From: David Sterba <dave@jikos.cz>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH 2/4] Btrfs: use i_size_read() in btrfs_defrag_file()
Date: Thu, 22 Sep 2011 12:58:17 +0200 [thread overview]
Message-ID: <20110922105817.GW22205@twin.jikos.cz> (raw)
In-Reply-To: <4E608C37.90908@cn.fujitsu.com>
On Fri, Sep 02, 2011 at 03:56:39PM +0800, Li Zefan wrote:
> Don't use inode->i_size directly, since we're not holding i_mutex.
>
> This also fixes another bug, that i_size can change after it's checked
> against 0 and then (i_size - 1) can be negative.
>
> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
> ---
> fs/btrfs/ioctl.c | 7 ++++---
> 1 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 31fe6d4..6f2b257 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -972,6 +972,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
> struct btrfs_super_block *disk_super;
> struct file_ra_state *ra = NULL;
> unsigned long last_index;
> + u64 isize = i_size_read(inode);
> u64 features;
> u64 last_len = 0;
> u64 skip = 0;
> @@ -997,7 +998,7 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
> compress_type = range->compress_type;
> }
>
> - if (inode->i_size == 0)
> + if (isize == 0)
> return 0;
>
> /*
> @@ -1022,10 +1023,10 @@ int btrfs_defrag_file(struct inode *inode, struct file *file,
>
> /* find the last page to defrag */
> if (range->start + range->len > range->start) {
> - last_index = min_t(u64, inode->i_size - 1,
> + last_index = min_t(u64, isize - 1,
> range->start + range->len - 1) >> PAGE_CACHE_SHIFT;
> } else {
> - last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT;
> + last_index = (isize - 1) >> PAGE_CACHE_SHIFT;
> }
>
> if (newer_than) {
> --
> 1.7.3.1
> --
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> More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2011-09-22 10:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-02 7:56 [PATCH 1/4] Btrfs: fix defragmentation regression Li Zefan
2011-09-02 7:56 ` [PATCH 2/4] Btrfs: use i_size_read() in btrfs_defrag_file() Li Zefan
2011-09-22 10:58 ` David Sterba [this message]
2011-09-02 7:56 ` [PATCH 3/4] Btrfs: fix wrong max_to_defrag " Li Zefan
2011-09-22 10:42 ` David Sterba
2011-09-02 7:57 ` [PATCH 4/4] Btrfs: honor extent thresh during defragmentation Li Zefan
2011-09-02 8:42 ` [PATCH 1/4] Btrfs: fix defragmentation regression Christoph Hellwig
2011-10-18 8:48 ` Dan Merillat
2011-10-18 8:52 ` Li Zefan
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