* [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned
@ 2017-01-08 14:47 Chandan Rajendra
2017-01-09 13:52 ` Christoph Hellwig
` (4 more replies)
0 siblings, 5 replies; 9+ messages in thread
From: Chandan Rajendra @ 2017-01-08 14:47 UTC (permalink / raw)
To: axboe, jack
Cc: Chandan Rajendra, linux-block, linux-fsdevel, linux-kernel,
anton, linuxppc-dev
The code currently uses sdio->blkbits to compute the number of blocks to
be cleaned. However sdio->blkbits is derived from the logical block size
of the underlying block device (Refer to the definition of
do_blockdev_direct_IO()). Due to this, generic/299 test would rarely
fail when executed on an ext4 filesystem with 64k as the block size and
when using a virtio based disk (having 512 byte as the logical block
size) inside a kvm guest.
This commit fixes the bug by using inode->i_blkbits to compute the
number of blocks to be cleaned.
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
---
fs/direct-io.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/direct-io.c b/fs/direct-io.c
index aeae8c0..b20adf9 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -905,6 +905,7 @@ static inline void dio_zero_block(struct dio *dio, struct dio_submit *sdio,
static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
struct buffer_head *map_bh)
{
+ const unsigned i_blkbits = dio->inode->i_blkbits;
const unsigned blkbits = sdio->blkbits;
int ret = 0;
@@ -949,7 +950,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
clean_bdev_aliases(
map_bh->b_bdev,
map_bh->b_blocknr,
- map_bh->b_size >> blkbits);
+ map_bh->b_size >> i_blkbits);
}
if (!sdio->blkfactor)
--
2.5.5
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned
2017-01-08 14:47 [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned Chandan Rajendra
@ 2017-01-09 13:52 ` Christoph Hellwig
2017-01-09 15:32 ` Jens Axboe
` (3 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Christoph Hellwig @ 2017-01-09 13:52 UTC (permalink / raw)
To: Chandan Rajendra
Cc: axboe, jack, linux-block, linux-fsdevel, linux-kernel, anton,
linuxppc-dev
On Sun, Jan 08, 2017 at 08:17:10PM +0530, Chandan Rajendra wrote:
> The code currently uses sdio->blkbits to compute the number of blocks to
> be cleaned. However sdio->blkbits is derived from the logical block size
> of the underlying block device (Refer to the definition of
> do_blockdev_direct_IO()). Due to this, generic/299 test would rarely
> fail when executed on an ext4 filesystem with 64k as the block size and
> when using a virtio based disk (having 512 byte as the logical block
> size) inside a kvm guest.
>
> This commit fixes the bug by using inode->i_blkbits to compute the
> number of blocks to be cleaned.
Looks fine,
Reviewed-by: Christoph Hellwig <hch@lst.de>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned
2017-01-08 14:47 [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned Chandan Rajendra
2017-01-09 13:52 ` Christoph Hellwig
@ 2017-01-09 15:32 ` Jens Axboe
2017-01-09 16:04 ` Jeff Moyer
` (2 subsequent siblings)
4 siblings, 0 replies; 9+ messages in thread
From: Jens Axboe @ 2017-01-09 15:32 UTC (permalink / raw)
To: Chandan Rajendra, jack
Cc: linux-block, linux-fsdevel, linux-kernel, anton, linuxppc-dev
On 01/08/2017 07:47 AM, Chandan Rajendra wrote:
> The code currently uses sdio->blkbits to compute the number of blocks to
> be cleaned. However sdio->blkbits is derived from the logical block size
> of the underlying block device (Refer to the definition of
> do_blockdev_direct_IO()). Due to this, generic/299 test would rarely
> fail when executed on an ext4 filesystem with 64k as the block size and
> when using a virtio based disk (having 512 byte as the logical block
> size) inside a kvm guest.
>
> This commit fixes the bug by using inode->i_blkbits to compute the
> number of blocks to be cleaned.
Thanks, added for 4.10.
--
Jens Axboe
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned
2017-01-08 14:47 [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned Chandan Rajendra
2017-01-09 13:52 ` Christoph Hellwig
2017-01-09 15:32 ` Jens Axboe
@ 2017-01-09 16:04 ` Jeff Moyer
2017-01-09 20:20 ` Jan Kara
2017-01-09 21:42 ` [PATCH] direct-io: don't introduce another read of inode->i_blkbits Jeff Moyer
4 siblings, 0 replies; 9+ messages in thread
From: Jeff Moyer @ 2017-01-09 16:04 UTC (permalink / raw)
To: Chandan Rajendra
Cc: axboe, jack, linux-block, linux-fsdevel, linux-kernel, anton,
linuxppc-dev
Chandan Rajendra <chandan@linux.vnet.ibm.com> writes:
> The code currently uses sdio->blkbits to compute the number of blocks to
> be cleaned. However sdio->blkbits is derived from the logical block size
> of the underlying block device (Refer to the definition of
> do_blockdev_direct_IO()). Due to this, generic/299 test would rarely
> fail when executed on an ext4 filesystem with 64k as the block size and
> when using a virtio based disk (having 512 byte as the logical block
> size) inside a kvm guest.
>
> This commit fixes the bug by using inode->i_blkbits to compute the
> number of blocks to be cleaned.
>
> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
> ---
> fs/direct-io.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/direct-io.c b/fs/direct-io.c
> index aeae8c0..b20adf9 100644
> --- a/fs/direct-io.c
> +++ b/fs/direct-io.c
> @@ -905,6 +905,7 @@ static inline void dio_zero_block(struct dio *dio, struct dio_submit *sdio,
> static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
> struct buffer_head *map_bh)
> {
> + const unsigned i_blkbits = dio->inode->i_blkbits;
NAK. Please see commit ab73857e354 ("direct-io: don't read
inode->i_blkbits multiple times").
I think you want:
const unsigned i_blkbits = sdio->blkbits + sdio->blkfactor;
as is used elsewhere in the code.
Cheers,
Jeff
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned
2017-01-08 14:47 [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned Chandan Rajendra
` (2 preceding siblings ...)
2017-01-09 16:04 ` Jeff Moyer
@ 2017-01-09 20:20 ` Jan Kara
2017-01-09 21:42 ` [PATCH] direct-io: don't introduce another read of inode->i_blkbits Jeff Moyer
4 siblings, 0 replies; 9+ messages in thread
From: Jan Kara @ 2017-01-09 20:20 UTC (permalink / raw)
To: Chandan Rajendra
Cc: axboe, jack, linux-block, linux-fsdevel, linux-kernel, anton,
linuxppc-dev
On Sun 08-01-17 20:17:10, Chandan Rajendra wrote:
> The code currently uses sdio->blkbits to compute the number of blocks to
> be cleaned. However sdio->blkbits is derived from the logical block size
> of the underlying block device (Refer to the definition of
> do_blockdev_direct_IO()). Due to this, generic/299 test would rarely
> fail when executed on an ext4 filesystem with 64k as the block size and
> when using a virtio based disk (having 512 byte as the logical block
> size) inside a kvm guest.
>
> This commit fixes the bug by using inode->i_blkbits to compute the
> number of blocks to be cleaned.
Ah, good catch. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>
Honza
> Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
> ---
> fs/direct-io.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/direct-io.c b/fs/direct-io.c
> index aeae8c0..b20adf9 100644
> --- a/fs/direct-io.c
> +++ b/fs/direct-io.c
> @@ -905,6 +905,7 @@ static inline void dio_zero_block(struct dio *dio, struct dio_submit *sdio,
> static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
> struct buffer_head *map_bh)
> {
> + const unsigned i_blkbits = dio->inode->i_blkbits;
> const unsigned blkbits = sdio->blkbits;
> int ret = 0;
>
> @@ -949,7 +950,7 @@ static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
> clean_bdev_aliases(
> map_bh->b_bdev,
> map_bh->b_blocknr,
> - map_bh->b_size >> blkbits);
> + map_bh->b_size >> i_blkbits);
> }
>
> if (!sdio->blkfactor)
> --
> 2.5.5
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH] direct-io: don't introduce another read of inode->i_blkbits
2017-01-08 14:47 [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned Chandan Rajendra
` (3 preceding siblings ...)
2017-01-09 20:20 ` Jan Kara
@ 2017-01-09 21:42 ` Jeff Moyer
2017-01-09 21:44 ` Jens Axboe
2017-01-10 5:27 ` Chandan Rajendra
4 siblings, 2 replies; 9+ messages in thread
From: Jeff Moyer @ 2017-01-09 21:42 UTC (permalink / raw)
To: axboe, Chandan Rajendra
Cc: jack, linux-block, linux-fsdevel, linux-kernel, anton, linuxppc-dev
Commit 20ce44d545844 ("do_direct_IO: Use inode->i_blkbits to compute
block count to be cleaned") introduced a regression: if the block size
of the block device is changed while a direct I/O request is being
setup, it can result in a panic. See commit ab73857e354ab ("direct-io:
don't read inode->i_blkbits multiple times") for the reasoning, and
commit b87570f5d3496 ("Fix a crash when block device is read and block
size is changed at the same time") for a more detailed problem
description and reproducer.
Fixes: 20ce44d545844
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
---
Chandan, can you please test this to ensure this still fixes your problem?
diff --git a/fs/direct-io.c b/fs/direct-io.c
index b20adf9..c87bae4 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -905,8 +905,8 @@ static inline void dio_zero_block(struct dio *dio, struct dio_submit *sdio,
static int do_direct_IO(struct dio *dio, struct dio_submit *sdio,
struct buffer_head *map_bh)
{
- const unsigned i_blkbits = dio->inode->i_blkbits;
const unsigned blkbits = sdio->blkbits;
+ const unsigned i_blkbits = blkbits + sdio->blkfactor;
int ret = 0;
while (sdio->block_in_file < sdio->final_block_in_request) {
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] direct-io: don't introduce another read of inode->i_blkbits
2017-01-09 21:42 ` [PATCH] direct-io: don't introduce another read of inode->i_blkbits Jeff Moyer
@ 2017-01-09 21:44 ` Jens Axboe
2017-01-10 5:27 ` Chandan Rajendra
1 sibling, 0 replies; 9+ messages in thread
From: Jens Axboe @ 2017-01-09 21:44 UTC (permalink / raw)
To: Jeff Moyer, Chandan Rajendra
Cc: jack, linux-block, linux-fsdevel, linux-kernel, anton, linuxppc-dev
On 01/09/2017 02:42 PM, Jeff Moyer wrote:
> Commit 20ce44d545844 ("do_direct_IO: Use inode->i_blkbits to compute
> block count to be cleaned") introduced a regression: if the block size
> of the block device is changed while a direct I/O request is being
> setup, it can result in a panic. See commit ab73857e354ab ("direct-io:
> don't read inode->i_blkbits multiple times") for the reasoning, and
> commit b87570f5d3496 ("Fix a crash when block device is read and block
> size is changed at the same time") for a more detailed problem
> description and reproducer.
>
> Fixes: 20ce44d545844
> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
>
> ---
> Chandan, can you please test this to ensure this still fixes your problem?
Please, that would be great. And if so, then let's fold the two.
--
Jens Axboe
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] direct-io: don't introduce another read of inode->i_blkbits
2017-01-09 21:42 ` [PATCH] direct-io: don't introduce another read of inode->i_blkbits Jeff Moyer
2017-01-09 21:44 ` Jens Axboe
@ 2017-01-10 5:27 ` Chandan Rajendra
2017-01-10 20:31 ` Jens Axboe
1 sibling, 1 reply; 9+ messages in thread
From: Chandan Rajendra @ 2017-01-10 5:27 UTC (permalink / raw)
To: Jeff Moyer
Cc: axboe, jack, linux-block, linux-fsdevel, linux-kernel, anton,
linuxppc-dev
On Monday, January 09, 2017 04:42:58 PM Jeff Moyer wrote:
> Commit 20ce44d545844 ("do_direct_IO: Use inode->i_blkbits to compute
> block count to be cleaned") introduced a regression: if the block size
> of the block device is changed while a direct I/O request is being
> setup, it can result in a panic. See commit ab73857e354ab ("direct-io:
> don't read inode->i_blkbits multiple times") for the reasoning, and
> commit b87570f5d3496 ("Fix a crash when block device is read and block
> size is changed at the same time") for a more detailed problem
> description and reproducer.
>
> Fixes: 20ce44d545844
> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
>
> ---
> Chandan, can you please test this to ensure this still fixes your problem?
This patch fixes the failure,
Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
--
chandan
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] direct-io: don't introduce another read of inode->i_blkbits
2017-01-10 5:27 ` Chandan Rajendra
@ 2017-01-10 20:31 ` Jens Axboe
0 siblings, 0 replies; 9+ messages in thread
From: Jens Axboe @ 2017-01-10 20:31 UTC (permalink / raw)
To: Chandan Rajendra, Jeff Moyer
Cc: jack, linux-block, linux-fsdevel, linux-kernel, anton, linuxppc-dev
On 01/09/2017 10:27 PM, Chandan Rajendra wrote:
> On Monday, January 09, 2017 04:42:58 PM Jeff Moyer wrote:
>> Commit 20ce44d545844 ("do_direct_IO: Use inode->i_blkbits to compute
>> block count to be cleaned") introduced a regression: if the block size
>> of the block device is changed while a direct I/O request is being
>> setup, it can result in a panic. See commit ab73857e354ab ("direct-io:
>> don't read inode->i_blkbits multiple times") for the reasoning, and
>> commit b87570f5d3496 ("Fix a crash when block device is read and block
>> size is changed at the same time") for a more detailed problem
>> description and reproducer.
>>
>> Fixes: 20ce44d545844
>> Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
>>
>> ---
>> Chandan, can you please test this to ensure this still fixes your problem?
>
> This patch fixes the failure,
>
> Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
>
I've updated the patch, thanks guys.
--
Jens Axboe
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2017-01-10 20:31 UTC | newest]
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2017-01-08 14:47 [PATCH] do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned Chandan Rajendra
2017-01-09 13:52 ` Christoph Hellwig
2017-01-09 15:32 ` Jens Axboe
2017-01-09 16:04 ` Jeff Moyer
2017-01-09 20:20 ` Jan Kara
2017-01-09 21:42 ` [PATCH] direct-io: don't introduce another read of inode->i_blkbits Jeff Moyer
2017-01-09 21:44 ` Jens Axboe
2017-01-10 5:27 ` Chandan Rajendra
2017-01-10 20:31 ` Jens Axboe
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