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Message-ID: <877is4scre.fsf@duaron.myhome.or.jp>
Date: Sun, 22 Apr 2007 23:29:57 +0900
From: OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To: 7eggert@....de
Cc: Juergen Beisert <juergen127@...uzholzen.de>,
linux-kernel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: Wrong free clusters count on FAT32
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp> writes:
>> - You forgot to update Documentation/
>
> Sure. If you can post the patch, it'll be great.
Updated patch is here.
Thanks.
--
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
It seems that the recent Windows changed specification, and it's
undocumented. Windows doesn't update ->free_clusters correctly.
This patch doesn't use ->free_clusters by default. (instead, add
"usefree" for forcing to use it)
Signed-off-by: OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
---
Documentation/filesystems/vfat.txt | 7 +++++++
fs/fat/inode.c | 14 +++++++++++---
include/linux/msdos_fs.h | 3 ++-
3 files changed, 20 insertions(+), 4 deletions(-)
diff -puN fs/fat/inode.c~fat_dont-use_free_clusters-for-fat32 fs/fat/inode.c
--- linux-2.6/fs/fat/inode.c~fat_dont-use_free_clusters-for-fat32 2007-04-22 13:07:05.000000000 +0900
+++ linux-2.6-hirofumi/fs/fat/inode.c 2007-04-22 13:18:07.000000000 +0900
@@ -825,6 +825,8 @@ static int fat_show_options(struct seq_f
}
if (opts->name_check != 'n')
seq_printf(m, ",check=%c", opts->name_check);
+ if (opts->usefree)
+ seq_puts(m, ",usefree");
if (opts->quiet)
seq_puts(m, ",quiet");
if (opts->showexec)
@@ -850,7 +852,7 @@ static int fat_show_options(struct seq_f
enum {
Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
- Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_nocase,
+ Opt_umask, Opt_dmask, Opt_fmask, Opt_codepage, Opt_usefree, Opt_nocase,
Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable,
Opt_dots, Opt_nodots,
Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
@@ -872,6 +874,7 @@ static match_table_t fat_tokens = {
{Opt_dmask, "dmask=%o"},
{Opt_fmask, "fmask=%o"},
{Opt_codepage, "codepage=%u"},
+ {Opt_usefree, "usefree"},
{Opt_nocase, "nocase"},
{Opt_quiet, "quiet"},
{Opt_showexec, "showexec"},
@@ -951,7 +954,7 @@ static int parse_options(char *options,
opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK = 0;
opts->utf8 = opts->unicode_xlate = 0;
opts->numtail = 1;
- opts->nocase = 0;
+ opts->usefree = opts->nocase = 0;
*debug = 0;
if (!options)
@@ -979,6 +982,9 @@ static int parse_options(char *options,
case Opt_check_n:
opts->name_check = 'n';
break;
+ case Opt_usefree:
+ opts->usefree = 1;
+ break;
case Opt_nocase:
if (!is_vfat)
opts->nocase = 1;
@@ -1306,7 +1312,9 @@ int fat_fill_super(struct super_block *s
le32_to_cpu(fsinfo->signature2),
sbi->fsinfo_sector);
} else {
- sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
+ if (sbi->options.usefree)
+ sbi->free_clusters =
+ le32_to_cpu(fsinfo->free_clusters);
sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
}
diff -puN include/linux/msdos_fs.h~fat_dont-use_free_clusters-for-fat32 include/linux/msdos_fs.h
--- linux-2.6/include/linux/msdos_fs.h~fat_dont-use_free_clusters-for-fat32 2007-04-22 13:07:05.000000000 +0900
+++ linux-2.6-hirofumi/include/linux/msdos_fs.h 2007-04-22 13:09:14.000000000 +0900
@@ -205,7 +205,8 @@ struct fat_mount_options {
numtail:1, /* Does first alias have a numeric '~1' type tail? */
atari:1, /* Use Atari GEMDOS variation of MS-DOS fs */
flush:1, /* write things quickly */
- nocase:1; /* Does this need case conversion? 0=need case conversion*/
+ nocase:1, /* Does this need case conversion? 0=need case conversion*/
+ usefree:1; /* Use free_clusters for FAT32 */
};
#define FAT_HASH_BITS 8
diff -puN Documentation/filesystems/vfat.txt~fat_dont-use_free_clusters-for-fat32 Documentation/filesystems/vfat.txt
--- linux-2.6/Documentation/filesystems/vfat.txt~fat_dont-use_free_clusters-for-fat32 2007-04-22 23:06:21.000000000 +0900
+++ linux-2.6-hirofumi/Documentation/filesystems/vfat.txt 2007-04-22 23:28:19.000000000 +0900
@@ -34,6 +34,13 @@ iocharset=name -- Character set to use f
NOTE: "iocharset=utf8" is not recommended. If unsure,
you should consider the following option instead.
+usefree -- Use the "free clusters" value stored on FSINFO. It'll
+ be used to determine number of free clusters without
+ scanning disk. But it's not used by default, because
+ recent Windows don't update it correctly in some
+ case. If you are sure the "free clusters" on FSINFO is
+ correct, by this option you can avoid scanning disk.
+
utf8=<bool> -- UTF-8 is the filesystem safe version of Unicode that
is used by the console. It can be enabled for the
filesystem with this option. If 'uni_xlate' gets set,
_
-
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