[U-Boot] [PATCH v2] fs/ext4/ext4fs.c, fs/fs.c fs/fat/fat_write.c: Adjust 64bit math methods

[Tom Rini]

On Wed, Nov 26, 2014 at 12:36:27PM -0700, Simon Glass wrote:
> Hi Tom,
> 
> On 26 November 2014 at 12:29, Tom Rini <trini at ti.com> wrote:
> > The changes to introduce loff_t into filesize means that we need to do
> > 64bit math on 32bit platforms.  Make sure we use the right wrappers for
> > these operations.
> >
> > Cc: Daniel Schwierzeck <daniel.schwierzeck at gmail.com>
> > Cc: Suriyan Ramasami <suriyan.r at gmail.com>
> > Cc: Simon Glass <sjg at chromium.org>
> > Signed-off-by: Tom Rini <trini at ti.com>
> 
> This fixes things for me, thanks! But please see below.
> 
> > ---
> >  fs/ext4/ext4fs.c   |   11 ++++++-----
> >  fs/fat/fat_write.c |   10 ++++++----
> >  fs/fs.c            |    6 ++++--
> >  3 files changed, 16 insertions(+), 11 deletions(-)
> >
> > diff --git a/fs/ext4/ext4fs.c b/fs/ext4/ext4fs.c
> > index 943b5bc..258b9379 100644
> > --- a/fs/ext4/ext4fs.c
> > +++ b/fs/ext4/ext4fs.c
> > @@ -25,6 +25,7 @@
> >  #include <ext_common.h>
> >  #include <ext4fs.h>
> >  #include "ext4_common.h"
> > +#include <div64.h>
> >
> >  int ext4fs_symlinknest;
> >  struct ext_filesystem ext_fs;
> > @@ -67,11 +68,11 @@ int ext4fs_read_file(struct ext2fs_node *node, loff_t pos,
> >         if (len > filesize)
> >                 len = filesize;
> >
> > -       blockcnt = ((len + pos) + blocksize - 1) / blocksize;
> > +       blockcnt = lldiv(((len + pos) + blocksize - 1), blocksize);
> >
> > -       for (i = pos / blocksize; i < blockcnt; i++) {
> > +       for (i = lldiv(pos, blocksize); i < blockcnt; i++) {
> >                 lbaint_t blknr;
> > -               int blockoff = pos % blocksize;
> > +               int blockoff = pos - (blocksize * i);
> >                 int blockend = blocksize;
> >                 int skipfirst = 0;
> >                 blknr = read_allocated_block(&(node->inode), i);
> > @@ -82,7 +83,7 @@ int ext4fs_read_file(struct ext2fs_node *node, loff_t pos,
> >
> >                 /* Last block.  */
> >                 if (i == blockcnt - 1) {
> > -                       blockend = (len + pos) % blocksize;
> > +                       blockend = (len + pos) - (blocksize * i);
> 
> Actually do you think it would be clearer to use div_u64_rem() here?

I don't think so only since we don't care about the quotient only the
remainder.  In the FAT case we needed both (and that's what got me
seeing the <linux/math64.h> functions.

> 
> >
> >                         /* The last portion is exactly blocksize. */
> >                         if (!blockend)
> > @@ -90,7 +91,7 @@ int ext4fs_read_file(struct ext2fs_node *node, loff_t pos,
> >                 }
> >
> >                 /* First block. */
> > -               if (i == pos / blocksize) {
> > +               if (i == lldiv(pos, blocksize)) {
> >                         skipfirst = blockoff;
> >                         blockend -= skipfirst;
> >                 }
> > diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c
> > index 88dd495..473723b 100644
> > --- a/fs/fat/fat_write.c
> > +++ b/fs/fat/fat_write.c
> > @@ -13,6 +13,8 @@
> >  #include <asm/byteorder.h>
> >  #include <part.h>
> >  #include <linux/ctype.h>
> > +#include <div64.h>
> > +#include <linux/math64.h>
> >  #include "fat.c"
> >
> >  static void uppercase(char *str, int len)
> > @@ -770,7 +772,7 @@ static void fill_dentry(fsdata *mydata, dir_entry *dentptr,
> >   */
> >  static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
> >  {
> > -       __u32 startsect, sect_num;
> > +       __u32 startsect, sect_num, offset;
> >
> >         if (clustnum > 0) {
> >                 startsect = mydata->data_begin +
> > @@ -779,13 +781,13 @@ static int check_overflow(fsdata *mydata, __u32 clustnum, loff_t size)
> >                 startsect = mydata->rootdir_sect;
> >         }
> >
> > -       sect_num = size / mydata->sect_size;
> > -       if (size % mydata->sect_size)
> > +       sect_num = div_u64_rem(size, mydata->sect_size, &offset);
> > +
> > +       if (offset != 0)
> >                 sect_num++;
> >
> >         if (startsect + sect_num > cur_part_info.start + total_sector)
> >                 return -1;
> > -
> >         return 0;
> >  }
> >
> > diff --git a/fs/fs.c b/fs/fs.c
> > index 3da7860..52078139 100644
> > --- a/fs/fs.c
> > +++ b/fs/fs.c
> > @@ -23,6 +23,8 @@
> >  #include <fs.h>
> >  #include <sandboxfs.h>
> >  #include <asm/io.h>
> > +#include <div64.h>
> > +#include <linux/math64.h>
> >
> >  DECLARE_GLOBAL_DATA_PTR;
> >
> > @@ -399,7 +401,7 @@ int do_load(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
> >         printf("%llu bytes read in %lu ms", len_read, time);
> >         if (time > 0) {
> >                 puts(" (");
> > -               print_size(len_read / time * 1000, "/s");
> > +               print_size(div_u64(len_read, time * 1000), "/s");
> 
> The old code multiplies by 1000 but the new code divides. I think it should be:
> 
>                print_size(div_u64(len_read, time) * 1000, "/s");
> 
> >                 puts(")");
> >         }
> >         puts("\n");
> > @@ -469,7 +471,7 @@ int do_save(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[],
> >         printf("%llu bytes written in %lu ms", len, time);
> >         if (time > 0) {
> >                 puts(" (");
> > -               print_size(len / time * 1000, "/s");
> > +               print_size(div_u64(len, time * 1000), "/s");
> 
> and here.

Whoops, those are bugs, fixed.

-- 
Tom
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