Messages in this thread | | | Subject | Re: [patch 6/8] fuse: clean up setting i_size in write | From | Miklos Szeredi <> | Date | Tue, 18 Mar 2008 09:16:49 +0100 |
| |
> On Mon, 17 Mar 2008 20:19:14 +0100 Miklos Szeredi <miklos@szeredi.hu> wrote: > > > From: Miklos Szeredi <mszeredi@suse.cz> > > > > Extract common code for setting i_size in write functions into a > > common helper. > > > > Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> > > --- > > fs/fuse/file.c | 28 +++++++++++++++------------- > > 1 file changed, 15 insertions(+), 13 deletions(-) > > > > Index: linux/fs/fuse/file.c > > =================================================================== > > --- linux.orig/fs/fuse/file.c 2008-03-17 18:26:04.000000000 +0100 > > +++ linux/fs/fuse/file.c 2008-03-17 18:26:28.000000000 +0100 > > @@ -610,13 +610,24 @@ static int fuse_write_begin(struct file > > return 0; > > } > > > > +static void fuse_write_update_size(struct inode *inode, loff_t pos) > > +{ > > + struct fuse_conn *fc = get_fuse_conn(inode); > > + struct fuse_inode *fi = get_fuse_inode(inode); > > + > > + spin_lock(&fc->lock); > > + fi->attr_version = ++fc->attr_version; > > + if (pos > inode->i_size) > > + i_size_write(inode, pos); > > + spin_unlock(&fc->lock); > > +} > > > > ... > > > > @@ -766,12 +772,8 @@ static ssize_t fuse_direct_io(struct fil > > } > > fuse_put_request(fc, req); > > if (res > 0) { > > - if (write) { > > - spin_lock(&fc->lock); > > - if (pos > inode->i_size) > > - i_size_write(inode, pos); > > - spin_unlock(&fc->lock); > > - } > > + if (write) > > + fuse_write_update_size(inode, pos); > > We require that i_mutex be held here, to prevent i_size_write() deadlocks. > Is it held? >
No, fuse uses the per connection spinlock to protect against concurrent calls to i_size_write(), because in some cases holding i_mutex would be difficult.
Fuse already got painfully bitten by the i_size_write() deadlock, so I'm well aware of the problem :)
Miklos
| |