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Message-ID: <20140306190622.GE9875@birch.djwong.org>
Date: Thu, 6 Mar 2014 11:06:22 -0800
From: "Darrick J. Wong" <darrick.wong@...cle.com>
To: Robert Yang <liezhi.yang@...driver.com>
Cc: tytso@....edu, dvhart@...ux.intel.com, linux-ext4@...r.kernel.org
Subject: Re: [PATCH V4 05/11] misc/create_inode.c: copy regular file
I noticed a few things while merging -next into my dev tree...
On Sat, Mar 01, 2014 at 03:06:09AM -0500, Robert Yang wrote:
> The do_write_internal() is used for copying file from native fs to
> target, most of the code are from debugfs/debugfs.c, the
> debugfs/debugfs.c will be modified to use this function.
>
> Signed-off-by: Robert Yang <liezhi.yang@...driver.com>
> Reviewed-by: Darren Hart <dvhart@...ux.intel.com>
> ---
> misc/create_inode.c | 183 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 183 insertions(+)
>
> diff --git a/misc/create_inode.c b/misc/create_inode.c
> index f845103..98f4a93 100644
> --- a/misc/create_inode.c
> +++ b/misc/create_inode.c
> @@ -8,6 +8,16 @@
> # endif
> #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
> +
> /* Make a special file which is block, character and fifo */
> errcode_t do_mknod_internal(ext2_ino_t cwd, const char *name, struct stat *st)
> {
> @@ -127,9 +137,182 @@ errcode_t do_mkdir_internal(ext2_ino_t cwd, const char *name, struct stat *st)
> {
> }
>
> +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;
> + char *ptr;
> + char *zero_buf;
> + int cmp;
> +
> + retval = ext2fs_file_open(current_fs, newfile,
> + EXT2_FILE_WRITE, &e2_file);
> + if (retval)
> + return retval;
> +
> + retval = ext2fs_get_mem(bufsize, &buf);
> + if (retval) {
> + com_err("copy_file", retval, "can't allocate buffer\n");
> + return retval;
> + }
> +
> + /* 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");
> + ext2fs_free_mem(&buf);
> + return retval;
> + }
> +
> + while (1) {
> + got = read(fd, buf, bufsize);
> + if (got == 0)
> + break;
> + if (got < 0) {
> + retval = errno;
> + 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);
> + if (retval)
> + goto fail;
> +
> + got -= written;
> + ptr += written;
> + }
> + }
> + ext2fs_free_mem(&buf);
> + ext2fs_free_mem(&zero_buf);
> + retval = ext2fs_file_close(e2_file);
> + return retval;
> +
> +fail:
> + ext2fs_free_mem(&buf);
> + ext2fs_free_mem(&zero_buf);
> + (void) ext2fs_file_close(e2_file);
> + return retval;
> +}
> +
> /* Copy the native file to the fs */
> errcode_t do_write_internal(ext2_ino_t cwd, const char *src, const char *dest)
> {
> + int fd;
> + struct stat statbuf;
> + ext2_ino_t newfile;
> + errcode_t retval;
> + struct ext2_inode inode;
> + int bufsize = IO_BUFSIZE;
> + int make_holes = 0;
> +
> + fd = open(src, O_RDONLY);
> + if (fd < 0) {
> + com_err(src, errno, 0);
> + return errno;
> + }
> + if (fstat(fd, &statbuf) < 0) {
> + com_err(src, errno, 0);
> + close(fd);
> + return errno;
> + }
> +
> + retval = ext2fs_namei(current_fs, root, cwd, dest, &newfile);
> + if (retval == 0) {
> + com_err(__func__, 0, "The file '%s' already exists\n", dest);
> + close(fd);
> + return errno;
> + }
> +
> + retval = ext2fs_new_inode(current_fs, cwd, 010755, 0, &newfile);
> + if (retval) {
> + com_err(__func__, retval, 0);
> + close(fd);
> + return errno;
Why return errno here, instead of retval?
> + }
> +#ifdef DEBUGFS
> + printf("Allocated inode: %u\n", newfile);
> +#endif
> + retval = ext2fs_link(current_fs, cwd, dest, newfile,
> + EXT2_FT_REG_FILE);
> + if (retval == EXT2_ET_DIR_NO_SPACE) {
> + retval = ext2fs_expand_dir(current_fs, cwd);
> + if (retval) {
> + com_err(__func__, retval, "while expanding directory");
> + close(fd);
> + return errno;
Or here...
> + }
> + retval = ext2fs_link(current_fs, cwd, dest, newfile,
> + EXT2_FT_REG_FILE);
> + }
> + if (retval) {
> + com_err(dest, retval, 0);
> + close(fd);
> + return errno;
Or here...
--D
> + }
> + if (ext2fs_test_inode_bitmap2(current_fs->inode_map, newfile))
> + com_err(__func__, 0, "Warning: inode already set");
> + ext2fs_inode_alloc_stats2(current_fs, newfile, +1, 0);
> + memset(&inode, 0, sizeof(inode));
> + inode.i_mode = (statbuf.st_mode & ~LINUX_S_IFMT) | LINUX_S_IFREG;
> + inode.i_atime = inode.i_ctime = inode.i_mtime =
> + current_fs->now ? current_fs->now : time(0);
> + inode.i_links_count = 1;
> + inode.i_size = statbuf.st_size;
> + if (current_fs->super->s_feature_incompat &
> + EXT3_FEATURE_INCOMPAT_EXTENTS) {
> + int i;
> + struct ext3_extent_header *eh;
> +
> + eh = (struct ext3_extent_header *) &inode.i_block[0];
> + eh->eh_depth = 0;
> + eh->eh_entries = 0;
> + eh->eh_magic = ext2fs_cpu_to_le16(EXT3_EXT_MAGIC);
> + i = (sizeof(inode.i_block) - sizeof(*eh)) /
> + sizeof(struct ext3_extent);
> + eh->eh_max = ext2fs_cpu_to_le16(i);
> + inode.i_flags |= EXT4_EXTENTS_FL;
> + }
> +
> + if ((retval = ext2fs_write_new_inode(current_fs, newfile, &inode))) {
> + com_err(__func__, retval, "while creating inode %u", newfile);
> + close(fd);
> + return errno;
> + }
> + if (LINUX_S_ISREG(inode.i_mode)) {
> + 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);
> + }
> + close(fd);
> +
> + return 0;
> }
>
> /* Copy files from source_dir to fs */
> --
> 1.7.10.4
>
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