linux-kernel - Re: [f2fs-dev] [PATCH] f2fs-tools: change fiemap print out format

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Date:   Fri, 20 Aug 2021 08:20:39 -0700
From:   Daeho Jeong <daeho43@...il.com>
To:     Chao Yu <chao@...nel.org>
Cc:     linux-kernel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com,
        Daeho Jeong <daehojeong@...gle.com>
Subject: Re: [f2fs-dev] [PATCH] f2fs-tools: change fiemap print out format

On Fri, Aug 20, 2021 at 3:15 AM Chao Yu <chao@...nel.org> wrote:
>
> On 2021/8/9 5:52, Daeho Jeong wrote:
> > From: Daeho Jeong <daehojeong@...gle.com>
> >
> > Given fiemap way to print out extents in the kernel, we can correctly
> > print the layout of each file in a unit of extent, not block. So, I
> > changed fiemap print out way like below.
> >
> > Fiemap: offset = 0 len = 60
> >       logical addr.    physical addr.   length           flags
> > 0     0000000000000000 00000020032df000 0000000000004000 00001008
> > 1     0000000000004000 00000020032e0000 0000000000004000 00001008
> > 2     0000000000008000 00000020032e1000 0000000000004000 00001008
> > 3     000000000000c000 00000020032e2000 0000000000004000 00001008
> >
> > Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
> > ---
> >   tools/f2fs_io/f2fs_io.c | 53 ++++++++++++++++++++++++++---------------
> >   1 file changed, 34 insertions(+), 19 deletions(-)
> >
> > diff --git a/tools/f2fs_io/f2fs_io.c b/tools/f2fs_io/f2fs_io.c
> > index 42dbd60..0d2948e 100644
> > --- a/tools/f2fs_io/f2fs_io.c
> > +++ b/tools/f2fs_io/f2fs_io.c
> > @@ -731,11 +731,11 @@ static void do_randread(int argc, char **argv, const struct cmd_desc *cmd)
> >   #if defined(HAVE_LINUX_FIEMAP_H) && defined(HAVE_LINUX_FS_H)
> >   static void do_fiemap(int argc, char **argv, const struct cmd_desc *cmd)
> >   {
> > -     unsigned count, i;
> > -     int fd;
> > -     __u64 phy_addr;
> > -     struct fiemap *fm = xmalloc(sizeof(struct fiemap) +
> > -                     sizeof(struct fiemap_extent));
> > +     unsigned int i;
> > +     int fd, extents_mem_size;
> > +     u64 start, length;
> > +     u32 mapped_extents;
> > +     struct fiemap *fm = xmalloc(sizeof(struct fiemap));
> >
> >       if (argc != 4) {
> >               fputs("Excess arguments\n\n", stderr);
> > @@ -743,26 +743,41 @@ static void do_fiemap(int argc, char **argv, const struct cmd_desc *cmd)
> >               exit(1);
> >       }
> >
> > -     fm->fm_start = atoi(argv[1]) * F2FS_BLKSIZE;
> > -     fm->fm_length = F2FS_BLKSIZE;
> > -     fm->fm_extent_count = 1;
> > -     count = atoi(argv[2]);
> > +     memset(fm, 0, sizeof(struct fiemap));
> > +     start = atoi(argv[1]) * F2FS_BLKSIZE;
> > +     length = atoi(argv[2]) * F2FS_BLKSIZE;
> > +     fm->fm_start = start;
> > +     fm->fm_length = length;
> >
> >       fd = xopen(argv[3], O_RDONLY | O_LARGEFILE, 0);
> >
> > -     printf("Fiemap: offset = %08"PRIx64" len = %d\n",
> > -                             (u64)fm->fm_start / F2FS_BLKSIZE, count);
> > -     for (i = 0; i < count; i++) {
> > -             if (ioctl(fd, FS_IOC_FIEMAP, fm) < 0)
> > -                     die_errno("FIEMAP failed");
> > +     printf("Fiemap: offset = %"PRIu64" len = %"PRIu64"\n",
> > +                             start / F2FS_BLKSIZE, length / F2FS_BLKSIZE);
> > +     if (ioctl(fd, FS_IOC_FIEMAP, fm) < 0)
> > +             die_errno("FIEMAP failed");
> > +
> > +     mapped_extents = fm->fm_mapped_extents;
> > +     extents_mem_size = sizeof(struct fiemap_extent) * mapped_extents;
> > +     free(fm);
> > +     fm = xmalloc(sizeof(struct fiemap) + extents_mem_size);
> >
> > -             phy_addr = fm->fm_extents[0].fe_physical / F2FS_BLKSIZE;
> > -             printf("%llu: %llu\n", fm->fm_start / F2FS_BLKSIZE, phy_addr);
> > +     memset(fm, 0, sizeof(struct fiemap));
> > +     memset(fm->fm_extents, 0, extents_mem_size);
>
> Is that equals to memset(fm, 0, sizeof(struct fiemap) + extents_mem_size);?
>

Oh, you're right~

> > +     fm->fm_start = start;
> > +     fm->fm_length = length;
> > +     fm->fm_extent_count = mapped_extents;
> >
> > -             if (fm->fm_extents[0].fe_flags & FIEMAP_EXTENT_LAST)
> > -                     break;
> > +     if (ioctl(fd, FS_IOC_FIEMAP, fm) < 0)
> > +             die_errno("FIEMAP failed");
> >
> > -             fm->fm_start += F2FS_BLKSIZE;
> > +     printf("\t%-17s%-17s%-17s%s\n", "logical addr.", "physical addr.", "length", "flags");
> > +     for (i = 0; i < fm->fm_mapped_extents; i++) {
> > +             printf("%d\t%.16llx %.16llx %.16llx %.8x\n", i,
> > +                 fm->fm_extents[i].fe_logical, fm->fm_extents[i].fe_physical,
> > +                 fm->fm_extents[i].fe_length, fm->fm_extents[i].fe_flags);
> > +
> > +             if (fm->fm_extents[i].fe_flags & FIEMAP_EXTENT_LAST)
> > +                     break;
> >       }
> >       printf("\n");
> >       free(fm);
> >