shhuiw@gmail.com
2012-Nov-30 06:02 UTC
[PATCH] Btrfs: remove warning check in io_ctl_map_page
From: Wang Sheng-Hui <shhuiw@gmail.com>
io_ctl_map_page is called by many functions in free-space-cache.
In some scenarios, the ->cur is not null, e.g. io_ctl_add_entry.
Remove the check here.
Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
---
fs/btrfs/free-space-cache.c | 1 -
1 files changed, 0 insertions(+), 1 deletions(-)
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index c3318cb..4ea66d4 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -307,7 +307,6 @@ static void io_ctl_unmap_page(struct io_ctl *io_ctl)
static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
{
- WARN_ON(io_ctl->cur);
BUG_ON(io_ctl->index >= io_ctl->num_pages);
io_ctl->page = io_ctl->pages[io_ctl->index++];
io_ctl->cur = kmap(io_ctl->page);
--
1.6.0.2
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On Fri, Nov 30, 2012 at 02:02:26PM +0800, shhuiw@gmail.com wrote:> From: Wang Sheng-Hui <shhuiw@gmail.com> > > io_ctl_map_page is called by many functions in free-space-cache. > In some scenarios, the ->cur is not null, e.g. io_ctl_add_entry. > Remove the check here.Hi Wang, Seems to be impossible according to the code, even in io_ctl_add_entry(). So have you seen such a warning in your flight running? If you do, maybe you can post it here and we can figure out the whys. thanks, liubo> > Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com> > --- > fs/btrfs/free-space-cache.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c > index c3318cb..4ea66d4 100644 > --- a/fs/btrfs/free-space-cache.c > +++ b/fs/btrfs/free-space-cache.c > @@ -307,7 +307,6 @@ static void io_ctl_unmap_page(struct io_ctl *io_ctl) > > static void io_ctl_map_page(struct io_ctl *io_ctl, int clear) > { > - WARN_ON(io_ctl->cur); > BUG_ON(io_ctl->index >= io_ctl->num_pages); > io_ctl->page = io_ctl->pages[io_ctl->index++]; > io_ctl->cur = kmap(io_ctl->page); > -- > 1.6.0.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Wang Sheng-Hui
2012-Nov-30 11:18 UTC
Re: [PATCH] Btrfs: remove warning check in io_ctl_map_page
On 2012年11月30日 17:02, Liu Bo wrote:> On Fri, Nov 30, 2012 at 02:02:26PM +0800, shhuiw@gmail.com wrote: >> From: Wang Sheng-Hui <shhuiw@gmail.com> >> >> io_ctl_map_page is called by many functions in free-space-cache. >> In some scenarios, the ->cur is not null, e.g. io_ctl_add_entry. >> Remove the check here. > > Hi Wang, > > Seems to be impossible according to the code, even in io_ctl_add_entry(). > > So have you seen such a warning in your flight running? If you do, > maybe you can post it here and we can figure out the whys. >Hi Liu Bo, I just walked through the code. reread io_ctl_add_entry, and just noticed that io_ctl_set_crc is called before io_ctl_map_page, which can guarantee the ->cur is set to null before map. Thanks for helping me understand the code. Regards, Sheng-Hui> thanks, > liubo > >> >> Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com> >> --- >> fs/btrfs/free-space-cache.c | 1 - >> 1 files changed, 0 insertions(+), 1 deletions(-) >> >> diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c >> index c3318cb..4ea66d4 100644 >> --- a/fs/btrfs/free-space-cache.c >> +++ b/fs/btrfs/free-space-cache.c >> @@ -307,7 +307,6 @@ static void io_ctl_unmap_page(struct io_ctl *io_ctl) >> >> static void io_ctl_map_page(struct io_ctl *io_ctl, int clear) >> { >> - WARN_ON(io_ctl->cur); >> BUG_ON(io_ctl->index >= io_ctl->num_pages); >> io_ctl->page = io_ctl->pages[io_ctl->index++]; >> io_ctl->cur = kmap(io_ctl->page); >> -- >> 1.6.0.2 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html