Messages in this thread | | | From | OGAWA Hirofumi <> | Subject | Re: [PATCH] FAT: optimize FSINFO writeback | Date | Wed, 01 Jul 2009 05:57:15 +0900 |
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steve@digidescorp.com writes:
> Only write the FSINFO block back to disk when its contents change. > This optimization can be important when the underlying physical media > can wear out, i.e. Flash.
I have no objection to this though. Was this tested on recent version? Well, now, we are using sb->s_dirty for fsinfo, so I'm wondering why this happen frequently.
Thanks.
> Signed-off-by: Steven J. Magnani <steve@digidescorp.com> > --- > diff -uprN a/fs/fat/misc.c b/fs/fat/misc.c > --- a/fs/fat/misc.c 2009-06-29 11:12:40.000000000 -0500 > +++ b/fs/fat/misc.c 2009-06-29 11:46:45.000000000 -0500 > @@ -61,11 +61,25 @@ void fat_clusters_flush(struct super_blo > le32_to_cpu(fsinfo->signature2), > sbi->fsinfo_sector); > } else { > - if (sbi->free_clusters != -1) > - fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters); > - if (sbi->prev_free != -1) > - fsinfo->next_cluster = cpu_to_le32(sbi->prev_free); > - mark_buffer_dirty(bh); > + char write_needed = 0; > + __le32 le_value; > + > + if (sbi->free_clusters != -1) { > + le_value = cpu_to_le32(sbi->free_clusters); > + if (fsinfo->free_clusters != le_value) { > + fsinfo->free_clusters = le_value; > + write_needed = 1; > + } > + } > + if (sbi->prev_free != -1) { > + le_value = cpu_to_le32(sbi->prev_free); > + if (fsinfo->next_cluster != le_value) { > + fsinfo->next_cluster = le_value; > + write_needed = 1; > + } > + } > + if (write_needed) > + mark_buffer_dirty(bh); > } > brelse(bh); > } >
-- OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
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