lkml.org 
[lkml]   [2006]   [Oct]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: fuse: fix hang on SMP
On 16/10/06 16:51 -0700, Andrew Morton wrote:
>On Mon, 16 Oct 2006 18:27:10 +0200
>Miklos Szeredi <miklos@szeredi.hu> wrote:
>
>> Fuse didn't always call i_size_write() with i_mutex held which caused
>> rare hangs on SMP/32bit.
>
>Yes, that is a bit of a trap. I'll maintain a patch in -mm which spits a
>warning if i_size_write() is called without i_mutex held.
>

>+void i_size_write(struct inode *inode, loff_t i_size)
>+{
>+ WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex));


Miklos' patch would generate this warning because he uses the spinlock
inside struct fuse_conn to synchronize the write:

+static void fuse_vmtruncate(struct inode *inode, loff_t offset)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ int need_trunc;
+
+ spin_lock(&fc->lock);
+ need_trunc = inode->i_size > offset;
+ i_size_write(inode, offset);
+ spin_unlock(&fc->lock);

--
Mike D. Day
IBM LTC
Cell: 919 412-3900
Sametime: ncmike@us.ibm.com AIM: ncmikeday Yahoo: ultra.runner
PGP key: http://www.ncultra.org/ncmike/pubkey.asc
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2006-10-17 14:57    [W:0.076 / U:0.948 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site