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-rw-r--r--fs/tracefs/event_inode.c175
-rw-r--r--fs/tracefs/inode.c1
-rw-r--r--fs/tracefs/internal.h9
3 files changed, 132 insertions, 53 deletions
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 56d1741fe0..a878cea70f 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -35,6 +35,18 @@ static DEFINE_MUTEX(eventfs_mutex);
/* Choose something "unique" ;-) */
#define EVENTFS_FILE_INODE_INO 0x12c4e37
+struct eventfs_root_inode {
+ struct eventfs_inode ei;
+ struct inode *parent_inode;
+ struct dentry *events_dir;
+};
+
+static struct eventfs_root_inode *get_root_inode(struct eventfs_inode *ei)
+{
+ WARN_ON_ONCE(!ei->is_events);
+ return container_of(ei, struct eventfs_root_inode, ei);
+}
+
/* Just try to make something consistent and unique */
static int eventfs_dir_ino(struct eventfs_inode *ei)
{
@@ -57,11 +69,25 @@ enum {
EVENTFS_SAVE_MODE = BIT(16),
EVENTFS_SAVE_UID = BIT(17),
EVENTFS_SAVE_GID = BIT(18),
- EVENTFS_TOPLEVEL = BIT(19),
};
#define EVENTFS_MODE_MASK (EVENTFS_SAVE_MODE - 1)
+static void free_ei_rcu(struct rcu_head *rcu)
+{
+ struct eventfs_inode *ei = container_of(rcu, struct eventfs_inode, rcu);
+ struct eventfs_root_inode *rei;
+
+ kfree(ei->entry_attrs);
+ kfree_const(ei->name);
+ if (ei->is_events) {
+ rei = get_root_inode(ei);
+ kfree(rei);
+ } else {
+ kfree(ei);
+ }
+}
+
/*
* eventfs_inode reference count management.
*
@@ -73,12 +99,17 @@ enum {
static void release_ei(struct kref *ref)
{
struct eventfs_inode *ei = container_of(ref, struct eventfs_inode, kref);
+ const struct eventfs_entry *entry;
WARN_ON_ONCE(!ei->is_freed);
- kfree(ei->entry_attrs);
- kfree_const(ei->name);
- kfree_rcu(ei, rcu);
+ for (int i = 0; i < ei->nr_entries; i++) {
+ entry = &ei->entries[i];
+ if (entry->release)
+ entry->release(entry->name, ei->data);
+ }
+
+ call_rcu(&ei->rcu, free_ei_rcu);
}
static inline void put_ei(struct eventfs_inode *ei)
@@ -95,6 +126,18 @@ static inline void free_ei(struct eventfs_inode *ei)
}
}
+/*
+ * Called when creation of an ei fails, do not call release() functions.
+ */
+static inline void cleanup_ei(struct eventfs_inode *ei)
+{
+ if (ei) {
+ /* Set nr_entries to 0 to prevent release() function being called */
+ ei->nr_entries = 0;
+ free_ei(ei);
+ }
+}
+
static inline struct eventfs_inode *get_ei(struct eventfs_inode *ei)
{
if (ei)
@@ -182,18 +225,25 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
return ret;
}
-static void update_top_events_attr(struct eventfs_inode *ei, struct super_block *sb)
+static void update_events_attr(struct eventfs_inode *ei, struct super_block *sb)
{
- struct inode *root;
+ struct eventfs_root_inode *rei;
+ struct inode *parent;
- /* Only update if the "events" was on the top level */
- if (!ei || !(ei->attr.mode & EVENTFS_TOPLEVEL))
- return;
+ rei = get_root_inode(ei);
- /* Get the tracefs root inode. */
- root = d_inode(sb->s_root);
- ei->attr.uid = root->i_uid;
- ei->attr.gid = root->i_gid;
+ /* Use the parent inode permissions unless root set its permissions */
+ parent = rei->parent_inode;
+
+ if (rei->ei.attr.mode & EVENTFS_SAVE_UID)
+ ei->attr.uid = rei->ei.attr.uid;
+ else
+ ei->attr.uid = parent->i_uid;
+
+ if (rei->ei.attr.mode & EVENTFS_SAVE_GID)
+ ei->attr.gid = rei->ei.attr.gid;
+ else
+ ei->attr.gid = parent->i_gid;
}
static void set_top_events_ownership(struct inode *inode)
@@ -202,10 +252,10 @@ static void set_top_events_ownership(struct inode *inode)
struct eventfs_inode *ei = ti->private;
/* The top events directory doesn't get automatically updated */
- if (!ei || !ei->is_events || !(ei->attr.mode & EVENTFS_TOPLEVEL))
+ if (!ei || !ei->is_events)
return;
- update_top_events_attr(ei, inode->i_sb);
+ update_events_attr(ei, inode->i_sb);
if (!(ei->attr.mode & EVENTFS_SAVE_UID))
inode->i_uid = ei->attr.uid;
@@ -234,7 +284,7 @@ static int eventfs_permission(struct mnt_idmap *idmap,
return generic_permission(idmap, inode, mask);
}
-static const struct inode_operations eventfs_root_dir_inode_operations = {
+static const struct inode_operations eventfs_dir_inode_operations = {
.lookup = eventfs_root_lookup,
.setattr = eventfs_set_attr,
.getattr = eventfs_get_attr,
@@ -302,7 +352,7 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
// Walk upwards until you find the events inode
} while (!ei->is_events);
- update_top_events_attr(ei, dentry->d_sb);
+ update_events_attr(ei, dentry->d_sb);
return ei;
}
@@ -334,6 +384,7 @@ static void update_inode_attr(struct dentry *dentry, struct inode *inode,
/**
* lookup_file - look up a file in the tracefs filesystem
+ * @parent_ei: Pointer to the eventfs_inode that represents parent of the file
* @dentry: the dentry to look up
* @mode: the permission that the file should have.
* @attr: saved attributes changed by user
@@ -387,6 +438,7 @@ static struct dentry *lookup_file(struct eventfs_inode *parent_ei,
/**
* lookup_dir_entry - look up a dir in the tracefs filesystem
* @dentry: the directory to look up
+ * @pei: Pointer to the parent eventfs_inode if available
* @ei: the eventfs_inode that represents the directory to create
*
* This function will look up a dentry for a directory represented by
@@ -406,7 +458,7 @@ static struct dentry *lookup_dir_entry(struct dentry *dentry,
update_inode_attr(dentry, inode, &ei->attr,
S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
- inode->i_op = &eventfs_root_dir_inode_operations;
+ inode->i_op = &eventfs_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
/* All directories will have the same inode number */
@@ -423,19 +475,43 @@ static struct dentry *lookup_dir_entry(struct dentry *dentry,
return NULL;
}
+static inline struct eventfs_inode *init_ei(struct eventfs_inode *ei, const char *name)
+{
+ ei->name = kstrdup_const(name, GFP_KERNEL);
+ if (!ei->name)
+ return NULL;
+ kref_init(&ei->kref);
+ return ei;
+}
+
static inline struct eventfs_inode *alloc_ei(const char *name)
{
struct eventfs_inode *ei = kzalloc(sizeof(*ei), GFP_KERNEL);
+ struct eventfs_inode *result;
if (!ei)
return NULL;
- ei->name = kstrdup_const(name, GFP_KERNEL);
- if (!ei->name) {
+ result = init_ei(ei, name);
+ if (!result)
kfree(ei);
+
+ return result;
+}
+
+static inline struct eventfs_inode *alloc_root_ei(const char *name)
+{
+ struct eventfs_root_inode *rei = kzalloc(sizeof(*rei), GFP_KERNEL);
+ struct eventfs_inode *ei;
+
+ if (!rei)
return NULL;
- }
- kref_init(&ei->kref);
+
+ rei->ei.is_events = 1;
+ ei = init_ei(&rei->ei, name);
+ if (!ei)
+ kfree(rei);
+
return ei;
}
@@ -452,16 +528,20 @@ void eventfs_d_release(struct dentry *dentry)
/**
* lookup_file_dentry - create a dentry for a file of an eventfs_inode
+ * @dentry: The parent dentry under which the new file's dentry will be created
* @ei: the eventfs_inode that the file will be created under
* @idx: the index into the entry_attrs[] of the @ei
- * @parent: The parent dentry of the created file.
- * @name: The name of the file to create
* @mode: The mode of the file.
* @data: The data to use to set the inode of the file with on open()
* @fops: The fops of the file to be created.
*
- * Create a dentry for a file of an eventfs_inode @ei and place it into the
- * address located at @e_dentry.
+ * This function creates a dentry for a file associated with an
+ * eventfs_inode @ei. It uses the entry attributes specified by @idx,
+ * if available. The file will have the specified @mode and its inode will be
+ * set up with @data upon open. The file operations will be set to @fops.
+ *
+ * Return: Returns a pointer to the newly created file's dentry or an error
+ * pointer.
*/
static struct dentry *
lookup_file_dentry(struct dentry *dentry,
@@ -498,7 +578,7 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
struct dentry *result = NULL;
ti = get_tracefs(dir);
- if (!(ti->flags & TRACEFS_EVENT_INODE))
+ if (WARN_ON_ONCE(!(ti->flags & TRACEFS_EVENT_INODE)))
return ERR_PTR(-EIO);
mutex_lock(&eventfs_mutex);
@@ -510,7 +590,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
list_for_each_entry(ei_child, &ei->children, list) {
if (strcmp(ei_child->name, name) != 0)
continue;
- if (ei_child->is_freed)
+ /* A child is freed and removed from the list at the same time */
+ if (WARN_ON_ONCE(ei_child->is_freed))
goto out;
result = lookup_dir_entry(dentry, ei, ei_child);
goto out;
@@ -701,7 +782,7 @@ struct eventfs_inode *eventfs_create_dir(const char *name, struct eventfs_inode
/* Was the parent freed? */
if (list_empty(&ei->list)) {
- free_ei(ei);
+ cleanup_ei(ei);
ei = NULL;
}
return ei;
@@ -724,6 +805,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
int size, void *data)
{
struct dentry *dentry = tracefs_start_creating(name, parent);
+ struct eventfs_root_inode *rei;
struct eventfs_inode *ei;
struct tracefs_inode *ti;
struct inode *inode;
@@ -736,7 +818,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
if (IS_ERR(dentry))
return ERR_CAST(dentry);
- ei = alloc_ei(name);
+ ei = alloc_root_ei(name);
if (!ei)
goto fail;
@@ -745,39 +827,38 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
goto fail;
// Note: we have a ref to the dentry from tracefs_start_creating()
- ei->events_dir = dentry;
+ rei = get_root_inode(ei);
+ rei->events_dir = dentry;
+ rei->parent_inode = d_inode(dentry->d_sb->s_root);
+
ei->entries = entries;
ei->nr_entries = size;
- ei->is_events = 1;
ei->data = data;
/* Save the ownership of this directory */
uid = d_inode(dentry->d_parent)->i_uid;
gid = d_inode(dentry->d_parent)->i_gid;
- /*
- * If the events directory is of the top instance, then parent
- * is NULL. Set the attr.mode to reflect this and its permissions will
- * default to the tracefs root dentry.
- */
- if (!parent)
- ei->attr.mode = EVENTFS_TOPLEVEL;
-
- /* This is used as the default ownership of the files and directories */
ei->attr.uid = uid;
ei->attr.gid = gid;
+ /*
+ * When the "events" directory is created, it takes on the
+ * permissions of its parent. But can be reset on remount.
+ */
+ ei->attr.mode |= EVENTFS_SAVE_UID | EVENTFS_SAVE_GID;
+
INIT_LIST_HEAD(&ei->children);
INIT_LIST_HEAD(&ei->list);
ti = get_tracefs(inode);
- ti->flags |= TRACEFS_EVENT_INODE | TRACEFS_EVENT_TOP_INODE;
+ ti->flags |= TRACEFS_EVENT_INODE;
ti->private = ei;
inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
inode->i_uid = uid;
inode->i_gid = gid;
- inode->i_op = &eventfs_root_dir_inode_operations;
+ inode->i_op = &eventfs_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
dentry->d_fsdata = get_ei(ei);
@@ -800,7 +881,7 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
return ei;
fail:
- free_ei(ei);
+ cleanup_ei(ei);
tracefs_failed_creating(dentry);
return ERR_PTR(-ENOMEM);
}
@@ -859,13 +940,15 @@ void eventfs_remove_dir(struct eventfs_inode *ei)
*/
void eventfs_remove_events_dir(struct eventfs_inode *ei)
{
+ struct eventfs_root_inode *rei;
struct dentry *dentry;
- dentry = ei->events_dir;
+ rei = get_root_inode(ei);
+ dentry = rei->events_dir;
if (!dentry)
return;
- ei->events_dir = NULL;
+ rei->events_dir = NULL;
eventfs_remove_dir(ei);
/*
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index e30b74228e..417c840e64 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -817,7 +817,6 @@ static int __init tracefs_init(void)
tracefs_inode_cachep = kmem_cache_create("tracefs_inode_cache",
sizeof(struct tracefs_inode),
0, (SLAB_RECLAIM_ACCOUNT|
- SLAB_MEM_SPREAD|
SLAB_ACCOUNT),
init_once);
if (!tracefs_inode_cachep)
diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h
index 824cbe8367..f704d83483 100644
--- a/fs/tracefs/internal.h
+++ b/fs/tracefs/internal.h
@@ -4,10 +4,9 @@
enum {
TRACEFS_EVENT_INODE = BIT(1),
- TRACEFS_EVENT_TOP_INODE = BIT(2),
- TRACEFS_GID_PERM_SET = BIT(3),
- TRACEFS_UID_PERM_SET = BIT(4),
- TRACEFS_INSTANCE_INODE = BIT(5),
+ TRACEFS_GID_PERM_SET = BIT(2),
+ TRACEFS_UID_PERM_SET = BIT(3),
+ TRACEFS_INSTANCE_INODE = BIT(4),
};
struct tracefs_inode {
@@ -40,7 +39,6 @@ struct eventfs_attr {
* @children: link list into the child eventfs_inode
* @entries: the array of entries representing the files in the directory
* @name: the name of the directory to create
- * @events_dir: the dentry of the events directory
* @entry_attrs: Saved mode and ownership of the @d_children
* @data: The private data to pass to the callbacks
* @attr: Saved mode and ownership of eventfs_inode itself
@@ -58,7 +56,6 @@ struct eventfs_inode {
struct list_head children;
const struct eventfs_entry *entries;
const char *name;
- struct dentry *events_dir;
struct eventfs_attr *entry_attrs;
void *data;
struct eventfs_attr attr;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-18 15:45:07 +0000