[PATCH v4 0/2] Add subcommand that dumps file extents

[PATCH v4 0/2] Add subcommand that dumps file extents

[Sidong Yang]

This patch series add an subcommand in inspect-internal. It dumps file extents of
the file that user provided. For avoiding duplicated code, the patch that export
functions is in this series.

Sidong Yang (2):
  btrfs-progs: export util functions about file extent items
  btrfs-progs: cmds: Add subcommand that dumps file extents

---
v2:
 - Prints type and compression
 - Use the terms from file_extents_item like disk_bytenr not like
   "physical"
v3:
 - export util functions for removing duplication
 - change the way to loop with search ioctl
v4:
 - export COMPRESS_STR_LEN for using function safely
---

 Makefile                         |   2 +-
 cmds/commands.h                  |   2 +-
 cmds/inspect-dump-file-extents.c | 134 +++++++++++++++++++++++++++++++
 cmds/inspect.c                   |   1 +
 kernel-shared/print-tree.c       |  18 ++---
 kernel-shared/print-tree.h       |   5 ++
 6 files changed, 151 insertions(+), 11 deletions(-)
 create mode 100644 cmds/inspect-dump-file-extents.c

-- 
2.25.1

[PATCH v4 1/2] btrfs-progs: export util functions about file extent items

[Sidong Yang]

This patch export two functions that convert enum about file extents to
string. It can be used in other code like inspect-internal command. And
this patch also make compress_type_to_str() function more safe by using
strncpy() than strcpy().

Signed-off-by: Sidong Yang <realwakka@gmail.com>
---
 kernel-shared/print-tree.c | 18 +++++++++---------
 kernel-shared/print-tree.h |  5 +++++
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/kernel-shared/print-tree.c b/kernel-shared/print-tree.c
index e5d4b453..ce1c0ed3 100644
--- a/kernel-shared/print-tree.c
+++ b/kernel-shared/print-tree.c
@@ -338,27 +338,27 @@ static void print_uuids(struct extent_buffer *eb)
 	printf("fs uuid %s\nchunk uuid %s\n", fs_uuid, chunk_uuid);
 }
 
-static void compress_type_to_str(u8 compress_type, char *ret)
+void btrfs_compress_type_to_str(u8 compress_type, char *ret)
 {
 	switch (compress_type) {
 	case BTRFS_COMPRESS_NONE:
-		strcpy(ret, "none");
+		strncpy(ret, "none", BTRFS_COMPRESS_STR_LEN);
 		break;
 	case BTRFS_COMPRESS_ZLIB:
-		strcpy(ret, "zlib");
+		strncpy(ret, "zlib", BTRFS_COMPRESS_STR_LEN);
 		break;
 	case BTRFS_COMPRESS_LZO:
-		strcpy(ret, "lzo");
+		strncpy(ret, "lzo", BTRFS_COMPRESS_STR_LEN);
 		break;
 	case BTRFS_COMPRESS_ZSTD:
-		strcpy(ret, "zstd");
+		strncpy(ret, "zstd", BTRFS_COMPRESS_STR_LEN);
 		break;
 	default:
-		sprintf(ret, "UNKNOWN.%d", compress_type);
+		snprintf(ret, BTRFS_COMPRESS_STR_LEN, "UNKNOWN.%d", compress_type);
 	}
 }
 
-static const char* file_extent_type_to_str(u8 type)
+const char* btrfs_file_extent_type_to_str(u8 type)
 {
 	switch (type) {
 	case BTRFS_FILE_EXTENT_INLINE: return "inline";
@@ -376,12 +376,12 @@ static void print_file_extent_item(struct extent_buffer *eb,
 	unsigned char extent_type = btrfs_file_extent_type(eb, fi);
 	char compress_str[16];
 
-	compress_type_to_str(btrfs_file_extent_compression(eb, fi),
+	btrfs_compress_type_to_str(btrfs_file_extent_compression(eb, fi),
 			     compress_str);
 
 	printf("\t\tgeneration %llu type %hhu (%s)\n",
 			btrfs_file_extent_generation(eb, fi),
-			extent_type, file_extent_type_to_str(extent_type));
+			extent_type, btrfs_file_extent_type_to_str(extent_type));
 
 	if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
 		printf("\t\tinline extent data size %u ram_bytes %llu compression %hhu (%s)\n",
diff --git a/kernel-shared/print-tree.h b/kernel-shared/print-tree.h
index 80fb6ef7..3b96e89d 100644
--- a/kernel-shared/print-tree.h
+++ b/kernel-shared/print-tree.h
@@ -33,6 +33,8 @@ enum {
 	BTRFS_PRINT_TREE_DEFAULT = BTRFS_PRINT_TREE_BFS,
 };
 
+#define BTRFS_COMPRESS_STR_LEN 12
+
 void btrfs_print_tree(struct extent_buffer *eb, unsigned int mode);
 void btrfs_print_leaf(struct extent_buffer *eb, unsigned int mode);
 
@@ -43,4 +45,7 @@ void print_objectid(FILE *stream, u64 objectid, u8 type);
 void print_key_type(FILE *stream, u64 objectid, u8 type);
 void btrfs_print_superblock(struct btrfs_super_block *sb, int full);
 
+void btrfs_compress_type_to_str(u8 compress_type, char *ret);
+const char* btrfs_file_extent_type_to_str(u8 type);
+
 #endif
-- 
2.25.1

[PATCH v4 2/2] btrfs-progs: cmds: Add subcommand that dumps file extents

[Sidong Yang]

This patch adds an subcommand in inspect-internal. It dumps file extents of
the file that user provided. It helps to show the internal information
about file extents comprise the file.

Signed-off-by: Sidong Yang <realwakka@gmail.com>
---
 Makefile                         |   2 +-
 cmds/commands.h                  |   2 +-
 cmds/inspect-dump-file-extents.c | 134 +++++++++++++++++++++++++++++++
 cmds/inspect.c                   |   1 +
 4 files changed, 137 insertions(+), 2 deletions(-)
 create mode 100644 cmds/inspect-dump-file-extents.c

diff --git a/Makefile b/Makefile
index a1cc457b..911e16de 100644
--- a/Makefile
+++ b/Makefile
@@ -156,7 +156,7 @@ cmds_objects = cmds/subvolume.o cmds/filesystem.o cmds/device.o cmds/scrub.o \
 	       cmds/restore.o cmds/rescue.o cmds/rescue-chunk-recover.o \
 	       cmds/rescue-super-recover.o \
 	       cmds/property.o cmds/filesystem-usage.o cmds/inspect-dump-tree.o \
-	       cmds/inspect-dump-super.o cmds/inspect-tree-stats.o cmds/filesystem-du.o \
+	       cmds/inspect-dump-super.o cmds/inspect-tree-stats.o cmds/inspect-dump-file-extents.o cmds/filesystem-du.o \
 	       mkfs/common.o check/mode-common.o check/mode-lowmem.o
 libbtrfs_objects = common/send-stream.o common/send-utils.o kernel-lib/rbtree.o btrfs-list.o \
 		   kernel-lib/radix-tree.o common/extent-cache.o kernel-shared/extent_io.o \
diff --git a/cmds/commands.h b/cmds/commands.h
index 8fa85d6c..55de248e 100644
--- a/cmds/commands.h
+++ b/cmds/commands.h
@@ -154,5 +154,5 @@ DECLARE_COMMAND(select_super);
 DECLARE_COMMAND(dump_super);
 DECLARE_COMMAND(debug_tree);
 DECLARE_COMMAND(rescue);
-
+DECLARE_COMMAND(inspect_dump_file_extents);
 #endif
diff --git a/cmds/inspect-dump-file-extents.c b/cmds/inspect-dump-file-extents.c
new file mode 100644
index 00000000..5e5bc6f7
--- /dev/null
+++ b/cmds/inspect-dump-file-extents.c
@@ -0,0 +1,134 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <fcntl.h>
+
+#include <sys/ioctl.h>
+
+#include "common/utils.h"
+#include "cmds/commands.h"
+#include "kernel-shared/print-tree.h"
+
+static const char * const cmd_inspect_dump_file_extents_usage[] = {
+	"btrfs inspect-internal dump-extent path",
+	"Dump file extent in a textual form",
+	NULL
+};
+
+static int cmd_inspect_dump_file_extents(const struct cmd_struct *cmd,
+										 int argc, char **argv)
+{
+	int fd;
+	struct stat statbuf;
+	struct btrfs_ioctl_ino_lookup_args lookup;
+	struct btrfs_ioctl_search_args args;
+	struct btrfs_ioctl_search_key *sk = &args.key;
+	struct btrfs_file_extent_item *extent_item;
+	struct btrfs_ioctl_search_header *header;
+	u64 buf_off;
+	u64 len;
+	u64 start;
+	u64 disk_bytenr;
+	u64 disk_num_bytes;
+	u64 offset;
+	int ret;
+	int i;
+	char compress_str[BTRFS_COMPRESS_STR_LEN];
+
+	fd = open(argv[optind], O_RDONLY);
+	if (fd < 0) {
+		error("cannot open %s: %m", argv[optind]);
+		ret = 1;
+		goto out;
+	}
+
+	if (fstat(fd, &statbuf) < 0) {
+		error("failed to fstat %s: %m", argv[optind]);
+		ret = 1;
+		goto out;
+	}
+
+	lookup.treeid = 0;
+	lookup.objectid = BTRFS_FIRST_FREE_OBJECTID;
+
+	if (ioctl(fd, BTRFS_IOC_INO_LOOKUP, &lookup) < 0) {
+		error("failed to lookup inode %s: %m", argv[optind]);
+		ret = 1;
+		goto out;
+	}
+
+	sk->tree_id = lookup.treeid;
+	sk->min_objectid = statbuf.st_ino;
+	sk->max_objectid = statbuf.st_ino;
+	sk->min_offset = 0;
+	sk->max_offset = UINT64_MAX;
+	sk->min_transid = 0;
+	sk->max_transid = UINT64_MAX;
+	sk->min_type = sk->max_type = BTRFS_EXTENT_DATA_KEY;
+	sk->nr_items = UINT32_MAX;
+
+again:
+	if (ioctl(fd, BTRFS_IOC_TREE_SEARCH, &args)) {
+		error("failed to search tree ioctl %s: %m", argv[optind]);
+		ret = 1;
+		goto out;
+	}
+
+	buf_off = 0;
+	for(i=0; i<sk->nr_items; ++i) {
+		header = (struct btrfs_ioctl_search_header *)(args.buf + buf_off);
+
+		if (btrfs_search_header_type(header) == BTRFS_EXTENT_DATA_KEY) {
+			extent_item = (struct btrfs_file_extent_item *)(header + 1);
+			start = btrfs_search_header_offset(header);
+
+			printf("type = %s, start = %llu, ",
+				   btrfs_file_extent_type_to_str(extent_item->type), start);
+			switch (extent_item->type) {
+			case BTRFS_FILE_EXTENT_INLINE:
+				len = le64_to_cpu(extent_item->ram_bytes);
+				printf("len = %llu\n", len);
+				break;
+			case BTRFS_FILE_EXTENT_REG:
+			case BTRFS_FILE_EXTENT_PREALLOC:
+				len = le64_to_cpu(extent_item->num_bytes);
+				disk_bytenr = le64_to_cpu(extent_item->disk_bytenr);
+				disk_num_bytes = le64_to_cpu(extent_item->disk_num_bytes);
+				offset = le64_to_cpu(extent_item->offset);
+				btrfs_compress_type_to_str(extent_item->compression, compress_str);
+				printf("len = %llu, disk_bytenr = %llu, disk_num_bytes = %llu,"
+					   " offset = %llu, compression = %s\n",
+					   len, disk_bytenr, disk_num_bytes, offset, compress_str);
+
+				break;
+			}
+
+		}
+		buf_off += sizeof(*header) + btrfs_search_header_len(header);
+	}
+	if (sk->nr_items > 512) {
+		sk->nr_items = UINT32_MAX;
+		sk->min_offset = start + 1;
+		goto again;
+	}
+	ret = 0;
+out:
+	close(fd);
+	return ret;
+}
+DEFINE_SIMPLE_COMMAND(inspect_dump_file_extents, "dump-file-extents");
diff --git a/cmds/inspect.c b/cmds/inspect.c
index 2ef5f4b6..dfb0e27b 100644
--- a/cmds/inspect.c
+++ b/cmds/inspect.c
@@ -696,6 +696,7 @@ static const struct cmd_group inspect_cmd_group = {
 		&cmd_struct_inspect_dump_tree,
 		&cmd_struct_inspect_dump_super,
 		&cmd_struct_inspect_tree_stats,
+		&cmd_struct_inspect_dump_file_extents,
 		NULL
 	}
 };
-- 
2.25.1

Re: [PATCH v4 2/2] btrfs-progs: cmds: Add subcommand that dumps file extents

[David Sterba]

On Sun, Jul 18, 2021 at 06:46:01AM +0000, Sidong Yang wrote:
> This patch adds an subcommand in inspect-internal. It dumps file extents of
> the file that user provided. It helps to show the internal information
> about file extents comprise the file.

Do you have an example of the output? That's the most interesting part.
Thanks.

Re: [PATCH v4 2/2] btrfs-progs: cmds: Add subcommand that dumps file extents

[Sidong Yang]

On Tue, Aug 17, 2021 at 03:30:22PM +0200, David Sterba wrote:
> On Sun, Jul 18, 2021 at 06:46:01AM +0000, Sidong Yang wrote:
> > This patch adds an subcommand in inspect-internal. It dumps file extents of
> > the file that user provided. It helps to show the internal information
> > about file extents comprise the file.
> 
> Do you have an example of the output? That's the most interesting part.
> Thanks.

Thanks for reply.
This is an example of the output below.

# ./btrfs inspect-internal dump-file-extent /mnt/test1
type = regular, start = 2097152, len = 3227648, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
type = regular, start = 5324800, len = 16728064, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
type = regular, start = 22052864, len = 8486912, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
type = regular, start = 30572544, len = 36540416, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
type = regular, start = 67112960, len = 5299630080, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none

Thanks,
Sidong

Re: [PATCH v4 2/2] btrfs-progs: cmds: Add subcommand that dumps file extents

[David Sterba]

On Wed, Aug 18, 2021 at 12:38:19AM +0000, Sidong Yang wrote:
> On Tue, Aug 17, 2021 at 03:30:22PM +0200, David Sterba wrote:
> > On Sun, Jul 18, 2021 at 06:46:01AM +0000, Sidong Yang wrote:
> > > This patch adds an subcommand in inspect-internal. It dumps file extents of
> > > the file that user provided. It helps to show the internal information
> > > about file extents comprise the file.
> > 
> > Do you have an example of the output? That's the most interesting part.
> > Thanks.
> 
> Thanks for reply.
> This is an example of the output below.
> 
> # ./btrfs inspect-internal dump-file-extent /mnt/test1
> type = regular, start = 2097152, len = 3227648, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> type = regular, start = 5324800, len = 16728064, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> type = regular, start = 22052864, len = 8486912, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> type = regular, start = 30572544, len = 36540416, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> type = regular, start = 67112960, len = 5299630080, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none

This resembles a debugging output, something like we have for
tracepoints but I think this should be more human readable, with
possiblity of parsing by scripts/tools.

So to not just duplicate what filefrag or xfs_io -c fiemap do, we can
optionally enhance the information with the specifics of btrfs, like on
which devices the extents are, which compression is there etc. But the
basic output should be more or less like filefrag.

Re: [PATCH v4 2/2] btrfs-progs: cmds: Add subcommand that dumps file extents

[Sidong Yang]

On Wed, Aug 18, 2021 at 06:59:24PM +0200, David Sterba wrote:
> On Wed, Aug 18, 2021 at 12:38:19AM +0000, Sidong Yang wrote:
> > On Tue, Aug 17, 2021 at 03:30:22PM +0200, David Sterba wrote:
> > > On Sun, Jul 18, 2021 at 06:46:01AM +0000, Sidong Yang wrote:
> > > > This patch adds an subcommand in inspect-internal. It dumps file extents of
> > > > the file that user provided. It helps to show the internal information
> > > > about file extents comprise the file.
> > > 
> > > Do you have an example of the output? That's the most interesting part.
> > > Thanks.
> > 
> > Thanks for reply.
> > This is an example of the output below.
> > 
> > # ./btrfs inspect-internal dump-file-extent /mnt/test1
> > type = regular, start = 2097152, len = 3227648, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> > type = regular, start = 5324800, len = 16728064, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> > type = regular, start = 22052864, len = 8486912, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> > type = regular, start = 30572544, len = 36540416, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> > type = regular, start = 67112960, len = 5299630080, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> 
> This resembles a debugging output, something like we have for
> tracepoints but I think this should be more human readable, with
> possiblity of parsing by scripts/tools.

Yes, I agree. I think It would be text or json.
> 
> So to not just duplicate what filefrag or xfs_io -c fiemap do, we can
> optionally enhance the information with the specifics of btrfs, like on
> which devices the extents are, which compression is there etc. But the
> basic output should be more or less like filefrag.

Yeah, this is the limit for this patch. for more than filefrag or
xfs_io, it should provide more specifics. compression type is already
included. But it would be better that it describe which device 
has the extents. it goes to v2.

Re: [PATCH v4 2/2] btrfs-progs: cmds: Add subcommand that dumps file extents

[Qu Wenruo]

On 2021/8/18 上午8:38, Sidong Yang wrote:
> On Tue, Aug 17, 2021 at 03:30:22PM +0200, David Sterba wrote:
>> On Sun, Jul 18, 2021 at 06:46:01AM +0000, Sidong Yang wrote:
>>> This patch adds an subcommand in inspect-internal. It dumps file extents of
>>> the file that user provided. It helps to show the internal information
>>> about file extents comprise the file.
>>
>> Do you have an example of the output? That's the most interesting part.
>> Thanks.
>
> Thanks for reply.
> This is an example of the output below.
>
> # ./btrfs inspect-internal dump-file-extent /mnt/test1
> type = regular, start = 2097152, len = 3227648, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> type = regular, start = 5324800, len = 16728064, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> type = regular, start = 22052864, len = 8486912, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> type = regular, start = 30572544, len = 36540416, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none
> type = regular, start = 67112960, len = 5299630080, disk_bytenr = 0, disk_num_bytes = 0, offset = 0, compression = none

Could you give an example which includes both real (non-hole) extents
and real extents (better to include regular, compressed, preallocated
and inline).

Currently the output only contains holes, and for holes, a lot of
members makes no sense, like disk_bytenr/disk_num_bytes/offset (even it
can be non-zero) and compression.

Thanks,
Qu

>
> Thanks,
> Sidong
>

Re: [PATCH v4 2/2] btrfs-progs: cmds: Add subcommand that dumps file extents

[Qu Wenruo]

On 2021/8/19 下午2:03, Qu Wenruo wrote:
>
>
> On 2021/8/18 上午8:38, Sidong Yang wrote:
>> On Tue, Aug 17, 2021 at 03:30:22PM +0200, David Sterba wrote:
>>> On Sun, Jul 18, 2021 at 06:46:01AM +0000, Sidong Yang wrote:
>>>> This patch adds an subcommand in inspect-internal. It dumps file
>>>> extents of
>>>> the file that user provided. It helps to show the internal information
>>>> about file extents comprise the file.
>>>
>>> Do you have an example of the output? That's the most interesting part.
>>> Thanks.
>>
>> Thanks for reply.
>> This is an example of the output below.
>>
>> # ./btrfs inspect-internal dump-file-extent /mnt/test1
>> type = regular, start = 2097152, len = 3227648, disk_bytenr = 0,
>> disk_num_bytes = 0, offset = 0, compression = none
>> type = regular, start = 5324800, len = 16728064, disk_bytenr = 0,
>> disk_num_bytes = 0, offset = 0, compression = none
>> type = regular, start = 22052864, len = 8486912, disk_bytenr = 0,
>> disk_num_bytes = 0, offset = 0, compression = none
>> type = regular, start = 30572544, len = 36540416, disk_bytenr = 0,
>> disk_num_bytes = 0, offset = 0, compression = none
>> type = regular, start = 67112960, len = 5299630080, disk_bytenr = 0,
>> disk_num_bytes = 0, offset = 0, compression = none
>
> Could you give an example which includes both real (non-hole) extents
> and real extents (better to include regular, compressed, preallocated
> and inline).

Tons of typos... I mean to include both holes (like the existing
example) and non-holes extents...

>
> Currently the output only contains holes, and for holes, a lot of
> members makes no sense, like disk_bytenr/disk_num_bytes/offset (even it
> can be non-zero) and compression.
>
> Thanks,
> Qu
>
>>
>> Thanks,
>> Sidong
>>

Re: [PATCH v4 2/2] btrfs-progs: cmds: Add subcommand that dumps file extents

[Sidong Yang]

On Thu, Aug 19, 2021 at 02:05:52PM +0800, Qu Wenruo wrote:
> 
> 
> On 2021/8/19 下午2:03, Qu Wenruo wrote:
> > 
> > 
> > On 2021/8/18 上午8:38, Sidong Yang wrote:
> > > On Tue, Aug 17, 2021 at 03:30:22PM +0200, David Sterba wrote:
> > > > On Sun, Jul 18, 2021 at 06:46:01AM +0000, Sidong Yang wrote:
> > > > > This patch adds an subcommand in inspect-internal. It dumps file
> > > > > extents of
> > > > > the file that user provided. It helps to show the internal information
> > > > > about file extents comprise the file.
> > > > 
> > > > Do you have an example of the output? That's the most interesting part.
> > > > Thanks.
> > > 
> > > Thanks for reply.
> > > This is an example of the output below.
> > > 
> > > # ./btrfs inspect-internal dump-file-extent /mnt/test1
> > > type = regular, start = 2097152, len = 3227648, disk_bytenr = 0,
> > > disk_num_bytes = 0, offset = 0, compression = none
> > > type = regular, start = 5324800, len = 16728064, disk_bytenr = 0,
> > > disk_num_bytes = 0, offset = 0, compression = none
> > > type = regular, start = 22052864, len = 8486912, disk_bytenr = 0,
> > > disk_num_bytes = 0, offset = 0, compression = none
> > > type = regular, start = 30572544, len = 36540416, disk_bytenr = 0,
> > > disk_num_bytes = 0, offset = 0, compression = none
> > > type = regular, start = 67112960, len = 5299630080, disk_bytenr = 0,
> > > disk_num_bytes = 0, offset = 0, compression = none
> > 
> > Could you give an example which includes both real (non-hole) extents
> > and real extents (better to include regular, compressed, preallocated
> > and inline).
> 
> Tons of typos... I mean to include both holes (like the existing
> example) and non-holes extents...

Sorry, I had no idea about holes. But I found some test code in
xfstests. It helpes me to make hole in file.

xfs_io -c "fpunch 96K 32K" /mnt/a/foobar
xfs_io -c "fpunch 64K 128K" /mnt/a/foobar

and the example is below.

# ./btrfs inspect dump-file-extent /mnt/a/foobar 
type = regular, start = 0, len = 98304, disk_bytenr = 21651456,
disk_num_bytes = 4096, offset = 0, compression = zstd
type = regular, start = 98304, len = 32768, disk_bytenr = 0,
disk_num_bytes = 0, offset = 0, compression = none

I'm afaid that I understand your request correctly. Is it what you want?
> 
> > 
> > Currently the output only contains holes, and for holes, a lot of
> > members makes no sense, like disk_bytenr/disk_num_bytes/offset (even it
> > can be non-zero) and compression.
> > 
> > Thanks,
> > Qu
> > 
> > > 
> > > Thanks,
> > > Sidong
> > > 

Re: [PATCH v4 2/2] btrfs-progs: cmds: Add subcommand that dumps file extents

[Qu Wenruo]

On 2021/8/19 下午11:27, Sidong Yang wrote:
> On Thu, Aug 19, 2021 at 02:05:52PM +0800, Qu Wenruo wrote:
>>
>>
>> On 2021/8/19 下午2:03, Qu Wenruo wrote:
>>>
>>>
>>> On 2021/8/18 上午8:38, Sidong Yang wrote:
>>>> On Tue, Aug 17, 2021 at 03:30:22PM +0200, David Sterba wrote:
>>>>> On Sun, Jul 18, 2021 at 06:46:01AM +0000, Sidong Yang wrote:
>>>>>> This patch adds an subcommand in inspect-internal. It dumps file
>>>>>> extents of
>>>>>> the file that user provided. It helps to show the internal information
>>>>>> about file extents comprise the file.
>>>>>
>>>>> Do you have an example of the output? That's the most interesting part.
>>>>> Thanks.
>>>>
>>>> Thanks for reply.
>>>> This is an example of the output below.
>>>>
>>>> # ./btrfs inspect-internal dump-file-extent /mnt/test1
>>>> type = regular, start = 2097152, len = 3227648, disk_bytenr = 0,
>>>> disk_num_bytes = 0, offset = 0, compression = none
>>>> type = regular, start = 5324800, len = 16728064, disk_bytenr = 0,
>>>> disk_num_bytes = 0, offset = 0, compression = none
>>>> type = regular, start = 22052864, len = 8486912, disk_bytenr = 0,
>>>> disk_num_bytes = 0, offset = 0, compression = none
>>>> type = regular, start = 30572544, len = 36540416, disk_bytenr = 0,
>>>> disk_num_bytes = 0, offset = 0, compression = none
>>>> type = regular, start = 67112960, len = 5299630080, disk_bytenr = 0,
>>>> disk_num_bytes = 0, offset = 0, compression = none
>>>
>>> Could you give an example which includes both real (non-hole) extents
>>> and real extents (better to include regular, compressed, preallocated
>>> and inline).
>>
>> Tons of typos... I mean to include both holes (like the existing
>> example) and non-holes extents...
>
> Sorry, I had no idea about holes. But I found some test code in
> xfstests. It helpes me to make hole in file.
>
> xfs_io -c "fpunch 96K 32K" /mnt/a/foobar
> xfs_io -c "fpunch 64K 128K" /mnt/a/foobar
>
> and the example is below.
>
> # ./btrfs inspect dump-file-extent /mnt/a/foobar
> type = regular, start = 0, len = 98304, disk_bytenr = 21651456,
> disk_num_bytes = 4096, offset = 0, compression = zstd
> type = regular, start = 98304, len = 32768, disk_bytenr = 0,
> disk_num_bytes = 0, offset = 0, compression = none
>
> I'm afaid that I understand your request correctly. Is it what you want?

This example is much better.

But still, for holes, things like
disk_bytenr/disk_num_bytes/offset/compression makes no sense and can be
skipped.

Furthermore, for hole/prealloc they need extra type other than "regular"

Thanks,
Qu
>>
>>>
>>> Currently the output only contains holes, and for holes, a lot of
>>> members makes no sense, like disk_bytenr/disk_num_bytes/offset (even it
>>> can be non-zero) and compression.
>>>
>>> Thanks,
>>> Qu
>>>
>>>>
>>>> Thanks,
>>>> Sidong
>>>>

Re: [PATCH v4 2/2] btrfs-progs: cmds: Add subcommand that dumps file extents

[Sidong Yang]

On Fri, Aug 20, 2021 at 06:16:18AM +0800, Qu Wenruo wrote:
> 
> 
> On 2021/8/19 下午11:27, Sidong Yang wrote:
> > On Thu, Aug 19, 2021 at 02:05:52PM +0800, Qu Wenruo wrote:
> > > 
> > > 
> > > On 2021/8/19 下午2:03, Qu Wenruo wrote:
> > > > 
> > > > 
> > > > On 2021/8/18 上午8:38, Sidong Yang wrote:
> > > > > On Tue, Aug 17, 2021 at 03:30:22PM +0200, David Sterba wrote:
> > > > > > On Sun, Jul 18, 2021 at 06:46:01AM +0000, Sidong Yang wrote:
> > > > > > > This patch adds an subcommand in inspect-internal. It dumps file
> > > > > > > extents of
> > > > > > > the file that user provided. It helps to show the internal information
> > > > > > > about file extents comprise the file.
> > > > > > 
> > > > > > Do you have an example of the output? That's the most interesting part.
> > > > > > Thanks.
> > > > > 
> > > > > Thanks for reply.
> > > > > This is an example of the output below.
> > > > > 
> > > > > # ./btrfs inspect-internal dump-file-extent /mnt/test1
> > > > > type = regular, start = 2097152, len = 3227648, disk_bytenr = 0,
> > > > > disk_num_bytes = 0, offset = 0, compression = none
> > > > > type = regular, start = 5324800, len = 16728064, disk_bytenr = 0,
> > > > > disk_num_bytes = 0, offset = 0, compression = none
> > > > > type = regular, start = 22052864, len = 8486912, disk_bytenr = 0,
> > > > > disk_num_bytes = 0, offset = 0, compression = none
> > > > > type = regular, start = 30572544, len = 36540416, disk_bytenr = 0,
> > > > > disk_num_bytes = 0, offset = 0, compression = none
> > > > > type = regular, start = 67112960, len = 5299630080, disk_bytenr = 0,
> > > > > disk_num_bytes = 0, offset = 0, compression = none
> > > > 
> > > > Could you give an example which includes both real (non-hole) extents
> > > > and real extents (better to include regular, compressed, preallocated
> > > > and inline).
> > > 
> > > Tons of typos... I mean to include both holes (like the existing
> > > example) and non-holes extents...
> > 
> > Sorry, I had no idea about holes. But I found some test code in
> > xfstests. It helpes me to make hole in file.
> > 
> > xfs_io -c "fpunch 96K 32K" /mnt/a/foobar
> > xfs_io -c "fpunch 64K 128K" /mnt/a/foobar
> > 
> > and the example is below.
> > 
> > # ./btrfs inspect dump-file-extent /mnt/a/foobar
> > type = regular, start = 0, len = 98304, disk_bytenr = 21651456,
> > disk_num_bytes = 4096, offset = 0, compression = zstd
> > type = regular, start = 98304, len = 32768, disk_bytenr = 0,
> > disk_num_bytes = 0, offset = 0, compression = none
> > 
> > I'm afaid that I understand your request correctly. Is it what you want?
> 
> This example is much better.
> 
> But still, for holes, things like
> disk_bytenr/disk_num_bytes/offset/compression makes no sense and can be
> skipped.

Okay. If disk_bytenr is zero, other information after this would be
skipped in next version.
> 
> Furthermore, for hole/prealloc they need extra type other than "regular"

For now, It already has prealloc type. but no hole type. All the types
are inline/prealloc/regular/hole? If so, disk_bytenr should be checked
before print it's type.

Thanks,
Sidong
> 
> Thanks,
> Qu
> > > 
> > > > 
> > > > Currently the output only contains holes, and for holes, a lot of
> > > > members makes no sense, like disk_bytenr/disk_num_bytes/offset (even it
> > > > can be non-zero) and compression.
> > > > 
> > > > Thanks,
> > > > Qu
> > > > 
> > > > > 
> > > > > Thanks,
> > > > > Sidong
> > > > >