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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 19/19] fs: do not assign default i_ino in new_inode
Date: Mon, 18 Oct 2010 11:11:39 +0200	[thread overview]
Message-ID: <1287393099.2409.8.camel@edumazet-laptop> (raw)
In-Reply-To: <20101016163517.GF20086@infradead.org>

Le samedi 16 octobre 2010 à 12:35 -0400, Christoph Hellwig a écrit :

> What's the point, really?  Assigning i_ino in new_inode always has been
> an utterly stupid idea to start with.  I fixed the few filesystem that
> need it to do it explicitly.  There's nothing unsafe about it - checking
> callers of new_inode for manual i_ino assignment was trivial.
> 
> Conditional code like the one you suggested is simply evil - it
> complicates things instead of simplifying them.

This is what we call code factorization. I wont call it evil.

If we want to change get_next_ino(void) implementation to 
get_next_ino(struct inode *), or even get_next_inode(struct inode
*inode, struct super_block *sb)
 then we must go through all fs after your patch to add the new
parameter.

I proposed an implementation on get_next_ino() on 32bit arches, with no
per_cpu and shared counter, assuming we know the inode pointer. With
your patch, it become very difficult to implement such an idea.




  reply	other threads:[~2010-10-18  9:11 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-16  8:13 Inode Lock Scalability V4 Dave Chinner
2010-10-16  8:13 ` [PATCH 01/19] fs: switch bdev inode bdi's correctly Dave Chinner
2010-10-16  9:30   ` Nick Piggin
2010-10-16 16:31   ` Christoph Hellwig
2010-10-16  8:13 ` [PATCH 02/19] kernel: add bl_list Dave Chinner
2010-10-16  9:51   ` Nick Piggin
2010-10-16 16:32     ` Christoph Hellwig
2010-10-16  8:13 ` [PATCH 03/19] fs: Convert nr_inodes and nr_unused to per-cpu counters Dave Chinner
2010-10-16  8:29   ` Eric Dumazet
2010-10-16 10:04     ` Dave Chinner
2010-10-16 10:04       ` Dave Chinner
2010-10-16 10:27       ` Eric Dumazet
2010-10-16 10:27         ` Eric Dumazet
2010-10-16 17:26         ` Peter Zijlstra
2010-10-17  1:09           ` Dave Chinner
2010-10-17  1:12             ` Christoph Hellwig
2010-10-17  2:16               ` Dave Chinner
2010-10-16  8:13 ` [PATCH 04/19] fs: Implement lazy LRU updates for inodes Dave Chinner
2010-10-16  9:29   ` Nick Piggin
2010-10-16 16:59     ` Christoph Hellwig
2010-10-16 17:29       ` Nick Piggin
2010-10-16 17:34         ` Nick Piggin
2010-10-17  0:47           ` Christoph Hellwig
2010-10-17  0:47         ` Christoph Hellwig
2010-10-17  2:09           ` Nick Piggin
2010-10-17  1:53       ` Dave Chinner
2010-10-16  8:13 ` [PATCH 05/19] fs: inode split IO and LRU lists Dave Chinner
2010-10-16  8:14 ` [PATCH 06/19] fs: Clean up inode reference counting Dave Chinner
2010-10-16  8:14 ` [PATCH 07/19] exofs: use iput() for inode reference count decrements Dave Chinner
2010-10-16  8:14 ` [PATCH 08/19] fs: rework icount to be a locked variable Dave Chinner
2010-10-16  8:14 ` [PATCH 09/19] fs: Factor inode hash operations into functions Dave Chinner
2010-10-16  8:14 ` [PATCH 10/19] fs: Introduce per-bucket inode hash locks Dave Chinner
2010-10-16  8:14 ` [PATCH 11/19] fs: add a per-superblock lock for the inode list Dave Chinner
2010-10-16  8:14 ` [PATCH 12/19] fs: split locking of inode writeback and LRU lists Dave Chinner
2010-10-16  8:14 ` [PATCH 13/19] fs: Protect inode->i_state with the inode->i_lock Dave Chinner
2010-10-16  8:14 ` [PATCH 14/19] fs: introduce a per-cpu last_ino allocator Dave Chinner
2010-10-16  8:14 ` [PATCH 15/19] fs: Make iunique independent of inode_lock Dave Chinner
2010-10-16  8:14 ` [PATCH 16/19] fs: icache remove inode_lock Dave Chinner
2010-10-16  8:14 ` [PATCH 17/19] fs: Reduce inode I_FREEING and factor inode disposal Dave Chinner
2010-10-17  1:30   ` Christoph Hellwig
2010-10-17  2:49     ` Nick Piggin
2010-10-17  4:13       ` Dave Chinner
2010-10-17  4:35         ` Nick Piggin
2010-10-17  5:13           ` Nick Piggin
2010-10-17  6:52             ` Dave Chinner
2010-10-17  7:05               ` Nick Piggin
2010-10-17 23:39                 ` Dave Chinner
2010-10-18 21:27               ` Sage Weil
2010-10-19  3:54                 ` Nick Piggin
2010-10-16  8:14 ` [PATCH 18/19] fs: split __inode_add_to_list Dave Chinner
2010-10-16  8:14 ` [PATCH 19/19] fs: do not assign default i_ino in new_inode Dave Chinner
2010-10-16  9:09   ` Eric Dumazet
2010-10-16  9:09     ` Eric Dumazet
2010-10-16 16:35     ` Christoph Hellwig
2010-10-18  9:11       ` Eric Dumazet [this message]
2010-10-18 14:48         ` Christoph Hellwig
2010-10-16 17:55 ` Inode Lock Scalability V4 Nick Piggin
2010-10-17  2:47   ` Dave Chinner
2010-10-17  2:55     ` Nick Piggin
2010-10-17  2:57       ` Nick Piggin
2010-10-17  6:10       ` Dave Chinner
2010-10-17  6:34         ` Nick Piggin

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