@@ -40,6 +40,15 @@ static DEFINE_MUTEX(eventfs_mutex);
*/
DEFINE_STATIC_SRCU(eventfs_srcu);
+/* Mode is unsigned short, use the upper bits for flags */
+enum {
+ EVENTFS_SAVE_MODE = BIT(16),
+ EVENTFS_SAVE_UID = BIT(17),
+ EVENTFS_SAVE_GID = BIT(18),
+};
+
+#define EVENTFS_MODE_MASK (EVENTFS_SAVE_MODE - 1)
+
static struct dentry *eventfs_root_lookup(struct inode *dir,
struct dentry *dentry,
unsigned int flags);
@@ -47,8 +56,89 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file);
static int dcache_readdir_wrapper(struct file *file, struct dir_context *ctx);
static int eventfs_release(struct inode *inode, struct file *file);
+static void update_attr(struct eventfs_attr *attr, struct iattr *iattr)
+{
+ unsigned int ia_valid = iattr->ia_valid;
+
+ if (ia_valid & ATTR_MODE) {
+ attr->mode = (attr->mode & ~EVENTFS_MODE_MASK) |
+ (iattr->ia_mode & EVENTFS_MODE_MASK) |
+ EVENTFS_SAVE_MODE;
+ }
+ if (ia_valid & ATTR_UID) {
+ attr->mode |= EVENTFS_SAVE_UID;
+ attr->uid = iattr->ia_uid;
+ }
+ if (ia_valid & ATTR_GID) {
+ attr->mode |= EVENTFS_SAVE_GID;
+ attr->gid = iattr->ia_gid;
+ }
+}
+
+static int eventfs_set_attr(struct mnt_idmap *idmap, struct dentry *dentry,
+ struct iattr *iattr)
+{
+ const struct eventfs_entry *entry;
+ struct eventfs_inode *ei;
+ const char *name;
+ int ret;
+
+ mutex_lock(&eventfs_mutex);
+ ei = dentry->d_fsdata;
+ /* The LSB is set when the eventfs_inode is being freed */
+ if (((unsigned long)ei & 1UL) || ei->is_freed) {
+ /* Do not allow changes if the event is about to be removed. */
+ mutex_unlock(&eventfs_mutex);
+ return -ENODEV;
+ }
+
+ /* Preallocate the children mode array if necessary */
+ if (!(dentry->d_inode->i_mode & S_IFDIR)) {
+ if (!ei->entry_attrs) {
+ ei->entry_attrs = kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries,
+ GFP_KERNEL);
+ if (!ei->entry_attrs) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+ }
+
+ ret = simple_setattr(idmap, dentry, iattr);
+ if (ret < 0)
+ goto out;
+
+ /*
+ * If this is a dir, then update the ei cache, only the file
+ * mode is saved in the ei->m_children, and the ownership is
+ * determined by the parent directory.
+ */
+ if (dentry->d_inode->i_mode & S_IFDIR) {
+ update_attr(&ei->attr, iattr);
+
+ } else {
+ name = dentry->d_name.name;
+
+ for (int i = 0; i < ei->nr_entries; i++) {
+ entry = &ei->entries[i];
+ if (strcmp(name, entry->name) == 0) {
+ update_attr(&ei->entry_attrs[i], iattr);
+ break;
+ }
+ }
+ }
+ out:
+ mutex_unlock(&eventfs_mutex);
+ return ret;
+}
+
static const struct inode_operations eventfs_root_dir_inode_operations = {
.lookup = eventfs_root_lookup,
+ .setattr = eventfs_set_attr,
+};
+
+static const struct inode_operations eventfs_file_inode_operations = {
+ .setattr = eventfs_set_attr,
};
static const struct file_operations eventfs_file_operations = {
@@ -59,10 +149,30 @@ static const struct file_operations eventfs_file_operations = {
.release = eventfs_release,
};
+static void update_inode_attr(struct inode *inode, struct eventfs_attr *attr, umode_t mode)
+{
+ if (!attr) {
+ inode->i_mode = mode;
+ return;
+ }
+
+ if (attr->mode & EVENTFS_SAVE_MODE)
+ inode->i_mode = attr->mode & EVENTFS_MODE_MASK;
+ else
+ inode->i_mode = mode;
+
+ if (attr->mode & EVENTFS_SAVE_UID)
+ inode->i_uid = attr->uid;
+
+ if (attr->mode & EVENTFS_SAVE_GID)
+ inode->i_gid = attr->gid;
+}
+
/**
* create_file - create a file in the tracefs filesystem
* @name: the name of the file to create.
* @mode: the permission that the file should have.
+ * @attr: saved attributes changed by user
* @parent: parent dentry for this file.
* @data: something that the caller will want to get to later on.
* @fop: struct file_operations that should be used for this file.
@@ -72,6 +182,7 @@ static const struct file_operations eventfs_file_operations = {
* call.
*/
static struct dentry *create_file(const char *name, umode_t mode,
+ struct eventfs_attr *attr,
struct dentry *parent, void *data,
const struct file_operations *fop)
{
@@ -95,7 +206,10 @@ static struct dentry *create_file(const char *name, umode_t mode,
if (unlikely(!inode))
return eventfs_failed_creating(dentry);
- inode->i_mode = mode;
+ /* If the user updated the directory's attributes, use them */
+ update_inode_attr(inode, attr, mode);
+
+ inode->i_op = &eventfs_file_inode_operations;
inode->i_fop = fop;
inode->i_private = data;
@@ -108,19 +222,19 @@ static struct dentry *create_file(const char *name, umode_t mode,
/**
* create_dir - create a dir in the tracefs filesystem
- * @name: the name of the file to create.
+ * @ei: the eventfs_inode that represents the directory to create
* @parent: parent dentry for this file.
*
* This function will create a dentry for a directory represented by
* a eventfs_inode.
*/
-static struct dentry *create_dir(const char *name, struct dentry *parent)
+static struct dentry *create_dir(struct eventfs_inode *ei, struct dentry *parent)
{
struct tracefs_inode *ti;
struct dentry *dentry;
struct inode *inode;
- dentry = eventfs_start_creating(name, parent);
+ dentry = eventfs_start_creating(ei->name, parent);
if (IS_ERR(dentry))
return dentry;
@@ -128,7 +242,9 @@ static struct dentry *create_dir(const char *name, struct dentry *parent)
if (unlikely(!inode))
return eventfs_failed_creating(dentry);
- inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
+ /* If the user updated the directory's attributes, use them */
+ update_inode_attr(inode, &ei->attr, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO);
+
inode->i_op = &eventfs_root_dir_inode_operations;
inode->i_fop = &eventfs_file_operations;
@@ -146,6 +262,7 @@ static void free_ei(struct eventfs_inode *ei)
{
kfree_const(ei->name);
kfree(ei->d_children);
+ kfree(ei->entry_attrs);
kfree(ei);
}
@@ -231,7 +348,7 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
/**
* create_file_dentry - create a dentry for a file of an eventfs_inode
* @ei: the eventfs_inode that the file will be created under
- * @e_dentry: a pointer to the d_children[] of the @ei
+ * @idx: the index into the d_children[] 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.
@@ -244,10 +361,12 @@ void eventfs_set_ei_status_free(struct tracefs_inode *ti, struct dentry *dentry)
* just do a dget() on it and return. Otherwise create the dentry and attach it.
*/
static struct dentry *
-create_file_dentry(struct eventfs_inode *ei, struct dentry **e_dentry,
+create_file_dentry(struct eventfs_inode *ei, int idx,
struct dentry *parent, const char *name, umode_t mode, void *data,
const struct file_operations *fops, bool lookup)
{
+ struct eventfs_attr *attr = NULL;
+ struct dentry **e_dentry = &ei->d_children[idx];
struct dentry *dentry;
bool invalidate = false;
@@ -264,13 +383,18 @@ create_file_dentry(struct eventfs_inode *ei, struct dentry **e_dentry,
mutex_unlock(&eventfs_mutex);
return *e_dentry;
}
+
+ /* ei->entry_attrs are protected by SRCU */
+ if (ei->entry_attrs)
+ attr = &ei->entry_attrs[idx];
+
mutex_unlock(&eventfs_mutex);
/* The lookup already has the parent->d_inode locked */
if (!lookup)
inode_lock(parent->d_inode);
- dentry = create_file(name, mode, parent, data, fops);
+ dentry = create_file(name, mode, attr, parent, data, fops);
if (!lookup)
inode_unlock(parent->d_inode);
@@ -378,7 +502,7 @@ create_dir_dentry(struct eventfs_inode *pei, struct eventfs_inode *ei,
if (!lookup)
inode_lock(parent->d_inode);
- dentry = create_dir(ei->name, parent);
+ dentry = create_dir(ei, parent);
if (!lookup)
inode_unlock(parent->d_inode);
@@ -495,8 +619,7 @@ static struct dentry *eventfs_root_lookup(struct inode *dir,
if (r <= 0)
continue;
ret = simple_lookup(dir, dentry, flags);
- create_file_dentry(ei, &ei->d_children[i],
- ei_dentry, name, mode, cdata,
+ create_file_dentry(ei, i, ei_dentry, name, mode, cdata,
fops, true);
break;
}
@@ -629,8 +752,7 @@ static int dcache_dir_open_wrapper(struct inode *inode, struct file *file)
r = entry->callback(name, &mode, &cdata, &fops);
if (r <= 0)
continue;
- d = create_file_dentry(ei, &ei->d_children[i],
- parent, name, mode, cdata, fops, false);
+ d = create_file_dentry(ei, i, parent, name, mode, cdata, fops, false);
if (d) {
ret = add_dentries(&dentries, d, cnt);
if (ret < 0)
@@ -13,6 +13,18 @@ struct tracefs_inode {
struct inode vfs_inode;
};
+/*
+ * struct eventfs_attr - cache the mode and ownership of a eventfs entry
+ * @mode: saved mode plus flags of what is saved
+ * @uid: saved uid if changed
+ * @gid: saved gid if changed
+ */
+struct eventfs_attr {
+ int mode;
+ kuid_t uid;
+ kgid_t gid;
+};
+
/*
* struct eventfs_inode - hold the properties of the eventfs directories.
* @list: link list into the parent directory
@@ -22,6 +34,8 @@ struct tracefs_inode {
* @dentry: the dentry of the directory
* @d_parent: pointer to the parent's dentry
* @d_children: The array of dentries to represent the files when created
+ * @entry_attrs: Saved mode and ownership of the @d_children
+ * @attr: Saved mode and ownership of eventfs_inode itself
* @data: The private data to pass to the callbacks
* @is_freed: Flag set if the eventfs is on its way to be freed
* Note if is_freed is set, then dentry is corrupted.
@@ -35,6 +49,8 @@ struct eventfs_inode {
struct dentry *dentry; /* Check is_freed to access */
struct dentry *d_parent;
struct dentry **d_children;
+ struct eventfs_attr *entry_attrs;
+ struct eventfs_attr attr;
void *data;
/*
* Union - used for deletion