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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-12 14:08:19 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-12 14:08:19 -0700
commit7b47a9e7c8f672b6fb0b77fca11a63a8a77f5a91 (patch)
treecf05645120ba2323c36acefdea6e62addf320f8c /kernel/cgroup/cgroup.c
parentdbc2fba3fc46084f502aec53183995a632998dcd (diff)
parentc99c2171fc61476afac0dfb59fb2c447a01fb1e0 (diff)
downloadlinux-7b47a9e7c8f672b6fb0b77fca11a63a8a77f5a91.tar.bz2
Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs mount infrastructure updates from Al Viro: "The rest of core infrastructure; no new syscalls in that pile, but the old parts are switched to new infrastructure. At that point conversions of individual filesystems can happen independently; some are done here (afs, cgroup, procfs, etc.), there's also a large series outside of that pile dealing with NFS (quite a bit of option-parsing stuff is getting used there - it's one of the most convoluted filesystems in terms of mount-related logics), but NFS bits are the next cycle fodder. It got seriously simplified since the last cycle; documentation is probably the weakest bit at the moment - I considered dropping the commit introducing Documentation/filesystems/mount_api.txt (cutting the size increase by quarter ;-), but decided that it would be better to fix it up after -rc1 instead. That pile allows to do followup work in independent branches, which should make life much easier for the next cycle. fs/super.c size increase is unpleasant; there's a followup series that allows to shrink it considerably, but I decided to leave that until the next cycle" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits) afs: Use fs_context to pass parameters over automount afs: Add fs_context support vfs: Add some logging to the core users of the fs_context log vfs: Implement logging through fs_context vfs: Provide documentation for new mount API vfs: Remove kern_mount_data() hugetlbfs: Convert to fs_context cpuset: Use fs_context kernfs, sysfs, cgroup, intel_rdt: Support fs_context cgroup: store a reference to cgroup_ns into cgroup_fs_context cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper cgroup_do_mount(): massage calling conventions cgroup: stash cgroup_root reference into cgroup_fs_context cgroup2: switch to option-by-option parsing cgroup1: switch to option-by-option parsing cgroup: take options parsing into ->parse_monolithic() cgroup: fold cgroup1_mount() into cgroup1_get_tree() cgroup: start switching to fs_context ipc: Convert mqueue fs to fs_context proc: Add fs_context support to procfs ...
Diffstat (limited to 'kernel/cgroup/cgroup.c')
-rw-r--r--kernel/cgroup/cgroup.c223
1 files changed, 133 insertions, 90 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index eef24a25bda7..3f2b4bde0f9c 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -54,6 +54,7 @@
#include <linux/proc_ns.h>
#include <linux/nsproxy.h>
#include <linux/file.h>
+#include <linux/fs_parser.h>
#include <linux/sched/cputime.h>
#include <linux/psi.h>
#include <net/sock.h>
@@ -1772,26 +1773,37 @@ int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
return len;
}
-static int parse_cgroup_root_flags(char *data, unsigned int *root_flags)
-{
- char *token;
+enum cgroup2_param {
+ Opt_nsdelegate,
+ nr__cgroup2_params
+};
- *root_flags = 0;
+static const struct fs_parameter_spec cgroup2_param_specs[] = {
+ fsparam_flag ("nsdelegate", Opt_nsdelegate),
+ {}
+};
- if (!data || *data == '\0')
- return 0;
+static const struct fs_parameter_description cgroup2_fs_parameters = {
+ .name = "cgroup2",
+ .specs = cgroup2_param_specs,
+};
- while ((token = strsep(&data, ",")) != NULL) {
- if (!strcmp(token, "nsdelegate")) {
- *root_flags |= CGRP_ROOT_NS_DELEGATE;
- continue;
- }
+static int cgroup2_parse_param(struct fs_context *fc, struct fs_parameter *param)
+{
+ struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+ struct fs_parse_result result;
+ int opt;
- pr_err("cgroup2: unknown option \"%s\"\n", token);
- return -EINVAL;
- }
+ opt = fs_parse(fc, &cgroup2_fs_parameters, param, &result);
+ if (opt < 0)
+ return opt;
- return 0;
+ switch (opt) {
+ case Opt_nsdelegate:
+ ctx->flags |= CGRP_ROOT_NS_DELEGATE;
+ return 0;
+ }
+ return -EINVAL;
}
static void apply_cgroup_root_flags(unsigned int root_flags)
@@ -1811,16 +1823,11 @@ static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root
return 0;
}
-static int cgroup_remount(struct kernfs_root *kf_root, int *flags, char *data)
+static int cgroup_reconfigure(struct fs_context *fc)
{
- unsigned int root_flags;
- int ret;
-
- ret = parse_cgroup_root_flags(data, &root_flags);
- if (ret)
- return ret;
+ struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
- apply_cgroup_root_flags(root_flags);
+ apply_cgroup_root_flags(ctx->flags);
return 0;
}
@@ -1908,8 +1915,9 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp)
INIT_WORK(&cgrp->release_agent_work, cgroup1_release_agent);
}
-void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts)
+void init_cgroup_root(struct cgroup_fs_context *ctx)
{
+ struct cgroup_root *root = ctx->root;
struct cgroup *cgrp = &root->cgrp;
INIT_LIST_HEAD(&root->root_list);
@@ -1918,12 +1926,12 @@ void init_cgroup_root(struct cgroup_root *root, struct cgroup_sb_opts *opts)
init_cgroup_housekeeping(cgrp);
idr_init(&root->cgroup_idr);
- root->flags = opts->flags;
- if (opts->release_agent)
- strscpy(root->release_agent_path, opts->release_agent, PATH_MAX);
- if (opts->name)
- strscpy(root->name, opts->name, MAX_CGROUP_ROOT_NAMELEN);
- if (opts->cpuset_clone_children)
+ root->flags = ctx->flags;
+ if (ctx->release_agent)
+ strscpy(root->release_agent_path, ctx->release_agent, PATH_MAX);
+ if (ctx->name)
+ strscpy(root->name, ctx->name, MAX_CGROUP_ROOT_NAMELEN);
+ if (ctx->cpuset_clone_children)
set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags);
}
@@ -2028,60 +2036,104 @@ out:
return ret;
}
-struct dentry *cgroup_do_mount(struct file_system_type *fs_type, int flags,
- struct cgroup_root *root, unsigned long magic,
- struct cgroup_namespace *ns)
+int cgroup_do_get_tree(struct fs_context *fc)
{
- struct dentry *dentry;
- bool new_sb = false;
+ struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+ int ret;
- dentry = kernfs_mount(fs_type, flags, root->kf_root, magic, &new_sb);
+ ctx->kfc.root = ctx->root->kf_root;
+ if (fc->fs_type == &cgroup2_fs_type)
+ ctx->kfc.magic = CGROUP2_SUPER_MAGIC;
+ else
+ ctx->kfc.magic = CGROUP_SUPER_MAGIC;
+ ret = kernfs_get_tree(fc);
/*
* In non-init cgroup namespace, instead of root cgroup's dentry,
* we return the dentry corresponding to the cgroupns->root_cgrp.
*/
- if (!IS_ERR(dentry) && ns != &init_cgroup_ns) {
+ if (!ret && ctx->ns != &init_cgroup_ns) {
struct dentry *nsdentry;
- struct super_block *sb = dentry->d_sb;
+ struct super_block *sb = fc->root->d_sb;
struct cgroup *cgrp;
mutex_lock(&cgroup_mutex);
spin_lock_irq(&css_set_lock);
- cgrp = cset_cgroup_from_root(ns->root_cset, root);
+ cgrp = cset_cgroup_from_root(ctx->ns->root_cset, ctx->root);
spin_unlock_irq(&css_set_lock);
mutex_unlock(&cgroup_mutex);
nsdentry = kernfs_node_dentry(cgrp->kn, sb);
- dput(dentry);
- if (IS_ERR(nsdentry))
+ dput(fc->root);
+ fc->root = nsdentry;
+ if (IS_ERR(nsdentry)) {
+ ret = PTR_ERR(nsdentry);
deactivate_locked_super(sb);
- dentry = nsdentry;
+ }
}
- if (!new_sb)
- cgroup_put(&root->cgrp);
+ if (!ctx->kfc.new_sb_created)
+ cgroup_put(&ctx->root->cgrp);
- return dentry;
+ return ret;
}
-static struct dentry *cgroup_mount(struct file_system_type *fs_type,
- int flags, const char *unused_dev_name,
- void *data)
+/*
+ * Destroy a cgroup filesystem context.
+ */
+static void cgroup_fs_context_free(struct fs_context *fc)
{
- struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
- struct dentry *dentry;
+ struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
+
+ kfree(ctx->name);
+ kfree(ctx->release_agent);
+ put_cgroup_ns(ctx->ns);
+ kernfs_free_fs_context(fc);
+ kfree(ctx);
+}
+
+static int cgroup_get_tree(struct fs_context *fc)
+{
+ struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
int ret;
- get_cgroup_ns(ns);
+ cgrp_dfl_visible = true;
+ cgroup_get_live(&cgrp_dfl_root.cgrp);
+ ctx->root = &cgrp_dfl_root;
- /* Check if the caller has permission to mount. */
- if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) {
- put_cgroup_ns(ns);
- return ERR_PTR(-EPERM);
- }
+ ret = cgroup_do_get_tree(fc);
+ if (!ret)
+ apply_cgroup_root_flags(ctx->flags);
+ return ret;
+}
+
+static const struct fs_context_operations cgroup_fs_context_ops = {
+ .free = cgroup_fs_context_free,
+ .parse_param = cgroup2_parse_param,
+ .get_tree = cgroup_get_tree,
+ .reconfigure = cgroup_reconfigure,
+};
+
+static const struct fs_context_operations cgroup1_fs_context_ops = {
+ .free = cgroup_fs_context_free,
+ .parse_param = cgroup1_parse_param,
+ .get_tree = cgroup1_get_tree,
+ .reconfigure = cgroup1_reconfigure,
+};
+
+/*
+ * Initialise the cgroup filesystem creation/reconfiguration context. Notably,
+ * we select the namespace we're going to use.
+ */
+static int cgroup_init_fs_context(struct fs_context *fc)
+{
+ struct cgroup_fs_context *ctx;
+
+ ctx = kzalloc(sizeof(struct cgroup_fs_context), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
/*
* The first time anyone tries to mount a cgroup, enable the list
@@ -2090,29 +2142,18 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
if (!use_task_css_set_links)
cgroup_enable_task_cg_lists();
- if (fs_type == &cgroup2_fs_type) {
- unsigned int root_flags;
-
- ret = parse_cgroup_root_flags(data, &root_flags);
- if (ret) {
- put_cgroup_ns(ns);
- return ERR_PTR(ret);
- }
-
- cgrp_dfl_visible = true;
- cgroup_get_live(&cgrp_dfl_root.cgrp);
-
- dentry = cgroup_do_mount(&cgroup2_fs_type, flags, &cgrp_dfl_root,
- CGROUP2_SUPER_MAGIC, ns);
- if (!IS_ERR(dentry))
- apply_cgroup_root_flags(root_flags);
- } else {
- dentry = cgroup1_mount(&cgroup_fs_type, flags, data,
- CGROUP_SUPER_MAGIC, ns);
- }
-
- put_cgroup_ns(ns);
- return dentry;
+ ctx->ns = current->nsproxy->cgroup_ns;
+ get_cgroup_ns(ctx->ns);
+ fc->fs_private = &ctx->kfc;
+ if (fc->fs_type == &cgroup2_fs_type)
+ fc->ops = &cgroup_fs_context_ops;
+ else
+ fc->ops = &cgroup1_fs_context_ops;
+ if (fc->user_ns)
+ put_user_ns(fc->user_ns);
+ fc->user_ns = get_user_ns(ctx->ns->user_ns);
+ fc->global = true;
+ return 0;
}
static void cgroup_kill_sb(struct super_block *sb)
@@ -2135,17 +2176,19 @@ static void cgroup_kill_sb(struct super_block *sb)
}
struct file_system_type cgroup_fs_type = {
- .name = "cgroup",
- .mount = cgroup_mount,
- .kill_sb = cgroup_kill_sb,
- .fs_flags = FS_USERNS_MOUNT,
+ .name = "cgroup",
+ .init_fs_context = cgroup_init_fs_context,
+ .parameters = &cgroup1_fs_parameters,
+ .kill_sb = cgroup_kill_sb,
+ .fs_flags = FS_USERNS_MOUNT,
};
static struct file_system_type cgroup2_fs_type = {
- .name = "cgroup2",
- .mount = cgroup_mount,
- .kill_sb = cgroup_kill_sb,
- .fs_flags = FS_USERNS_MOUNT,
+ .name = "cgroup2",
+ .init_fs_context = cgroup_init_fs_context,
+ .parameters = &cgroup2_fs_parameters,
+ .kill_sb = cgroup_kill_sb,
+ .fs_flags = FS_USERNS_MOUNT,
};
int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
@@ -5280,7 +5323,6 @@ int cgroup_rmdir(struct kernfs_node *kn)
static struct kernfs_syscall_ops cgroup_kf_syscall_ops = {
.show_options = cgroup_show_options,
- .remount_fs = cgroup_remount,
.mkdir = cgroup_mkdir,
.rmdir = cgroup_rmdir,
.show_path = cgroup_show_path,
@@ -5347,11 +5389,12 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early)
*/
int __init cgroup_init_early(void)
{
- static struct cgroup_sb_opts __initdata opts;
+ static struct cgroup_fs_context __initdata ctx;
struct cgroup_subsys *ss;
int i;
- init_cgroup_root(&cgrp_dfl_root, &opts);
+ ctx.root = &cgrp_dfl_root;
+ init_cgroup_root(&ctx);
cgrp_dfl_root.cgrp.self.flags |= CSS_NO_REF;
RCU_INIT_POINTER(init_task.cgroups, &init_css_set);