[PATCH] Adding code to collect i_mutex usage during orphan

[T Makphaibulchoke]

Signed-off-by: T. Makphaibulchoke <tmac@xxxxxx>
---
 fs/ext4/namei.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 4a1a6a0..e747e43 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -48,6 +48,46 @@
 #define NAMEI_RA_BLOCKS  4
 #define NAMEI_RA_SIZE	     (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
 
+static unsigned long num_add_call;
+static unsigned long num_del_call;
+static unsigned long num_add_mutex_lock;
+static unsigned long num_del_mutex_lock;
+static unsigned long num_add_error;
+static unsigned long num_del_error;
+
+static struct kobject *ext4_orphan_kobj;
+
+static ssize_t ext4_print_count(struct kobject *kobj, struct kobj_attribute
+	*attr, char *buff)
+{
+	return sprintf(buff, "Add_mutex_lock %ld(%ld), Del_mutex_lock %ld(%ld).\n",
+		num_add_mutex_lock, num_add_call,
+		num_del_mutex_lock, num_del_call);
+}
+
+static ssize_t ext4_print_error(struct kobject *kobj, struct kobj_attribute
+	*attr, char *buff)
+{
+	return sprintf(buff, "Add_mutex_lock %ld(%ld), Del_mutex_lock %ld(%ld).\n",
+		num_add_error, num_add_call, num_del_error, num_del_call);
+}
+
+static struct kobj_attribute ext4_show_count =
+	__ATTR(ext4_mutex_lock, 0444, ext4_print_count, NULL);
+
+static struct kobj_attribute ext4_show_error =
+	__ATTR(ext4_mutex_error, 0444, ext4_print_error, NULL);
+
+static struct attribute * attrs[] = {
+	&ext4_show_count.attr,
+	&ext4_show_error.attr,
+	NULL
+};
+
+static struct attribute_group attr_group = {
+	.attrs = attrs
+};
+
 static struct buffer_head *ext4_append(handle_t *handle,
 					struct inode *inode,
 					ext4_lblk_t *block)
@@ -2557,9 +2597,21 @@ int ext4_orphan_add(handle_t *handle, struct inode *inode)
 	if (!EXT4_SB(sb)->s_journal)
 		return 0;
 
+	if (!ext4_orphan_kobj) {
+		ext4_orphan_kobj = kobject_create_and_add("ext4_orphan", NULL);
+		if (ext4_orphan_kobj) {
+			int ret = sysfs_create_group(ext4_orphan_kobj,
+				&attr_group);
+			pr_warning("%s: sys_create_group ret %d.\n",
+				__func__, ret);
+		}
+	}
+
+	++num_add_call;
 	if (!mutex_is_locked(&inode->i_mutex)) {
 		lock_mutex = 1;
 		mutex_lock(&inode->i_mutex);
+		++num_add_mutex_lock;
 	}
 
 	if (!list_empty(&EXT4_I(inode)->i_orphan))
@@ -2588,6 +2640,7 @@ int ext4_orphan_add(handle_t *handle, struct inode *inode)
 	 */
 	if (NEXT_ORPHAN(inode) && NEXT_ORPHAN(inode) <=
 		(le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count))) {
+			++num_add_error;
 			brelse(iloc.bh);
 			mutex_lock(&EXT4_SB(sb)->s_ondisk_orphan_lock);
 			////spin_lock(&EXT4_SB(sb)->s_orphan_lock);
@@ -2655,9 +2708,11 @@ int ext4_orphan_del(handle_t *handle, struct inode *inode)
 		!(sbi->s_mount_state & EXT4_ORPHAN_FS))
 		return 0;
 
+	++num_del_call;
 	if (!mutex_is_locked(&inode->i_mutex)) {
 		lock_mutex = 1;
 		mutex_lock(&inode->i_mutex);
+		++num_del_mutex_lock;
 	}
 
 	if (list_empty(&ei->i_orphan)) {
@@ -2679,6 +2734,7 @@ int ext4_orphan_del(handle_t *handle, struct inode *inode)
 		list_del_init(&ei->i_orphan);
 		mutex_unlock(&sbi->s_ondisk_orphan_lock);
 		////spin_unlock(&sbi->s_orphan_lock);
+		++num_del_error;
 	} else
 		err = ext4_reserve_inode_write(handle, inode, &iloc);
 
-- 
1.7.11.3


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