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ovl: move all parameter handling into params.{c,h} 

While initially I thought that we couldn't move all new mount api
handling into params.{c,h} it turns out it is possible. So this just
moves a good chunk of code out of super.c and into params.{c,h}.

Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
This commit is contained in:
Christian Brauner 2023-06-26 12:23:36 +02:00 committed by Amir Goldstein
parent a901a3568f
commit 7fb7998b59
4 changed files with 581 additions and 564 deletions
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41
fs/overlayfs/overlayfs.h
View File

@ -70,14 +70,6 @@ enum {
OVL_XINO_ON,
};
/* The set of options that user requested explicitly via mount options */
struct ovl_opt_set {
bool metacopy;
bool redirect;
bool nfs_export;
bool index;
};
/*
* The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
* where:
@ -368,30 +360,6 @@ static inline bool ovl_open_flags_need_copy_up(int flags)
return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
}
/* params.c */
#define OVL_MAX_STACK 500
struct ovl_fs_context_layer {
char *name;
struct path path;
};
struct ovl_fs_context {
struct path upper;
struct path work;
size_t capacity;
size_t nr; /* includes nr_data */
size_t nr_data;
struct ovl_opt_set set;
struct ovl_fs_context_layer *lower;
};
int ovl_parse_param_upperdir(const char *name, struct fs_context *fc,
bool workdir);
int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc);
void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx);
/* util.c */
int ovl_want_write(struct dentry *dentry);
void ovl_drop_write(struct dentry *dentry);
@ -791,3 +759,12 @@ int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
/* export.c */
extern const struct export_operations ovl_export_operations;
/* super.c */
int ovl_fill_super(struct super_block *sb, struct fs_context *fc);
/* Will this overlay be forced to mount/remount ro? */
static inline bool ovl_force_readonly(struct ovl_fs *ofs)
{
return (!ovl_upper_mnt(ofs) || !ofs->workdir);
}

532
fs/overlayfs/params.c
View File

@ -1,12 +1,124 @@
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/namei.h>
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include <linux/posix_acl_xattr.h>
#include <linux/seq_file.h>
#include <linux/xattr.h>
#include "overlayfs.h"
#include "params.h"
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(redirect_dir,
"Default to on or off for the redirect_dir feature");
static bool ovl_redirect_always_follow =
IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW);
module_param_named(redirect_always_follow, ovl_redirect_always_follow,
bool, 0644);
MODULE_PARM_DESC(redirect_always_follow,
"Follow redirects even if redirect_dir feature is turned off");
static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO);
module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644);
MODULE_PARM_DESC(xino_auto,
"Auto enable xino feature");
static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX);
module_param_named(index, ovl_index_def, bool, 0644);
MODULE_PARM_DESC(index,
"Default to on or off for the inodes index feature");
static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT);
module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644);
MODULE_PARM_DESC(nfs_export,
"Default to on or off for the NFS export feature");
static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY);
module_param_named(metacopy, ovl_metacopy_def, bool, 0644);
MODULE_PARM_DESC(metacopy,
"Default to on or off for the metadata only copy up feature");
enum {
Opt_lowerdir,
Opt_upperdir,
Opt_workdir,
Opt_default_permissions,
Opt_redirect_dir,
Opt_index,
Opt_uuid,
Opt_nfs_export,
Opt_userxattr,
Opt_xino,
Opt_metacopy,
Opt_volatile,
};
static const struct constant_table ovl_parameter_bool[] = {
{ "on", true },
{ "off", false },
{}
};
static const struct constant_table ovl_parameter_xino[] = {
{ "off", OVL_XINO_OFF },
{ "auto", OVL_XINO_AUTO },
{ "on", OVL_XINO_ON },
{}
};
const char *ovl_xino_mode(struct ovl_config *config)
{
return ovl_parameter_xino[config->xino].name;
}
static int ovl_xino_def(void)
{
return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF;
}
const struct constant_table ovl_parameter_redirect_dir[] = {
{ "off", OVL_REDIRECT_OFF },
{ "follow", OVL_REDIRECT_FOLLOW },
{ "nofollow", OVL_REDIRECT_NOFOLLOW },
{ "on", OVL_REDIRECT_ON },
{}
};
static const char *ovl_redirect_mode(struct ovl_config *config)
{
return ovl_parameter_redirect_dir[config->redirect_mode].name;
}
static int ovl_redirect_mode_def(void)
{
return ovl_redirect_dir_def ? OVL_REDIRECT_ON :
ovl_redirect_always_follow ? OVL_REDIRECT_FOLLOW :
OVL_REDIRECT_NOFOLLOW;
}
#define fsparam_string_empty(NAME, OPT) \
__fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL)
const struct fs_parameter_spec ovl_parameter_spec[] = {
fsparam_string_empty("lowerdir", Opt_lowerdir),
fsparam_string("upperdir", Opt_upperdir),
fsparam_string("workdir", Opt_workdir),
fsparam_flag("default_permissions", Opt_default_permissions),
fsparam_enum("redirect_dir", Opt_redirect_dir, ovl_parameter_redirect_dir),
fsparam_enum("index", Opt_index, ovl_parameter_bool),
fsparam_enum("uuid", Opt_uuid, ovl_parameter_bool),
fsparam_enum("nfs_export", Opt_nfs_export, ovl_parameter_bool),
fsparam_flag("userxattr", Opt_userxattr),
fsparam_enum("xino", Opt_xino, ovl_parameter_xino),
fsparam_enum("metacopy", Opt_metacopy, ovl_parameter_bool),
fsparam_flag("volatile", Opt_volatile),
{}
};
static ssize_t ovl_parse_param_split_lowerdirs(char *str)
{
@ -110,8 +222,8 @@ static int ovl_mount_dir(const char *name, struct path *path)
return err;
}
int ovl_parse_param_upperdir(const char *name, struct fs_context *fc,
bool workdir)
static int ovl_parse_param_upperdir(const char *name, struct fs_context *fc,
bool workdir)
{
int err;
struct ovl_fs *ofs = fc->s_fs_info;
@ -154,7 +266,7 @@ int ovl_parse_param_upperdir(const char *name, struct fs_context *fc,
return 0;
}
void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx)
static void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx)
{
for (size_t nr = 0; nr < ctx->nr; nr++) {
path_put(&ctx->lower[nr].path);
@ -179,7 +291,7 @@ void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx)
* Append data "/lower5" as data lower layer. This requires that
* there's at least one regular lower layer present.
*/
int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc)
static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc)
{
int err;
struct ovl_fs_context *ctx = fc->fs_private;
@ -387,3 +499,415 @@ out_err:
/* Intentionally don't realloc to a smaller size. */
return err;
}
static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
int err = 0;
struct fs_parse_result result;
struct ovl_fs *ofs = fc->s_fs_info;
struct ovl_config *config = &ofs->config;
struct ovl_fs_context *ctx = fc->fs_private;
int opt;
if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
/*
* On remount overlayfs has always ignored all mount
* options no matter if malformed or not so for
* backwards compatibility we do the same here.
*/
if (fc->oldapi)
return 0;
/*
* Give us the freedom to allow changing mount options
* with the new mount api in the future. So instead of
* silently ignoring everything we report a proper
* error. This is only visible for users of the new
* mount api.
*/
return invalfc(fc, "No changes allowed in reconfigure");
}
opt = fs_parse(fc, ovl_parameter_spec, param, &result);
if (opt < 0)
return opt;
switch (opt) {
case Opt_lowerdir:
err = ovl_parse_param_lowerdir(param->string, fc);
break;
case Opt_upperdir:
fallthrough;
case Opt_workdir:
err = ovl_parse_param_upperdir(param->string, fc,
(Opt_workdir == opt));
break;
case Opt_default_permissions:
config->default_permissions = true;
break;
case Opt_redirect_dir:
config->redirect_mode = result.uint_32;
if (config->redirect_mode == OVL_REDIRECT_OFF) {
config->redirect_mode = ovl_redirect_always_follow ?
OVL_REDIRECT_FOLLOW :
OVL_REDIRECT_NOFOLLOW;
}
ctx->set.redirect = true;
break;
case Opt_index:
config->index = result.uint_32;
ctx->set.index = true;
break;
case Opt_uuid:
config->uuid = result.uint_32;
break;
case Opt_nfs_export:
config->nfs_export = result.uint_32;
ctx->set.nfs_export = true;
break;
case Opt_xino:
config->xino = result.uint_32;
break;
case Opt_metacopy:
config->metacopy = result.uint_32;
ctx->set.metacopy = true;
break;
case Opt_volatile:
config->ovl_volatile = true;
break;
case Opt_userxattr:
config->userxattr = true;
break;
default:
pr_err("unrecognized mount option \"%s\" or missing value\n",
param->key);
return -EINVAL;
}
return err;
}
static int ovl_get_tree(struct fs_context *fc)
{
return get_tree_nodev(fc, ovl_fill_super);
}
static inline void ovl_fs_context_free(struct ovl_fs_context *ctx)
{
ovl_parse_param_drop_lowerdir(ctx);
path_put(&ctx->upper);
path_put(&ctx->work);
kfree(ctx->lower);
kfree(ctx);
}
static void ovl_free(struct fs_context *fc)
{
struct ovl_fs *ofs = fc->s_fs_info;
struct ovl_fs_context *ctx = fc->fs_private;
/*
* ofs is stored in the fs_context when it is initialized.
* ofs is transferred to the superblock on a successful mount,
* but if an error occurs before the transfer we have to free
* it here.
*/
if (ofs)
ovl_free_fs(ofs);
if (ctx)
ovl_fs_context_free(ctx);
}
static int ovl_reconfigure(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
struct ovl_fs *ofs = sb->s_fs_info;
struct super_block *upper_sb;
int ret = 0;
if (!(fc->sb_flags & SB_RDONLY) && ovl_force_readonly(ofs))
return -EROFS;
if (fc->sb_flags & SB_RDONLY && !sb_rdonly(sb)) {
upper_sb = ovl_upper_mnt(ofs)->mnt_sb;
if (ovl_should_sync(ofs)) {
down_read(&upper_sb->s_umount);
ret = sync_filesystem(upper_sb);
up_read(&upper_sb->s_umount);
}
}
return ret;
}
static const struct fs_context_operations ovl_context_ops = {
.parse_param = ovl_parse_param,
.get_tree = ovl_get_tree,
.reconfigure = ovl_reconfigure,
.free = ovl_free,
};
/*
* This is called during fsopen() and will record the user namespace of
* the caller in fc->user_ns since we've raised FS_USERNS_MOUNT. We'll
* need it when we actually create the superblock to verify that the
* process creating the superblock is in the same user namespace as
* process that called fsopen().
*/
int ovl_init_fs_context(struct fs_context *fc)
{
struct ovl_fs_context *ctx;
struct ovl_fs *ofs;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
if (!ctx)
return -ENOMEM;
/*
* By default we allocate for three lower layers. It's likely
* that it'll cover most users.
*/
ctx->lower = kmalloc_array(3, sizeof(*ctx->lower), GFP_KERNEL_ACCOUNT);
if (!ctx->lower)
goto out_err;
ctx->capacity = 3;
ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL);
if (!ofs)
goto out_err;
ofs->config.redirect_mode = ovl_redirect_mode_def();
ofs->config.index = ovl_index_def;
ofs->config.uuid = true;
ofs->config.nfs_export = ovl_nfs_export_def;
ofs->config.xino = ovl_xino_def();
ofs->config.metacopy = ovl_metacopy_def;
fc->s_fs_info = ofs;
fc->fs_private = ctx;
fc->ops = &ovl_context_ops;
return 0;
out_err:
ovl_fs_context_free(ctx);
return -ENOMEM;
}
void ovl_free_fs(struct ovl_fs *ofs)
{
struct vfsmount **mounts;
unsigned i;
iput(ofs->workbasedir_trap);
iput(ofs->indexdir_trap);
iput(ofs->workdir_trap);
dput(ofs->whiteout);
dput(ofs->indexdir);
dput(ofs->workdir);
if (ofs->workdir_locked)
ovl_inuse_unlock(ofs->workbasedir);
dput(ofs->workbasedir);
if (ofs->upperdir_locked)
ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root);
/* Hack! Reuse ofs->layers as a vfsmount array before freeing it */
mounts = (struct vfsmount **) ofs->layers;
for (i = 0; i < ofs->numlayer; i++) {
iput(ofs->layers[i].trap);
mounts[i] = ofs->layers[i].mnt;
kfree(ofs->layers[i].name);
}
kern_unmount_array(mounts, ofs->numlayer);
kfree(ofs->layers);
for (i = 0; i < ofs->numfs; i++)
free_anon_bdev(ofs->fs[i].pseudo_dev);
kfree(ofs->fs);
kfree(ofs->config.upperdir);
kfree(ofs->config.workdir);
if (ofs->creator_cred)
put_cred(ofs->creator_cred);
kfree(ofs);
}
int ovl_fs_params_verify(const struct ovl_fs_context *ctx,
struct ovl_config *config)
{
struct ovl_opt_set set = ctx->set;
if (ctx->nr_data > 0 && !config->metacopy) {
pr_err("lower data-only dirs require metacopy support.\n");
return -EINVAL;
}
/* Workdir/index are useless in non-upper mount */
if (!config->upperdir) {
if (config->workdir) {
pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
config->workdir);
kfree(config->workdir);
config->workdir = NULL;
}
if (config->index && set.index) {
pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n");
set.index = false;
}
config->index = false;
}
if (!config->upperdir && config->ovl_volatile) {
pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n");
config->ovl_volatile = false;
}
/*
* This is to make the logic below simpler. It doesn't make any other
* difference, since redirect_dir=on is only used for upper.
*/
if (!config->upperdir && config->redirect_mode == OVL_REDIRECT_FOLLOW)
config->redirect_mode = OVL_REDIRECT_ON;
/* Resolve metacopy -> redirect_dir dependency */
if (config->metacopy && config->redirect_mode != OVL_REDIRECT_ON) {
if (set.metacopy && set.redirect) {
pr_err("conflicting options: metacopy=on,redirect_dir=%s\n",
ovl_redirect_mode(config));
return -EINVAL;
}
if (set.redirect) {
/*
* There was an explicit redirect_dir=... that resulted
* in this conflict.
*/
pr_info("disabling metacopy due to redirect_dir=%s\n",
ovl_redirect_mode(config));
config->metacopy = false;
} else {
/* Automatically enable redirect otherwise. */
config->redirect_mode = OVL_REDIRECT_ON;
}
}
/* Resolve nfs_export -> index dependency */
if (config->nfs_export && !config->index) {
if (!config->upperdir &&
config->redirect_mode != OVL_REDIRECT_NOFOLLOW) {
pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n");
config->nfs_export = false;
} else if (set.nfs_export && set.index) {
pr_err("conflicting options: nfs_export=on,index=off\n");
return -EINVAL;
} else if (set.index) {
/*
* There was an explicit index=off that resulted
* in this conflict.
*/
pr_info("disabling nfs_export due to index=off\n");
config->nfs_export = false;
} else {
/* Automatically enable index otherwise. */
config->index = true;
}
}
/* Resolve nfs_export -> !metacopy dependency */
if (config->nfs_export && config->metacopy) {
if (set.nfs_export && set.metacopy) {
pr_err("conflicting options: nfs_export=on,metacopy=on\n");
return -EINVAL;
}
if (set.metacopy) {
/*
* There was an explicit metacopy=on that resulted
* in this conflict.
*/
pr_info("disabling nfs_export due to metacopy=on\n");
config->nfs_export = false;
} else {
/*
* There was an explicit nfs_export=on that resulted
* in this conflict.
*/
pr_info("disabling metacopy due to nfs_export=on\n");
config->metacopy = false;
}
}
/* Resolve userxattr -> !redirect && !metacopy dependency */
if (config->userxattr) {
if (set.redirect &&
config->redirect_mode != OVL_REDIRECT_NOFOLLOW) {
pr_err("conflicting options: userxattr,redirect_dir=%s\n",
ovl_redirect_mode(config));
return -EINVAL;
}
if (config->metacopy && set.metacopy) {
pr_err("conflicting options: userxattr,metacopy=on\n");
return -EINVAL;
}
/*
* Silently disable default setting of redirect and metacopy.
* This shall be the default in the future as well: these
* options must be explicitly enabled if used together with
* userxattr.
*/
config->redirect_mode = OVL_REDIRECT_NOFOLLOW;
config->metacopy = false;
}
return 0;
}
/**
* ovl_show_options
* @m: the seq_file handle
* @dentry: The dentry to query
*
* Prints the mount options for a given superblock.
* Returns zero; does not fail.
*/
int ovl_show_options(struct seq_file *m, struct dentry *dentry)
{
struct super_block *sb = dentry->d_sb;
struct ovl_fs *ofs = sb->s_fs_info;
size_t nr, nr_merged_lower = ofs->numlayer - ofs->numdatalayer;
const struct ovl_layer *data_layers = &ofs->layers[nr_merged_lower];
/* ofs->layers[0] is the upper layer */
seq_printf(m, ",lowerdir=%s", ofs->layers[1].name);
/* dump regular lower layers */
for (nr = 2; nr < nr_merged_lower; nr++)
seq_printf(m, ":%s", ofs->layers[nr].name);
/* dump data lower layers */
for (nr = 0; nr < ofs->numdatalayer; nr++)
seq_printf(m, "::%s", data_layers[nr].name);
if (ofs->config.upperdir) {
seq_show_option(m, "upperdir", ofs->config.upperdir);
seq_show_option(m, "workdir", ofs->config.workdir);
}
if (ofs->config.default_permissions)
seq_puts(m, ",default_permissions");
if (ofs->config.redirect_mode != ovl_redirect_mode_def())
seq_printf(m, ",redirect_dir=%s",
ovl_redirect_mode(&ofs->config));
if (ofs->config.index != ovl_index_def)
seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off");
if (!ofs->config.uuid)
seq_puts(m, ",uuid=off");
if (ofs->config.nfs_export != ovl_nfs_export_def)
seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ?
"on" : "off");
if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(ofs))
seq_printf(m, ",xino=%s", ovl_xino_mode(&ofs->config));
if (ofs->config.metacopy != ovl_metacopy_def)
seq_printf(m, ",metacopy=%s",
ofs->config.metacopy ? "on" : "off");
if (ofs->config.ovl_volatile)
seq_puts(m, ",volatile");
if (ofs->config.userxattr)
seq_puts(m, ",userxattr");
return 0;
}

42
fs/overlayfs/params.h Normal file
View File

@ -0,0 +1,42 @@
/* SPDX-License-Identifier: GPL-2.0-only */
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
struct ovl_fs;
struct ovl_config;
extern const struct fs_parameter_spec ovl_parameter_spec[];
extern const struct constant_table ovl_parameter_redirect_dir[];
/* The set of options that user requested explicitly via mount options */
struct ovl_opt_set {
bool metacopy;
bool redirect;
bool nfs_export;
bool index;
};
#define OVL_MAX_STACK 500
struct ovl_fs_context_layer {
char *name;
struct path path;
};
struct ovl_fs_context {
struct path upper;
struct path work;
size_t capacity;
size_t nr; /* includes nr_data */
size_t nr_data;
struct ovl_opt_set set;
struct ovl_fs_context_layer *lower;
};
int ovl_init_fs_context(struct fs_context *fc);
void ovl_free_fs(struct ovl_fs *ofs);
int ovl_fs_params_verify(const struct ovl_fs_context *ctx,
struct ovl_config *config);
int ovl_show_options(struct seq_file *m, struct dentry *dentry);
const char *ovl_xino_mode(struct ovl_config *config);

530
fs/overlayfs/super.c
View File

@ -19,6 +19,7 @@
#include <linux/fs_context.h>
#include <linux/fs_parser.h>
#include "overlayfs.h"
#include "params.h"
MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Overlay filesystem");
@ -27,38 +28,6 @@ MODULE_LICENSE("GPL");
struct ovl_dir_cache;
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(redirect_dir,
"Default to on or off for the redirect_dir feature");
static bool ovl_redirect_always_follow =
IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_ALWAYS_FOLLOW);
module_param_named(redirect_always_follow, ovl_redirect_always_follow,
bool, 0644);
MODULE_PARM_DESC(redirect_always_follow,
"Follow redirects even if redirect_dir feature is turned off");
static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX);
module_param_named(index, ovl_index_def, bool, 0644);
MODULE_PARM_DESC(index,
"Default to on or off for the inodes index feature");
static bool ovl_nfs_export_def = IS_ENABLED(CONFIG_OVERLAY_FS_NFS_EXPORT);
module_param_named(nfs_export, ovl_nfs_export_def, bool, 0644);
MODULE_PARM_DESC(nfs_export,
"Default to on or off for the NFS export feature");
static bool ovl_xino_auto_def = IS_ENABLED(CONFIG_OVERLAY_FS_XINO_AUTO);
module_param_named(xino_auto, ovl_xino_auto_def, bool, 0644);
MODULE_PARM_DESC(xino_auto,
"Auto enable xino feature");
static bool ovl_metacopy_def = IS_ENABLED(CONFIG_OVERLAY_FS_METACOPY);
module_param_named(metacopy, ovl_metacopy_def, bool, 0644);
MODULE_PARM_DESC(metacopy,
"Default to on or off for the metadata only copy up feature");
static struct dentry *ovl_d_real(struct dentry *dentry,
const struct inode *inode)
{
@ -211,43 +180,6 @@ static void ovl_destroy_inode(struct inode *inode)
kfree(oi->lowerdata_redirect);
}
static void ovl_free_fs(struct ovl_fs *ofs)
{
struct vfsmount **mounts;
unsigned i;
iput(ofs->workbasedir_trap);
iput(ofs->indexdir_trap);
iput(ofs->workdir_trap);
dput(ofs->whiteout);
dput(ofs->indexdir);
dput(ofs->workdir);
if (ofs->workdir_locked)
ovl_inuse_unlock(ofs->workbasedir);
dput(ofs->workbasedir);
if (ofs->upperdir_locked)
ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root);
/* Hack! Reuse ofs->layers as a vfsmount array before freeing it */
mounts = (struct vfsmount **) ofs->layers;
for (i = 0; i < ofs->numlayer; i++) {
iput(ofs->layers[i].trap);
mounts[i] = ofs->layers[i].mnt;
kfree(ofs->layers[i].name);
}
kern_unmount_array(mounts, ofs->numlayer);
kfree(ofs->layers);
for (i = 0; i < ofs->numfs; i++)
free_anon_bdev(ofs->fs[i].pseudo_dev);
kfree(ofs->fs);
kfree(ofs->config.upperdir);
kfree(ofs->config.workdir);
if (ofs->creator_cred)
put_cred(ofs->creator_cred);
kfree(ofs);
}
static void ovl_put_super(struct super_block *sb)
{
struct ovl_fs *ofs = sb->s_fs_info;
@ -323,122 +255,6 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
return err;
}
/* Will this overlay be forced to mount/remount ro? */
static bool ovl_force_readonly(struct ovl_fs *ofs)
{
return (!ovl_upper_mnt(ofs) || !ofs->workdir);
}
static const struct constant_table ovl_parameter_redirect_dir[] = {
{ "off", OVL_REDIRECT_OFF },
{ "follow", OVL_REDIRECT_FOLLOW },
{ "nofollow", OVL_REDIRECT_NOFOLLOW },
{ "on", OVL_REDIRECT_ON },
{}
};
static const char *ovl_redirect_mode(struct ovl_config *config)
{
return ovl_parameter_redirect_dir[config->redirect_mode].name;
}
static int ovl_redirect_mode_def(void)
{
return ovl_redirect_dir_def ? OVL_REDIRECT_ON :
ovl_redirect_always_follow ? OVL_REDIRECT_FOLLOW :
OVL_REDIRECT_NOFOLLOW;
}
static const struct constant_table ovl_parameter_xino[] = {
{ "off", OVL_XINO_OFF },
{ "auto", OVL_XINO_AUTO },
{ "on", OVL_XINO_ON },
{}
};
static const char *ovl_xino_mode(struct ovl_config *config)
{
return ovl_parameter_xino[config->xino].name;
}
static inline int ovl_xino_def(void)
{
return ovl_xino_auto_def ? OVL_XINO_AUTO : OVL_XINO_OFF;
}
/**
* ovl_show_options
* @m: the seq_file handle
* @dentry: The dentry to query
*
* 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 *ofs = sb->s_fs_info;
size_t nr, nr_merged_lower = ofs->numlayer - ofs->numdatalayer;
const struct ovl_layer *data_layers = &ofs->layers[nr_merged_lower];
/* ofs->layers[0] is the upper layer */
seq_printf(m, ",lowerdir=%s", ofs->layers[1].name);
/* dump regular lower layers */
for (nr = 2; nr < nr_merged_lower; nr++)
seq_printf(m, ":%s", ofs->layers[nr].name);
/* dump data lower layers */
for (nr = 0; nr < ofs->numdatalayer; nr++)
seq_printf(m, "::%s", data_layers[nr].name);
if (ofs->config.upperdir) {
seq_show_option(m, "upperdir", ofs->config.upperdir);
seq_show_option(m, "workdir", ofs->config.workdir);
}
if (ofs->config.default_permissions)
seq_puts(m, ",default_permissions");
if (ofs->config.redirect_mode != ovl_redirect_mode_def())
seq_printf(m, ",redirect_dir=%s",
ovl_redirect_mode(&ofs->config));
if (ofs->config.index != ovl_index_def)
seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off");
if (!ofs->config.uuid)
seq_puts(m, ",uuid=off");
if (ofs->config.nfs_export != ovl_nfs_export_def)
seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ?
"on" : "off");
if (ofs->config.xino != ovl_xino_def() && !ovl_same_fs(ofs))
seq_printf(m, ",xino=%s", ovl_xino_mode(&ofs->config));
if (ofs->config.metacopy != ovl_metacopy_def)
seq_printf(m, ",metacopy=%s",
ofs->config.metacopy ? "on" : "off");
if (ofs->config.ovl_volatile)
seq_puts(m, ",volatile");
if (ofs->config.userxattr)
seq_puts(m, ",userxattr");
return 0;
}
static int ovl_reconfigure(struct fs_context *fc)
{
struct super_block *sb = fc->root->d_sb;
struct ovl_fs *ofs = sb->s_fs_info;
struct super_block *upper_sb;
int ret = 0;
if (!(fc->sb_flags & SB_RDONLY) && ovl_force_readonly(ofs))
return -EROFS;
if (fc->sb_flags & SB_RDONLY && !sb_rdonly(sb)) {
upper_sb = ovl_upper_mnt(ofs)->mnt_sb;
if (ovl_should_sync(ofs)) {
down_read(&upper_sb->s_umount);
ret = sync_filesystem(upper_sb);
up_read(&upper_sb->s_umount);
}
}
return ret;
}
static const struct super_operations ovl_super_operations = {
.alloc_inode = ovl_alloc_inode,
.free_inode = ovl_free_inode,
@ -450,262 +266,6 @@ static const struct super_operations ovl_super_operations = {
.show_options = ovl_show_options,
};
enum {
Opt_lowerdir,
Opt_upperdir,
Opt_workdir,
Opt_default_permissions,
Opt_redirect_dir,
Opt_index,
Opt_uuid,
Opt_nfs_export,
Opt_userxattr,
Opt_xino,
Opt_metacopy,
Opt_volatile,
};
static const struct constant_table ovl_parameter_bool[] = {
{ "on", true },
{ "off", false },
{}
};
#define fsparam_string_empty(NAME, OPT) \
__fsparam(fs_param_is_string, NAME, OPT, fs_param_can_be_empty, NULL)
static const struct fs_parameter_spec ovl_parameter_spec[] = {
fsparam_string_empty("lowerdir", Opt_lowerdir),
fsparam_string("upperdir", Opt_upperdir),
fsparam_string("workdir", Opt_workdir),
fsparam_flag("default_permissions", Opt_default_permissions),
fsparam_enum("redirect_dir", Opt_redirect_dir, ovl_parameter_redirect_dir),
fsparam_enum("index", Opt_index, ovl_parameter_bool),
fsparam_enum("uuid", Opt_uuid, ovl_parameter_bool),
fsparam_enum("nfs_export", Opt_nfs_export, ovl_parameter_bool),
fsparam_flag("userxattr", Opt_userxattr),
fsparam_enum("xino", Opt_xino, ovl_parameter_xino),
fsparam_enum("metacopy", Opt_metacopy, ovl_parameter_bool),
fsparam_flag("volatile", Opt_volatile),
{}
};
static int ovl_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
int err = 0;
struct fs_parse_result result;
struct ovl_fs *ofs = fc->s_fs_info;
struct ovl_config *config = &ofs->config;
struct ovl_fs_context *ctx = fc->fs_private;
int opt;
if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE) {
/*
* On remount overlayfs has always ignored all mount
* options no matter if malformed or not so for
* backwards compatibility we do the same here.
*/
if (fc->oldapi)
return 0;
/*
* Give us the freedom to allow changing mount options
* with the new mount api in the future. So instead of
* silently ignoring everything we report a proper
* error. This is only visible for users of the new
* mount api.
*/
return invalfc(fc, "No changes allowed in reconfigure");
}
opt = fs_parse(fc, ovl_parameter_spec, param, &result);
if (opt < 0)
return opt;
switch (opt) {
case Opt_lowerdir:
err = ovl_parse_param_lowerdir(param->string, fc);
break;
case Opt_upperdir:
fallthrough;
case Opt_workdir:
err = ovl_parse_param_upperdir(param->string, fc,
(Opt_workdir == opt));
break;
case Opt_default_permissions:
config->default_permissions = true;
break;
case Opt_redirect_dir:
config->redirect_mode = result.uint_32;
if (config->redirect_mode == OVL_REDIRECT_OFF) {
config->redirect_mode = ovl_redirect_always_follow ?
OVL_REDIRECT_FOLLOW :
OVL_REDIRECT_NOFOLLOW;
}
ctx->set.redirect = true;
break;
case Opt_index:
config->index = result.uint_32;
ctx->set.index = true;
break;
case Opt_uuid:
config->uuid = result.uint_32;
break;
case Opt_nfs_export:
config->nfs_export = result.uint_32;
ctx->set.nfs_export = true;
break;
case Opt_xino:
config->xino = result.uint_32;
break;
case Opt_metacopy:
config->metacopy = result.uint_32;
ctx->set.metacopy = true;
break;
case Opt_volatile:
config->ovl_volatile = true;
break;
case Opt_userxattr:
config->userxattr = true;
break;
default:
pr_err("unrecognized mount option \"%s\" or missing value\n",
param->key);
return -EINVAL;
}
return err;
}
static int ovl_fs_params_verify(const struct ovl_fs_context *ctx,
struct ovl_config *config)
{
struct ovl_opt_set set = ctx->set;
if (ctx->nr_data > 0 && !config->metacopy) {
pr_err("lower data-only dirs require metacopy support.\n");
return -EINVAL;
}
/* Workdir/index are useless in non-upper mount */
if (!config->upperdir) {
if (config->workdir) {
pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n",
config->workdir);
kfree(config->workdir);
config->workdir = NULL;
}
if (config->index && set.index) {
pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n");
set.index = false;
}
config->index = false;
}
if (!config->upperdir && config->ovl_volatile) {
pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n");
config->ovl_volatile = false;
}
/*
* This is to make the logic below simpler. It doesn't make any other
* difference, since redirect_dir=on is only used for upper.
*/
if (!config->upperdir && config->redirect_mode == OVL_REDIRECT_FOLLOW)
config->redirect_mode = OVL_REDIRECT_ON;
/* Resolve metacopy -> redirect_dir dependency */
if (config->metacopy && config->redirect_mode != OVL_REDIRECT_ON) {
if (set.metacopy && set.redirect) {
pr_err("conflicting options: metacopy=on,redirect_dir=%s\n",
ovl_redirect_mode(config));
return -EINVAL;
}
if (set.redirect) {
/*
* There was an explicit redirect_dir=... that resulted
* in this conflict.
*/
pr_info("disabling metacopy due to redirect_dir=%s\n",
ovl_redirect_mode(config));
config->metacopy = false;
} else {
/* Automatically enable redirect otherwise. */
config->redirect_mode = OVL_REDIRECT_ON;
}
}
/* Resolve nfs_export -> index dependency */
if (config->nfs_export && !config->index) {
if (!config->upperdir &&
config->redirect_mode != OVL_REDIRECT_NOFOLLOW) {
pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n");
config->nfs_export = false;
} else if (set.nfs_export && set.index) {
pr_err("conflicting options: nfs_export=on,index=off\n");
return -EINVAL;
} else if (set.index) {
/*
* There was an explicit index=off that resulted
* in this conflict.
*/
pr_info("disabling nfs_export due to index=off\n");
config->nfs_export = false;
} else {
/* Automatically enable index otherwise. */
config->index = true;
}
}
/* Resolve nfs_export -> !metacopy dependency */
if (config->nfs_export && config->metacopy) {
if (set.nfs_export && set.metacopy) {
pr_err("conflicting options: nfs_export=on,metacopy=on\n");
return -EINVAL;
}
if (set.metacopy) {
/*
* There was an explicit metacopy=on that resulted
* in this conflict.
*/
pr_info("disabling nfs_export due to metacopy=on\n");
config->nfs_export = false;
} else {
/*
* There was an explicit nfs_export=on that resulted
* in this conflict.
*/
pr_info("disabling metacopy due to nfs_export=on\n");
config->metacopy = false;
}
}
/* Resolve userxattr -> !redirect && !metacopy dependency */
if (config->userxattr) {
if (set.redirect &&
config->redirect_mode != OVL_REDIRECT_NOFOLLOW) {
pr_err("conflicting options: userxattr,redirect_dir=%s\n",
ovl_redirect_mode(config));
return -EINVAL;
}
if (config->metacopy && set.metacopy) {
pr_err("conflicting options: userxattr,metacopy=on\n");
return -EINVAL;
}
/*
* Silently disable default setting of redirect and metacopy.
* This shall be the default in the future as well: these
* options must be explicitly enabled if used together with
* userxattr.
*/
config->redirect_mode = OVL_REDIRECT_NOFOLLOW;
config->metacopy = false;
}
return 0;
}
#define OVL_WORKDIR_NAME "work"
#define OVL_INDEXDIR_NAME "index"
@ -1758,7 +1318,7 @@ static struct dentry *ovl_get_root(struct super_block *sb,
return root;
}
static int ovl_fill_super(struct super_block *sb, struct fs_context *fc)
int ovl_fill_super(struct super_block *sb, struct fs_context *fc)
{
struct ovl_fs *ofs = sb->s_fs_info;
struct ovl_fs_context *ctx = fc->fs_private;
@ -1919,92 +1479,6 @@ out_err:
return err;
}
static int ovl_get_tree(struct fs_context *fc)
{
return get_tree_nodev(fc, ovl_fill_super);
}
static inline void ovl_fs_context_free(struct ovl_fs_context *ctx)
{
ovl_parse_param_drop_lowerdir(ctx);
path_put(&ctx->upper);
path_put(&ctx->work);
kfree(ctx->lower);
kfree(ctx);
}
static void ovl_free(struct fs_context *fc)
{
struct ovl_fs *ofs = fc->s_fs_info;
struct ovl_fs_context *ctx = fc->fs_private;
/*
* ofs is stored in the fs_context when it is initialized.
* ofs is transferred to the superblock on a successful mount,
* but if an error occurs before the transfer we have to free
* it here.
*/
if (ofs)
ovl_free_fs(ofs);
if (ctx)
ovl_fs_context_free(ctx);
}
static const struct fs_context_operations ovl_context_ops = {
.parse_param = ovl_parse_param,
.get_tree = ovl_get_tree,
.reconfigure = ovl_reconfigure,
.free = ovl_free,
};
/*
* This is called during fsopen() and will record the user namespace of
* the caller in fc->user_ns since we've raised FS_USERNS_MOUNT. We'll
* need it when we actually create the superblock to verify that the
* process creating the superblock is in the same user namespace as
* process that called fsopen().
*/
static int ovl_init_fs_context(struct fs_context *fc)
{
struct ovl_fs_context *ctx;
struct ovl_fs *ofs;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
if (!ctx)
return -ENOMEM;
/*
* By default we allocate for three lower layers. It's likely
* that it'll cover most users.
*/
ctx->lower = kmalloc_array(3, sizeof(*ctx->lower), GFP_KERNEL_ACCOUNT);
if (!ctx->lower)
goto out_err;
ctx->capacity = 3;
ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL);
if (!ofs)
goto out_err;
ofs->config.redirect_mode = ovl_redirect_mode_def();
ofs->config.index = ovl_index_def;
ofs->config.uuid = true;
ofs->config.nfs_export = ovl_nfs_export_def;
ofs->config.xino = ovl_xino_def();
ofs->config.metacopy = ovl_metacopy_def;
fc->s_fs_info = ofs;
fc->fs_private = ctx;
fc->ops = &ovl_context_ops;
return 0;
out_err:
ovl_fs_context_free(ctx);
return -ENOMEM;
}
static struct file_system_type ovl_fs_type = {
.owner = THIS_MODULE,
.name = "overlay",