From: Matthew Wilcox <willy@infradead.org>
To: Sean Anderson <seanga2@gmail.com>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-doc@vger.kernel.org, corbet@lwn.net
Subject: Re: [PATCH] Documentation: filesystems: update filesystem locking documentation
Date: Mon, 31 Jul 2017 10:23:59 -0700 [thread overview]
Message-ID: <20170731172359.GJ15980@bombadil.infradead.org> (raw)
In-Reply-To: <2adf1174-ee74-5655-7b2e-3ea8b28ec2ae@gmail.com>
On Mon, Jul 31, 2017 at 11:53:35AM -0400, Sean Anderson wrote:
> - i_mutex(inode)
> -lookup: yes
> + i_rwsem(inode)
> +lookup: shared
> create: yes
Could you change all the 'yes' to 'exclusive' when it's changed from mutex
to rwsem?
> link: yes (both)
> mknod: yes
> @@ -92,7 +92,7 @@ atomic_open: yes
> tmpfile: no
>
>
> - Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
> + Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_rwsem on
> victim.
> cross-directory ->rename() has (per-superblock) ->s_vfs_rename_sem.
>
> @@ -111,7 +111,7 @@ prototypes:
>
> locking rules:
> all may block
> - i_mutex(inode)
> + i_rwsem(inode)
> list: no
> get: no
> set: yes
> @@ -217,7 +217,7 @@ prototypes:
> locking rules:
> All except set_page_dirty and freepage may block
>
> - PageLocked(page) i_mutex
> + PageLocked(page) i_rwsem
> writepage: yes, unlocks (see below)
> readpage: yes, unlocks
> writepages:
> @@ -439,6 +439,7 @@ prototypes:
> ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
> ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
> int (*iterate) (struct file *, struct dir_context *);
> + int (*iterate_shared) (struct file *, struct dir_context *);
> unsigned int (*poll) (struct file *, struct poll_table_struct *);
> long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
> long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
> @@ -480,6 +481,10 @@ mutex or just to use i_size_read() instead.
> Note: this does not protect the file->f_pos against concurrent modifications
> since this is something the userspace has to take care about.
>
> +->iterate() is called with i_rwsem held.
> +
> +->iterate_shared() is called with i_rwsem shared.
> +
> ->fasync() is responsible for maintaining the FASYNC bit in filp->f_flags.
> Most instances call fasync_helper(), which does that maintenance, so it's
> not normally something one needs to worry about. Return values > 0 will be
> --
> 2.13.2
>
next prev parent reply other threads:[~2017-07-31 17:24 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-31 15:53 [PATCH] Documentation: filesystems: update filesystem locking documentation Sean Anderson
2017-07-31 17:23 ` Matthew Wilcox [this message]
2017-08-01 11:09 ` [PATCH v2] " Sean Anderson
2017-08-01 11:15 ` Jeff Layton
2017-08-01 14:22 ` Jonathan Corbet
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