[01/19] btrfs: qgroup: New function declaration for new reserve implement
diff mbox

Message ID 1441702615-18333-2-git-send-email-quwenruo@cn.fujitsu.com
State New
Headers show

Commit Message

Qu Wenruo Sept. 8, 2015, 8:56 a.m. UTC
Add new structures and functions for new qgroup reserve implement dirty
phase.
Which will focus on avoiding over-reserve as in that case, which means
for already reserved dirty space range, we won't reserve space again.

This patch adds the needed structure declaration and comments.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
---
 fs/btrfs/btrfs_inode.h |  4 ++++
 fs/btrfs/qgroup.c      | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 fs/btrfs/qgroup.h      |  3 +++
 3 files changed, 65 insertions(+)

Comments

Tsutomu Itoh Sept. 9, 2015, 12:01 a.m. UTC | #1
Hi, Qu,

On 2015/09/08 17:56, Qu Wenruo wrote:
> Add new structures and functions for new qgroup reserve implement dirty
> phase.
> Which will focus on avoiding over-reserve as in that case, which means
> for already reserved dirty space range, we won't reserve space again.
> 
> This patch adds the needed structure declaration and comments.
> 
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
> ---
>   fs/btrfs/btrfs_inode.h |  4 ++++
>   fs/btrfs/qgroup.c      | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
>   fs/btrfs/qgroup.h      |  3 +++
>   3 files changed, 65 insertions(+)
> 
> diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
> index 81220b2..e3ece65 100644
> --- a/fs/btrfs/btrfs_inode.h
> +++ b/fs/btrfs/btrfs_inode.h
> @@ -24,6 +24,7 @@
>   #include "extent_io.h"
>   #include "ordered-data.h"
>   #include "delayed-inode.h"
> +#include "qgroup.h"
>   
>   /*
>    * ordered_data_close is set by truncate when a file that used
> @@ -195,6 +196,9 @@ struct btrfs_inode {
>   	struct timespec i_otime;
>   
>   	struct inode vfs_inode;
> +
> +	/* qgroup dirty map for data space reserve */
> +	struct btrfs_qgroup_data_rsv_map *qgroup_rsv_map;
>   };
>   
>   extern unsigned char btrfs_filetype_table[];
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index e9ace09..561c36d 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -91,6 +91,64 @@ struct btrfs_qgroup {
>   	u64 new_refcnt;
>   };
>   
> +/*
> + * Record one range of reserved space.
> + */
> +struct data_rsv_range {
> +	struct rb_node node;
> +	u64 start;
> +	u64 len;
> +};
> +
> +/*
> + * Record per inode reserved range.
> + * This is mainly used to resolve reserved space leaking problem.
> + * One of the cause is the mismatch with reserve and free.
> + *
> + * New qgroup will handle reserve in two phase.
> + * 1) Dirty phase.
> + *    Pages are just marked dirty, but not written to disk.
> + * 2) Flushed phase
> + *    Pages are written to disk, but transaction is not committed yet.
> + *

> + * At Diryt phase, we only need to focus on avoiding over-reserve.

         dirty

> + *
> + * The idea is like below.
> + * 1) Write [0,8K)
> + * 0	4K	8K	12K	16K
> + * |////////////|
> + * Reserve +8K, total reserved: 8K
> + *
> + * 2) Write [0,4K)
> + * 0	4K	8K	12K	16K
> + * |////////////|
> + * Reserve 0, total reserved 8K
> + *
> + * 3) Write [12K,16K)
> + * 0	4K	8K	12K	16K

> + * |////////////|	|///////|
> + * Reserve +4K, tocal reserved 12K

                   total

> + *
> + * 4) Flush [0,8K)
> + * Can happen without commit transaction, like fallocate will trigger the
> + * write.
> + * 0	4K	8K	12K	16K
> + *			|///////|

> + * Reserve 0, tocal reserved 12K

                 total

Thanks,
Tsutomu

> + * As the extent is written to disk, not dirty any longer, the range get
> + * removed.
> + * But as its delayed_refs is not run, its reserved space will not be freed.
> + * And things continue to Flushed phase.
> + *
> + * By this method, we can avoid over-reserve, which will lead to reserved
> + * space leak.
> + */
> +struct btrfs_qgroup_data_rsv_map {
> +	struct rb_root root;
> +	u64 reserved;
> +	spinlock_t lock;
> +};
> +
>   static void btrfs_qgroup_update_old_refcnt(struct btrfs_qgroup *qg, u64 seq,
>   					   int mod)
>   {
> diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
> index 6387dcf..2f863a4 100644
> --- a/fs/btrfs/qgroup.h
> +++ b/fs/btrfs/qgroup.h
> @@ -33,6 +33,9 @@ struct btrfs_qgroup_extent_record {
>   	struct ulist *old_roots;
>   };
>   
> +/* For per-inode dirty range reserve */
> +struct btrfs_qgroup_data_rsv_map;
> +
>   int btrfs_quota_enable(struct btrfs_trans_handle *trans,
>   		       struct btrfs_fs_info *fs_info);
>   int btrfs_quota_disable(struct btrfs_trans_handle *trans,
> 


--
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

Patch
diff mbox

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 81220b2..e3ece65 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -24,6 +24,7 @@ 
 #include "extent_io.h"
 #include "ordered-data.h"
 #include "delayed-inode.h"
+#include "qgroup.h"
 
 /*
  * ordered_data_close is set by truncate when a file that used
@@ -195,6 +196,9 @@  struct btrfs_inode {
 	struct timespec i_otime;
 
 	struct inode vfs_inode;
+
+	/* qgroup dirty map for data space reserve */
+	struct btrfs_qgroup_data_rsv_map *qgroup_rsv_map;
 };
 
 extern unsigned char btrfs_filetype_table[];
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index e9ace09..561c36d 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -91,6 +91,64 @@  struct btrfs_qgroup {
 	u64 new_refcnt;
 };
 
+/*
+ * Record one range of reserved space.
+ */
+struct data_rsv_range {
+	struct rb_node node;
+	u64 start;
+	u64 len;
+};
+
+/*
+ * Record per inode reserved range.
+ * This is mainly used to resolve reserved space leaking problem.
+ * One of the cause is the mismatch with reserve and free.
+ *
+ * New qgroup will handle reserve in two phase.
+ * 1) Dirty phase.
+ *    Pages are just marked dirty, but not written to disk.
+ * 2) Flushed phase
+ *    Pages are written to disk, but transaction is not committed yet.
+ *
+ * At Diryt phase, we only need to focus on avoiding over-reserve.
+ *
+ * The idea is like below.
+ * 1) Write [0,8K)
+ * 0	4K	8K	12K	16K
+ * |////////////|
+ * Reserve +8K, total reserved: 8K
+ *
+ * 2) Write [0,4K)
+ * 0	4K	8K	12K	16K
+ * |////////////|
+ * Reserve 0, total reserved 8K
+ *
+ * 3) Write [12K,16K)
+ * 0	4K	8K	12K	16K
+ * |////////////|	|///////|
+ * Reserve +4K, tocal reserved 12K
+ *
+ * 4) Flush [0,8K)
+ * Can happen without commit transaction, like fallocate will trigger the
+ * write.
+ * 0	4K	8K	12K	16K
+ *			|///////|
+ * Reserve 0, tocal reserved 12K
+ * As the extent is written to disk, not dirty any longer, the range get
+ * removed.
+ * But as its delayed_refs is not run, its reserved space will not be freed.
+ * And things continue to Flushed phase.
+ *
+ * By this method, we can avoid over-reserve, which will lead to reserved
+ * space leak.
+ */
+struct btrfs_qgroup_data_rsv_map {
+	struct rb_root root;
+	u64 reserved;
+	spinlock_t lock;
+};
+
 static void btrfs_qgroup_update_old_refcnt(struct btrfs_qgroup *qg, u64 seq,
 					   int mod)
 {
diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
index 6387dcf..2f863a4 100644
--- a/fs/btrfs/qgroup.h
+++ b/fs/btrfs/qgroup.h
@@ -33,6 +33,9 @@  struct btrfs_qgroup_extent_record {
 	struct ulist *old_roots;
 };
 
+/* For per-inode dirty range reserve */
+struct btrfs_qgroup_data_rsv_map;
+
 int btrfs_quota_enable(struct btrfs_trans_handle *trans,
 		       struct btrfs_fs_info *fs_info);
 int btrfs_quota_disable(struct btrfs_trans_handle *trans,