Merge branch 'efivarfs' into next

fs/efivarfs/file.c

@@ -36,28 +36,41 @@ static ssize_t efivarfs_file_write(struct file *file,
 	if (IS_ERR(data))
 		return PTR_ERR(data);
 
+	inode_lock(inode);
+	if (var->removed) {
+		/*
+		 * file got removed; don't allow a set.  Caused by an
+		 * unsuccessful create or successful delete write
+		 * racing with us.
+		 */
+		bytes = -EIO;
+		goto out;
+	}
+
 	bytes = efivar_entry_set_get_size(var, attributes, &datasize,
 					  data, &set);
-	if (!set && bytes) {
+	if (!set) {
 		if (bytes == -ENOENT)
 			bytes = -EIO;
 		goto out;
 	}
 
 	if (bytes == -ENOENT) {
-		drop_nlink(inode);
+		/*
-		d_delete(file->f_path.dentry);
+		 * zero size signals to release that the write deleted
-		dput(file->f_path.dentry);
+		 * the variable
+		 */
+		i_size_write(inode, 0);
 	} else {
-		inode_lock(inode);
 		i_size_write(inode, datasize + sizeof(attributes));
 		inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
-		inode_unlock(inode);
 	}
 
 	bytes = count;
 
 out:
+	inode_unlock(inode);
+
 	kfree(data);
 
 	return bytes;
@@ -106,8 +119,36 @@ out_free:
 	return size;
 }
 
+static int efivarfs_file_release(struct inode *inode, struct file *file)
+{
+	struct efivar_entry *var = inode->i_private;
+
+	inode_lock(inode);
+	var->removed = (--var->open_count == 0 && i_size_read(inode) == 0);
+	inode_unlock(inode);
+
+	if (var->removed)
+		simple_recursive_removal(file->f_path.dentry, NULL);
+
+	return 0;
+}
+
+static int efivarfs_file_open(struct inode *inode, struct file *file)
+{
+	struct efivar_entry *entry = inode->i_private;
+
+	file->private_data = entry;
+
+	inode_lock(inode);
+	entry->open_count++;
+	inode_unlock(inode);
+
+	return 0;
+}
+
 const struct file_operations efivarfs_file_operations = {
-	.open	= simple_open,
+	.open		= efivarfs_file_open,
 	.read		= efivarfs_file_read,
 	.write		= efivarfs_file_write,
+	.release	= efivarfs_file_release,
 };

fs/efivarfs/inode.c

@@ -77,39 +77,34 @@ static bool efivarfs_valid_name(const char *str, int len)
 static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
 			   struct dentry *dentry, umode_t mode, bool excl)
 {
-	struct efivarfs_fs_info *info = dir->i_sb->s_fs_info;
 	struct inode *inode = NULL;
 	struct efivar_entry *var;
 	int namelen, i = 0, err = 0;
 	bool is_removable = false;
+	efi_guid_t vendor;
 
 	if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
 		return -EINVAL;
 
-	var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
-	if (!var)
-		return -ENOMEM;
-
 	/* length of the variable name itself: remove GUID and separator */
 	namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
 
-	err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
+	err = guid_parse(dentry->d_name.name + namelen + 1, &vendor);
 	if (err)
-		goto out;
+		return err;
-	if (guid_equal(&var->var.VendorGuid, &LINUX_EFI_RANDOM_SEED_TABLE_GUID)) {
+	if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
-		err = -EPERM;
+		return -EPERM;
-		goto out;
-	}
 
-	if (efivar_variable_is_removable(var->var.VendorGuid,
+	if (efivar_variable_is_removable(vendor,
 					 dentry->d_name.name, namelen))
 		is_removable = true;
 
 	inode = efivarfs_get_inode(dir->i_sb, dir, mode, 0, is_removable);
-	if (!inode) {
+	if (!inode)
-		err = -ENOMEM;
+		return -ENOMEM;
-		goto out;
+	var = efivar_entry(inode);
-	}
+
+	var->var.VendorGuid = vendor;
 
 	for (i = 0; i < namelen; i++)
 		var->var.VariableName[i] = dentry->d_name.name[i];
@@ -117,21 +112,11 @@ static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
 	var->var.VariableName[i] = '\0';
 
 	inode->i_private = var;
-	kmemleak_ignore(var);
-
-	err = efivar_entry_add(var, &info->efivarfs_list);
-	if (err)
-		goto out;
 
 	d_instantiate(dentry, inode);
 	dget(dentry);
-out:
+
-	if (err) {
+	return 0;
-		kfree(var);
-		if (inode)
-			iput(inode);
-	}
-	return err;
 }
 
 static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)

fs/efivarfs/internal.h

@@ -6,7 +6,6 @@
 #ifndef EFIVAR_FS_INTERNAL_H
 #define EFIVAR_FS_INTERNAL_H
 
-#include <linux/list.h>
 #include <linux/efi.h>
 
 struct efivarfs_mount_opts {
@@ -16,7 +15,6 @@ struct efivarfs_mount_opts {
 
 struct efivarfs_fs_info {
 	struct efivarfs_mount_opts mount_opts;
-	struct list_head efivarfs_list;
 	struct super_block *sb;
 	struct notifier_block nb;
 };
@@ -24,22 +22,23 @@ struct efivarfs_fs_info {
 struct efi_variable {
 	efi_char16_t  VariableName[EFI_VAR_NAME_LEN/sizeof(efi_char16_t)];
 	efi_guid_t    VendorGuid;
-	__u32         Attributes;
 };
 
 struct efivar_entry {
 	struct efi_variable var;
-	struct list_head list;
+	struct inode vfs_inode;
-	struct kobject kobj;
+	unsigned long open_count;
+	bool removed;
 };
 
-int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
+static inline struct efivar_entry *efivar_entry(struct inode *inode)
-			    struct list_head *),
+{
-		void *data, struct list_head *head);
+	return container_of(inode, struct efivar_entry, vfs_inode);
+}
+
+int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
+		void *data);
 
-int efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
-void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
-void efivar_entry_remove(struct efivar_entry *entry);
 int efivar_entry_delete(struct efivar_entry *entry);
 
 int efivar_entry_size(struct efivar_entry *entry, unsigned long *size);
@@ -50,13 +49,14 @@ int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
 int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
 			      unsigned long *size, void *data, bool *set);
 
-int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
-		      struct list_head *head, void *data);
 
 bool efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
 		     unsigned long data_size);
 bool efivar_variable_is_removable(efi_guid_t vendor, const char *name,
 				  size_t len);
+char *efivar_get_utf8name(const efi_char16_t *name16, efi_guid_t *vendor);
+bool efivarfs_variable_is_present(efi_char16_t *variable_name,
+				  efi_guid_t *vendor, void *data);
 
 extern const struct file_operations efivarfs_file_operations;
 extern const struct inode_operations efivarfs_dir_inode_operations;

fs/efivarfs/super.c

@@ -39,9 +39,24 @@ static int efivarfs_ops_notifier(struct notifier_block *nb, unsigned long event,
 	return NOTIFY_OK;
 }
 
-static void efivarfs_evict_inode(struct inode *inode)
+static struct inode *efivarfs_alloc_inode(struct super_block *sb)
 {
-	clear_inode(inode);
+	struct efivar_entry *entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+
+	if (!entry)
+		return NULL;
+
+	inode_init_once(&entry->vfs_inode);
+	entry->removed = false;
+
+	return &entry->vfs_inode;
+}
+
+static void efivarfs_free_inode(struct inode *inode)
+{
+	struct efivar_entry *entry = efivar_entry(inode);
+
+	kfree(entry);
 }
 
 static int efivarfs_show_options(struct seq_file *m, struct dentry *root)
@@ -106,7 +121,8 @@ static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 static const struct super_operations efivarfs_ops = {
 	.statfs = efivarfs_statfs,
 	.drop_inode = generic_delete_inode,
-	.evict_inode = efivarfs_evict_inode,
+	.alloc_inode = efivarfs_alloc_inode,
+	.free_inode = efivarfs_free_inode,
 	.show_options = efivarfs_show_options,
 };
 
@@ -181,9 +197,37 @@ static struct dentry *efivarfs_alloc_dentry(struct dentry *parent, char *name)
 	return ERR_PTR(-ENOMEM);
 }
 
+bool efivarfs_variable_is_present(efi_char16_t *variable_name,
+				  efi_guid_t *vendor, void *data)
+{
+	char *name = efivar_get_utf8name(variable_name, vendor);
+	struct super_block *sb = data;
+	struct dentry *dentry;
+	struct qstr qstr;
+
+	if (!name)
+		/*
+		 * If the allocation failed there'll already be an
+		 * error in the log (and likely a huge and growing
+		 * number of them since they system will be under
+		 * extreme memory pressure), so simply assume
+		 * collision for safety but don't add to the log
+		 * flood.
+		 */
+		return true;
+
+	qstr.name = name;
+	qstr.len = strlen(name);
+	dentry = d_hash_and_lookup(sb->s_root, &qstr);
+	kfree(name);
+	if (!IS_ERR_OR_NULL(dentry))
+		dput(dentry);
+
+	return dentry != NULL;
+}
+
 static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
-			     unsigned long name_size, void *data,
+			     unsigned long name_size, void *data)
-			     struct list_head *list)
 {
 	struct super_block *sb = (struct super_block *)data;
 	struct efivar_entry *entry;
@@ -198,39 +242,26 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
 	if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
 		return 0;
 
-	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+	name = efivar_get_utf8name(name16, &vendor);
-	if (!entry)
+	if (!name)
 		return err;
 
-	memcpy(entry->var.VariableName, name16, name_size);
+	/* length of the variable name itself: remove GUID and separator */
-	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
+	len = strlen(name) - EFI_VARIABLE_GUID_LEN - 1;
 
-	len = ucs2_utf8size(entry->var.VariableName);
+	if (efivar_variable_is_removable(vendor, name, len))
-
-	/* name, plus '-', plus GUID, plus NUL*/
-	name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
-	if (!name)
-		goto fail;
-
-	ucs2_as_utf8(name, entry->var.VariableName, len);
-
-	if (efivar_variable_is_removable(entry->var.VendorGuid, name, len))
 		is_removable = true;
 
-	name[len] = '-';
-
-	efi_guid_to_str(&entry->var.VendorGuid, name + len + 1);
-
-	name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
-
-	/* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */
-	strreplace(name, '/', '!');
-
 	inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0,
 				   is_removable);
 	if (!inode)
 		goto fail_name;
 
+	entry = efivar_entry(inode);
+
+	memcpy(entry->var.VariableName, name16, name_size);
+	memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
+
 	dentry = efivarfs_alloc_dentry(root, name);
 	if (IS_ERR(dentry)) {
 		err = PTR_ERR(dentry);
@@ -238,14 +269,13 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
 	}
 
 	__efivar_entry_get(entry, NULL, &size, NULL);
-	__efivar_entry_add(entry, list);
 
 	/* copied by the above to local storage in the dentry. */
 	kfree(name);
 
 	inode_lock(inode);
 	inode->i_private = entry;
-	i_size_write(inode, size + sizeof(entry->var.Attributes));
+	i_size_write(inode, size + sizeof(__u32)); /* attributes + data */
 	inode_unlock(inode);
 	d_add(dentry, inode);
 
@@ -255,16 +285,8 @@ fail_inode:
 	iput(inode);
 fail_name:
 	kfree(name);
-fail:
-	kfree(entry);
-	return err;
-}
 
-static int efivarfs_destroy(struct efivar_entry *entry, void *data)
+	return err;
-{
-	efivar_entry_remove(entry);
-	kfree(entry);
-	return 0;
 }
 
 enum {
@@ -336,7 +358,7 @@ static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (err)
 		return err;
 
-	return efivar_init(efivarfs_callback, sb, &sfi->efivarfs_list);
+	return efivar_init(efivarfs_callback, sb);
 }
 
 static int efivarfs_get_tree(struct fs_context *fc)
@@ -371,8 +393,6 @@ static int efivarfs_init_fs_context(struct fs_context *fc)
 	if (!sfi)
 		return -ENOMEM;
 
-	INIT_LIST_HEAD(&sfi->efivarfs_list);
-
 	sfi->mount_opts.uid = GLOBAL_ROOT_UID;
 	sfi->mount_opts.gid = GLOBAL_ROOT_GID;
 
@@ -388,8 +408,6 @@ static void efivarfs_kill_sb(struct super_block *sb)
 	blocking_notifier_chain_unregister(&efivar_ops_nh, &sfi->nb);
 	kill_litter_super(sb);
 
-	/* Remove all entries and destroy */
-	efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL);
 	kfree(sfi);
 }
 

fs/efivarfs/vars.c

@@ -225,6 +225,31 @@ variable_matches(const char *var_name, size_t len, const char *match_name,
 	}
 }
 
+char *
+efivar_get_utf8name(const efi_char16_t *name16, efi_guid_t *vendor)
+{
+	int len = ucs2_utf8size(name16);
+	char *name;
+
+	/* name, plus '-', plus GUID, plus NUL*/
+	name = kmalloc(len + 1 + EFI_VARIABLE_GUID_LEN + 1, GFP_KERNEL);
+	if (!name)
+		return NULL;
+
+	ucs2_as_utf8(name, name16, len);
+
+	name[len] = '-';
+
+	efi_guid_to_str(vendor, name + len + 1);
+
+	name[len + EFI_VARIABLE_GUID_LEN+1] = '\0';
+
+	/* replace invalid slashes like kobject_set_name_vargs does for /sys/firmware/efi/vars. */
+	strreplace(name, '/', '!');
+
+	return name;
+}
+
 bool
 efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data,
 		unsigned long data_size)
@@ -288,28 +313,6 @@ efivar_variable_is_removable(efi_guid_t vendor, const char *var_name,
 	return found;
 }
 
-static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor,
-				struct list_head *head)
-{
-	struct efivar_entry *entry, *n;
-	unsigned long strsize1, strsize2;
-	bool found = false;
-
-	strsize1 = ucs2_strsize(variable_name, EFI_VAR_NAME_LEN);
-	list_for_each_entry_safe(entry, n, head, list) {
-		strsize2 = ucs2_strsize(entry->var.VariableName, EFI_VAR_NAME_LEN);
-		if (strsize1 == strsize2 &&
-			!memcmp(variable_name, &(entry->var.VariableName),
-				strsize2) &&
-			!efi_guidcmp(entry->var.VendorGuid,
-				*vendor)) {
-			found = true;
-			break;
-		}
-	}
-	return found;
-}
-
 /*
  * Returns the size of variable_name, in bytes, including the
  * terminating NULL character, or variable_name_size if no NULL
@@ -361,16 +364,14 @@ static void dup_variable_bug(efi_char16_t *str16, efi_guid_t *vendor_guid,
  * efivar_init - build the initial list of EFI variables
  * @func: callback function to invoke for every variable
  * @data: function-specific data to pass to @func
- * @head: initialised head of variable list
  *
  * Get every EFI variable from the firmware and invoke @func. @func
- * should call efivar_entry_add() to build the list of variables.
+ * should populate the initial dentry and inode tree.
  *
  * Returns 0 on success, or a kernel error code on failure.
  */
-int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
+int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
-			    struct list_head *),
+		void *data)
-		void *data, struct list_head *head)
 {
 	unsigned long variable_name_size = 512;
 	efi_char16_t *variable_name;
@@ -414,14 +415,14 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
 			 * we'll ever see a different variable name,
 			 * and may end up looping here forever.
 			 */
-			if (variable_is_present(variable_name, &vendor_guid,
+			if (efivarfs_variable_is_present(variable_name,
-						head)) {
+							 &vendor_guid, data)) {
 				dup_variable_bug(variable_name, &vendor_guid,
 						 variable_name_size);
 				status = EFI_NOT_FOUND;
 			} else {
 				err = func(variable_name, vendor_guid,
-					   variable_name_size, data, head);
+					   variable_name_size, data);
 				if (err)
 					status = EFI_NOT_FOUND;
 			}
@@ -453,70 +454,12 @@ free:
 }
 
 /**
- * efivar_entry_add - add entry to variable list
+ * efivar_entry_delete - delete variable
- * @entry: entry to add to list
- * @head: list head
- *
- * Returns 0 on success, or a kernel error code on failure.
- */
-int efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
-{
-	int err;
-
-	err = efivar_lock();
-	if (err)
-		return err;
-	list_add(&entry->list, head);
-	efivar_unlock();
-
-	return 0;
-}
-
-/**
- * __efivar_entry_add - add entry to variable list
- * @entry: entry to add to list
- * @head: list head
- */
-void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
-{
-	list_add(&entry->list, head);
-}
-
-/**
- * efivar_entry_remove - remove entry from variable list
- * @entry: entry to remove from list
- *
- * Returns 0 on success, or a kernel error code on failure.
- */
-void efivar_entry_remove(struct efivar_entry *entry)
-{
-	list_del(&entry->list);
-}
-
-/*
- * efivar_entry_list_del_unlock - remove entry from variable list
- * @entry: entry to remove
- *
- * Remove @entry from the variable list and release the list lock.
- *
- * NOTE: slightly weird locking semantics here - we expect to be
- * called with the efivars lock already held, and we release it before
- * returning. This is because this function is usually called after
- * set_variable() while the lock is still held.
- */
-static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
-{
-	list_del(&entry->list);
-	efivar_unlock();
-}
-
-/**
- * efivar_entry_delete - delete variable and remove entry from list
  * @entry: entry containing variable to delete
  *
- * Delete the variable from the firmware and remove @entry from the
+ * Delete the variable from the firmware. It is the caller's
- * variable list. It is the caller's responsibility to free @entry
+ * responsibility to free @entry (by deleting the dentry/inode) once
- * once we return.
+ * we return.
  *
  * Returns 0 on success, -EINTR if we can't grab the semaphore,
  * converted EFI status code if set_variable() fails.
@@ -533,12 +476,10 @@ int efivar_entry_delete(struct efivar_entry *entry)
 	status = efivar_set_variable_locked(entry->var.VariableName,
 					    &entry->var.VendorGuid,
 					    0, 0, NULL, false);
-	if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) {
 	efivar_unlock();
+	if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND))
 		return efi_status_to_err(status);
-	}
 
-	efivar_entry_list_del_unlock(entry);
 	return 0;
 }
 
@@ -632,7 +573,7 @@ int efivar_entry_get(struct efivar_entry *entry, u32 *attributes,
  * get_variable() fail.
  *
  * If the EFI variable does not exist when calling set_variable()
- * (EFI_NOT_FOUND), @entry is removed from the variable list.
+ * (EFI_NOT_FOUND).
  */
 int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
 			      unsigned long *size, void *data, bool *set)
@@ -648,9 +589,8 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
 		return -EINVAL;
 
 	/*
-	 * The lock here protects the get_variable call, the conditional
+	 * The lock here protects the get_variable call and the
-	 * set_variable call, and removal of the variable from the efivars
+	 * conditional set_variable call
-	 * list (in the case of an authenticated delete).
 	 */
 	err = efivar_lock();
 	if (err)
@@ -676,9 +616,6 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
 				    &entry->var.VendorGuid,
 				    NULL, size, NULL);
 
-	if (status == EFI_NOT_FOUND)
-		efivar_entry_list_del_unlock(entry);
-	else
 	efivar_unlock();
 
 	if (status && status != EFI_BUFFER_TOO_SMALL)
@@ -691,37 +628,3 @@ out:
 	return err;
 
 }
-
-/**
- * efivar_entry_iter - iterate over variable list
- * @func: callback function
- * @head: head of variable list
- * @data: function-specific data to pass to callback
- *
- * Iterate over the list of EFI variables and call @func with every
- * entry on the list. It is safe for @func to remove entries in the
- * list via efivar_entry_delete() while iterating.
- *
- * Some notes for the callback function:
- *  - a non-zero return value indicates an error and terminates the loop
- *  - @func is called from atomic context
- */
-int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
-		      struct list_head *head, void *data)
-{
-	struct efivar_entry *entry, *n;
-	int err = 0;
-
-	err = efivar_lock();
-	if (err)
-		return err;
-
-	list_for_each_entry_safe(entry, n, head, list) {
-		err = func(entry, data);
-		if (err)
-			break;
-	}
-	efivar_unlock();
-
-	return err;
-}