[OE-core] [PATCH 2/4] e2fsprogs: let debugfs do sparse copy

[Robert Yang]

Let debugfs do sparse copy when src is a sparse file, just like
"cp --sparse=auto"

[YOCTO #3848]

Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
---
 .../e2fsprogs/e2fsprogs-1.42.7/sparse_copy.patch   |  114 ++++++++++++++++++++
 .../recipes-devtools/e2fsprogs/e2fsprogs_1.42.7.bb |    1 +
 2 files changed, 115 insertions(+)
 create mode 100644 meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.7/sparse_copy.patch

diff --git a/meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.7/sparse_copy.patch b/meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.7/sparse_copy.patch
new file mode 100644
index 0000000..f20fcaf
--- /dev/null
+++ b/meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.7/sparse_copy.patch
@@ -0,0 +1,114 @@
+debugfs.c: do sparse copy when src is a sparse file
+
+Let debugfs do sparse copy when src is a sparse file, just like
+"cp --sparse=auto"
+
+Upstream-Status: Pending
+
+Signed-off-by: Robert Yang <liezhi.yang at windriver.com>
+---
+ debugfs/debugfs.c | 54 ++++++++++++++++++++++++++++++++++++++++++++----------
+ 1 file changed, 44 insertions(+), 10 deletions(-)
+
+diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c
+index 5cdc86a..015bfad 100644
+--- a/debugfs/debugfs.c
++++ b/debugfs/debugfs.c
+@@ -37,6 +37,16 @@ extern char *optarg;
+ #include "../version.h"
+ #include "jfs_user.h"
+ 
++/* 32KiB is the minimium blksize to best minimize system call overhead. */
++#ifndef IO_BUFSIZE
++#define IO_BUFSIZE 32*1024
++#endif
++
++/* Block size for `st_blocks'. */
++#ifndef S_BLKSIZE
++#define S_BLKSIZE 512
++#endif
++
+ ss_request_table *extra_cmds;
+ const char *debug_prog_name;
+ int sci_idx;
+@@ -1559,13 +1569,13 @@ void do_find_free_inode(int argc, char *argv[])
+ }
+ 
+ #ifndef READ_ONLY
+-static errcode_t copy_file(int fd, ext2_ino_t newfile)
++static errcode_t copy_file(int fd, ext2_ino_t newfile, int bufsiz, int make_holes)
+ {
+ 	ext2_file_t	e2_file;
+ 	errcode_t	retval;
+ 	int		got;
+ 	unsigned int	written;
+-	char		buf[8192];
++	char		buf[bufsiz];
+ 	char		*ptr;
+ 
+ 	retval = ext2fs_file_open(current_fs, newfile,
+@@ -1582,14 +1592,30 @@ static errcode_t copy_file(int fd, ext2_ino_t newfile)
+ 			goto fail;
+ 		}
+ 		ptr = buf;
++		char *cp = ptr;
+ 		while (got > 0) {
+-			retval = ext2fs_file_write(e2_file, ptr,
+-						   got, &written);
+-			if (retval)
+-				goto fail;
+-
+-			got -= written;
+-			ptr += written;
++			int count = got;
++			if (make_holes) {
++				/* Check whether all is zero */
++				while (count-- && *cp++ == 0) {
++					continue;
++				}
++				if (count < 0) {
++					/* The whole block is zero, make a hole */
++					retval = ext2fs_file_lseek(e2_file, got, EXT2_SEEK_CUR, 0);
++					if (retval)
++						goto fail;
++					got = 0;
++				}
++			}
++			/* Normal copy */
++			if (got > 0) {
++				retval = ext2fs_file_write(e2_file, ptr, got, &written);
++				if (retval)
++					goto fail;
++				got -= written;
++				ptr += written;
++			}
+ 		}
+ 	}
+ 	retval = ext2fs_file_close(e2_file);
+@@ -1608,6 +1634,8 @@ void do_write(int argc, char *argv[])
+ 	ext2_ino_t	newfile;
+ 	errcode_t	retval;
+ 	struct ext2_inode inode;
++	int make_holes = 0;
++	int bufsiz = IO_BUFSIZE;
+ 
+ 	if (common_args_process(argc, argv, 3, 3, "write",
+ 				"<native file> <new file>", CHECK_FS_RW))
+@@ -1672,7 +1700,13 @@ void do_write(int argc, char *argv[])
+ 		return;
+ 	}
+ 	if (LINUX_S_ISREG(inode.i_mode)) {
+-		retval = copy_file(fd, newfile);
++		if (statbuf.st_blocks < statbuf.st_size / S_BLKSIZE) {
++			make_holes = 1;
++			/* Use the I/O blocksize (st_blksize) as the buffer
++			 * size when copy sparse file */
++			bufsiz = statbuf.st_blksize;
++		}
++		retval = copy_file(fd, newfile, bufsiz, make_holes);
+ 		if (retval)
+ 			com_err("copy_file", retval, 0);
+ 	}
+-- 
+1.7.11.2
+
diff --git a/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.42.7.bb b/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.42.7.bb
index 898ee88..b547036 100644
--- a/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.42.7.bb
+++ b/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.42.7.bb
@@ -5,6 +5,7 @@ PR = "r0"
 SRC_URI += "file://acinclude.m4 \
             file://remove.ldconfig.call.patch \
             file://debugfs-too-short.patch \
+            file://sparse_copy.patch \
 "
 
 SRC_URI[md5sum] = "a1ec22ef003688dae9f76c74881b22b9"
-- 
1.7.10.4