1 files changed, 437 insertions, 3 deletions

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 751997d..5066537 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -41,6 +41,9 @@
 #include <linux/crc16.h>
 #include <asm/uaccess.h>
 
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+
 #include "ext4.h"
 #include "ext4_jbd2.h"
 #include "xattr.h"
@@ -52,6 +55,8 @@
 
 struct proc_dir_entry *ext4_proc_root;
 static struct kset *ext4_kset;
+struct ext4_lazy_init *ext4_li_info;
+struct mutex ext4_li_mtx;
 
 static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
 			     unsigned long journal_devnum);
@@ -70,6 +75,8 @@ static void ext4_write_super(struct super_block *sb);
 static int ext4_freeze(struct super_block *sb);
 static int ext4_get_sb(struct file_system_type *fs_type, int flags,
 		       const char *dev_name, void *data, struct vfsmount *mnt);
+static void ext4_destroy_lazyinit_thread(void);
+static void ext4_unregister_li_request(struct super_block *sb);
 
 #if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
 static struct file_system_type ext3_fs_type = {
@@ -720,6 +727,7 @@ static void ext4_put_super(struct super_block *sb)
 	}
 
 	del_timer(&sbi->s_err_report);
+	ext4_unregister_li_request(sb);
 	ext4_release_system_zone(sb);
 	ext4_mb_release(sb);
 	ext4_ext_release(sb);
@@ -1046,6 +1054,12 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
 	    !(def_mount_opts & EXT4_DEFM_BLOCK_VALIDITY))
 		seq_puts(seq, ",block_validity");
 
+	if (!test_opt(sb, INIT_INODE_TABLE))
+		seq_puts(seq, ",noinit_inode_table");
+	else if (sbi->s_li_wait_mult)
+		seq_printf(seq, ",init_inode_table=%u",
+			   (unsigned) sbi->s_li_wait_mult);
+
 	ext4_show_quota_options(seq, sb);
 
 	return 0;
@@ -1220,6 +1234,7 @@ enum {
 	Opt_inode_readahead_blks, Opt_journal_ioprio,
 	Opt_dioread_nolock, Opt_dioread_lock,
 	Opt_discard, Opt_nodiscard,
+	Opt_init_inode_table, Opt_noinit_inode_table,
 };
 
 static const match_table_t tokens = {
@@ -1290,6 +1305,9 @@ static const match_table_t tokens = {
 	{Opt_dioread_lock, "dioread_lock"},
 	{Opt_discard, "discard"},
 	{Opt_nodiscard, "nodiscard"},
+	{Opt_init_inode_table, "init_itable=%u"},
+	{Opt_init_inode_table, "init_itable"},
+	{Opt_noinit_inode_table, "noinit_itable"},
 	{Opt_err, NULL},
 };
 
@@ -1760,6 +1778,20 @@ set_qf_format:
 		case Opt_dioread_lock:
 			clear_opt(sbi->s_mount_opt, DIOREAD_NOLOCK);
 			break;
+		case Opt_init_inode_table:
+			set_opt(sbi->s_mount_opt, INIT_INODE_TABLE);
+			if (args[0].from) {
+				if (match_int(&args[0], &option))
+					return 0;
+			} else
+				option = EXT4_DEF_LI_WAIT_MULT;
+			if (option < 0)
+				return 0;
+			sbi->s_li_wait_mult = option;
+			break;
+		case Opt_noinit_inode_table:
+			clear_opt(sbi->s_mount_opt, INIT_INODE_TABLE);
+			break;
 		default:
 			ext4_msg(sb, KERN_ERR,
 			       "Unrecognized mount option \"%s\" "
@@ -1943,7 +1975,8 @@ int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 block_group,
 }
 
 /* Called at mount-time, super-block is locked */
-static int ext4_check_descriptors(struct super_block *sb)
+static int ext4_check_descriptors(struct super_block *sb,
+				  ext4_group_t *first_not_zeroed)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
@@ -1952,7 +1985,7 @@ static int ext4_check_descriptors(struct super_block *sb)
 	ext4_fsblk_t inode_bitmap;
 	ext4_fsblk_t inode_table;
 	int flexbg_flag = 0;
-	ext4_group_t i;
+	ext4_group_t i, grp = sbi->s_groups_count;
 
 	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
 		flexbg_flag = 1;
@@ -1968,6 +2001,10 @@ static int ext4_check_descriptors(struct super_block *sb)
 			last_block = first_block +
 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
 
+		if ((grp == sbi->s_groups_count) &&
+		   !(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
+			grp = i;
+
 		block_bitmap = ext4_block_bitmap(sb, gdp);
 		if (block_bitmap < first_block || block_bitmap > last_block) {
 			ext4_msg(sb, KERN_ERR, "ext4_check_descriptors: "
@@ -2005,6 +2042,8 @@ static int ext4_check_descriptors(struct super_block *sb)
 		if (!flexbg_flag)
 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
 	}
+	if (NULL != first_not_zeroed)
+		*first_not_zeroed = grp;
 
 	ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
 	sbi->s_es->s_free_inodes_count =cpu_to_le32(ext4_count_free_inodes(sb));
@@ -2543,6 +2582,378 @@ static void print_daily_error_info(unsigned long arg)
 	mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ);  /* Once a day */
 }
 
+static void ext4_lazyinode_timeout(unsigned long data)
+{
+	struct task_struct *p = (struct task_struct *)data;
+	wake_up_process(p);
+}
+
+/* Find next suitable group and run ext4_init_inode_table */
+static int ext4_run_li_request(struct ext4_li_request *elr)
+{
+	struct ext4_group_desc *gdp = NULL;
+	ext4_group_t group, ngroups;
+	struct super_block *sb;
+	unsigned long timeout = 0;
+	int ret = 0;
+
+	sb = elr->lr_super;
+	ngroups = EXT4_SB(sb)->s_groups_count;
+
+	for (group = elr->lr_next_group; group < ngroups; group++) {
+		gdp = ext4_get_group_desc(sb, group, NULL);
+		if (!gdp) {
+			ret = 1;
+			break;
+		}
+
+		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
+			break;
+	}
+
+	if (group == ngroups)
+		ret = 1;
+
+	if (!ret) {
+		timeout = jiffies;
+		ret = ext4_init_inode_table(sb, group,
+					    elr->lr_timeout ? 0 : 1);
+		if (elr->lr_timeout == 0) {
+			timeout = jiffies - timeout;
+			if (elr->lr_sbi->s_li_wait_mult)
+				timeout *= elr->lr_sbi->s_li_wait_mult;
+			else
+				timeout *= 20;
+			elr->lr_timeout = timeout;
+		}
+		elr->lr_next_sched = jiffies + elr->lr_timeout;
+		elr->lr_next_group = group + 1;
+	}
+
+	return ret;
+}
+
+/*
+ * Remove lr_request from the list_request and free the
+ * request tructure. Should be called with li_list_mtx held
+ */
+static void ext4_remove_li_request(struct ext4_li_request *elr)
+{
+	struct ext4_sb_info *sbi;
+
+	if (!elr)
+		return;
+
+	sbi = elr->lr_sbi;
+
+	list_del(&elr->lr_request);
+	sbi->s_li_request = NULL;
+	kfree(elr);
+}
+
+static void ext4_unregister_li_request(struct super_block *sb)
+{
+	struct ext4_li_request *elr = EXT4_SB(sb)->s_li_request;
+
+	if (!ext4_li_info)
+		return;
+
+	mutex_lock(&ext4_li_info->li_list_mtx);
+	ext4_remove_li_request(elr);
+	mutex_unlock(&ext4_li_info->li_list_mtx);
+}
+
+/*
+ * This is the function where ext4lazyinit thread lives. It walks
+ * through the request list searching for next scheduled filesystem.
+ * When such a fs is found, run the lazy initialization request
+ * (ext4_rn_li_request) and keep track of the time spend in this
+ * function. Based on that time we compute next schedule time of
+ * the request. When walking through the list is complete, compute
+ * next waking time and put itself into sleep.
+ */
+static int ext4_lazyinit_thread(void *arg)
+{
+	struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
+	struct list_head *pos, *n;
+	struct ext4_li_request *elr;
+	unsigned long next_wakeup;
+	DEFINE_WAIT(wait);
+	int ret;
+
+	BUG_ON(NULL == eli);
+
+	eli->li_timer.data = (unsigned long)current;
+	eli->li_timer.function = ext4_lazyinode_timeout;
+
+	eli->li_task = current;
+	wake_up(&eli->li_wait_task);
+
+cont_thread:
+	while (true) {
+		next_wakeup = MAX_JIFFY_OFFSET;
+
+		mutex_lock(&eli->li_list_mtx);
+		if (list_empty(&eli->li_request_list)) {
+			mutex_unlock(&eli->li_list_mtx);
+			goto exit_thread;
+		}
+
+		list_for_each_safe(pos, n, &eli->li_request_list) {
+			elr = list_entry(pos, struct ext4_li_request,
+					 lr_request);
+
+			if (time_after_eq(jiffies, elr->lr_next_sched))
+				ret = ext4_run_li_request(elr);
+
+			if (ret) {
+				ret = 0;
+				ext4_remove_li_request(elr);
+				continue;
+			}
+
+			if (time_before(elr->lr_next_sched, next_wakeup))
+				next_wakeup = elr->lr_next_sched;
+		}
+		mutex_unlock(&eli->li_list_mtx);
+
+		if (freezing(current))
+			refrigerator();
+
+		if (time_after_eq(jiffies, next_wakeup)) {
+			cond_resched();
+			continue;
+		}
+
+		eli->li_timer.expires = next_wakeup;
+		add_timer(&eli->li_timer);
+		prepare_to_wait(&eli->li_wait_daemon, &wait,
+				TASK_INTERRUPTIBLE);
+		if (time_before(jiffies, next_wakeup))
+			schedule();
+		finish_wait(&eli->li_wait_daemon, &wait);
+	}
+
+exit_thread:
+	/*
+	 * It looks like the request list is empty, but we need
+	 * to check it under the li_list_mtx lock, to prevent any
+	 * additions into it, and of course we should lock ext4_li_mtx
+	 * to atomically free the list and ext4_li_info, because at
+	 * this point another ext4 filesystem could be registering
+	 * new one.
+	 */
+	mutex_lock(&ext4_li_mtx);
+	mutex_lock(&eli->li_list_mtx);
+	if (!list_empty(&eli->li_request_list)) {
+		mutex_unlock(&eli->li_list_mtx);
+		mutex_unlock(&ext4_li_mtx);
+		goto cont_thread;
+	}
+	mutex_unlock(&eli->li_list_mtx);
+	del_timer_sync(&ext4_li_info->li_timer);
+	eli->li_task = NULL;
+	wake_up(&eli->li_wait_task);
+
+	kfree(ext4_li_info);
+	ext4_li_info = NULL;
+	mutex_unlock(&ext4_li_mtx);
+
+	return 0;
+}
+
+static void ext4_clear_request_list(void)
+{
+	struct list_head *pos, *n;
+	struct ext4_li_request *elr;
+
+	mutex_lock(&ext4_li_info->li_list_mtx);
+	if (list_empty(&ext4_li_info->li_request_list))
+		return;
+
+	list_for_each_safe(pos, n, &ext4_li_info->li_request_list) {
+		elr = list_entry(pos, struct ext4_li_request,
+				 lr_request);
+		ext4_remove_li_request(elr);
+	}
+	mutex_unlock(&ext4_li_info->li_list_mtx);
+}
+
+static int ext4_run_lazyinit_thread(void)
+{
+	struct task_struct *t;
+
+	t = kthread_run(ext4_lazyinit_thread, ext4_li_info, "ext4lazyinit");
+	if (IS_ERR(t)) {
+		int err = PTR_ERR(t);
+		ext4_clear_request_list();
+		del_timer_sync(&ext4_li_info->li_timer);
+		kfree(ext4_li_info);
+		ext4_li_info = NULL;
+		printk(KERN_CRIT "EXT4: error %d creating inode table "
+				 "initialization thread\n",
+				 err);
+		return err;
+	}
+	ext4_li_info->li_state |= EXT4_LAZYINIT_RUNNING;
+
+	wait_event(ext4_li_info->li_wait_task, ext4_li_info->li_task != NULL);
+	return 0;
+}
+
+/*
+ * Check whether it make sense to run itable init. thread or not.
+ * If there is at least one uninitialized inode table, return
+ * corresponding group number, else the loop goes through all
+ * groups and return total number of groups.
+ */
+static ext4_group_t ext4_has_uninit_itable(struct super_block *sb)
+{
+	ext4_group_t group, ngroups = EXT4_SB(sb)->s_groups_count;
+	struct ext4_group_desc *gdp = NULL;
+
+	for (group = 0; group < ngroups; group++) {
+		gdp = ext4_get_group_desc(sb, group, NULL);
+		if (!gdp)
+			continue;
+
+		if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED)))
+			break;
+	}
+
+	return group;
+}
+
+static int ext4_li_info_new(void)
+{
+	struct ext4_lazy_init *eli = NULL;
+
+	eli = kzalloc(sizeof(*eli), GFP_KERNEL);
+	if (!eli)
+		return -ENOMEM;
+
+	eli->li_task = NULL;
+	INIT_LIST_HEAD(&eli->li_request_list);
+	mutex_init(&eli->li_list_mtx);
+
+	init_waitqueue_head(&eli->li_wait_daemon);
+	init_waitqueue_head(&eli->li_wait_task);
+	init_timer(&eli->li_timer);
+	eli->li_state |= EXT4_LAZYINIT_QUIT;
+
+	ext4_li_info = eli;
+
+	return 0;
+}
+
+static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
+					    ext4_group_t start)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_li_request *elr;
+	unsigned long rnd;
+
+	elr = kzalloc(sizeof(*elr), GFP_KERNEL);
+	if (!elr)
+		return NULL;
+
+	elr->lr_super = sb;
+	elr->lr_sbi = sbi;
+	elr->lr_next_group = start;
+
+	/*
+	 * Randomize first schedule time of the request to
+	 * spread the inode table initialization requests
+	 * better.
+	 */
+	get_random_bytes(&rnd, sizeof(rnd));
+	elr->lr_next_sched = jiffies + (unsigned long)rnd %
+			     (EXT4_DEF_LI_MAX_START_DELAY * HZ);
+
+	return elr;
+}
+
+static int ext4_register_li_request(struct super_block *sb,
+				    ext4_group_t first_not_zeroed)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_li_request *elr;
+	ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
+	int ret = 0;
+
+	if (sbi->s_li_request != NULL)
+		goto out;
+
+	if (first_not_zeroed == ngroups ||
+	    (sb->s_flags & MS_RDONLY) ||
+	    !test_opt(sb, INIT_INODE_TABLE)) {
+		sbi->s_li_request = NULL;
+		goto out;
+	}
+
+	if (first_not_zeroed == ngroups) {
+		sbi->s_li_request = NULL;
+		goto out;
+	}
+
+	elr = ext4_li_request_new(sb, first_not_zeroed);
+	if (!elr) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	mutex_lock(&ext4_li_mtx);
+
+	if (NULL == ext4_li_info) {
+		ret = ext4_li_info_new();
+		if (ret)
+			goto out;
+	}
+
+	mutex_lock(&ext4_li_info->li_list_mtx);
+	list_add(&elr->lr_request, &ext4_li_info->li_request_list);
+	mutex_unlock(&ext4_li_info->li_list_mtx);
+
+	sbi->s_li_request = elr;
+
+	if (!(ext4_li_info->li_state & EXT4_LAZYINIT_RUNNING)) {
+		ret = ext4_run_lazyinit_thread();
+		if (ret)
+			goto out;
+	}
+
+	mutex_unlock(&ext4_li_mtx);
+
+out:
+	if (ret) {
+		mutex_unlock(&ext4_li_mtx);
+		kfree(elr);
+	}
+	return ret;
+}
+
+/*
+ * We do not need to lock anything since this is called on
+ * module unload.
+ */
+static void ext4_destroy_lazyinit_thread(void)
+{
+	/*
+	 * If thread exited earlier
+	 * there's nothing to be done.
+	 */
+	if (!ext4_li_info)
+		return;
+
+	ext4_clear_request_list();
+
+	while (ext4_li_info->li_task) {
+		wake_up(&ext4_li_info->li_wait_daemon);
+		wait_event(ext4_li_info->li_wait_task,
+			   ext4_li_info->li_task == NULL);
+	}
+}
+
 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 				__releases(kernel_lock)
 				__acquires(kernel_lock)
@@ -2568,6 +2979,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 	__u64 blocks_count;
 	int err;
 	unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;
+	ext4_group_t first_not_zeroed;
 
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi)
@@ -2630,6 +3042,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 
 	/* Set defaults before we parse the mount options */
 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
+	set_opt(sbi->s_mount_opt, INIT_INODE_TABLE);
 	if (def_mount_opts & EXT4_DEFM_DEBUG)
 		set_opt(sbi->s_mount_opt, DEBUG);
 	if (def_mount_opts & EXT4_DEFM_BSDGROUPS) {
@@ -2909,7 +3322,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 			goto failed_mount2;
 		}
 	}
-	if (!ext4_check_descriptors(sb)) {
+	if (!ext4_check_descriptors(sb, &first_not_zeroed)) {
 		ext4_msg(sb, KERN_ERR, "group descriptors corrupted!");
 		goto failed_mount2;
 	}
@@ -3130,6 +3543,10 @@ no_journal:
 		goto failed_mount4;
 	}
 
+	err = ext4_register_li_request(sb, first_not_zeroed);
+	if (err)
+		goto failed_mount4;
+
 	sbi->s_kobj.kset = ext4_kset;
 	init_completion(&sbi->s_kobj_unregister);
 	err = kobject_init_and_add(&sbi->s_kobj, &ext4_ktype, NULL,
@@ -3847,6 +4264,19 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 			enable_quota = 1;
 		}
 	}
+
+	/*
+	 * Reinitialize lazy itable initialization thread based on
+	 * current settings
+	 */
+	if ((sb->s_flags & MS_RDONLY) || !test_opt(sb, INIT_INODE_TABLE))
+		ext4_unregister_li_request(sb);
+	else {
+		ext4_group_t first_not_zeroed;
+		first_not_zeroed = ext4_has_uninit_itable(sb);
+		ext4_register_li_request(sb, first_not_zeroed);
+	}
+
 	ext4_setup_system_zone(sb);
 	if (sbi->s_journal == NULL)
 		ext4_commit_super(sb, 1);
@@ -4317,6 +4747,9 @@ static int __init init_ext4_fs(void)
 	err = register_filesystem(&ext4_fs_type);
 	if (err)
 		goto out;
+
+	ext4_li_info = NULL;
+	mutex_init(&ext4_li_mtx);
 	return 0;
 out:
 	unregister_as_ext2();
@@ -4336,6 +4769,7 @@ out4:
 
 static void __exit exit_ext4_fs(void)
 {
+	ext4_destroy_lazyinit_thread();
 	unregister_as_ext2();
 	unregister_as_ext3();
 	unregister_filesystem(&ext4_fs_type);