On Thu, 2013-08-22 at 09:13 -0400, Robert Yang wrote:
> Let debugfs do sparse copy when src is a sparse file, just like
> "cp --sparse=auto"
> 
> This patch has been reviewed by the linux-ext4 mailing list, but isn't
> merged atm.
> 
> [YOCTO #3848]

Minor whitespace nit below, but will likely be caught by upstream.

--
Darren

> 
> Signed-off-by: Robert Yang <[email protected]>
> ---
>  .../e2fsprogs-1.42.8/debugfs-sparse-copy.patch     |  147 
> ++++++++++++++++++++
>  .../recipes-devtools/e2fsprogs/e2fsprogs_1.42.8.bb |    1 +
>  2 files changed, 148 insertions(+)
>  create mode 100644 
> meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.8/debugfs-sparse-copy.patch
> 
> diff --git 
> a/meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.8/debugfs-sparse-copy.patch 
> b/meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.8/debugfs-sparse-copy.patch
> new file mode 100644
> index 0000000..c87bcbf
> --- /dev/null
> +++ 
> b/meta/recipes-devtools/e2fsprogs/e2fsprogs-1.42.8/debugfs-sparse-copy.patch
> @@ -0,0 +1,147 @@
> +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"
> +
> +* For the:
> +  #define IO_BUFSIZE 64*1024
> +  this is a suggested value from gnu coreutils:
> +  
> http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=blob;f=src/ioblksize.h;h=1ae93255e7d0ccf0855208c7ae5888209997bf16;hb=HEAD
> +
> +* Use malloc() to allocate memory for the buffer since put 64K (or
> +  more) on the stack seems not a good idea.
> +
> +Upstream-Status: Submitted
> +
> +Signed-off-by: Robert Yang <[email protected]>
> +Acked-by: Darren Hart <[email protected]>
> +---
> + debugfs/debugfs.c | 61 
> +++++++++++++++++++++++++++++++++++++++++++++++++++----
> + 1 file changed, 57 insertions(+), 4 deletions(-)
> +
> +diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c
> +--- a/debugfs/debugfs.c
> ++++ b/debugfs/debugfs.c
> +@@ -41,6 +41,16 @@ extern char *optarg;
> + #define BUFSIZ 8192
> + #endif
> + 
> ++/* 64KiB is the minimium blksize to best minimize system call overhead. */
> ++#ifndef IO_BUFSIZE
> ++#define IO_BUFSIZE 64*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;
> +@@ -1575,22 +1585,36 @@ 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 bufsize, int 
> make_holes)
> + {
> +     ext2_file_t     e2_file;
> +     errcode_t       retval;
> +     int             got;
> +     unsigned int    written;
> +-    char            buf[8192];
> ++    char            *buf;
> +     char            *ptr;
> ++    char            *zero_buf;
> ++    int             cmp;
> + 
> +     retval = ext2fs_file_open(current_fs, newfile,
> +                               EXT2_FILE_WRITE, &e2_file);
> +     if (retval)
> +             return retval;
> + 
> ++    if (!(buf = (char *) malloc(bufsize))){
> ++            com_err("copy_file", errno, "can't allocate buffer\n");
> ++            return;
> ++    }
> ++
> ++        /* This is used for checking whether the whole block is zero */

Whitespace/indentation error ^


> ++    retval = ext2fs_get_memzero(bufsize, &zero_buf);
> ++    if (retval) {
> ++            com_err("copy_file", retval, "can't allocate buffer\n");
> ++            return retval;
> ++    }
> ++
> +     while (1) {
> +-            got = read(fd, buf, sizeof(buf));
> ++            got = read(fd, buf, bufsize);
> +             if (got == 0)
> +                     break;
> +             if (got < 0) {
> +@@ -1598,6 +1622,21 @@ static errcode_t copy_file(int fd, ext2_ino_t newfile)
> +                     goto fail;
> +             }
> +             ptr = buf;
> ++
> ++            /* Sparse copy */
> ++            if (make_holes) {
> ++                    /* Check whether all is zero */
> ++                    cmp = memcmp(ptr, zero_buf, got);
> ++                    if (cmp == 0) {
> ++                             /* The whole block is zero, make a hole */
> ++                            retval = ext2fs_file_lseek(e2_file, got, 
> EXT2_SEEK_CUR, NULL);
> ++                            if (retval)
> ++                                    goto fail;
> ++                            got = 0;
> ++                    }
> ++            }
> ++
> ++            /* Normal copy */
> +             while (got > 0) {
> +                     retval = ext2fs_file_write(e2_file, ptr,
> +                                                got, &written);
> +@@ -1608,10 +1647,14 @@ static errcode_t copy_file(int fd, ext2_ino_t 
> newfile)
> +                     ptr += written;
> +             }
> +     }
> ++    free(buf);
> ++    ext2fs_free_mem(&zero_buf);
> +     retval = ext2fs_file_close(e2_file);
> +     return retval;
> + 
> + fail:
> ++    free(buf);
> ++    ext2fs_free_mem(&zero_buf);
> +     (void) ext2fs_file_close(e2_file);
> +     return retval;
> + }
> +@@ -1624,6 +1667,8 @@ void do_write(int argc, char *argv[])
> +     ext2_ino_t      newfile;
> +     errcode_t       retval;
> +     struct ext2_inode inode;
> ++    int             bufsize = IO_BUFSIZE;
> ++    int             make_holes = 0;
> + 
> +     if (common_args_process(argc, argv, 3, 3, "write",
> +                             "<native file> <new file>", CHECK_FS_RW))
> +@@ -1699,7 +1744,15 @@ 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 I/O blocksize as buffer size when
> ++                     * copying sparse files.
> ++                     */
> ++                    bufsize = statbuf.st_blksize;
> ++            }
> ++            retval = copy_file(fd, newfile, bufsize, make_holes);
> +             if (retval)
> +                     com_err("copy_file", retval, 0);
> +     }
> +-- 
> +1.8.1.2
> +
> diff --git a/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.42.8.bb 
> b/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.42.8.bb
> index f97de7f..5d65bbc 100644
> --- a/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.42.8.bb
> +++ b/meta/recipes-devtools/e2fsprogs/e2fsprogs_1.42.8.bb
> @@ -4,6 +4,7 @@ require e2fsprogs.inc
>  SRC_URI += "file://acinclude.m4 \
>              file://remove.ldconfig.call.patch \
>              file://debugfs-too-short.patch \
> +            file://debugfs-sparse-copy.patch \
>  "
>  
>  SRC_URI[md5sum] = "8ef664b6eb698aa6b733df59b17b9ed4"

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel


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