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From: "Steve French" <smfrench@gmail.com>
To: "Andi Kleen" <ak@suse.de>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Trond Myklebust" <Trond.Myklebust@netapp.com>,
swhiteho@redhat.com, sfrench@samba.org, vandrove@vc.cvut.cz,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] [8/18] BKL-removal: Remove BKL from remote_llseek
Date: Mon, 28 Jan 2008 12:33:42 -0600 [thread overview]
Message-ID: <524f69650801281033o542e18c5y696dc239b70f1307@mail.gmail.com> (raw)
In-Reply-To: <200801280917.52574.ak@suse.de>
On Jan 28, 2008 2:17 AM, Andi Kleen <ak@suse.de> wrote:
> > I completely agree. If one thread writes A and another writes B then the
> > kernel should record either A or B, not ((A & 0xffffffff00000000) | (B &
> > 0xffffffff))
>
> The problem is pretty nasty unfortunately. To solve it properly I think
> the file_operations->read/write prototypes would need to be changed
> because otherwise it is not possible to do atomic relative updates
> of f_pos. Right now the actual update is burrowed deeply in the low level
> read/write implementation. But that would be a huge impact all over
> the tree :/
If there were a wrapper around reads and writes of f_pos as there is
for i_size e.g. it would hit a lot of code, but not as many as I had
originally thought. the most important ones are in the vfs itself, where
there are only 59 uses of the field (not all need to be changed). ext3
has fewer (25), and cifs only 12 uses.
--
Thanks,
Steve
next prev parent reply other threads:[~2008-01-28 18:34 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-27 2:17 [PATCH] [0/18] Implement some low hanging BKL removal fruit in fs/* Andi Kleen
2008-01-27 2:17 ` [PATCH] [1/18] BKL-removal: Convert ext2 over to use unlocked_ioctl Andi Kleen
2008-01-27 2:17 ` [PATCH] [2/18] BKL-removal: Remove incorrect BKL comment in ext2 Andi Kleen
2008-01-27 2:17 ` [PATCH] [3/18] BKL-removal: Convert ext3 to use unlocked_ioctl Andi Kleen
2008-01-28 5:33 ` Andrew Morton
2008-01-28 6:02 ` Andi Kleen
2008-01-27 2:17 ` [PATCH] [4/18] ext3: Remove incorrect BKL comment Andi Kleen
2008-01-27 2:17 ` [PATCH] [5/18] BKL-removal: Remove incorrect comment refering to lock_kernel() from jbd/jbd2 Andi Kleen
2008-01-27 2:17 ` [PATCH] [6/18] BKL-removal: Convert ext4 to use unlocked_ioctl Andi Kleen
2008-01-27 2:17 ` [PATCH] [7/18] BKL-removal: Remove incorrect comments refering to BKL from ext4 Andi Kleen
2008-01-27 2:17 ` [PATCH] [8/18] BKL-removal: Remove BKL from remote_llseek Andi Kleen
2008-01-27 16:57 ` Steve French
2008-01-27 17:56 ` Trond Myklebust
2008-01-27 22:18 ` Steve French
2008-01-27 23:08 ` Trond Myklebust
2008-01-28 2:58 ` Andi Kleen
2008-01-28 4:13 ` Trond Myklebust
2008-01-28 4:38 ` Andi Kleen
2008-01-28 4:51 ` Trond Myklebust
2008-01-28 5:13 ` Andrew Morton
2008-01-28 8:17 ` Andi Kleen
2008-01-28 18:33 ` Steve French [this message]
2008-01-28 19:34 ` Dave Kleikamp
2008-01-28 12:56 ` Alan Cox
2008-01-28 13:27 ` Andi Kleen
2008-01-28 13:38 ` Alan Cox
2008-01-28 14:10 ` Andi Kleen
2008-01-28 14:50 ` Alan Cox
2008-01-28 15:13 ` Diego Calleja
2008-01-28 2:44 ` Andi Kleen
2008-01-28 2:43 ` Andi Kleen
2008-01-27 2:17 ` [PATCH] [9/18] BKL-removal: Use unlocked_ioctl for jfs Andi Kleen
2008-01-27 23:05 ` Dave Kleikamp
2008-01-27 2:17 ` [PATCH] [10/18] BKL-removal: Implement a compat_ioctl handler for JFS Andi Kleen
2008-01-27 23:05 ` Dave Kleikamp
2008-01-27 2:17 ` [PATCH] [11/18] BKL-removal: Convert ocfs2 over to unlocked_ioctl Andi Kleen
2008-01-27 2:17 ` [PATCH] [12/18] BKL-removal: Convert CIFS " Andi Kleen
2008-01-27 2:17 ` [PATCH] [13/18] BKL-removal: Add compat_ioctl for cifs Andi Kleen
2008-01-27 2:17 ` [PATCH] [14/18] BKL-removal: Add unlocked_fasync Andi Kleen
2008-01-27 7:05 ` KOSAKI Motohiro
2008-01-27 2:17 ` [PATCH] [15/18] BKL-removal: Convert pipe over to unlocked_fasync Andi Kleen
2008-01-27 2:17 ` [PATCH] [16/18] BKL-removal: Convert socket fasync " Andi Kleen
2008-01-27 2:17 ` [PATCH] [17/18] BKL-removal: Convert fuse " Andi Kleen
2008-01-27 2:17 ` [PATCH] [18/18] BKL-removal: Convert bad_inode " Andi Kleen
2008-01-28 1:59 ` [PATCH] [0/18] Implement some low hanging BKL removal fruit in fs/* Nick Piggin
2008-01-28 3:15 ` Andi Kleen
[not found] <9Q5hR-3MI-9@gated-at.bofh.it>
[not found] ` <9Qsob-7is-1@gated-at.bofh.it>
[not found] ` <9QtDz-121-11@gated-at.bofh.it>
[not found] ` <9QtWX-1qg-15@gated-at.bofh.it>
[not found] ` <9Qugj-1PK-1@gated-at.bofh.it>
2008-01-28 9:44 ` [PATCH] [8/18] BKL-removal: Remove BKL from remote_llseek Bodo Eggert
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