summaryrefslogtreecommitdiff
path: root/fs/overlayfs/super.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/overlayfs/super.c')
-rw-r--r--fs/overlayfs/super.c2049
1 files changed, 1225 insertions, 824 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index d86e89f97201..ba9146f22a2c 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1,10 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2011 Novell 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 <uapi/linux/magic.h>
@@ -17,8 +14,12 @@
#include <linux/statfs.h>
#include <linux/seq_file.h>
#include <linux/posix_acl_xattr.h>
+#include <linux/exportfs.h>
+#include <linux/file.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
#include "overlayfs.h"
-#include "ovl_entry.h"
+#include "params.h"
MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Overlay filesystem");
@@ -27,169 +28,186 @@ MODULE_LICENSE("GPL");
struct ovl_dir_cache;
-#define OVL_MAX_STACK 500
-
-static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR);
-module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644);
-MODULE_PARM_DESC(ovl_redirect_dir_def,
- "Default to on or off for the redirect_dir feature");
-
-static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX);
-module_param_named(index, ovl_index_def, bool, 0644);
-MODULE_PARM_DESC(ovl_index_def,
- "Default to on or off for the inodes index feature");
-
-static void ovl_dentry_release(struct dentry *dentry)
-{
- struct ovl_entry *oe = dentry->d_fsdata;
-
- if (oe) {
- unsigned int i;
-
- for (i = 0; i < oe->numlower; i++)
- dput(oe->lowerstack[i].dentry);
- kfree_rcu(oe, rcu);
- }
-}
-
-static int ovl_check_append_only(struct inode *inode, int flag)
-{
- /*
- * This test was moot in vfs may_open() because overlay inode does
- * not have the S_APPEND flag, so re-check on real upper inode
- */
- if (IS_APPEND(inode)) {
- if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND))
- return -EPERM;
- if (flag & O_TRUNC)
- return -EPERM;
- }
-
- return 0;
-}
-
-static struct dentry *ovl_d_real(struct dentry *dentry,
- const struct inode *inode,
- unsigned int open_flags)
+static struct dentry *ovl_d_real(struct dentry *dentry, enum d_real_type type)
{
- struct dentry *real;
+ struct dentry *upper, *lower;
int err;
- if (!d_is_reg(dentry)) {
- if (!inode || inode == d_inode(dentry))
- return dentry;
+ switch (type) {
+ case D_REAL_DATA:
+ case D_REAL_METADATA:
+ break;
+ default:
goto bug;
}
- if (d_is_negative(dentry))
+ if (!d_is_reg(dentry)) {
+ /* d_real_inode() is only relevant for regular files */
return dentry;
-
- if (open_flags) {
- err = ovl_open_maybe_copy_up(dentry, open_flags);
- if (err)
- return ERR_PTR(err);
}
- real = ovl_dentry_upper(dentry);
- if (real && (!inode || inode == d_inode(real))) {
- if (!inode) {
- err = ovl_check_append_only(d_inode(real), open_flags);
- if (err)
- return ERR_PTR(err);
- }
- return real;
+ upper = ovl_dentry_upper(dentry);
+ if (upper && (type == D_REAL_METADATA ||
+ ovl_has_upperdata(d_inode(dentry))))
+ return upper;
+
+ if (type == D_REAL_METADATA) {
+ lower = ovl_dentry_lower(dentry);
+ goto real_lower;
}
- real = ovl_dentry_lower(dentry);
- if (!real)
+ /*
+ * Best effort lazy lookup of lowerdata for D_REAL_DATA case to return
+ * the real lowerdata dentry. The only current caller of d_real() with
+ * D_REAL_DATA is d_real_inode() from trace_uprobe and this caller is
+ * likely going to be followed reading from the file, before placing
+ * uprobes on offset within the file, so lowerdata should be available
+ * when setting the uprobe.
+ */
+ err = ovl_verify_lowerdata(dentry);
+ if (err)
+ goto bug;
+ lower = ovl_dentry_lowerdata(dentry);
+ if (!lower)
goto bug;
- /* Handle recursion */
- real = d_real(real, inode, open_flags);
+real_lower:
+ /* Handle recursion into stacked lower fs */
+ return d_real(lower, type);
- if (!inode || inode == d_inode(real))
- return real;
bug:
- WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry,
- inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0);
+ WARN(1, "%s(%pd4, %d): real dentry not found\n", __func__, dentry, type);
return dentry;
}
-static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags)
+static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak)
{
- struct ovl_entry *oe = dentry->d_fsdata;
- unsigned int i;
int ret = 1;
- for (i = 0; i < oe->numlower; i++) {
- struct dentry *d = oe->lowerstack[i].dentry;
-
- if (d->d_flags & DCACHE_OP_REVALIDATE) {
- ret = d->d_op->d_revalidate(d, flags);
- if (ret < 0)
- return ret;
- if (!ret) {
- if (!(flags & LOOKUP_RCU))
- d_invalidate(d);
- return -ESTALE;
- }
+ if (!d)
+ return 1;
+
+ if (weak) {
+ if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE)
+ ret = d->d_op->d_weak_revalidate(d, flags);
+ } else if (d->d_flags & DCACHE_OP_REVALIDATE) {
+ struct dentry *parent;
+ struct inode *dir;
+ struct name_snapshot n;
+
+ if (flags & LOOKUP_RCU) {
+ parent = READ_ONCE(d->d_parent);
+ dir = d_inode_rcu(parent);
+ if (!dir)
+ return -ECHILD;
+ } else {
+ parent = dget_parent(d);
+ dir = d_inode(parent);
+ }
+ take_dentry_name_snapshot(&n, d);
+ ret = d->d_op->d_revalidate(dir, &n.name, d, flags);
+ release_dentry_name_snapshot(&n);
+ if (!(flags & LOOKUP_RCU))
+ dput(parent);
+ if (!ret) {
+ if (!(flags & LOOKUP_RCU))
+ d_invalidate(d);
+ ret = -ESTALE;
}
}
- return 1;
+ return ret;
}
-static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags)
+static int ovl_dentry_revalidate_common(struct dentry *dentry,
+ unsigned int flags, bool weak)
{
- struct ovl_entry *oe = dentry->d_fsdata;
+ struct ovl_entry *oe;
+ struct ovl_path *lowerstack;
+ struct inode *inode = d_inode_rcu(dentry);
+ struct dentry *upper;
unsigned int i;
int ret = 1;
- for (i = 0; i < oe->numlower; i++) {
- struct dentry *d = oe->lowerstack[i].dentry;
-
- if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) {
- ret = d->d_op->d_weak_revalidate(d, flags);
- if (ret <= 0)
- break;
- }
+ if (!inode) {
+ /*
+ * Lookup of negative dentries will call ovl_dentry_init_flags()
+ * with NULL upperdentry and NULL oe, resulting in the
+ * DCACHE_OP*_REVALIDATE flags being cleared. Hence the only
+ * way to get a negative inode is due to a race with dentry
+ * destruction.
+ */
+ WARN_ON(!(flags & LOOKUP_RCU));
+ return -ECHILD;
}
+
+ oe = OVL_I_E(inode);
+ lowerstack = ovl_lowerstack(oe);
+ upper = ovl_i_dentry_upper(inode);
+ if (upper)
+ ret = ovl_revalidate_real(upper, flags, weak);
+
+ for (i = 0; ret > 0 && i < ovl_numlower(oe); i++)
+ ret = ovl_revalidate_real(lowerstack[i].dentry, flags, weak);
+
return ret;
}
+static int ovl_dentry_revalidate(struct inode *dir, const struct qstr *name,
+ struct dentry *dentry, unsigned int flags)
+{
+ return ovl_dentry_revalidate_common(dentry, flags, false);
+}
+
+static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags)
+{
+ return ovl_dentry_revalidate_common(dentry, flags, true);
+}
+
static const struct dentry_operations ovl_dentry_operations = {
- .d_release = ovl_dentry_release,
.d_real = ovl_d_real,
+ .d_revalidate = ovl_dentry_revalidate,
+ .d_weak_revalidate = ovl_dentry_weak_revalidate,
};
-static const struct dentry_operations ovl_reval_dentry_operations = {
- .d_release = ovl_dentry_release,
+#if IS_ENABLED(CONFIG_UNICODE)
+static const struct dentry_operations ovl_dentry_ci_operations = {
.d_real = ovl_d_real,
.d_revalidate = ovl_dentry_revalidate,
.d_weak_revalidate = ovl_dentry_weak_revalidate,
+ .d_hash = generic_ci_d_hash,
+ .d_compare = generic_ci_d_compare,
};
+#endif
static struct kmem_cache *ovl_inode_cachep;
static struct inode *ovl_alloc_inode(struct super_block *sb)
{
- struct ovl_inode *oi = kmem_cache_alloc(ovl_inode_cachep, GFP_KERNEL);
+ struct ovl_inode *oi = alloc_inode_sb(sb, ovl_inode_cachep, GFP_KERNEL);
+
+ if (!oi)
+ return NULL;
oi->cache = NULL;
oi->redirect = NULL;
oi->version = 0;
oi->flags = 0;
oi->__upperdentry = NULL;
- oi->lower = NULL;
+ oi->lowerdata_redirect = NULL;
+ oi->oe = NULL;
mutex_init(&oi->lock);
return &oi->vfs_inode;
}
-static void ovl_i_callback(struct rcu_head *head)
+static void ovl_free_inode(struct inode *inode)
{
- struct inode *inode = container_of(head, struct inode, i_rcu);
+ struct ovl_inode *oi = OVL_I(inode);
- kmem_cache_free(ovl_inode_cachep, OVL_I(inode));
+ kfree(oi->redirect);
+ kfree(oi->oe);
+ mutex_destroy(&oi->lock);
+ kmem_cache_free(ovl_inode_cachep, oi);
}
static void ovl_destroy_inode(struct inode *inode)
@@ -197,57 +215,59 @@ static void ovl_destroy_inode(struct inode *inode)
struct ovl_inode *oi = OVL_I(inode);
dput(oi->__upperdentry);
- kfree(oi->redirect);
- mutex_destroy(&oi->lock);
-
- call_rcu(&inode->i_rcu, ovl_i_callback);
+ ovl_stack_put(ovl_lowerstack(oi->oe), ovl_numlower(oi->oe));
+ if (S_ISDIR(inode->i_mode))
+ ovl_dir_cache_free(inode);
+ else
+ kfree(oi->lowerdata_redirect);
}
static void ovl_put_super(struct super_block *sb)
{
- struct ovl_fs *ufs = sb->s_fs_info;
- unsigned i;
-
- dput(ufs->indexdir);
- dput(ufs->workdir);
- ovl_inuse_unlock(ufs->workbasedir);
- dput(ufs->workbasedir);
- if (ufs->upper_mnt)
- ovl_inuse_unlock(ufs->upper_mnt->mnt_root);
- mntput(ufs->upper_mnt);
- for (i = 0; i < ufs->numlower; i++)
- mntput(ufs->lower_mnt[i]);
- kfree(ufs->lower_mnt);
-
- kfree(ufs->config.lowerdir);
- kfree(ufs->config.upperdir);
- kfree(ufs->config.workdir);
- put_cred(ufs->creator_cred);
- kfree(ufs);
+ struct ovl_fs *ofs = OVL_FS(sb);
+
+ if (ofs)
+ ovl_free_fs(ofs);
}
+/* Sync real dirty inodes in upper filesystem (if it exists) */
static int ovl_sync_fs(struct super_block *sb, int wait)
{
- struct ovl_fs *ufs = sb->s_fs_info;
+ struct ovl_fs *ofs = OVL_FS(sb);
struct super_block *upper_sb;
int ret;
- if (!ufs->upper_mnt)
- return 0;
- upper_sb = ufs->upper_mnt->mnt_sb;
- if (!upper_sb->s_op->sync_fs)
+ ret = ovl_sync_status(ofs);
+
+ if (ret < 0)
+ return -EIO;
+
+ if (!ret)
+ return ret;
+
+ /*
+ * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC).
+ * All the super blocks will be iterated, including upper_sb.
+ *
+ * If this is a syncfs(2) call, then we do need to call
+ * sync_filesystem() on upper_sb, but enough if we do it when being
+ * called with wait == 1.
+ */
+ if (!wait)
return 0;
- /* real inodes have already been synced by sync_filesystem(ovl_sb) */
+ upper_sb = ovl_upper_mnt(ofs)->mnt_sb;
+
down_read(&upper_sb->s_umount);
- ret = upper_sb->s_op->sync_fs(upper_sb, wait);
+ ret = sync_filesystem(upper_sb);
up_read(&upper_sb->s_umount);
+
return ret;
}
/**
* ovl_statfs
- * @sb: The overlayfs super block
+ * @dentry: The dentry to query
* @buf: The struct kstatfs to fill in with stats
*
* Get the filesystem statistics. As writes always target the upper layer
@@ -255,8 +275,9 @@ static int ovl_sync_fs(struct super_block *sb, int wait)
*/
static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
{
- struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
- struct dentry *root_dentry = dentry->d_sb->s_root;
+ struct super_block *sb = dentry->d_sb;
+ struct ovl_fs *ofs = OVL_FS(sb);
+ struct dentry *root_dentry = sb->s_root;
struct path path;
int err;
@@ -266,207 +287,38 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
if (!err) {
buf->f_namelen = ofs->namelen;
buf->f_type = OVERLAYFS_SUPER_MAGIC;
+ if (ovl_has_fsid(ofs))
+ buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);
}
return err;
}
-/* Will this overlay be forced to mount/remount ro? */
-static bool ovl_force_readonly(struct ovl_fs *ufs)
-{
- return (!ufs->upper_mnt || !ufs->workdir);
-}
-
-/**
- * ovl_show_options
- *
- * Prints the mount options for a given superblock.
- * Returns zero; does not fail.
- */
-static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
-{
- struct super_block *sb = dentry->d_sb;
- struct ovl_fs *ufs = sb->s_fs_info;
-
- seq_show_option(m, "lowerdir", ufs->config.lowerdir);
- if (ufs->config.upperdir) {
- seq_show_option(m, "upperdir", ufs->config.upperdir);
- seq_show_option(m, "workdir", ufs->config.workdir);
- }
- if (ufs->config.default_permissions)
- seq_puts(m, ",default_permissions");
- if (ufs->config.redirect_dir != ovl_redirect_dir_def)
- seq_printf(m, ",redirect_dir=%s",
- ufs->config.redirect_dir ? "on" : "off");
- if (ufs->config.index != ovl_index_def)
- seq_printf(m, ",index=%s",
- ufs->config.index ? "on" : "off");
- return 0;
-}
-
-static int ovl_remount(struct super_block *sb, int *flags, char *data)
-{
- struct ovl_fs *ufs = sb->s_fs_info;
-
- if (!(*flags & MS_RDONLY) && ovl_force_readonly(ufs))
- return -EROFS;
-
- return 0;
-}
-
static const struct super_operations ovl_super_operations = {
.alloc_inode = ovl_alloc_inode,
+ .free_inode = ovl_free_inode,
.destroy_inode = ovl_destroy_inode,
- .drop_inode = generic_delete_inode,
+ .drop_inode = inode_just_drop,
.put_super = ovl_put_super,
.sync_fs = ovl_sync_fs,
.statfs = ovl_statfs,
.show_options = ovl_show_options,
- .remount_fs = ovl_remount,
-};
-
-enum {
- OPT_LOWERDIR,
- OPT_UPPERDIR,
- OPT_WORKDIR,
- OPT_DEFAULT_PERMISSIONS,
- OPT_REDIRECT_DIR_ON,
- OPT_REDIRECT_DIR_OFF,
- OPT_INDEX_ON,
- OPT_INDEX_OFF,
- OPT_ERR,
-};
-
-static const match_table_t ovl_tokens = {
- {OPT_LOWERDIR, "lowerdir=%s"},
- {OPT_UPPERDIR, "upperdir=%s"},
- {OPT_WORKDIR, "workdir=%s"},
- {OPT_DEFAULT_PERMISSIONS, "default_permissions"},
- {OPT_REDIRECT_DIR_ON, "redirect_dir=on"},
- {OPT_REDIRECT_DIR_OFF, "redirect_dir=off"},
- {OPT_INDEX_ON, "index=on"},
- {OPT_INDEX_OFF, "index=off"},
- {OPT_ERR, NULL}
};
-static char *ovl_next_opt(char **s)
-{
- char *sbegin = *s;
- char *p;
-
- if (sbegin == NULL)
- return NULL;
-
- for (p = sbegin; *p; p++) {
- if (*p == '\\') {
- p++;
- if (!*p)
- break;
- } else if (*p == ',') {
- *p = '\0';
- *s = p + 1;
- return sbegin;
- }
- }
- *s = NULL;
- return sbegin;
-}
-
-static int ovl_parse_opt(char *opt, struct ovl_config *config)
-{
- char *p;
-
- while ((p = ovl_next_opt(&opt)) != NULL) {
- int token;
- substring_t args[MAX_OPT_ARGS];
-
- if (!*p)
- continue;
-
- token = match_token(p, ovl_tokens, args);
- switch (token) {
- case OPT_UPPERDIR:
- kfree(config->upperdir);
- config->upperdir = match_strdup(&args[0]);
- if (!config->upperdir)
- return -ENOMEM;
- break;
-
- case OPT_LOWERDIR:
- kfree(config->lowerdir);
- config->lowerdir = match_strdup(&args[0]);
- if (!config->lowerdir)
- return -ENOMEM;
- break;
-
- case OPT_WORKDIR:
- kfree(config->workdir);
- config->workdir = match_strdup(&args[0]);
- if (!config->workdir)
- return -ENOMEM;
- break;
-
- case OPT_DEFAULT_PERMISSIONS:
- config->default_permissions = true;
- break;
-
- case OPT_REDIRECT_DIR_ON:
- config->redirect_dir = true;
- break;
-
- case OPT_REDIRECT_DIR_OFF:
- config->redirect_dir = false;
- break;
-
- case OPT_INDEX_ON:
- config->index = true;
- break;
-
- case OPT_INDEX_OFF:
- config->index = false;
- break;
-
- default:
- pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p);
- return -EINVAL;
- }
- }
-
- /* Workdir is useless in non-upper mount */
- if (!config->upperdir && config->workdir) {
- pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
- config->workdir);
- kfree(config->workdir);
- config->workdir = NULL;
- }
-
- return 0;
-}
-
#define OVL_WORKDIR_NAME "work"
#define OVL_INDEXDIR_NAME "index"
-static struct dentry *ovl_workdir_create(struct super_block *sb,
- struct ovl_fs *ufs,
- struct dentry *dentry,
+static struct dentry *ovl_workdir_create(struct ovl_fs *ofs,
const char *name, bool persist)
{
- struct inode *dir = dentry->d_inode;
- struct vfsmount *mnt = ufs->upper_mnt;
+ struct inode *dir = ofs->workbasedir->d_inode;
+ struct vfsmount *mnt = ovl_upper_mnt(ofs);
struct dentry *work;
int err;
bool retried = false;
- bool locked = false;
-
- err = mnt_want_write(mnt);
- if (err)
- goto out_err;
-
- inode_lock_nested(dir, I_MUTEX_PARENT);
- locked = true;
retry:
- work = lookup_one_len(name, dentry, strlen(name));
+ work = ovl_start_creating_upper(ofs, ofs->workbasedir, &QSTR(name));
if (!IS_ERR(work)) {
struct iattr attr = {
@@ -475,23 +327,30 @@ retry:
};
if (work->d_inode) {
+ end_creating_keep(work);
+ if (persist)
+ return work;
err = -EEXIST;
if (retried)
goto out_dput;
-
- if (persist)
- goto out_unlock;
-
retried = true;
- ovl_workdir_cleanup(dir, mnt, work, 0);
+ err = ovl_workdir_cleanup(ofs, ofs->workbasedir, mnt, work, 0);
dput(work);
+ if (err == -EINVAL)
+ return ERR_PTR(err);
+
goto retry;
}
- err = ovl_create_real(dir, work,
- &(struct cattr){.mode = S_IFDIR | 0},
- NULL, true);
- if (err)
+ work = ovl_do_mkdir(ofs, dir, work, attr.ia_mode);
+ end_creating_keep(work);
+ err = PTR_ERR(work);
+ if (IS_ERR(work))
+ goto out_err;
+
+ /* Weird filesystem returning with hashed negative (kernfs)? */
+ err = -EINVAL;
+ if (d_really_is_negative(work))
goto out_dput;
/*
@@ -507,17 +366,17 @@ retry:
* allowed as upper are limited to "normal" ones, where checking
* for the above two errors is sufficient.
*/
- err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_DEFAULT);
+ err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_DEFAULT);
if (err && err != -ENODATA && err != -EOPNOTSUPP)
goto out_dput;
- err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_ACCESS);
+ err = ovl_do_remove_acl(ofs, work, XATTR_NAME_POSIX_ACL_ACCESS);
if (err && err != -ENODATA && err != -EOPNOTSUPP)
goto out_dput;
/* Clear any inherited mode bits */
inode_lock(work->d_inode);
- err = notify_change(work, &attr, NULL);
+ err = ovl_do_notify_change(ofs, work, &attr);
inode_unlock(work->d_inode);
if (err)
goto out_dput;
@@ -525,663 +384,1204 @@ retry:
err = PTR_ERR(work);
goto out_err;
}
-out_unlock:
- mnt_drop_write(mnt);
- if (locked)
- inode_unlock(dir);
-
return work;
out_dput:
dput(work);
out_err:
- pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n",
- ufs->config.workdir, name, -err);
- sb->s_flags |= MS_RDONLY;
- work = NULL;
- goto out_unlock;
+ pr_warn("failed to create directory %s/%s (errno: %i); mounting read-only\n",
+ ofs->config.workdir, name, -err);
+ return NULL;
+}
+
+static int ovl_check_namelen(const struct path *path, struct ovl_fs *ofs,
+ const char *name)
+{
+ struct kstatfs statfs;
+ int err = vfs_statfs(path, &statfs);
+
+ if (err)
+ pr_err("statfs failed on '%s'\n", name);
+ else
+ ofs->namelen = max(ofs->namelen, statfs.f_namelen);
+
+ return err;
}
-static void ovl_unescape(char *s)
+static int ovl_lower_dir(const char *name, const struct path *path,
+ struct ovl_fs *ofs, int *stack_depth)
{
- char *d = s;
-
- for (;; s++, d++) {
- if (*s == '\\')
- s++;
- *d = *s;
- if (!*s)
- break;
+ int fh_type;
+ int err;
+
+ err = ovl_check_namelen(path, ofs, name);
+ if (err)
+ return err;
+
+ *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth);
+
+ /*
+ * The inodes index feature and NFS export need to encode and decode
+ * file handles, so they require that all layers support them.
+ */
+ fh_type = ovl_can_decode_fh(path->dentry->d_sb);
+ if ((ofs->config.nfs_export ||
+ (ofs->config.index && ofs->config.upperdir)) && !fh_type) {
+ ofs->config.index = false;
+ ofs->config.nfs_export = false;
+ pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n",
+ name);
}
+ ofs->nofh |= !fh_type;
+ /*
+ * Decoding origin file handle is required for persistent st_ino.
+ * Without persistent st_ino, xino=auto falls back to xino=off.
+ */
+ if (ofs->config.xino == OVL_XINO_AUTO &&
+ ofs->config.upperdir && !fh_type) {
+ ofs->config.xino = OVL_XINO_OFF;
+ pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n",
+ name);
+ }
+
+ /* Check if lower fs has 32bit inode numbers */
+ if (fh_type != FILEID_INO32_GEN)
+ ofs->xino_mode = -1;
+
+ return 0;
}
-static int ovl_mount_dir_noesc(const char *name, struct path *path)
+/* Workdir should not be subdir of upperdir and vice versa */
+static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir)
{
- int err = -EINVAL;
+ bool ok = false;
- if (!*name) {
- pr_err("overlayfs: empty lowerdir\n");
- goto out;
+ if (workdir != upperdir) {
+ struct dentry *trap = lock_rename(workdir, upperdir);
+ if (!IS_ERR(trap))
+ unlock_rename(workdir, upperdir);
+ ok = (trap == NULL);
}
- err = kern_path(name, LOOKUP_FOLLOW, path);
+ return ok;
+}
+
+static int ovl_setup_trap(struct super_block *sb, struct dentry *dir,
+ struct inode **ptrap, const char *name)
+{
+ struct inode *trap;
+ int err;
+
+ trap = ovl_get_trap_inode(sb, dir);
+ err = PTR_ERR_OR_ZERO(trap);
if (err) {
- pr_err("overlayfs: failed to resolve '%s': %i\n", name, err);
+ if (err == -ELOOP)
+ pr_err("conflicting %s path\n", name);
+ return err;
+ }
+
+ *ptrap = trap;
+ return 0;
+}
+
+/*
+ * Determine how we treat concurrent use of upperdir/workdir based on the
+ * index feature. This is papering over mount leaks of container runtimes,
+ * for example, an old overlay mount is leaked and now its upperdir is
+ * attempted to be used as a lower layer in a new overlay mount.
+ */
+static int ovl_report_in_use(struct ovl_fs *ofs, const char *name)
+{
+ if (ofs->config.index) {
+ pr_err("%s is in-use as upperdir/workdir of another mount, mount with '-o index=off' to override exclusive upperdir protection.\n",
+ name);
+ return -EBUSY;
+ } else {
+ pr_warn("%s is in-use as upperdir/workdir of another mount, accessing files from both mounts will result in undefined behavior.\n",
+ name);
+ return 0;
+ }
+}
+
+static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs,
+ struct ovl_layer *upper_layer,
+ const struct path *upperpath)
+{
+ struct vfsmount *upper_mnt;
+ int err;
+
+ /* Upperdir path should not be r/o */
+ if (__mnt_is_readonly(upperpath->mnt)) {
+ pr_err("upper fs is r/o, try multi-lower layers mount\n");
+ err = -EINVAL;
goto out;
}
- err = -EINVAL;
- if (ovl_dentry_weird(path->dentry)) {
- pr_err("overlayfs: filesystem on '%s' not supported\n", name);
- goto out_put;
+
+ err = ovl_check_namelen(upperpath, ofs, ofs->config.upperdir);
+ if (err)
+ goto out;
+
+ err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap,
+ "upperdir");
+ if (err)
+ goto out;
+
+ upper_mnt = clone_private_mount(upperpath);
+ err = PTR_ERR(upper_mnt);
+ if (IS_ERR(upper_mnt)) {
+ pr_err("failed to clone upperpath\n");
+ goto out;
}
- if (!d_is_dir(path->dentry)) {
- pr_err("overlayfs: '%s' not a directory\n", name);
- goto out_put;
+
+ /* Don't inherit atime flags */
+ upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME);
+ upper_layer->mnt = upper_mnt;
+ upper_layer->idx = 0;
+ upper_layer->fsid = 0;
+
+ /*
+ * Inherit SB_NOSEC flag from upperdir.
+ *
+ * This optimization changes behavior when a security related attribute
+ * (suid/sgid/security.*) is changed on an underlying layer. This is
+ * okay because we don't yet have guarantees in that case, but it will
+ * need careful treatment once we want to honour changes to underlying
+ * filesystems.
+ */
+ if (upper_mnt->mnt_sb->s_flags & SB_NOSEC)
+ sb->s_flags |= SB_NOSEC;
+
+ if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) {
+ ofs->upperdir_locked = true;
+ } else {
+ err = ovl_report_in_use(ofs, "upperdir");
+ if (err)
+ goto out;
}
- return 0;
-out_put:
- path_put(path);
+ err = 0;
out:
return err;
}
-static int ovl_mount_dir(const char *name, struct path *path)
+/*
+ * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and
+ * negative values if error is encountered.
+ */
+static int ovl_check_rename_whiteout(struct ovl_fs *ofs)
{
- int err = -ENOMEM;
- char *tmp = kstrdup(name, GFP_KERNEL);
+ struct dentry *workdir = ofs->workdir;
+ struct dentry *temp;
+ struct dentry *whiteout;
+ struct name_snapshot name;
+ struct renamedata rd = {};
+ char name2[OVL_TEMPNAME_SIZE];
+ int err;
- if (tmp) {
- ovl_unescape(tmp);
- err = ovl_mount_dir_noesc(tmp, path);
+ temp = ovl_create_temp(ofs, workdir, OVL_CATTR(S_IFREG | 0));
+ err = PTR_ERR(temp);
+ if (IS_ERR(temp))
+ return err;
+
+ rd.mnt_idmap = ovl_upper_mnt_idmap(ofs);
+ rd.old_parent = workdir;
+ rd.new_parent = workdir;
+ rd.flags = RENAME_WHITEOUT;
+ ovl_tempname(name2);
+ err = start_renaming_dentry(&rd, 0, temp, &QSTR(name2));
+ if (err) {
+ dput(temp);
+ return err;
+ }
- if (!err)
- if (ovl_dentry_remote(path->dentry)) {
- pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n",
- tmp);
- path_put(path);
- err = -EINVAL;
- }
- kfree(tmp);
+ /* Name is inline and stable - using snapshot as a copy helper */
+ take_dentry_name_snapshot(&name, temp);
+ err = ovl_do_rename_rd(&rd);
+ end_renaming(&rd);
+ if (err) {
+ if (err == -EINVAL)
+ err = 0;
+ goto cleanup_temp;
}
+
+ whiteout = ovl_lookup_upper_unlocked(ofs, name.name.name,
+ workdir, name.name.len);
+ err = PTR_ERR(whiteout);
+ if (IS_ERR(whiteout))
+ goto cleanup_temp;
+
+ err = ovl_upper_is_whiteout(ofs, whiteout);
+
+ /* Best effort cleanup of whiteout and temp file */
+ if (err)
+ ovl_cleanup(ofs, workdir, whiteout);
+ dput(whiteout);
+
+cleanup_temp:
+ ovl_cleanup(ofs, workdir, temp);
+ release_dentry_name_snapshot(&name);
+ dput(temp);
+
return err;
}
-static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs,
- const char *name)
+static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs,
+ struct dentry *parent,
+ const char *name, umode_t mode)
{
- struct kstatfs statfs;
- int err = vfs_statfs(path, &statfs);
+ struct dentry *child;
+
+ child = ovl_start_creating_upper(ofs, parent, &QSTR(name));
+ if (!IS_ERR(child)) {
+ if (!child->d_inode)
+ child = ovl_create_real(ofs, parent, child,
+ OVL_CATTR(mode));
+ end_creating_keep(child);
+ }
+ dput(parent);
- if (err)
- pr_err("overlayfs: statfs failed on '%s'\n", name);
- else
- ofs->namelen = max(ofs->namelen, statfs.f_namelen);
+ return child;
+}
- return err;
+/*
+ * Creates $workdir/work/incompat/volatile/dirty file if it is not already
+ * present.
+ */
+static int ovl_create_volatile_dirty(struct ovl_fs *ofs)
+{
+ unsigned int ctr;
+ struct dentry *d = dget(ofs->workbasedir);
+ static const char *const volatile_path[] = {
+ OVL_WORKDIR_NAME, "incompat", "volatile", "dirty"
+ };
+ const char *const *name = volatile_path;
+
+ for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) {
+ d = ovl_lookup_or_create(ofs, d, *name, ctr > 1 ? S_IFDIR : S_IFREG);
+ if (IS_ERR(d))
+ return PTR_ERR(d);
+ }
+ dput(d);
+ return 0;
}
-static int ovl_lower_dir(const char *name, struct path *path,
- struct ovl_fs *ofs, int *stack_depth, bool *remote)
+static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs,
+ const struct path *workpath)
{
+ struct vfsmount *mnt = ovl_upper_mnt(ofs);
+ struct dentry *workdir;
+ struct file *tmpfile;
+ bool rename_whiteout;
+ bool d_type;
+ int fh_type;
int err;
- err = ovl_mount_dir_noesc(name, path);
+ err = mnt_want_write(mnt);
if (err)
+ return err;
+
+ workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false);
+ err = PTR_ERR(workdir);
+ if (IS_ERR_OR_NULL(workdir))
goto out;
- err = ovl_check_namelen(path, ofs, name);
+ ofs->workdir = workdir;
+
+ err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir");
if (err)
- goto out_put;
+ goto out;
- *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth);
+ /*
+ * Upper should support d_type, else whiteouts are visible. Given
+ * workdir and upper are on same fs, we can do iterate_dir() on
+ * workdir. This check requires successful creation of workdir in
+ * previous step.
+ */
+ err = ovl_check_d_type_supported(workpath);
+ if (err < 0)
+ goto out;
- if (ovl_dentry_remote(path->dentry))
- *remote = true;
+ d_type = err;
+ if (!d_type)
+ pr_warn("upper fs needs to support d_type.\n");
+
+ /* Check if upper/work fs supports O_TMPFILE */
+ tmpfile = ovl_do_tmpfile(ofs, ofs->workdir, S_IFREG | 0);
+ ofs->tmpfile = !IS_ERR(tmpfile);
+ if (ofs->tmpfile)
+ fput(tmpfile);
+ else
+ pr_warn("upper fs does not support tmpfile.\n");
+
+
+ /* Check if upper/work fs supports RENAME_WHITEOUT */
+ err = ovl_check_rename_whiteout(ofs);
+ if (err < 0)
+ goto out;
+
+ rename_whiteout = err;
+ if (!rename_whiteout)
+ pr_warn("upper fs does not support RENAME_WHITEOUT.\n");
+
+ /*
+ * Check if upper/work fs supports (trusted|user).overlay.* xattr
+ */
+ err = ovl_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1);
+ if (err) {
+ pr_warn("failed to set xattr on upper\n");
+ ofs->noxattr = true;
+ if (ovl_redirect_follow(ofs)) {
+ ofs->config.redirect_mode = OVL_REDIRECT_NOFOLLOW;
+ pr_warn("...falling back to redirect_dir=nofollow.\n");
+ }
+ if (ofs->config.metacopy) {
+ ofs->config.metacopy = false;
+ pr_warn("...falling back to metacopy=off.\n");
+ }
+ if (ofs->config.index) {
+ ofs->config.index = false;
+ pr_warn("...falling back to index=off.\n");
+ }
+ if (ovl_has_fsid(ofs)) {
+ ofs->config.uuid = OVL_UUID_NULL;
+ pr_warn("...falling back to uuid=null.\n");
+ }
+ /*
+ * xattr support is required for persistent st_ino.
+ * Without persistent st_ino, xino=auto falls back to xino=off.
+ */
+ if (ofs->config.xino == OVL_XINO_AUTO) {
+ ofs->config.xino = OVL_XINO_OFF;
+ pr_warn("...falling back to xino=off.\n");
+ }
+ if (err == -EPERM && !ofs->config.userxattr)
+ pr_info("try mounting with 'userxattr' option\n");
+ err = 0;
+ } else {
+ ovl_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE);
+ }
/*
- * The inodes index feature needs to encode and decode file
- * handles, so it requires that all layers support them.
+ * We allowed sub-optimal upper fs configuration and don't want to break
+ * users over kernel upgrade, but we never allowed remote upper fs, so
+ * we can enforce strict requirements for remote upper fs.
*/
- if (ofs->config.index && !ovl_can_decode_fh(path->dentry->d_sb)) {
+ if (ovl_dentry_remote(ofs->workdir) &&
+ (!d_type || !rename_whiteout || ofs->noxattr)) {
+ pr_err("upper fs missing required features.\n");
+ err = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * For volatile mount, create a incompat/volatile/dirty file to keep
+ * track of it.
+ */
+ if (ofs->config.ovl_volatile) {
+ err = ovl_create_volatile_dirty(ofs);
+ if (err < 0) {
+ pr_err("Failed to create volatile/dirty file.\n");
+ goto out;
+ }
+ }
+
+ /* Check if upper/work fs supports file handles */
+ fh_type = ovl_can_decode_fh(ofs->workdir->d_sb);
+ if (ofs->config.index && !fh_type) {
ofs->config.index = false;
- pr_warn("overlayfs: fs on '%s' does not support file handles, falling back to index=off.\n", name);
+ pr_warn("upper fs does not support file handles, falling back to index=off.\n");
}
+ ofs->nofh |= !fh_type;
- return 0;
+ /* Check if upper fs has 32bit inode numbers */
+ if (fh_type != FILEID_INO32_GEN)
+ ofs->xino_mode = -1;
-out_put:
- path_put(path);
+ /* NFS export of r/w mount depends on index */
+ if (ofs->config.nfs_export && !ofs->config.index) {
+ pr_warn("NFS export requires \"index=on\", falling back to nfs_export=off.\n");
+ ofs->config.nfs_export = false;
+ }
out:
+ mnt_drop_write(mnt);
return err;
}
-/* Workdir should not be subdir of upperdir and vice versa */
-static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir)
+static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs,
+ const struct path *upperpath,
+ const struct path *workpath)
{
- bool ok = false;
+ int err;
- if (workdir != upperdir) {
- ok = (lock_rename(workdir, upperdir) == NULL);
- unlock_rename(workdir, upperdir);
+ err = -EINVAL;
+ if (upperpath->mnt != workpath->mnt) {
+ pr_err("workdir and upperdir must reside under the same mount\n");
+ return err;
+ }
+ if (!ovl_workdir_ok(workpath->dentry, upperpath->dentry)) {
+ pr_err("workdir and upperdir must be separate subtrees\n");
+ return err;
}
- return ok;
-}
-static unsigned int ovl_split_lowerdirs(char *str)
-{
- unsigned int ctr = 1;
- char *s, *d;
-
- for (s = d = str;; s++, d++) {
- if (*s == '\\') {
- s++;
- } else if (*s == ':') {
- *d = '\0';
- ctr++;
- continue;
- }
- *d = *s;
- if (!*s)
- break;
+ ofs->workbasedir = dget(workpath->dentry);
+
+ if (ovl_inuse_trylock(ofs->workbasedir)) {
+ ofs->workdir_locked = true;
+ } else {
+ err = ovl_report_in_use(ofs, "workdir");
+ if (err)
+ return err;
}
- return ctr;
-}
-static int __maybe_unused
-ovl_posix_acl_xattr_get(const struct xattr_handler *handler,
- struct dentry *dentry, struct inode *inode,
- const char *name, void *buffer, size_t size)
-{
- return ovl_xattr_get(dentry, inode, handler->name, buffer, size);
+ err = ovl_setup_trap(sb, ofs->workbasedir, &ofs->workbasedir_trap,
+ "workdir");
+ if (err)
+ return err;
+
+ return ovl_make_workdir(sb, ofs, workpath);
}
-static int __maybe_unused
-ovl_posix_acl_xattr_set(const struct xattr_handler *handler,
- struct dentry *dentry, struct inode *inode,
- const char *name, const void *value,
- size_t size, int flags)
+static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs,
+ struct ovl_entry *oe, const struct path *upperpath)
{
- struct dentry *workdir = ovl_workdir(dentry);
- struct inode *realinode = ovl_inode_real(inode);
- struct posix_acl *acl = NULL;
+ struct vfsmount *mnt = ovl_upper_mnt(ofs);
+ struct dentry *indexdir;
+ struct dentry *origin = ovl_lowerstack(oe)->dentry;
+ const struct ovl_fh *fh;
int err;
- /* Check that everything is OK before copy-up */
- if (value) {
- acl = posix_acl_from_xattr(&init_user_ns, value, size);
- if (IS_ERR(acl))
- return PTR_ERR(acl);
- }
- err = -EOPNOTSUPP;
- if (!IS_POSIXACL(d_inode(workdir)))
- goto out_acl_release;
- if (!realinode->i_op->set_acl)
- goto out_acl_release;
- if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) {
- err = acl ? -EACCES : 0;
- goto out_acl_release;
- }
- err = -EPERM;
- if (!inode_owner_or_capable(inode))
- goto out_acl_release;
+ fh = ovl_get_origin_fh(ofs, origin);
+ if (IS_ERR(fh))
+ return PTR_ERR(fh);
- posix_acl_release(acl);
+ err = mnt_want_write(mnt);
+ if (err)
+ goto out_free_fh;
- /*
- * Check if sgid bit needs to be cleared (actual setacl operation will
- * be done with mounter's capabilities and so that won't do it for us).
- */
- if (unlikely(inode->i_mode & S_ISGID) &&
- handler->flags == ACL_TYPE_ACCESS &&
- !in_group_p(inode->i_gid) &&
- !capable_wrt_inode_uidgid(inode, CAP_FSETID)) {
- struct iattr iattr = { .ia_valid = ATTR_KILL_SGID };
+ /* Verify lower root is upper root origin */
+ err = ovl_verify_origin_fh(ofs, upperpath->dentry, fh, true);
+ if (err) {
+ pr_err("failed to verify upper root origin\n");
+ goto out;
+ }
- err = ovl_setattr(dentry, &iattr);
+ /* index dir will act also as workdir */
+ iput(ofs->workdir_trap);
+ ofs->workdir_trap = NULL;
+ dput(ofs->workdir);
+ ofs->workdir = NULL;
+ indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true);
+ if (IS_ERR(indexdir)) {
+ err = PTR_ERR(indexdir);
+ } else if (indexdir) {
+ ofs->workdir = indexdir;
+ err = ovl_setup_trap(sb, indexdir, &ofs->workdir_trap,
+ "indexdir");
if (err)
- return err;
- }
+ goto out;
- err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags);
- if (!err)
- ovl_copyattr(ovl_inode_real(inode), inode);
+ /*
+ * Verify upper root is exclusively associated with index dir.
+ * Older kernels stored upper fh in ".overlay.origin"
+ * xattr. If that xattr exists, verify that it is a match to
+ * upper dir file handle. In any case, verify or set xattr
+ * ".overlay.upper" to indicate that index may have
+ * directory entries.
+ */
+ if (ovl_check_origin_xattr(ofs, indexdir)) {
+ err = ovl_verify_origin_xattr(ofs, indexdir,
+ OVL_XATTR_ORIGIN,
+ upperpath->dentry, true,
+ false);
+ if (err)
+ pr_err("failed to verify index dir 'origin' xattr\n");
+ }
+ err = ovl_verify_upper(ofs, indexdir, upperpath->dentry, true);
+ if (err)
+ pr_err("failed to verify index dir 'upper' xattr\n");
- return err;
+ /* Cleanup bad/stale/orphan index entries */
+ if (!err)
+ err = ovl_indexdir_cleanup(ofs);
+ }
+ if (err || !indexdir)
+ pr_warn("try deleting index dir or mounting with '-o index=off' to disable inodes index.\n");
-out_acl_release:
- posix_acl_release(acl);
+out:
+ mnt_drop_write(mnt);
+out_free_fh:
+ kfree(fh);
return err;
}
-static int ovl_own_xattr_get(const struct xattr_handler *handler,
- struct dentry *dentry, struct inode *inode,
- const char *name, void *buffer, size_t size)
+static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid)
{
- return -EOPNOTSUPP;
-}
+ unsigned int i;
-static int ovl_own_xattr_set(const struct xattr_handler *handler,
- struct dentry *dentry, struct inode *inode,
- const char *name, const void *value,
- size_t size, int flags)
-{
- return -EOPNOTSUPP;
+ if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs))
+ return true;
+
+ /*
+ * We allow using single lower with null uuid for index and nfs_export
+ * for example to support those features with single lower squashfs.
+ * To avoid regressions in setups of overlay with re-formatted lower
+ * squashfs, do not allow decoding origin with lower null uuid unless
+ * user opted-in to one of the new features that require following the
+ * lower inode of non-dir upper.
+ */
+ if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid))
+ return false;
+
+ for (i = 0; i < ofs->numfs; i++) {
+ /*
+ * We use uuid to associate an overlay lower file handle with a
+ * lower layer, so we can accept lower fs with null uuid as long
+ * as all lower layers with null uuid are on the same fs.
+ * if we detect multiple lower fs with the same uuid, we
+ * disable lower file handle decoding on all of them.
+ */
+ if (ofs->fs[i].is_lower &&
+ uuid_equal(&ofs->fs[i].sb->s_uuid, uuid)) {
+ ofs->fs[i].bad_uuid = true;
+ return false;
+ }
+ }
+ return true;
}
-static int ovl_other_xattr_get(const struct xattr_handler *handler,
- struct dentry *dentry, struct inode *inode,
- const char *name, void *buffer, size_t size)
+/* Get a unique fsid for the layer */
+static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path)
{
- return ovl_xattr_get(dentry, inode, name, buffer, size);
+ struct super_block *sb = path->mnt->mnt_sb;
+ unsigned int i;
+ dev_t dev;
+ int err;
+ bool bad_uuid = false;
+ bool warn = false;
+
+ for (i = 0; i < ofs->numfs; i++) {
+ if (ofs->fs[i].sb == sb)
+ return i;
+ }
+
+ if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) {
+ bad_uuid = true;
+ if (ofs->config.xino == OVL_XINO_AUTO) {
+ ofs->config.xino = OVL_XINO_OFF;
+ warn = true;
+ }
+ if (ofs->config.index || ofs->config.nfs_export) {
+ ofs->config.index = false;
+ ofs->config.nfs_export = false;
+ warn = true;
+ }
+ if (warn) {
+ pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n",
+ uuid_is_null(&sb->s_uuid) ? "null" :
+ "conflicting",
+ path->dentry, ovl_xino_mode(&ofs->config));
+ }
+ }
+
+ err = get_anon_bdev(&dev);
+ if (err) {
+ pr_err("failed to get anonymous bdev for lowerpath\n");
+ return err;
+ }
+
+ ofs->fs[ofs->numfs].sb = sb;
+ ofs->fs[ofs->numfs].pseudo_dev = dev;
+ ofs->fs[ofs->numfs].bad_uuid = bad_uuid;
+
+ return ofs->numfs++;
}
-static int ovl_other_xattr_set(const struct xattr_handler *handler,
- struct dentry *dentry, struct inode *inode,
- const char *name, const void *value,
- size_t size, int flags)
+/*
+ * The fsid after the last lower fsid is used for the data layers.
+ * It is a "null fs" with a null sb, null uuid, and no pseudo dev.
+ */
+static int ovl_get_data_fsid(struct ovl_fs *ofs)
{
- return ovl_xattr_set(dentry, inode, name, value, size, flags);
+ return ofs->numfs;
}
-static const struct xattr_handler __maybe_unused
-ovl_posix_acl_access_xattr_handler = {
- .name = XATTR_NAME_POSIX_ACL_ACCESS,
- .flags = ACL_TYPE_ACCESS,
- .get = ovl_posix_acl_xattr_get,
- .set = ovl_posix_acl_xattr_set,
-};
-
-static const struct xattr_handler __maybe_unused
-ovl_posix_acl_default_xattr_handler = {
- .name = XATTR_NAME_POSIX_ACL_DEFAULT,
- .flags = ACL_TYPE_DEFAULT,
- .get = ovl_posix_acl_xattr_get,
- .set = ovl_posix_acl_xattr_set,
-};
-
-static const struct xattr_handler ovl_own_xattr_handler = {
- .prefix = OVL_XATTR_PREFIX,
- .get = ovl_own_xattr_get,
- .set = ovl_own_xattr_set,
-};
+/*
+ * Set the ovl sb encoding as the same one used by the first layer
+ */
+static int ovl_set_encoding(struct super_block *sb, struct super_block *fs_sb)
+{
+ if (!sb_has_encoding(fs_sb))
+ return 0;
-static const struct xattr_handler ovl_other_xattr_handler = {
- .prefix = "", /* catch all */
- .get = ovl_other_xattr_get,
- .set = ovl_other_xattr_set,
-};
+#if IS_ENABLED(CONFIG_UNICODE)
+ if (sb_has_strict_encoding(fs_sb)) {
+ pr_err("strict encoding not supported\n");
+ return -EINVAL;
+ }
-static const struct xattr_handler *ovl_xattr_handlers[] = {
-#ifdef CONFIG_FS_POSIX_ACL
- &ovl_posix_acl_access_xattr_handler,
- &ovl_posix_acl_default_xattr_handler,
+ sb->s_encoding = fs_sb->s_encoding;
+ sb->s_encoding_flags = fs_sb->s_encoding_flags;
#endif
- &ovl_own_xattr_handler,
- &ovl_other_xattr_handler,
- NULL
-};
+ return 0;
+}
-static int ovl_fill_super(struct super_block *sb, void *data, int silent)
+static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs,
+ struct ovl_fs_context *ctx, struct ovl_layer *layers)
{
- struct path upperpath = { };
- struct path workpath = { };
- struct dentry *root_dentry;
- struct ovl_entry *oe;
- struct ovl_fs *ufs;
- struct path *stack = NULL;
- char *lowertmp;
- char *lower;
- unsigned int numlower;
- unsigned int stacklen = 0;
- unsigned int i;
- bool remote = false;
- struct cred *cred;
int err;
+ unsigned int i;
+ size_t nr_merged_lower;
- err = -ENOMEM;
- ufs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL);
- if (!ufs)
- goto out;
+ ofs->fs = kcalloc(ctx->nr + 2, sizeof(struct ovl_sb), GFP_KERNEL);
+ if (ofs->fs == NULL)
+ return -ENOMEM;
- ufs->config.redirect_dir = ovl_redirect_dir_def;
- ufs->config.index = ovl_index_def;
- err = ovl_parse_opt((char *) data, &ufs->config);
- if (err)
- goto out_free_config;
+ /*
+ * idx/fsid 0 are reserved for upper fs even with lower only overlay
+ * and the last fsid is reserved for "null fs" of the data layers.
+ */
+ ofs->numfs++;
- err = -EINVAL;
- if (!ufs->config.lowerdir) {
- if (!silent)
- pr_err("overlayfs: missing 'lowerdir'\n");
- goto out_free_config;
+ /*
+ * All lower layers that share the same fs as upper layer, use the same
+ * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower
+ * only overlay to simplify ovl_fs_free().
+ * is_lower will be set if upper fs is shared with a lower layer.
+ */
+ err = get_anon_bdev(&ofs->fs[0].pseudo_dev);
+ if (err) {
+ pr_err("failed to get anonymous bdev for upper fs\n");
+ return err;
}
- sb->s_stack_depth = 0;
- sb->s_maxbytes = MAX_LFS_FILESIZE;
- if (ufs->config.upperdir) {
- if (!ufs->config.workdir) {
- pr_err("overlayfs: missing 'workdir'\n");
- goto out_free_config;
- }
-
- err = ovl_mount_dir(ufs->config.upperdir, &upperpath);
- if (err)
- goto out_free_config;
+ if (ovl_upper_mnt(ofs)) {
+ ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb;
+ ofs->fs[0].is_lower = false;
- /* Upper fs should not be r/o */
- if (upperpath.mnt->mnt_sb->s_flags & MS_RDONLY) {
- pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n");
- err = -EINVAL;
- goto out_put_upperpath;
+ if (ofs->casefold) {
+ err = ovl_set_encoding(sb, ofs->fs[0].sb);
+ if (err)
+ return err;
}
+ }
- err = ovl_check_namelen(&upperpath, ufs, ufs->config.upperdir);
- if (err)
- goto out_put_upperpath;
+ nr_merged_lower = ctx->nr - ctx->nr_data;
+ for (i = 0; i < ctx->nr; i++) {
+ struct ovl_fs_context_layer *l = &ctx->lower[i];
+ struct vfsmount *mnt;
+ struct inode *trap;
+ int fsid;
- err = -EBUSY;
- if (!ovl_inuse_trylock(upperpath.dentry)) {
- pr_err("overlayfs: upperdir is in-use by another mount\n");
- goto out_put_upperpath;
- }
+ if (i < nr_merged_lower)
+ fsid = ovl_get_fsid(ofs, &l->path);
+ else
+ fsid = ovl_get_data_fsid(ofs);
+ if (fsid < 0)
+ return fsid;
- err = ovl_mount_dir(ufs->config.workdir, &workpath);
+ /*
+ * Check if lower root conflicts with this overlay layers before
+ * checking if it is in-use as upperdir/workdir of "another"
+ * mount, because we do not bother to check in ovl_is_inuse() if
+ * the upperdir/workdir is in fact in-use by our
+ * upperdir/workdir.
+ */
+ err = ovl_setup_trap(sb, l->path.dentry, &trap, "lowerdir");
if (err)
- goto out_unlock_upperdentry;
+ return err;
- err = -EINVAL;
- if (upperpath.mnt != workpath.mnt) {
- pr_err("overlayfs: workdir and upperdir must reside under the same mount\n");
- goto out_put_workpath;
+ if (ovl_is_inuse(l->path.dentry)) {
+ err = ovl_report_in_use(ofs, "lowerdir");
+ if (err) {
+ iput(trap);
+ return err;
+ }
}
- if (!ovl_workdir_ok(workpath.dentry, upperpath.dentry)) {
- pr_err("overlayfs: workdir and upperdir must be separate subtrees\n");
- goto out_put_workpath;
+
+ mnt = clone_private_mount(&l->path);
+ err = PTR_ERR(mnt);
+ if (IS_ERR(mnt)) {
+ pr_err("failed to clone lowerpath\n");
+ iput(trap);
+ return err;
}
- err = -EBUSY;
- if (!ovl_inuse_trylock(workpath.dentry)) {
- pr_err("overlayfs: workdir is in-use by another mount\n");
- goto out_put_workpath;
+ /*
+ * Make lower layers R/O. That way fchmod/fchown on lower file
+ * will fail instead of modifying lower fs.
+ */
+ mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME;
+
+ layers[ofs->numlayer].trap = trap;
+ layers[ofs->numlayer].mnt = mnt;
+ layers[ofs->numlayer].idx = ofs->numlayer;
+ layers[ofs->numlayer].fsid = fsid;
+ layers[ofs->numlayer].fs = &ofs->fs[fsid];
+ /* Store for printing lowerdir=... in ovl_show_options() */
+ ofs->config.lowerdirs[ofs->numlayer] = l->name;
+ l->name = NULL;
+ ofs->numlayer++;
+ ofs->fs[fsid].is_lower = true;
+
+ if (ofs->casefold) {
+ if (!ovl_upper_mnt(ofs) && !sb_has_encoding(sb)) {
+ err = ovl_set_encoding(sb, ofs->fs[fsid].sb);
+ if (err)
+ return err;
+ }
+
+ if (!sb_same_encoding(sb, mnt->mnt_sb)) {
+ pr_err("all layers must have the same encoding\n");
+ return -EINVAL;
+ }
}
+ }
+
+ /*
+ * When all layers on same fs, overlay can use real inode numbers.
+ * With mount option "xino=<on|auto>", mounter declares that there are
+ * enough free high bits in underlying fs to hold the unique fsid.
+ * If overlayfs does encounter underlying inodes using the high xino
+ * bits reserved for fsid, it emits a warning and uses the original
+ * inode number or a non persistent inode number allocated from a
+ * dedicated range.
+ */
+ if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) {
+ if (ofs->config.xino == OVL_XINO_ON)
+ pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n");
+ ofs->xino_mode = 0;
+ } else if (ofs->config.xino == OVL_XINO_OFF) {
+ ofs->xino_mode = -1;
+ } else if (ofs->xino_mode < 0) {
+ /*
+ * This is a roundup of number of bits needed for encoding
+ * fsid, where fsid 0 is reserved for upper fs (even with
+ * lower only overlay) +1 extra bit is reserved for the non
+ * persistent inode number range that is used for resolving
+ * xino lower bits overflow.
+ */
+ BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30);
+ ofs->xino_mode = ilog2(ofs->numfs - 1) + 2;
+ }
- ufs->workbasedir = workpath.dentry;
- sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth;
+ if (ofs->xino_mode > 0) {
+ pr_info("\"xino\" feature enabled using %d upper inode bits.\n",
+ ofs->xino_mode);
}
- err = -ENOMEM;
- lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL);
- if (!lowertmp)
- goto out_unlock_workdentry;
- err = -EINVAL;
- stacklen = ovl_split_lowerdirs(lowertmp);
- if (stacklen > OVL_MAX_STACK) {
- pr_err("overlayfs: too many lower directories, limit is %d\n",
- OVL_MAX_STACK);
- goto out_free_lowertmp;
- } else if (!ufs->config.upperdir && stacklen == 1) {
- pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n");
- goto out_free_lowertmp;
+ return 0;
+}
+
+static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb,
+ struct ovl_fs_context *ctx,
+ struct ovl_fs *ofs,
+ struct ovl_layer *layers)
+{
+ int err;
+ unsigned int i;
+ size_t nr_merged_lower;
+ struct ovl_entry *oe;
+ struct ovl_path *lowerstack;
+
+ struct ovl_fs_context_layer *l;
+
+ if (!ofs->config.upperdir && ctx->nr == 1) {
+ pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n");
+ return ERR_PTR(-EINVAL);
}
- err = -ENOMEM;
- stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL);
- if (!stack)
- goto out_free_lowertmp;
+ if (ctx->nr == ctx->nr_data) {
+ pr_err("at least one non-data lowerdir is required\n");
+ return ERR_PTR(-EINVAL);
+ }
err = -EINVAL;
- lower = lowertmp;
- for (numlower = 0; numlower < stacklen; numlower++) {
- err = ovl_lower_dir(lower, &stack[numlower], ufs,
- &sb->s_stack_depth, &remote);
- if (err)
- goto out_put_lowerpath;
+ for (i = 0; i < ctx->nr; i++) {
+ l = &ctx->lower[i];
- lower = strchr(lower, '\0') + 1;
+ err = ovl_lower_dir(l->name, &l->path, ofs, &sb->s_stack_depth);
+ if (err)
+ return ERR_PTR(err);
}
err = -EINVAL;
sb->s_stack_depth++;
if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
- pr_err("overlayfs: maximum fs stacking depth exceeded\n");
- goto out_put_lowerpath;
+ pr_err("maximum fs stacking depth exceeded\n");
+ return ERR_PTR(err);
+ }
+
+ err = ovl_get_layers(sb, ofs, ctx, layers);
+ if (err)
+ return ERR_PTR(err);
+
+ err = -ENOMEM;
+ /* Data-only layers are not merged in root directory */
+ nr_merged_lower = ctx->nr - ctx->nr_data;
+ oe = ovl_alloc_entry(nr_merged_lower);
+ if (!oe)
+ return ERR_PTR(err);
+
+ lowerstack = ovl_lowerstack(oe);
+ for (i = 0; i < nr_merged_lower; i++) {
+ l = &ctx->lower[i];
+ lowerstack[i].dentry = dget(l->path.dentry);
+ lowerstack[i].layer = &ofs->layers[i + 1];
}
+ ofs->numdatalayer = ctx->nr_data;
+
+ return oe;
+}
+
+/*
+ * Check if this layer root is a descendant of:
+ * - another layer of this overlayfs instance
+ * - upper/work dir of any overlayfs instance
+ */
+static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs,
+ struct dentry *dentry, const char *name,
+ bool is_lower)
+{
+ struct dentry *next = dentry, *parent;
+ int err = 0;
+
+ if (!dentry)
+ return 0;
- if (ufs->config.upperdir) {
- ufs->upper_mnt = clone_private_mount(&upperpath);
- err = PTR_ERR(ufs->upper_mnt);
- if (IS_ERR(ufs->upper_mnt)) {
- pr_err("overlayfs: failed to clone upperpath\n");
- goto out_put_lowerpath;
+ parent = dget_parent(next);
+
+ /* Walk back ancestors to root (inclusive) looking for traps */
+ while (!err && parent != next) {
+ if (is_lower && ovl_lookup_trap_inode(sb, parent)) {
+ err = -ELOOP;
+ pr_err("overlapping %s path\n", name);
+ } else if (ovl_is_inuse(parent)) {
+ err = ovl_report_in_use(ofs, name);
}
+ next = parent;
+ parent = dget_parent(next);
+ dput(next);
+ }
- /* Don't inherit atime flags */
- ufs->upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME);
+ dput(parent);
- sb->s_time_gran = ufs->upper_mnt->mnt_sb->s_time_gran;
+ return err;
+}
+
+/*
+ * Check if any of the layers or work dirs overlap.
+ */
+static int ovl_check_overlapping_layers(struct super_block *sb,
+ struct ovl_fs *ofs)
+{
+ int i, err;
+
+ if (ovl_upper_mnt(ofs)) {
+ err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root,
+ "upperdir", false);
+ if (err)
+ return err;
- ufs->workdir = ovl_workdir_create(sb, ufs, workpath.dentry,
- OVL_WORKDIR_NAME, false);
/*
- * Upper should support d_type, else whiteouts are visible.
- * Given workdir and upper are on same fs, we can do
- * iterate_dir() on workdir. This check requires successful
- * creation of workdir in previous step.
+ * Checking workbasedir avoids hitting ovl_is_inuse(parent) of
+ * this instance and covers overlapping work and index dirs,
+ * unless work or index dir have been moved since created inside
+ * workbasedir. In that case, we already have their traps in
+ * inode cache and we will catch that case on lookup.
*/
- if (ufs->workdir) {
- struct dentry *temp;
-
- err = ovl_check_d_type_supported(&workpath);
- if (err < 0)
- goto out_put_workdir;
-
- /*
- * We allowed this configuration and don't want to
- * break users over kernel upgrade. So warn instead
- * of erroring out.
- */
- if (!err)
- pr_warn("overlayfs: upper fs needs to support d_type.\n");
-
- /* Check if upper/work fs supports O_TMPFILE */
- temp = ovl_do_tmpfile(ufs->workdir, S_IFREG | 0);
- ufs->tmpfile = !IS_ERR(temp);
- if (ufs->tmpfile)
- dput(temp);
- else
- pr_warn("overlayfs: upper fs does not support tmpfile.\n");
-
- /*
- * Check if upper/work fs supports trusted.overlay.*
- * xattr
- */
- err = ovl_do_setxattr(ufs->workdir, OVL_XATTR_OPAQUE,
- "0", 1, 0);
- if (err) {
- ufs->noxattr = true;
- pr_warn("overlayfs: upper fs does not support xattr.\n");
- } else {
- vfs_removexattr(ufs->workdir, OVL_XATTR_OPAQUE);
- }
+ err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir",
+ false);
+ if (err)
+ return err;
+ }
- /* Check if upper/work fs supports file handles */
- if (ufs->config.index &&
- !ovl_can_decode_fh(ufs->workdir->d_sb)) {
- ufs->config.index = false;
- pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n");
- }
- }
+ for (i = 1; i < ofs->numlayer; i++) {
+ err = ovl_check_layer(sb, ofs,
+ ofs->layers[i].mnt->mnt_root,
+ "lowerdir", true);
+ if (err)
+ return err;
}
- err = -ENOMEM;
- ufs->lower_mnt = kcalloc(numlower, sizeof(struct vfsmount *), GFP_KERNEL);
- if (ufs->lower_mnt == NULL)
- goto out_put_workdir;
- for (i = 0; i < numlower; i++) {
- struct vfsmount *mnt = clone_private_mount(&stack[i]);
+ return 0;
+}
- err = PTR_ERR(mnt);
- if (IS_ERR(mnt)) {
- pr_err("overlayfs: failed to clone lowerpath\n");
- goto out_put_lower_mnt;
+static struct dentry *ovl_get_root(struct super_block *sb,
+ struct dentry *upperdentry,
+ struct ovl_entry *oe)
+{
+ struct dentry *root;
+ struct ovl_fs *ofs = OVL_FS(sb);
+ struct ovl_path *lowerpath = ovl_lowerstack(oe);
+ unsigned long ino = d_inode(lowerpath->dentry)->i_ino;
+ int fsid = lowerpath->layer->fsid;
+ struct ovl_inode_params oip = {
+ .upperdentry = upperdentry,
+ .oe = oe,
+ };
+
+ root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0));
+ if (!root)
+ return NULL;
+
+ if (upperdentry) {
+ /* Root inode uses upper st_ino/i_ino */
+ ino = d_inode(upperdentry)->i_ino;
+ fsid = 0;
+ ovl_dentry_set_upper_alias(root);
+ if (ovl_is_impuredir(sb, upperdentry))
+ ovl_set_flag(OVL_IMPURE, d_inode(root));
+ }
+
+ /* Look for xwhiteouts marker except in the lowermost layer */
+ for (int i = 0; i < ovl_numlower(oe) - 1; i++, lowerpath++) {
+ struct path path = {
+ .mnt = lowerpath->layer->mnt,
+ .dentry = lowerpath->dentry,
+ };
+
+ /* overlay.opaque=x means xwhiteouts directory */
+ if (ovl_get_opaquedir_val(ofs, &path) == 'x') {
+ ovl_layer_set_xwhiteouts(ofs, lowerpath->layer);
+ ovl_dentry_set_xwhiteouts(root);
}
- /*
- * Make lower_mnt R/O. That way fchmod/fchown on lower file
- * will fail instead of modifying lower fs.
- */
- mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME;
+ }
- ufs->lower_mnt[ufs->numlower] = mnt;
- ufs->numlower++;
+ /* Root is always merge -> can have whiteouts */
+ ovl_set_flag(OVL_WHITEOUTS, d_inode(root));
+ ovl_dentry_set_flag(OVL_E_CONNECTED, root);
+ ovl_set_upperdata(d_inode(root));
+ ovl_inode_init(d_inode(root), &oip, ino, fsid);
+ WARN_ON(!!IS_CASEFOLDED(d_inode(root)) != ofs->casefold);
+ ovl_dentry_init_flags(root, upperdentry, oe, DCACHE_OP_WEAK_REVALIDATE);
+ /* root keeps a reference of upperdentry */
+ dget(upperdentry);
+
+ return root;
+}
- /* Check if all lower layers are on same sb */
- if (i == 0)
- ufs->same_sb = mnt->mnt_sb;
- else if (ufs->same_sb != mnt->mnt_sb)
- ufs->same_sb = NULL;
+static void ovl_set_d_op(struct super_block *sb)
+{
+#if IS_ENABLED(CONFIG_UNICODE)
+ struct ovl_fs *ofs = sb->s_fs_info;
+
+ if (ofs->casefold) {
+ set_default_d_op(sb, &ovl_dentry_ci_operations);
+ return;
}
+#endif
+ set_default_d_op(sb, &ovl_dentry_operations);
+}
- /* If the upper fs is nonexistent, we mark overlayfs r/o too */
- if (!ufs->upper_mnt)
- sb->s_flags |= MS_RDONLY;
- else if (ufs->upper_mnt->mnt_sb != ufs->same_sb)
- ufs->same_sb = NULL;
-
- if (!(ovl_force_readonly(ufs)) && ufs->config.index) {
- /* Verify lower root is upper root origin */
- err = ovl_verify_origin(upperpath.dentry, ufs->lower_mnt[0],
- stack[0].dentry, false, true);
- if (err) {
- pr_err("overlayfs: failed to verify upper root origin\n");
- goto out_put_lower_mnt;
+static int ovl_fill_super_creds(struct fs_context *fc, struct super_block *sb)
+{
+ struct ovl_fs *ofs = sb->s_fs_info;
+ struct cred *creator_cred = (struct cred *)ofs->creator_cred;
+ struct ovl_fs_context *ctx = fc->fs_private;
+ struct ovl_layer *layers;
+ struct ovl_entry *oe = NULL;
+ int err;
+
+ err = ovl_fs_params_verify(ctx, &ofs->config);
+ if (err)
+ return err;
+
+ err = -EINVAL;
+ if (ctx->nr == 0) {
+ if (!(fc->sb_flags & SB_SILENT))
+ pr_err("missing 'lowerdir'\n");
+ return err;
+ }
+
+ err = -ENOMEM;
+ layers = kcalloc(ctx->nr + 1, sizeof(struct ovl_layer), GFP_KERNEL);
+ if (!layers)
+ return err;
+
+ ofs->config.lowerdirs = kcalloc(ctx->nr + 1, sizeof(char *), GFP_KERNEL);
+ if (!ofs->config.lowerdirs) {
+ kfree(layers);
+ return err;
+ }
+ ofs->layers = layers;
+ /*
+ * Layer 0 is reserved for upper even if there's no upper.
+ * config.lowerdirs[0] is used for storing the user provided colon
+ * separated lowerdir string.
+ */
+ ofs->config.lowerdirs[0] = ctx->lowerdir_all;
+ ctx->lowerdir_all = NULL;
+ ofs->numlayer = 1;
+
+ sb->s_stack_depth = 0;
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+ atomic_long_set(&ofs->last_ino, 1);
+ /* Assume underlying fs uses 32bit inodes unless proven otherwise */
+ if (ofs->config.xino != OVL_XINO_OFF) {
+ ofs->xino_mode = BITS_PER_LONG - 32;
+ if (!ofs->xino_mode) {
+ pr_warn("xino not supported on 32bit kernel, falling back to xino=off.\n");
+ ofs->config.xino = OVL_XINO_OFF;
}
+ }
- ufs->indexdir = ovl_workdir_create(sb, ufs, workpath.dentry,
- OVL_INDEXDIR_NAME, true);
- if (ufs->indexdir) {
- /* Verify upper root is index dir origin */
- err = ovl_verify_origin(ufs->indexdir, ufs->upper_mnt,
- upperpath.dentry, true, true);
- if (err)
- pr_err("overlayfs: failed to verify index dir origin\n");
+ /* alloc/destroy_inode needed for setting up traps in inode cache */
+ sb->s_op = &ovl_super_operations;
+
+ if (ofs->config.upperdir) {
+ struct super_block *upper_sb;
- /* Cleanup bad/stale/orphan index entries */
- if (!err)
- err = ovl_indexdir_cleanup(ufs->indexdir,
- ufs->upper_mnt,
- stack, numlower);
+ err = -EINVAL;
+ if (!ofs->config.workdir) {
+ pr_err("missing 'workdir'\n");
+ return err;
}
- if (err || !ufs->indexdir)
- pr_warn("overlayfs: try deleting index dir or mounting with '-o index=off' to disable inodes index.\n");
+
+ err = ovl_get_upper(sb, ofs, &layers[0], &ctx->upper);
if (err)
- goto out_put_indexdir;
- }
+ return err;
- /* Show index=off/on in /proc/mounts for any of the reasons above */
- if (!ufs->indexdir)
- ufs->config.index = false;
+ upper_sb = ovl_upper_mnt(ofs)->mnt_sb;
+ if (!ovl_should_sync(ofs)) {
+ ofs->errseq = errseq_sample(&upper_sb->s_wb_err);
+ if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) {
+ err = -EIO;
+ pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n");
+ return err;
+ }
+ }
- if (remote)
- sb->s_d_op = &ovl_reval_dentry_operations;
- else
- sb->s_d_op = &ovl_dentry_operations;
+ err = ovl_get_workdir(sb, ofs, &ctx->upper, &ctx->work);
+ if (err)
+ return err;
- err = -ENOMEM;
- ufs->creator_cred = cred = prepare_creds();
- if (!cred)
- goto out_put_indexdir;
+ if (!ofs->workdir)
+ sb->s_flags |= SB_RDONLY;
- /* Never override disk quota limits or use reserved space */
- cap_lower(cred->cap_effective, CAP_SYS_RESOURCE);
+ sb->s_stack_depth = upper_sb->s_stack_depth;
+ sb->s_time_gran = upper_sb->s_time_gran;
+ }
+ oe = ovl_get_lowerstack(sb, ctx, ofs, layers);
+ err = PTR_ERR(oe);
+ if (IS_ERR(oe))
+ return err;
- err = -ENOMEM;
- oe = ovl_alloc_entry(numlower);
- if (!oe)
- goto out_put_cred;
+ /* If the upper fs is nonexistent, we mark overlayfs r/o too */
+ if (!ovl_upper_mnt(ofs))
+ sb->s_flags |= SB_RDONLY;
+
+ if (!ovl_origin_uuid(ofs) && ofs->numfs > 1) {
+ pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=null.\n");
+ ofs->config.uuid = OVL_UUID_NULL;
+ } else if (ovl_has_fsid(ofs) && ovl_upper_mnt(ofs)) {
+ /* Use per instance persistent uuid/fsid */
+ ovl_init_uuid_xattr(sb, ofs, &ctx->upper);
+ }
- sb->s_magic = OVERLAYFS_SUPER_MAGIC;
- sb->s_op = &ovl_super_operations;
- sb->s_xattr = ovl_xattr_handlers;
- sb->s_fs_info = ufs;
- sb->s_flags |= MS_POSIXACL | MS_NOREMOTELOCK;
+ if (!ovl_force_readonly(ofs) && ofs->config.index) {
+ err = ovl_get_indexdir(sb, ofs, oe, &ctx->upper);
+ if (err)
+ goto out_free_oe;
- root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0));
- if (!root_dentry)
- goto out_free_oe;
+ /* Force r/o mount with no index dir */
+ if (!ofs->workdir)
+ sb->s_flags |= SB_RDONLY;
+ }
- mntput(upperpath.mnt);
- for (i = 0; i < numlower; i++)
- mntput(stack[i].mnt);
- mntput(workpath.mnt);
- kfree(lowertmp);
+ err = ovl_check_overlapping_layers(sb, ofs);
+ if (err)
+ goto out_free_oe;
- if (upperpath.dentry) {
- oe->has_upper = true;
- if (ovl_is_impuredir(upperpath.dentry))
- ovl_set_flag(OVL_IMPURE, d_inode(root_dentry));
+ /* Show index=off in /proc/mounts for forced r/o mount */
+ if (!ofs->workdir) {
+ ofs->config.index = false;
+ if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) {
+ pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n");
+ ofs->config.nfs_export = false;
+ }
}
- for (i = 0; i < numlower; i++) {
- oe->lowerstack[i].dentry = stack[i].dentry;
- oe->lowerstack[i].mnt = ufs->lower_mnt[i];
+
+ if (ofs->config.metacopy && ofs->config.nfs_export) {
+ pr_warn("NFS export is not supported with metadata only copy up, falling back to nfs_export=off.\n");
+ ofs->config.nfs_export = false;
}
- kfree(stack);
- root_dentry->d_fsdata = oe;
+ /*
+ * Support encoding decodable file handles with nfs_export=on
+ * and encoding non-decodable file handles with nfs_export=off
+ * if all layers support file handles.
+ */
+ if (ofs->config.nfs_export)
+ sb->s_export_op = &ovl_export_operations;
+ else if (!ofs->nofh)
+ sb->s_export_op = &ovl_export_fid_operations;
- ovl_inode_init(d_inode(root_dentry), upperpath.dentry,
- ovl_dentry_lower(root_dentry));
+ /* Never override disk quota limits or use reserved space */
+ cap_lower(creator_cred->cap_effective, CAP_SYS_RESOURCE);
- sb->s_root = root_dentry;
+ sb->s_magic = OVERLAYFS_SUPER_MAGIC;
+ sb->s_xattr = ovl_xattr_handlers(ofs);
+ sb->s_fs_info = ofs;
+#ifdef CONFIG_FS_POSIX_ACL
+ sb->s_flags |= SB_POSIXACL;
+#endif
+ sb->s_iflags |= SB_I_SKIP_SYNC;
+ /*
+ * Ensure that umask handling is done by the filesystems used
+ * for the the upper layer instead of overlayfs as that would
+ * lead to unexpected results.
+ */
+ sb->s_iflags |= SB_I_NOUMASK;
+ sb->s_iflags |= SB_I_EVM_HMAC_UNSUPPORTED;
+
+ err = -ENOMEM;
+ sb->s_root = ovl_get_root(sb, ctx->upper.dentry, oe);
+ if (!sb->s_root)
+ goto out_free_oe;
return 0;
out_free_oe:
- kfree(oe);
-out_put_cred:
- put_cred(ufs->creator_cred);
-out_put_indexdir:
- dput(ufs->indexdir);
-out_put_lower_mnt:
- for (i = 0; i < ufs->numlower; i++)
- mntput(ufs->lower_mnt[i]);
- kfree(ufs->lower_mnt);
-out_put_workdir:
- dput(ufs->workdir);
- mntput(ufs->upper_mnt);
-out_put_lowerpath:
- for (i = 0; i < numlower; i++)
- path_put(&stack[i]);
- kfree(stack);
-out_free_lowertmp:
- kfree(lowertmp);
-out_unlock_workdentry:
- ovl_inuse_unlock(workpath.dentry);
-out_put_workpath:
- path_put(&workpath);
-out_unlock_upperdentry:
- ovl_inuse_unlock(upperpath.dentry);
-out_put_upperpath:
- path_put(&upperpath);
-out_free_config:
- kfree(ufs->config.lowerdir);
- kfree(ufs->config.upperdir);
- kfree(ufs->config.workdir);
- kfree(ufs);
-out:
+ ovl_free_entry(oe);
return err;
}
-static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags,
- const char *dev_name, void *raw_data)
+int ovl_fill_super(struct super_block *sb, struct fs_context *fc)
{
- return mount_nodev(fs_type, flags, raw_data, ovl_fill_super);
+ struct ovl_fs *ofs = sb->s_fs_info;
+ int err;
+
+ err = -EIO;
+ if (WARN_ON(fc->user_ns != current_user_ns()))
+ goto out_err;
+
+ ovl_set_d_op(sb);
+
+ if (!ofs->creator_cred) {
+ err = -ENOMEM;
+ ofs->creator_cred = prepare_creds();
+ if (!ofs->creator_cred)
+ goto out_err;
+ }
+
+ with_ovl_creds(sb)
+ err = ovl_fill_super_creds(fc, sb);
+
+out_err:
+ if (err) {
+ ovl_free_fs(ofs);
+ sb->s_fs_info = NULL;
+ }
+
+ return err;
}
-static struct file_system_type ovl_fs_type = {
- .owner = THIS_MODULE,
- .name = "overlay",
- .mount = ovl_mount,
- .kill_sb = kill_anon_super,
+struct file_system_type ovl_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "overlay",
+ .init_fs_context = ovl_init_fs_context,
+ .parameters = ovl_parameter_spec,
+ .fs_flags = FS_USERNS_MOUNT,
+ .kill_sb = kill_anon_super,
};
MODULE_ALIAS_FS("overlay");
@@ -1199,14 +1599,16 @@ static int __init ovl_init(void)
ovl_inode_cachep = kmem_cache_create("ovl_inode",
sizeof(struct ovl_inode), 0,
(SLAB_RECLAIM_ACCOUNT|
- SLAB_MEM_SPREAD|SLAB_ACCOUNT),
+ SLAB_ACCOUNT),
ovl_inode_init_once);
if (ovl_inode_cachep == NULL)
return -ENOMEM;
err = register_filesystem(&ovl_fs_type);
- if (err)
- kmem_cache_destroy(ovl_inode_cachep);
+ if (!err)
+ return 0;
+
+ kmem_cache_destroy(ovl_inode_cachep);
return err;
}
@@ -1221,7 +1623,6 @@ static void __exit ovl_exit(void)
*/
rcu_barrier();
kmem_cache_destroy(ovl_inode_cachep);
-
}
module_init(ovl_init);
generated by cgit (git 2.34.1) at 2025-12-25 01:21:07 +0000