Re: [PATCH] ReiserFS _get_block_create_0 wrong behavior when I/O fails

[Vladimir Saveliev <vs@namesys.com>]

Hello

On Thu, 2005-06-16 at 14:41, Vladimir Saveliev wrote:
> Hello
> 
> On Thu, 2005-06-16 at 21:04, fs wrote:
> > Dear Vladimir Saveliev,
> > On Wed, 2005-06-15 at 11:41, Vladimir Saveliev wrote:
> > 
> > > > Patch:
> > > > diff -uNp /tmp/linux-2.6.12-rc6/fs/reiserfs/inode.c /tmp/linux-2.6.12-rc6.new/fs/reiserfs/inode.c
> > > > --- /tmp/linux-2.6.12-rc6/fs/reiserfs/inode.c	2005-06-06 11:22:29.000000000 -0400
> > > > +++ /tmp/linux-2.6.12-rc6.new/fs/reiserfs/inode.c	2005-06-15 13:56:45.552564512 -0400
> > > > @@ -254,6 +254,7 @@ static int _get_block_create_0 (struct i
> > > >      char * p = NULL;
> > > >      int chars;
> > > >      int ret ;
> > > > +    int result ;
> > > >      int done = 0 ;
> > > >      unsigned long offset ;
> > > >  
> > > > @@ -262,7 +263,8 @@ static int _get_block_create_0 (struct i
> > > >  		  (loff_t)block * inode->i_sb->s_blocksize + 1, TYPE_ANY, 3);
> > > >  
> > > >  research:
> > > > -    if (search_for_position_by_key (inode->i_sb, &key, &path) != POSITION_FOUND) {
> > > > +    result = search_for_position_by_key (inode->i_sb, &key, &path) ;
> > > > +    if (result != POSITION_FOUND) {
> > > >  	pathrelse (&path);
> > > >          if (p)
> > > >              kunmap(bh_result->b_page) ;
> > > > @@ -270,7 +272,8 @@ research:
> > > >  	// That there is some MMAPED data associated with it that is yet to be written to disk.
> > > >  	if ((args & GET_BLOCK_NO_HOLE) && !PageUptodate(bh_result->b_page) ) {
> > > >  	    return -ENOENT ;
> > > > -	}
> > > > +	}else if (result == IO_ERROR)
> > > > +		return -EIO ;
> > > >          return 0 ;
> > > >      }
> > > >      
> > > 
> > > Your patch is incomplete. There is one more search_for_position_by_key
> > > at the end of this function. You probably want to check its return value
> > > also.
> > I notice there's a comment
> > 	if (search_for_position_by_key (inode->i_sb, &key, &path) !=
> > POSITION_FOUND)
> > 	    // we read something from tail, even if now we got IO_ERROR <-
> > Here, can you explain more ?


Yes. reiserfs may store file page in different blocks. In this do {}
while loop it looks for different parts of page in the tree. If
search_for_position_by_key fails - one part of page is not found and
-EIO is to be returned.

> > 	    break;
> > 
> > 
> > 
> > -
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