thr3ads.net - Btrfs devel - [PATCH] btrfs: add "no file data" flag to btrfs send ioctl [Jan 2013]

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Mark Fasheh

2013-Jan-07 21:51 UTC

[PATCH] btrfs: add "no file data" flag to btrfs send ioctl

This patch adds the flag, BTRFS_SEND_FLAG_NO_FILE_DATA to the btrfs send
ioctl code. When this flag is set, the btrfs send code will never write file
data into the stream (thus also avoiding expensive reads of that data in the
first place). BTRFS_SEND_C_UPDATE_EXTENT commands will be sent (instead of
BTRFS_SEND_C_WRITE) with an offset, length pair indicating the extent in
question.

This patch does not affect the operation of BTRFS_SEND_C_CLONE commands -
they will continue to be sent when a search finds an appropriate extent to
clone from.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
---
 fs/btrfs/ioctl.h |    7 +++++++
 fs/btrfs/send.c  |   45 +++++++++++++++++++++++++++++++++++++++++----
 fs/btrfs/send.h  |    1 +
 3 files changed, 49 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 731e287..1f6cfdd 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -363,6 +363,13 @@ struct btrfs_ioctl_received_subvol_args {
 	__u64	reserved[16];		/* in */
 };
 
+/*
+ * Caller doesn''t want file data in the send stream, even if the
+ * search of clone sources doesn''t find an extent. UPDATE_EXTENT
+ * commands will be sent instead of WRITE commands.
+ */
+#define BTRFS_SEND_FLAG_NO_FILE_DATA     0x1
+
 struct btrfs_ioctl_send_args {
 	__s64 send_fd;			/* in */
 	__u64 clone_sources_count;	/* in */
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index e78b297..d725536 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -85,6 +85,7 @@ struct send_ctx {
 	u32 send_max_size;
 	u64 total_send_size;
 	u64 cmd_send_size[BTRFS_SEND_C_MAX + 1];
+	u64 flags;	/* ''flags'' member of btrfs_ioctl_send_args is u64
*/
 
 	struct vfsmount *mnt;
 
@@ -3707,6 +3708,39 @@ out:
 	return ret;
 }
 
+/*
+ * Send an update extent command to user space.
+ */
+static int send_update_extent(struct send_ctx *sctx,
+			      u64 offset, u32 len)
+{
+	int ret = 0;
+	struct fs_path *p;
+
+	p = fs_path_alloc(sctx);
+	if (!p)
+		return -ENOMEM;
+
+	ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT);
+	if (ret < 0)
+		goto out;
+
+	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+	if (ret < 0)
+		goto out;
+
+	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len);
+
+	ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+	fs_path_free(sctx, p);
+	return ret;
+}
+
 static int send_write_or_clone(struct send_ctx *sctx,
 			       struct btrfs_path *path,
 			       struct btrfs_key *key,
@@ -3742,7 +3776,11 @@ static int send_write_or_clone(struct send_ctx *sctx,
 		goto out;
 	}
 
-	if (!clone_root) {
+	if (clone_root) {
+		ret = send_clone(sctx, offset, len, clone_root);
+	} else if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) {
+		ret = send_update_extent(sctx, offset, len);
+	} else {
 		while (pos < len) {
 			l = len - pos;
 			if (l > BTRFS_SEND_READ_SIZE)
@@ -3755,10 +3793,7 @@ static int send_write_or_clone(struct send_ctx *sctx,
 			pos += ret;
 		}
 		ret = 0;
-	} else {
-		ret = send_clone(sctx, offset, len, clone_root);
 	}
-
 out:
 	return ret;
 }
@@ -4570,6 +4605,8 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user
*arg_)
 	INIT_RADIX_TREE(&sctx->name_cache, GFP_NOFS);
 	INIT_LIST_HEAD(&sctx->name_cache_list);
 
+	sctx->flags = arg->flags;
+
 	sctx->send_filp = fget(arg->send_fd);
 	if (IS_ERR(sctx->send_filp)) {
 		ret = PTR_ERR(sctx->send_filp);
diff --git a/fs/btrfs/send.h b/fs/btrfs/send.h
index 1bf4f32..8bb18f7 100644
--- a/fs/btrfs/send.h
+++ b/fs/btrfs/send.h
@@ -86,6 +86,7 @@ enum btrfs_send_cmd {
 	BTRFS_SEND_C_UTIMES,
 
 	BTRFS_SEND_C_END,
+	BTRFS_SEND_C_UPDATE_EXTENT,
 	__BTRFS_SEND_C_MAX,
 };
 #define BTRFS_SEND_C_MAX (__BTRFS_SEND_C_MAX - 1)
-- 
1.7.7

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David Sterba

2013-Jan-07 22:01 UTC

head link

Re: [PATCH] btrfs: add "no file data" flag to btrfs send ioctl

On Mon, Jan 07, 2013 at 01:51:19PM -0800, Mark Fasheh
wrote:> +#define BTRFS_SEND_FLAG_NO_FILE_DATA     0x1
> +
> +	sctx->flags = arg->flags;
> +
For compatibility reasons, you should mask the user input value and only
allow the supported flag(s).

david
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Mark Fasheh

2013-Jan-07 23:33 UTC

head link

Re: [PATCH] btrfs: add "no file data" flag to btrfs send ioctl

On Mon, Jan 07, 2013 at 11:01:17PM +0100, David Sterba
wrote:> On Mon, Jan 07, 2013 at 01:51:19PM -0800, Mark Fasheh wrote:
> > +#define BTRFS_SEND_FLAG_NO_FILE_DATA     0x1
> > +
> 
> > +	sctx->flags = arg->flags;
> > +
> 
> For compatibility reasons, you should mask the user input value and only
> allow the supported flag(s).
Fixed, and tested. Thanks for the review David!
	--Mark

--
Mark Fasheh


From 601b60fa3fa9e319c11f91fd317dda3fac43b955 Mon Sep 17 00:00:00 2001

btrfs: add "no file data" flag to btrfs send ioctl

This patch adds the flag, BTRFS_SEND_FLAG_NO_FILE_DATA to the btrfs send
ioctl code. When this flag is set, the btrfs send code will never write file
data into the stream (thus also avoiding expensive reads of that data in the
first place). BTRFS_SEND_C_UPDATE_EXTENT commands will be sent (instead of
BTRFS_SEND_C_WRITE) with an offset, length pair indicating the extent in
question.

This patch does not affect the operation of BTRFS_SEND_C_CLONE commands -
they will continue to be sent when a search finds an appropriate extent to
clone from.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
---
 fs/btrfs/ioctl.h |    7 +++++++
 fs/btrfs/send.c  |   48 ++++++++++++++++++++++++++++++++++++++++++++----
 fs/btrfs/send.h  |    1 +
 3 files changed, 52 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 731e287..1f6cfdd 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -363,6 +363,13 @@ struct btrfs_ioctl_received_subvol_args {
 	__u64	reserved[16];		/* in */
 };
 
+/*
+ * Caller doesn''t want file data in the send stream, even if the
+ * search of clone sources doesn''t find an extent. UPDATE_EXTENT
+ * commands will be sent instead of WRITE commands.
+ */
+#define BTRFS_SEND_FLAG_NO_FILE_DATA     0x1
+
 struct btrfs_ioctl_send_args {
 	__s64 send_fd;			/* in */
 	__u64 clone_sources_count;	/* in */
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index e78b297..8d0c6b4 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -85,6 +85,7 @@ struct send_ctx {
 	u32 send_max_size;
 	u64 total_send_size;
 	u64 cmd_send_size[BTRFS_SEND_C_MAX + 1];
+	u64 flags;	/* ''flags'' member of btrfs_ioctl_send_args is u64
*/
 
 	struct vfsmount *mnt;
 
@@ -3707,6 +3708,39 @@ out:
 	return ret;
 }
 
+/*
+ * Send an update extent command to user space.
+ */
+static int send_update_extent(struct send_ctx *sctx,
+			      u64 offset, u32 len)
+{
+	int ret = 0;
+	struct fs_path *p;
+
+	p = fs_path_alloc(sctx);
+	if (!p)
+		return -ENOMEM;
+
+	ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT);
+	if (ret < 0)
+		goto out;
+
+	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+	if (ret < 0)
+		goto out;
+
+	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
+	TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len);
+
+	ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+	fs_path_free(sctx, p);
+	return ret;
+}
+
 static int send_write_or_clone(struct send_ctx *sctx,
 			       struct btrfs_path *path,
 			       struct btrfs_key *key,
@@ -3742,7 +3776,11 @@ static int send_write_or_clone(struct send_ctx *sctx,
 		goto out;
 	}
 
-	if (!clone_root) {
+	if (clone_root) {
+		ret = send_clone(sctx, offset, len, clone_root);
+	} else if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) {
+		ret = send_update_extent(sctx, offset, len);
+	} else {
 		while (pos < len) {
 			l = len - pos;
 			if (l > BTRFS_SEND_READ_SIZE)
@@ -3755,10 +3793,7 @@ static int send_write_or_clone(struct send_ctx *sctx,
 			pos += ret;
 		}
 		ret = 0;
-	} else {
-		ret = send_clone(sctx, offset, len, clone_root);
 	}
-
 out:
 	return ret;
 }
@@ -4570,6 +4605,11 @@ long btrfs_ioctl_send(struct file *mnt_file, void __user
*arg_)
 	INIT_RADIX_TREE(&sctx->name_cache, GFP_NOFS);
 	INIT_LIST_HEAD(&sctx->name_cache_list);
 
+	if (arg->flags & ~BTRFS_SEND_FLAG_NO_FILE_DATA)
+		return -EINVAL;
+
+	sctx->flags = arg->flags;
+
 	sctx->send_filp = fget(arg->send_fd);
 	if (IS_ERR(sctx->send_filp)) {
 		ret = PTR_ERR(sctx->send_filp);
diff --git a/fs/btrfs/send.h b/fs/btrfs/send.h
index 1bf4f32..8bb18f7 100644
--- a/fs/btrfs/send.h
+++ b/fs/btrfs/send.h
@@ -86,6 +86,7 @@ enum btrfs_send_cmd {
 	BTRFS_SEND_C_UTIMES,
 
 	BTRFS_SEND_C_END,
+	BTRFS_SEND_C_UPDATE_EXTENT,
 	__BTRFS_SEND_C_MAX,
 };
 #define BTRFS_SEND_C_MAX (__BTRFS_SEND_C_MAX - 1)
-- 
1.7.7

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Tsutomu Itoh

2013-Jan-08 00:34 UTC

head link

Re: [PATCH] btrfs: add "no file data" flag to btrfs send ioctl

(2013/01/08 8:33), Mark Fasheh wrote:> On Mon, Jan 07, 2013 at 11:01:17PM +0100, David Sterba wrote:
>> On Mon, Jan 07, 2013 at 01:51:19PM -0800, Mark Fasheh wrote:
>>> +#define BTRFS_SEND_FLAG_NO_FILE_DATA     0x1
>>> +
>>
>>> +	sctx->flags = arg->flags;
>>> +
>>
>> For compatibility reasons, you should mask the user input value and
only
>> allow the supported flag(s).
>
> Fixed, and tested. Thanks for the review David!
> 	--Mark
>
> --
> Mark Fasheh
>
>
>>From 601b60fa3fa9e319c11f91fd317dda3fac43b955 Mon Sep 17 00:00:00 2001
>
> btrfs: add "no file data" flag to btrfs send ioctl
>
> This patch adds the flag, BTRFS_SEND_FLAG_NO_FILE_DATA to the btrfs send
> ioctl code. When this flag is set, the btrfs send code will never write
file
> data into the stream (thus also avoiding expensive reads of that data in
the
> first place). BTRFS_SEND_C_UPDATE_EXTENT commands will be sent (instead of
> BTRFS_SEND_C_WRITE) with an offset, length pair indicating the extent in
> question.
>
> This patch does not affect the operation of BTRFS_SEND_C_CLONE commands -
> they will continue to be sent when a search finds an appropriate extent to
> clone from.
>
> Signed-off-by: Mark Fasheh <mfasheh@suse.de>
> ---
>   fs/btrfs/ioctl.h |    7 +++++++
>   fs/btrfs/send.c  |   48 ++++++++++++++++++++++++++++++++++++++++++++----
>   fs/btrfs/send.h  |    1 +
>   3 files changed, 52 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
> index 731e287..1f6cfdd 100644
> --- a/fs/btrfs/ioctl.h
> +++ b/fs/btrfs/ioctl.h
> @@ -363,6 +363,13 @@ struct btrfs_ioctl_received_subvol_args {
>   	__u64	reserved[16];		/* in */
>   };
>
> +/*
> + * Caller doesn''t want file data in the send stream, even if the
> + * search of clone sources doesn''t find an extent. UPDATE_EXTENT
> + * commands will be sent instead of WRITE commands.
> + */
> +#define BTRFS_SEND_FLAG_NO_FILE_DATA     0x1
> +
>   struct btrfs_ioctl_send_args {
>   	__s64 send_fd;			/* in */
>   	__u64 clone_sources_count;	/* in */
> diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
> index e78b297..8d0c6b4 100644
> --- a/fs/btrfs/send.c
> +++ b/fs/btrfs/send.c
> @@ -85,6 +85,7 @@ struct send_ctx {
>   	u32 send_max_size;
>   	u64 total_send_size;
>   	u64 cmd_send_size[BTRFS_SEND_C_MAX + 1];
> +	u64 flags;	/* ''flags'' member of btrfs_ioctl_send_args
is u64 */
>
>   	struct vfsmount *mnt;
>
> @@ -3707,6 +3708,39 @@ out:
>   	return ret;
>   }
>
> +/*
> + * Send an update extent command to user space.
> + */
> +static int send_update_extent(struct send_ctx *sctx,
> +			      u64 offset, u32 len)
> +{
> +	int ret = 0;
> +	struct fs_path *p;
> +
> +	p = fs_path_alloc(sctx);
> +	if (!p)
> +		return -ENOMEM;
> +
> +	ret = begin_cmd(sctx, BTRFS_SEND_C_UPDATE_EXTENT);
> +	if (ret < 0)
> +		goto out;
> +
> +	ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
> +	if (ret < 0)
> +		goto out;
> +
> +	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
> +	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
> +	TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len);
> +
> +	ret = send_cmd(sctx);
> +
> +tlv_put_failure:
> +out:
> +	fs_path_free(sctx, p);
> +	return ret;
> +}
> +
>   static int send_write_or_clone(struct send_ctx *sctx,
>   			       struct btrfs_path *path,
>   			       struct btrfs_key *key,
> @@ -3742,7 +3776,11 @@ static int send_write_or_clone(struct send_ctx
*sctx,
>   		goto out;
>   	}
>
> -	if (!clone_root) {
> +	if (clone_root) {
> +		ret = send_clone(sctx, offset, len, clone_root);
> +	} else if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) {
> +		ret = send_update_extent(sctx, offset, len);
> +	} else {
>   		while (pos < len) {
>   			l = len - pos;
>   			if (l > BTRFS_SEND_READ_SIZE)
> @@ -3755,10 +3793,7 @@ static int send_write_or_clone(struct send_ctx
*sctx,
>   			pos += ret;
>   		}
>   		ret = 0;
> -	} else {
> -		ret = send_clone(sctx, offset, len, clone_root);
>   	}
> -
>   out:
>   	return ret;
>   }
> @@ -4570,6 +4605,11 @@ long btrfs_ioctl_send(struct file *mnt_file, void
__user *arg_)
>   	INIT_RADIX_TREE(&sctx->name_cache, GFP_NOFS);
>   	INIT_LIST_HEAD(&sctx->name_cache_list);
>
> +	if (arg->flags & ~BTRFS_SEND_FLAG_NO_FILE_DATA)
> +		return -EINVAL;
I like

#define BTRFS_SEND_FLAGS	(BTRFS_SEND_FLAG_NO_FILE_DATA | ...)
	if (arg->flags & ~BTRFS_SEND_FLAGS)
		return -EINVAL;

even if current flag is only one.

Thanks,
Tsutomu
> +
> +	sctx->flags = arg->flags;
> +
>   	sctx->send_filp = fget(arg->send_fd);
>   	if (IS_ERR(sctx->send_filp)) {
>   		ret = PTR_ERR(sctx->send_filp);
> diff --git a/fs/btrfs/send.h b/fs/btrfs/send.h
> index 1bf4f32..8bb18f7 100644
> --- a/fs/btrfs/send.h
> +++ b/fs/btrfs/send.h
> @@ -86,6 +86,7 @@ enum btrfs_send_cmd {
>   	BTRFS_SEND_C_UTIMES,
>
>   	BTRFS_SEND_C_END,
> +	BTRFS_SEND_C_UPDATE_EXTENT,
>   	__BTRFS_SEND_C_MAX,
>   };
>   #define BTRFS_SEND_C_MAX (__BTRFS_SEND_C_MAX - 1)
>
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