Re: [PATCH] trivial: inode uses a mutex instead of a semaphore.

From: Jiri Kosina
Date: Mon May 10 2010 - 17:43:05 EST


On Tue, 27 Apr 2010, Thadeu Lima de Souza Cascardo wrote:

> Replace the introduced i_sem by an i_mutex in the filesystem locking
> documentation. This was introduced [1] after all occurrences were
> already replaced in the same text [2]. However, the term "inode
> semaphore" has not been replaced then, and it's replaced now.
>
> [1] afddba49d18f346e5cc2938b6ed7c512db18ca68
> [2] a7bc02f4f47fd0e7860c6589f0ad000d1476f7a3
>
> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@xxxxxxxxxxxxxx>
> Cc: Nick Piggin <npiggin@xxxxxxx>
> Cc: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>
> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> ---
> Documentation/filesystems/Locking | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
> index 06bbbed..af16080 100644
> --- a/Documentation/filesystems/Locking
> +++ b/Documentation/filesystems/Locking
> @@ -178,7 +178,7 @@ prototypes:
> locking rules:
> All except set_page_dirty may block
>
> - BKL PageLocked(page) i_sem
> + BKL PageLocked(page) i_mutex
> writepage: no yes, unlocks (see below)
> readpage: no yes, unlocks
> sync_page: no maybe
> @@ -429,7 +429,7 @@ check_flags: no
> implementations. If your fs is not using generic_file_llseek, you
> need to acquire and release the appropriate locks in your ->llseek().
> For many filesystems, it is probably safe to acquire the inode
> -semaphore. Note some filesystems (i.e. remote ones) provide no
> +mutex. Note some filesystems (i.e. remote ones) provide no
> protection for i_size so you will need to use the BKL.
>
> Note: ext2_release() was *the* source of contention on fs-intensive

This doesn't seem to be present in linux-next as of today. I have applied
the patch to trivial queue.

Thanks,

--
Jiri Kosina
SUSE Labs, Novell Inc.
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