[PATCH] Btrfs-progs/receive: sparse and pre-allocated file support, for btrfs-send mechanism

[PATCH] Btrfs-progs/receive: sparse and pre-allocated file support, for btrfs-send mechanism

[Chen Yang]

From: Chen Yang <chenyang.fnst@cn.fujitsu.com>
Date: Fri, 18 Jan 2013 14:54:31 +0800
Subject: [PATCH] Btrfs-progs/receive: sparse and pre-allocated file support
 for btrfs-send mechanism

When sending a file with sparse or pre-allocated part,
these parts will be sent as ZERO streams, and it's unnecessary.

To improve this, we add a punch command on the sending side, so the
receiving side changed with it. The main change is adding the punch
processing to receive command.

Signed-off-by: Cheng Yang <chenyang.fnst@cn.fujitsu.com>
---
 cmds-receive.c |   27 +++++++++++++++++++++++++++
 send-stream.c  |    6 ++++++
 send-stream.h  |    1 +
 send.h         |    3 ++-
 4 files changed, 36 insertions(+), 1 deletions(-)

diff --git a/cmds-receive.c b/cmds-receive.c
index a8be6fa..74cbfc4 100644
--- a/cmds-receive.c
+++ b/cmds-receive.c
@@ -37,6 +37,7 @@
 #include <sys/types.h>
 #include <sys/xattr.h>
 #include <uuid/uuid.h>
+#include <linux/falloc.h>
 
 #include "ctree.h"
 #include "ioctl.h"
@@ -508,6 +509,31 @@ out:
 	return ret;
 }
 
+static int process_punch(const char *path, u64 offset, u64 len, void *user)
+{
+	int ret = 0;
+	struct btrfs_receive *r = user;
+	char *full_path = path_cat(r->full_subvol_path, path);
+
+	ret = open_inode_for_write(r, full_path);
+	if (ret < 0)
+		goto out;
+
+	ret = fallocate(r->write_fd,
+		FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+		offset, len);
+	if (ret < 0) {
+		ret = -errno;
+		fprintf(stderr, "ERROR: punch %s failed. %s\n",
+				path, strerror(-ret));
+		goto out;
+	}
+
+out:
+	free(full_path);
+	return ret;
+}
+
 static int process_write(const char *path, const void *data, u64 offset,
 			 u64 len, void *user)
 {
@@ -777,6 +803,7 @@ struct btrfs_send_ops send_ops = {
 	.link = process_link,
 	.unlink = process_unlink,
 	.rmdir = process_rmdir,
+	.punch = process_punch,
 	.write = process_write,
 	.clone = process_clone,
 	.set_xattr = process_set_xattr,
diff --git a/send-stream.c b/send-stream.c
index 55fa728..9f3ede7 100644
--- a/send-stream.c
+++ b/send-stream.c
@@ -362,6 +362,12 @@ static int read_and_process_cmd(struct btrfs_send_stream *s)
 		TLV_GET_STRING(s, BTRFS_SEND_A_PATH, &path);
 		ret = s->ops->rmdir(path, s->user);
 		break;
+	case BTRFS_SEND_C_PUNCH:
+		TLV_GET_STRING(s, BTRFS_SEND_A_PATH, &path);
+		TLV_GET_U64(s, BTRFS_SEND_A_FILE_OFFSET, &offset);
+		TLV_GET_U64(s, BTRFS_SEND_A_SIZE, &len);
+		ret = s->ops->punch(path, offset, len, s->user);
+		break;
 	case BTRFS_SEND_C_WRITE:
 		TLV_GET_STRING(s, BTRFS_SEND_A_PATH, &path);
 		TLV_GET_U64(s, BTRFS_SEND_A_FILE_OFFSET, &offset);
diff --git a/send-stream.h b/send-stream.h
index b69b7f1..f83f2ac 100644
--- a/send-stream.h
+++ b/send-stream.h
@@ -34,6 +34,7 @@ struct btrfs_send_ops {
 	int (*link)(const char *path, const char *lnk, void *user);
 	int (*unlink)(const char *path, void *user);
 	int (*rmdir)(const char *path, void *user);
+	int (*punch)(const char *path, u64 offset, u64 len, void *user);
 	int (*write)(const char *path, const void *data, u64 offset, u64 len,
 		     void *user);
 	int (*clone)(const char *path, u64 offset, u64 len,
diff --git a/send.h b/send.h
index 9934e94..10a88d2 100644
--- a/send.h
+++ b/send.h
@@ -20,7 +20,7 @@
 #include "ctree.h"
 
 #define BTRFS_SEND_STREAM_MAGIC "btrfs-stream"
-#define BTRFS_SEND_STREAM_VERSION 1
+#define BTRFS_SEND_STREAM_VERSION 2
 
 #define BTRFS_SEND_BUF_SIZE (1024 * 64)
 #define BTRFS_SEND_READ_SIZE (1024 * 48)
@@ -80,6 +80,7 @@ enum btrfs_send_cmd {
 	BTRFS_SEND_C_WRITE,
 	BTRFS_SEND_C_CLONE,
 
+	BTRFS_SEND_C_PUNCH,
 	BTRFS_SEND_C_TRUNCATE,
 	BTRFS_SEND_C_CHMOD,
 	BTRFS_SEND_C_CHOWN,
-- 
1.7.7.6

Re: [PATCH] Btrfs-progs/receive: sparse and pre-allocated file support, for btrfs-send mechanism

[Alex Lyakas]

On Wed, Jan 23, 2013 at 1:04 PM, Chen Yang <chenyang.fnst@cn.fujitsu.com> wrote:
> From: Chen Yang <chenyang.fnst@cn.fujitsu.com>
> Date: Fri, 18 Jan 2013 14:54:31 +0800
> Subject: [PATCH] Btrfs-progs/receive: sparse and pre-allocated file support
>  for btrfs-send mechanism
>
> When sending a file with sparse or pre-allocated part,
> these parts will be sent as ZERO streams, and it's unnecessary.
>
> To improve this, we add a punch command on the sending side, so the
> receiving side changed with it. The main change is adding the punch
> processing to receive command.
>
> Signed-off-by: Cheng Yang <chenyang.fnst@cn.fujitsu.com>
> ---
>  cmds-receive.c |   27 +++++++++++++++++++++++++++
>  send-stream.c  |    6 ++++++
>  send-stream.h  |    1 +
>  send.h         |    3 ++-
>  4 files changed, 36 insertions(+), 1 deletions(-)
>
> diff --git a/cmds-receive.c b/cmds-receive.c
> index a8be6fa..74cbfc4 100644
> --- a/cmds-receive.c
> +++ b/cmds-receive.c
> @@ -37,6 +37,7 @@
>  #include <sys/types.h>
>  #include <sys/xattr.h>
>  #include <uuid/uuid.h>
> +#include <linux/falloc.h>
>
>  #include "ctree.h"
>  #include "ioctl.h"
> @@ -508,6 +509,31 @@ out:
>         return ret;
>  }
>
> +static int process_punch(const char *path, u64 offset, u64 len, void *user)
> +{
> +       int ret = 0;
> +       struct btrfs_receive *r = user;
> +       char *full_path = path_cat(r->full_subvol_path, path);
> +
> +       ret = open_inode_for_write(r, full_path);
> +       if (ret < 0)
> +               goto out;
> +
> +       ret = fallocate(r->write_fd,
> +               FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
> +               offset, len);
> +       if (ret < 0) {
> +               ret = -errno;
> +               fprintf(stderr, "ERROR: punch %s failed. %s\n",
> +                               path, strerror(-ret));
> +               goto out;
> +       }
> +
> +out:
> +       free(full_path);
> +       return ret;
> +}
> +
>  static int process_write(const char *path, const void *data, u64 offset,
>                          u64 len, void *user)
>  {
> @@ -777,6 +803,7 @@ struct btrfs_send_ops send_ops = {
>         .link = process_link,
>         .unlink = process_unlink,
>         .rmdir = process_rmdir,
> +       .punch = process_punch,
>         .write = process_write,
>         .clone = process_clone,
>         .set_xattr = process_set_xattr,
> diff --git a/send-stream.c b/send-stream.c
> index 55fa728..9f3ede7 100644
> --- a/send-stream.c
> +++ b/send-stream.c
> @@ -362,6 +362,12 @@ static int read_and_process_cmd(struct btrfs_send_stream *s)
>                 TLV_GET_STRING(s, BTRFS_SEND_A_PATH, &path);
>                 ret = s->ops->rmdir(path, s->user);
>                 break;
> +       case BTRFS_SEND_C_PUNCH:
> +               TLV_GET_STRING(s, BTRFS_SEND_A_PATH, &path);
> +               TLV_GET_U64(s, BTRFS_SEND_A_FILE_OFFSET, &offset);
> +               TLV_GET_U64(s, BTRFS_SEND_A_SIZE, &len);
> +               ret = s->ops->punch(path, offset, len, s->user);
> +               break;
>         case BTRFS_SEND_C_WRITE:
>                 TLV_GET_STRING(s, BTRFS_SEND_A_PATH, &path);
>                 TLV_GET_U64(s, BTRFS_SEND_A_FILE_OFFSET, &offset);
> diff --git a/send-stream.h b/send-stream.h
> index b69b7f1..f83f2ac 100644
> --- a/send-stream.h
> +++ b/send-stream.h
> @@ -34,6 +34,7 @@ struct btrfs_send_ops {
>         int (*link)(const char *path, const char *lnk, void *user);
>         int (*unlink)(const char *path, void *user);
>         int (*rmdir)(const char *path, void *user);
> +       int (*punch)(const char *path, u64 offset, u64 len, void *user);
>         int (*write)(const char *path, const void *data, u64 offset, u64 len,
>                      void *user);
>         int (*clone)(const char *path, u64 offset, u64 len,
> diff --git a/send.h b/send.h
> index 9934e94..10a88d2 100644
> --- a/send.h
> +++ b/send.h
> @@ -20,7 +20,7 @@
>  #include "ctree.h"
>
>  #define BTRFS_SEND_STREAM_MAGIC "btrfs-stream"
> -#define BTRFS_SEND_STREAM_VERSION 1
> +#define BTRFS_SEND_STREAM_VERSION 2
>
>  #define BTRFS_SEND_BUF_SIZE (1024 * 64)
>  #define BTRFS_SEND_READ_SIZE (1024 * 48)
> @@ -80,6 +80,7 @@ enum btrfs_send_cmd {
>         BTRFS_SEND_C_WRITE,
>         BTRFS_SEND_C_CLONE,
>
> +       BTRFS_SEND_C_PUNCH,
>         BTRFS_SEND_C_TRUNCATE,
>         BTRFS_SEND_C_CHMOD,
>         BTRFS_SEND_C_CHOWN,

I think this breaks the current protocol, because it changes the
numbers for existing commands, starting from BTRFS_SEND_C_TRUNCATE. I
don't think this will be acceptable for existing users.
I think the new commands should be added after BTRFS_SEND_C_END
command (unfortunately), like the snapper command that was added
recently.

Thanks,
Alex.


> --
> 1.7.7.6
>
> --
> 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

Re: [PATCH] Btrfs-progs/receive: sparse and pre-allocated file support, for btrfs-send mechanism

[Alex Lyakas]

On Thu, Jan 24, 2013 at 3:51 AM, Chen Yang <chenyang.fnst@cn.fujitsu.com> wrote:
>> On Wed, Jan 23, 2013 at 1:04 PM, Chen Yang <chenyang.fnst@cn.fujitsu.com> wrote:
>>> From: Chen Yang <chenyang.fnst@cn.fujitsu.com>
>>> Date: Fri, 18 Jan 2013 14:54:31 +0800
>>> Subject: [PATCH] Btrfs-progs/receive: sparse and pre-allocated file support
>>>  for btrfs-send mechanism
>>>
>>> When sending a file with sparse or pre-allocated part,
>>> these parts will be sent as ZERO streams, and it's unnecessary.
>>>
>>> To improve this, we add a punch command on the sending side, so the
>>> receiving side changed with it. The main change is adding the punch
>>> processing to receive command.
>>>
>>> Signed-off-by: Cheng Yang <chenyang.fnst@cn.fujitsu.com>
>>> ---
>>>  cmds-receive.c |   27 +++++++++++++++++++++++++++
>>>  send-stream.c  |    6 ++++++
>>>  send-stream.h  |    1 +
>>>  send.h         |    3 ++-
>>>  4 files changed, 36 insertions(+), 1 deletions(-)
>>>
>>> diff --git a/cmds-receive.c b/cmds-receive.c
>>> index a8be6fa..74cbfc4 100644
>>> --- a/cmds-receive.c
>>> +++ b/cmds-receive.c
>>> @@ -37,6 +37,7 @@
>>>  #include <sys/types.h>
>>>  #include <sys/xattr.h>
>>>  #include <uuid/uuid.h>
>>> +#include <linux/falloc.h>
>>>
>>>  #include "ctree.h"
>>>  #include "ioctl.h"
>>> @@ -508,6 +509,31 @@ out:
>>>         return ret;
>>>  }
>>>
>>> +static int process_punch(const char *path, u64 offset, u64 len, void *user)
>>> +{
>>> +       int ret = 0;
>>> +       struct btrfs_receive *r = user;
>>> +       char *full_path = path_cat(r->full_subvol_path, path);
>>> +
>>> +       ret = open_inode_for_write(r, full_path);
>>> +       if (ret < 0)
>>> +               goto out;
>>> +
>>> +       ret = fallocate(r->write_fd,
>>> +               FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
>>> +               offset, len);
>>> +       if (ret < 0) {
>>> +               ret = -errno;
>>> +               fprintf(stderr, "ERROR: punch %s failed. %s\n",
>>> +                               path, strerror(-ret));
>>> +               goto out;
>>> +       }
>>> +
>>> +out:
>>> +       free(full_path);
>>> +       return ret;
>>> +}
>>> +
>>>  static int process_write(const char *path, const void *data, u64 offset,
>>>                          u64 len, void *user)
>>>  {
>>> @@ -777,6 +803,7 @@ struct btrfs_send_ops send_ops = {
>>>         .link = process_link,
>>>         .unlink = process_unlink,
>>>         .rmdir = process_rmdir,
>>> +       .punch = process_punch,
>>>         .write = process_write,
>>>         .clone = process_clone,
>>>         .set_xattr = process_set_xattr,
>>> diff --git a/send-stream.c b/send-stream.c
>>> index 55fa728..9f3ede7 100644
>>> --- a/send-stream.c
>>> +++ b/send-stream.c
>>> @@ -362,6 +362,12 @@ static int read_and_process_cmd(struct btrfs_send_stream *s)
>>>                 TLV_GET_STRING(s, BTRFS_SEND_A_PATH, &path);
>>>                 ret = s->ops->rmdir(path, s->user);
>>>                 break;
>>> +       case BTRFS_SEND_C_PUNCH:
>>> +               TLV_GET_STRING(s, BTRFS_SEND_A_PATH, &path);
>>> +               TLV_GET_U64(s, BTRFS_SEND_A_FILE_OFFSET, &offset);
>>> +               TLV_GET_U64(s, BTRFS_SEND_A_SIZE, &len);
>>> +               ret = s->ops->punch(path, offset, len, s->user);
>>> +               break;
>>>         case BTRFS_SEND_C_WRITE:
>>>                 TLV_GET_STRING(s, BTRFS_SEND_A_PATH, &path);
>>>                 TLV_GET_U64(s, BTRFS_SEND_A_FILE_OFFSET, &offset);
>>> diff --git a/send-stream.h b/send-stream.h
>>> index b69b7f1..f83f2ac 100644
>>> --- a/send-stream.h
>>> +++ b/send-stream.h
>>> @@ -34,6 +34,7 @@ struct btrfs_send_ops {
>>>         int (*link)(const char *path, const char *lnk, void *user);
>>>         int (*unlink)(const char *path, void *user);
>>>         int (*rmdir)(const char *path, void *user);
>>> +       int (*punch)(const char *path, u64 offset, u64 len, void *user);
>>>         int (*write)(const char *path, const void *data, u64 offset, u64 len,
>>>                      void *user);
>>>         int (*clone)(const char *path, u64 offset, u64 len,
>>> diff --git a/send.h b/send.h
>>> index 9934e94..10a88d2 100644
>>> --- a/send.h
>>> +++ b/send.h
>>> @@ -20,7 +20,7 @@
>>>  #include "ctree.h"
>>>
>>>  #define BTRFS_SEND_STREAM_MAGIC "btrfs-stream"
>>> -#define BTRFS_SEND_STREAM_VERSION 1
>>> +#define BTRFS_SEND_STREAM_VERSION 2
>>>
>>>  #define BTRFS_SEND_BUF_SIZE (1024 * 64)
>>>  #define BTRFS_SEND_READ_SIZE (1024 * 48)
>>> @@ -80,6 +80,7 @@ enum btrfs_send_cmd {
>>>         BTRFS_SEND_C_WRITE,
>>>         BTRFS_SEND_C_CLONE,
>>>
>>> +       BTRFS_SEND_C_PUNCH,
>>>         BTRFS_SEND_C_TRUNCATE,
>>>         BTRFS_SEND_C_CHMOD,
>>>         BTRFS_SEND_C_CHOWN,
>>
>> I think this breaks the current protocol, because it changes the
>> numbers for existing commands, starting from BTRFS_SEND_C_TRUNCATE. I
>> don't think this will be acceptable for existing users.
>> I think the new commands should be added after BTRFS_SEND_C_END
>> command (unfortunately), like the snapper command that was added
>> recently.
>
> yes, I agree with you and I thought it's better to add the command
> after BTRFS_SEND_C_END command. But BTRFS_SEND_C_END seem like more special?

Yes, it's kind of special, but still we cannot change the numbers for
existing commands. If you add a new command, then users with an older
user-space and newer kernel will receive a clear (hopefully) error
about unsupported command. So they can go and upgrade the user-space
tool. (Although looking at the code, they will not receive any error
message, but instead the tool will exit silently returning a non-zero
code. This is also pretty bad.)
If you change the numbers of existing commands, users will start
receiving error messages like "ERROR: attribute 15 requested but not
present", and will need to start figuring out what user-code matches
what kernel-code.

Thanks,
Alex.


>
> Thanks,
> Chen.
>
>>
>> Thanks,
>> Alex.
>>
>>
>>> --
>>> 1.7.7.6
>>>
>>> --
>>> 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
>> --
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>>
>

Re: [PATCH] Btrfs-progs/receive: sparse and pre-allocated file support, for btrfs-send mechanism

[David Sterba]

On Wed, Jan 23, 2013 at 07:04:33PM +0800, Chen Yang wrote:
> When sending a file with sparse or pre-allocated part,
> these parts will be sent as ZERO streams, and it's unnecessary.
> 
> To improve this, we add a punch command on the sending side, so the
> receiving side changed with it. The main change is adding the punch
> processing to receive command.
> 
> +static int process_punch(const char *path, u64 offset, u64 len, void *user)
> +{
> +	int ret = 0;
> +	struct btrfs_receive *r = user;
> +	char *full_path = path_cat(r->full_subvol_path, path);
> +
> +	ret = open_inode_for_write(r, full_path);
> +	if (ret < 0)
> +		goto out;
> +
> +	ret = fallocate(r->write_fd,
> +		FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
> +		offset, len);

This unnecessarily fails if PUNCH_HOLE is not supported by the kernel
version, some sort of fallback should be applied.

> +	if (ret < 0) {
> +		ret = -errno;
> +		fprintf(stderr, "ERROR: punch %s failed. %s\n",
> +				path, strerror(-ret));
> +		goto out;
> +	}
> +
> +out:
> +	free(full_path);
> +	return ret;
> +}

david