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>
---
---
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
