Re: Possible dcache BUG

[Gene Heskett]

On Sunday 15 August 2004 04:48, viro@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx 
wrote:
>On Sun, Aug 15, 2004 at 12:09:44AM -0400, Gene Heskett wrote:
>> The only thing I've noted in the slabinfo reports is the
>> ext3_cache was well into 6 digits in kilobytes.  Now its only
>> 15,000 of its normal units (whatever they are) after the reboot.
>
>What did dcache numbers look like at that time?
>
>Anyway, we could try the patch below and see what shows in
> /proc/fs/ext3 with it [NOTE: patch is completely untested].  It
> should show major:minor:inumber:mode
>for all currently allocated ext3 inodes.  It won't be 100% accurate
> (we can miss some entries/get some twice if cache shrinks or grows
> at the time), but if the leak is so massive, we ought to see a
> *lot* of duplicates in there.  Seeing what kind of inodes really
> leaks could narrow the things down.
>
>See if cat /proc/fs/ext3 | sort | uniq -c | sort -nr gives anything
> interesting when leak happens (and check it right after boot to see
> if it works at all and doesn't oops, obviously ;-)

It doesn't Oops when I use that line, but at 15,000+ entries spit out 
all in one line of text, its a bit hard to locate real duplicates.  
But I think I see some right now!  Can this line be modified to spit 
them out, one entry per line with all dups sorted to be adjacent?

>diff -urN RC8-current/fs/ext3/super.c RC8-leak/fs/ext3/super.c
>--- RC8-current/fs/ext3/super.c	Sat Aug 14 05:35:37 2004
>+++ RC8-leak/fs/ext3/super.c	Sun Aug 15 04:41:09 2004
>@@ -35,6 +35,8 @@
> #include <linux/mount.h>
> #include <linux/namei.h>
> #include <linux/quotaops.h>
>+#include <linux/proc_fs.h>
>+#include <linux/seq_file.h>
> #include <asm/uaccess.h>
> #include "xattr.h"
> #include "acl.h"
>@@ -438,6 +440,9 @@
>
> static kmem_cache_t *ext3_inode_cachep;
>
>+static LIST_HEAD(ext3_list);
>+static spinlock_t ext3_list_lock = SPIN_LOCK_UNLOCKED;
>+
> /*
>  * Called inside transaction, so use GFP_NOFS
>  */
>@@ -453,11 +458,17 @@
> 	ei->i_default_acl = EXT3_ACL_NOT_CACHED;
> #endif
> 	ei->vfs_inode.i_version = 1;
>+	spin_lock(&ext3_list_lock);
>+	list_add(&ei->list, &ext3_list);
>+	spin_unlock(&ext3_list_lock);
> 	return &ei->vfs_inode;
> }
>
> static void ext3_destroy_inode(struct inode *inode)
> {
>+	spin_lock(&ext3_list_lock);
>+	list_del_init(&EXT3_I(inode)->list);
>+	spin_unlock(&ext3_list_lock);
> 	kmem_cache_free(ext3_inode_cachep, EXT3_I(inode));
> }
>
>@@ -475,20 +486,82 @@
> 		inode_init_once(&ei->vfs_inode);
> 	}
> }
>+
>+static void *ext3_cache_start(struct seq_file *m, loff_t *pos)
>+{
>+	struct list_head *p;
>+	loff_t l = *pos;
>+
>+	spin_lock(&ext3_list_lock);
>+	list_for_each(p, &ext3_list)
>+		if (!l--)
>+			return list_entry(p, struct ext3_inode_info, list);
>+	return NULL;
>+}
>+
>+static void *ext3_cache_next(struct seq_file *m, void *v, loff_t
> *pos) +{
>+	struct list_head *p = ((struct ext3_inode_info *)v)->list.next;
>+	(*pos)++;
>+	return p==&ext3_list ? NULL : list_entry(p, struct
> ext3_inode_info, list); +}
>+
>+static void ext3_cache_stop(struct seq_file *m, void *v)
>+{
>+	spin_unlock(&ext3_list_lock);
>+}
>+
>+static int ext3_cache_show(struct seq_file *m, void *v)
>+{
>+	struct ext3_inode_info *ei = v;
>+	struct inode *inode = &ei->vfs_inode;
>+	seq_printf(m, "%d:%d:%lu:%o",
>+		MAJOR(inode->i_sb->s_dev),
>+		MINOR(inode->i_sb->s_dev),
>+		inode->i_ino,
>+		inode->i_mode);
>+	return 0;
>+}
>+
>+static struct seq_operations ext3_cache_op = {
>+	.start	= ext3_cache_start,
>+	.next	= ext3_cache_next,
>+	.stop	= ext3_cache_stop,
>+	.show	= ext3_cache_show
>+};
>+
>+static int ext3_cache_open(struct inode *inode, struct file *file)
>+{
>+	return seq_open(file, &ext3_cache_op);
>+}
>+
>+static struct file_operations ext3_cache_operations = {
>+	.open		= ext3_cache_open,
>+	.read		= seq_read,
>+	.llseek		= seq_lseek,
>+	.release	= seq_release,
>+};
>
> static int init_inodecache(void)
> {
>+	struct proc_dir_entry *p;
> 	ext3_inode_cachep = kmem_cache_create("ext3_inode_cache",
> 					     sizeof(struct ext3_inode_info),
> 					     0, SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT,
> 					     init_once, NULL);
> 	if (ext3_inode_cachep == NULL)
> 		return -ENOMEM;
>+	p = create_proc_entry("fs/ext3", S_IRUGO, NULL);
>+	if (p) {
>+		p->owner = THIS_MODULE;
>+		p->proc_fops = &ext3_cache_operations;
>+	}
> 	return 0;
> }
>
> static void destroy_inodecache(void)
> {
>+	remove_proc_entry("fs/ext3", NULL);
> 	if (kmem_cache_destroy(ext3_inode_cachep))
> 		printk(KERN_INFO "ext3_inode_cache: not all structures were
> freed\n"); }
>diff -urN RC8-current/include/linux/ext3_fs_i.h
> RC8-leak/include/linux/ext3_fs_i.h ---
> RC8-current/include/linux/ext3_fs_i.h	Thu Oct  9 17:34:54 2003 +++
> RC8-leak/include/linux/ext3_fs_i.h	Sun Aug 15 04:11:03 2004 @@
> -107,6 +107,7 @@
> 	 * by other means, so we have truncate_sem.
> 	 */
> 	struct semaphore truncate_sem;
>+	struct list_head list;
> 	struct inode vfs_inode;
> };

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
99.24% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com attorneys please note, additions to this message
by Gene Heskett are:
Copyright 2004 by Maurice Eugene Heskett, all rights reserved.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/