On Mon, Aug 26, 2013 at 02:22:03PM +0800, Robert Yang wrote: > 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. > > Signed-off-by: Robert Yang <liezhi.yang@xxxxxxxxxxxxx> > Acked-by: Darren Hart <dvhart@xxxxxxxxxxxxxxx> > --- > debugfs/debugfs.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 58 insertions(+), 4 deletions(-) > > diff --git a/debugfs/debugfs.c b/debugfs/debugfs.c > index a6bc932..8c32eff 100644 > --- 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 +1585,37 @@ 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; > + } Ugh. I probably could have whined about this not using ext2fs_get_mem, but more importantly clang whines about the undefined return value. I'll fix it and send out a patch with my next patchbomb. --D > + > + /* This is used for checking whether the whole block is zero */ > + retval = ext2fs_get_memzero(bufsize, &zero_buf); > + if (retval) { > + com_err("copy_file", retval, "can't allocate buffer\n"); > + free(buf); > + return retval; > + } > + > while (1) { > - got = read(fd, buf, sizeof(buf)); > + got = read(fd, buf, bufsize); > if (got == 0) > break; > if (got < 0) { > @@ -1598,6 +1623,21 @@ 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 +1648,14 @@ 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 +1668,8 @@ 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 +1745,15 @@ 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
