[PATCH 1/2] Btrfs: fix hang when failing to submit bio of directIO

[PATCH 1/2] Btrfs: fix hang when failing to submit bio of directIO

[Liu Bo]

The hang is uncoverd by generic/019.

btrfs_endio_direct_write() skips the "finish_ordered_fn" part when it hits
an error, thus those added ordered extents will never get processed, which
block processes that waiting for them via btrfs_start_ordered_extent().

This fixes the above, and meanwhile finish_ordered_fn will do the space
accounting work.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
 fs/btrfs/inode.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 8bb0136..7bf150a 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7855,8 +7855,6 @@ static void btrfs_endio_direct_write(struct bio *bio, int err)
 	struct bio *dio_bio;
 	int ret;
 
-	if (err)
-		goto out_done;
 again:
 	ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
 						   &ordered_offset,
@@ -7879,7 +7877,6 @@ out_test:
 		ordered = NULL;
 		goto again;
 	}
-out_done:
 	dio_bio = dip->dio_bio;
 
 	kfree(dip);
-- 
2.1.0

[PATCH 2/2] Btrfs: fix warning of bytes_may_use

[Liu Bo]

While running generic/019, dmesg got several warnings from
btrfs_free_reserved_data_space().

Test generic/019 produces some disk failures so sumbit dio will get errors,
in which case, btrfs_direct_IO() goes to the error handling and free
bytes_may_use, but the problem is that bytes_may_use has been free'd
during get_block().

This adds a runtime flag to show if we've gone through get_block(), if so,
don't do the cleanup work.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
 fs/btrfs/btrfs_inode.h |  2 ++
 fs/btrfs/inode.c       | 16 +++++++++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 0ef5cc1..81220b2 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -44,6 +44,8 @@
 #define BTRFS_INODE_IN_DELALLOC_LIST		9
 #define BTRFS_INODE_READDIO_NEED_LOCK		10
 #define BTRFS_INODE_HAS_PROPS		        11
+/* DIO is ready to submit */
+#define BTRFS_INODE_DIO_READY		        12
 /*
  * The following 3 bits are meant only for the btree inode.
  * When any of them is set, it means an error happened while writing an
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 7bf150a..438b56f 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -7530,6 +7530,7 @@ unlock:
 
 		current->journal_info = outstanding_extents;
 		btrfs_free_reserved_data_space(inode, len);
+		set_bit(BTRFS_INODE_DIO_READY, &BTRFS_I(inode)->runtime_flags);
 	}
 
 	/*
@@ -8311,9 +8312,18 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
 				   btrfs_submit_direct, flags);
 	if (iov_iter_rw(iter) == WRITE) {
 		current->journal_info = NULL;
-		if (ret < 0 && ret != -EIOCBQUEUED)
-			btrfs_delalloc_release_space(inode, count);
-		else if (ret >= 0 && (size_t)ret < count)
+		if (ret < 0 && ret != -EIOCBQUEUED) {
+			/*
+			 * If the error comes from submitting stage,
+			 * btrfs_get_blocsk_direct() has free'd data space,
+			 * and metadata space will be handled by
+			 * finish_ordered_fn, don't do that again to make
+			 * sure bytes_may_use is correct.
+			 */
+			if (!test_and_clear_bit(BTRFS_INODE_DIO_READY,
+				     &BTRFS_I(inode)->runtime_flags))
+				btrfs_delalloc_release_space(inode, count);
+		} else if (ret >= 0 && (size_t)ret < count)
 			btrfs_delalloc_release_space(inode,
 						     count - (size_t)ret);
 	}
-- 
2.1.0

Re: [PATCH 1/2] Btrfs: fix hang when failing to submit bio of directIO

[Filipe David Manana]

On Wed, Jun 17, 2015 at 9:59 AM, Liu Bo <bo.li.liu@oracle.com> wrote:
> The hang is uncoverd by generic/019.
>
> btrfs_endio_direct_write() skips the "finish_ordered_fn" part when it hits
> an error, thus those added ordered extents will never get processed, which
> block processes that waiting for them via btrfs_start_ordered_extent().
>
> This fixes the above, and meanwhile finish_ordered_fn will do the space
> accounting work.
>
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>

> ---
>  fs/btrfs/inode.c | 3 ---
>  1 file changed, 3 deletions(-)
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 8bb0136..7bf150a 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -7855,8 +7855,6 @@ static void btrfs_endio_direct_write(struct bio *bio, int err)
>         struct bio *dio_bio;
>         int ret;
>
> -       if (err)
> -               goto out_done;
>  again:
>         ret = btrfs_dec_test_first_ordered_pending(inode, &ordered,
>                                                    &ordered_offset,
> @@ -7879,7 +7877,6 @@ out_test:
>                 ordered = NULL;
>                 goto again;
>         }
> -out_done:
>         dio_bio = dip->dio_bio;
>
>         kfree(dip);
> --
> 2.1.0
>
> --
> 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



-- 
Filipe David Manana,

"Reasonable men adapt themselves to the world.
 Unreasonable men adapt the world to themselves.
 That's why all progress depends on unreasonable men."

Re: [PATCH 2/2] Btrfs: fix warning of bytes_may_use

[Filipe David Manana]

On Wed, Jun 17, 2015 at 9:59 AM, Liu Bo <bo.li.liu@oracle.com> wrote:
> While running generic/019, dmesg got several warnings from
> btrfs_free_reserved_data_space().
>
> Test generic/019 produces some disk failures so sumbit dio will get errors,
> in which case, btrfs_direct_IO() goes to the error handling and free
> bytes_may_use, but the problem is that bytes_may_use has been free'd
> during get_block().
>
> This adds a runtime flag to show if we've gone through get_block(), if so,
> don't do the cleanup work.
>
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>

> ---
>  fs/btrfs/btrfs_inode.h |  2 ++
>  fs/btrfs/inode.c       | 16 +++++++++++++---
>  2 files changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
> index 0ef5cc1..81220b2 100644
> --- a/fs/btrfs/btrfs_inode.h
> +++ b/fs/btrfs/btrfs_inode.h
> @@ -44,6 +44,8 @@
>  #define BTRFS_INODE_IN_DELALLOC_LIST           9
>  #define BTRFS_INODE_READDIO_NEED_LOCK          10
>  #define BTRFS_INODE_HAS_PROPS                  11
> +/* DIO is ready to submit */
> +#define BTRFS_INODE_DIO_READY                  12
>  /*
>   * The following 3 bits are meant only for the btree inode.
>   * When any of them is set, it means an error happened while writing an
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index 7bf150a..438b56f 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -7530,6 +7530,7 @@ unlock:
>
>                 current->journal_info = outstanding_extents;
>                 btrfs_free_reserved_data_space(inode, len);
> +               set_bit(BTRFS_INODE_DIO_READY, &BTRFS_I(inode)->runtime_flags);
>         }
>
>         /*
> @@ -8311,9 +8312,18 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
>                                    btrfs_submit_direct, flags);
>         if (iov_iter_rw(iter) == WRITE) {
>                 current->journal_info = NULL;
> -               if (ret < 0 && ret != -EIOCBQUEUED)
> -                       btrfs_delalloc_release_space(inode, count);
> -               else if (ret >= 0 && (size_t)ret < count)
> +               if (ret < 0 && ret != -EIOCBQUEUED) {
> +                       /*
> +                        * If the error comes from submitting stage,
> +                        * btrfs_get_blocsk_direct() has free'd data space,
> +                        * and metadata space will be handled by
> +                        * finish_ordered_fn, don't do that again to make
> +                        * sure bytes_may_use is correct.
> +                        */
> +                       if (!test_and_clear_bit(BTRFS_INODE_DIO_READY,
> +                                    &BTRFS_I(inode)->runtime_flags))
> +                               btrfs_delalloc_release_space(inode, count);
> +               } else if (ret >= 0 && (size_t)ret < count)
>                         btrfs_delalloc_release_space(inode,
>                                                      count - (size_t)ret);
>         }
> --
> 2.1.0
>
> --
> 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



-- 
Filipe David Manana,

"Reasonable men adapt themselves to the world.
 Unreasonable men adapt the world to themselves.
 That's why all progress depends on unreasonable men."