ovl_lower_positive(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
- struct ovl_entry *poe = dentry->d_parent->d_fsdata;
- const struct qstr *name = &dentry->d_name;
- unsigned int i;
- bool positive = false;
- bool done = false;
-
- /*
- * If dentry is negative, then lower is positive iff this is a
- * whiteout.
- */
- if (!dentry->d_inode)
- return oe->opaque;
-
- /* Negative upper -> positive lower */
- if (!oe->__upperdentry)
- return true;
-
- /* Positive upper -> have to look up lower to see whether it exists */
- for (i = 0; !done && !positive && i < poe->numlower; i++) {
- struct dentry *this;
- struct dentry *lowerdir = poe->lowerstack[i].dentry;
-
- this = lookup_one_len_unlocked(name->name, lowerdir,
- name->len);
- if (IS_ERR(this)) {
- switch (PTR_ERR(this)) {
- case -ENOENT:
- case -ENAMETOOLONG:
- break;
-
- default:
- /*
- * Assume something is there, we just couldn't
- * access it.
- */
- positive = true;
- break;
- }
- } else {
- if (this->d_inode) {
- positive = !ovl_is_whiteout(this);
- done = true;
- }
- dput(this);
- }
- }
-
- return positive;
-}
-
-struct file *ovl_path_open(struct path *path, int flags)
-{
- return dentry_open(path, flags | O_NOATIME, current_cred());
-}
-
static void ovl_put_super(struct super_block *sb)
{
struct ovl_fs *ufs = sb->s_fs_info;
--- /dev/null
+/*
+ * Copyright (C) 2011 Novell Inc.
+ * Copyright (C) 2016 Red Hat, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include "overlayfs.h"
+#include "ovl_entry.h"
+
+int ovl_want_write(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ return mnt_want_write(ofs->upper_mnt);
+}
+
+void ovl_drop_write(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ mnt_drop_write(ofs->upper_mnt);
+}
+
+struct dentry *ovl_workdir(struct dentry *dentry)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ return ofs->workdir;
+}
+
+const struct cred *ovl_override_creds(struct super_block *sb)
+{
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ return override_creds(ofs->creator_cred);
+}
+
+struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
+{
+ size_t size = offsetof(struct ovl_entry, lowerstack[numlower]);
+ struct ovl_entry *oe = kzalloc(size, GFP_KERNEL);
+
+ if (oe)
+ oe->numlower = numlower;
+
+ return oe;
+}
+
+bool ovl_dentry_remote(struct dentry *dentry)
+{
+ return dentry->d_flags &
+ (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
+ DCACHE_OP_REAL);
+}
+
+bool ovl_dentry_weird(struct dentry *dentry)
+{
+ return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT |
+ DCACHE_MANAGE_TRANSIT |
+ DCACHE_OP_HASH |
+ DCACHE_OP_COMPARE);
+}
+
+enum ovl_path_type ovl_path_type(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ enum ovl_path_type type = 0;
+
+ if (oe->__upperdentry) {
+ type = __OVL_PATH_UPPER;
+
+ /*
+ * Non-dir dentry can hold lower dentry from previous
+ * location.
+ */
+ if (oe->numlower && d_is_dir(dentry))
+ type |= __OVL_PATH_MERGE;
+ } else {
+ if (oe->numlower > 1)
+ type |= __OVL_PATH_MERGE;
+ }
+ return type;
+}
+
+void ovl_path_upper(struct dentry *dentry, struct path *path)
+{
+ struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ path->mnt = ofs->upper_mnt;
+ path->dentry = ovl_upperdentry_dereference(oe);
+}
+
+void ovl_path_lower(struct dentry *dentry, struct path *path)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ *path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL };
+}
+
+enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
+{
+ enum ovl_path_type type = ovl_path_type(dentry);
+
+ if (!OVL_TYPE_UPPER(type))
+ ovl_path_lower(dentry, path);
+ else
+ ovl_path_upper(dentry, path);
+
+ return type;
+}
+
+struct dentry *ovl_dentry_upper(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return ovl_upperdentry_dereference(oe);
+}
+
+static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe)
+{
+ return oe->numlower ? oe->lowerstack[0].dentry : NULL;
+}
+
+struct dentry *ovl_dentry_lower(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return __ovl_dentry_lower(oe);
+}
+
+struct dentry *ovl_dentry_real(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ struct dentry *realdentry;
+
+ realdentry = ovl_upperdentry_dereference(oe);
+ if (!realdentry)
+ realdentry = __ovl_dentry_lower(oe);
+
+ return realdentry;
+}
+
+struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ return oe->cache;
+}
+
+void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ oe->cache = cache;
+}
+
+bool ovl_dentry_is_opaque(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ return oe->opaque;
+}
+
+bool ovl_dentry_is_whiteout(struct dentry *dentry)
+{
+ return !dentry->d_inode && ovl_dentry_is_opaque(dentry);
+}
+
+void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+ oe->opaque = opaque;
+}
+
+void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode));
+ WARN_ON(oe->__upperdentry);
+ /*
+ * Make sure upperdentry is consistent before making it visible to
+ * ovl_upperdentry_dereference().
+ */
+ smp_wmb();
+ oe->__upperdentry = upperdentry;
+}
+
+void ovl_inode_init(struct inode *inode, struct inode *realinode, bool is_upper)
+{
+ WRITE_ONCE(inode->i_private, (unsigned long) realinode |
+ (is_upper ? OVL_ISUPPER_MASK : 0));
+}
+
+void ovl_inode_update(struct inode *inode, struct inode *upperinode)
+{
+ WARN_ON(!upperinode);
+ WARN_ON(!inode_unhashed(inode));
+ WRITE_ONCE(inode->i_private,
+ (unsigned long) upperinode | OVL_ISUPPER_MASK);
+ if (!S_ISDIR(upperinode->i_mode))
+ __insert_inode_hash(inode, (unsigned long) upperinode);
+}
+
+void ovl_dentry_version_inc(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ WARN_ON(!inode_is_locked(dentry->d_inode));
+ oe->version++;
+}
+
+u64 ovl_dentry_version_get(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ WARN_ON(!inode_is_locked(dentry->d_inode));
+ return oe->version;
+}
+
+bool ovl_is_whiteout(struct dentry *dentry)
+{
+ struct inode *inode = dentry->d_inode;
+
+ return inode && IS_WHITEOUT(inode);
+}
+
+struct file *ovl_path_open(struct path *path, int flags)
+{
+ return dentry_open(path, flags | O_NOATIME, current_cred());
+}
projects / openwrt / staging / blogic.git / commitdiff