On Mon, Jun 26, 2023 at 4:40 PM Amir Goldstein <amir73il@xxxxxxxxx> wrote:
>
> On Mon, Jun 26, 2023 at 1:23 PM Christian Brauner <brauner@xxxxxxxxxx> wrote:
> >
> > 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@xxxxxxxxxx>
> > ---
> >
>
> Thank you for this cleanup!
>
> Alex,
>
> I took the liberty to resolve the conflicts with your branch, see:
>
> https://github.com/amir73il/linux/commits/overlay-verity
Thanks, I took a look at this and it seems good. Updated my branch to this too.
> Thanks,
> Amir.
>
> > ---
> > fs/overlayfs/overlayfs.h | 41 +---
> > fs/overlayfs/params.c | 532 ++++++++++++++++++++++++++++++++++++++++++++++-
> > fs/overlayfs/params.h | 42 ++++
> > fs/overlayfs/super.c | 530 +---------------------------------------------
> > 4 files changed, 581 insertions(+), 564 deletions(-)
> >
> > diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
> > index 5b6ac03af192..ece77737df8d 100644
> > --- a/fs/overlayfs/overlayfs.h
> > +++ b/fs/overlayfs/overlayfs.h
> > @@ -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:
> > @@ -134,6 +126,12 @@ struct ovl_fh {
> > #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
> > offsetof(struct ovl_fb, fid))
> >
> > +/* 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);
> > +}
> > +
> > extern const char *const ovl_xattr_table[][2];
> > static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
> > {
> > @@ -367,30 +365,6 @@ 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);
> > @@ -790,3 +764,6 @@ 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);
> > diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c
> > index d17d6b483dd0..b8c2f6056a9a 100644
> > --- a/fs/overlayfs/params.c
> > +++ b/fs/overlayfs/params.c
> > @@ -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 },
> > + {}
> > +};
> > +
> > +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 @@ int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc)
> > /* 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;
> > +}
> > diff --git a/fs/overlayfs/params.h b/fs/overlayfs/params.h
> > new file mode 100644
> > index 000000000000..8750da68ab2a
> > --- /dev/null
> > +++ b/fs/overlayfs/params.h
> > @@ -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);
> > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> > index c14c52560fd6..5b069f1a1e44 100644
> > --- a/fs/overlayfs/super.c
> > +++ b/fs/overlayfs/super.c
> > @@ -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@xxxxxxxxxx>");
> > 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 @@ static int ovl_fill_super(struct super_block *sb, struct fs_context *fc)
> > 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",
> >
> > ---
> > base-commit: 62149a745eee03194f025021640c80b84353089b
> > change-id: 20230625-fs-overlayfs-mount-api-param-993d1caa86ff
> >
>
--
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Alexander Larsson Red Hat, Inc
alexl@xxxxxxxxxx alexander.larsson@xxxxxxxxx
