fat: don't use free_clusters for fat32
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@mail.parknet.co.jp>
Cc: Juergen Beisert <juergen127@kreuzholzen.de>
Cc: Andreas Schwab <schwab@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/filesystems/vfat.txt b/Documentation/filesystems/vfat.txt
index 069cb10..fcc123f 100644
--- a/Documentation/filesystems/vfat.txt
+++ b/Documentation/filesystems/vfat.txt
@@ -57,6 +57,13 @@
currently exist in the directory, 'longfile.txt' will
be the short alias instead of 'longfi~1.txt'.
+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.
+
quiet -- Stops printing certain warning messages.
check=s|r|n -- Case sensitivity checking setting.
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index a8129e8..2c55e8d 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -825,6 +825,8 @@
}
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 @@
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 @@
{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 @@
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 @@
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;
@@ -1304,7 +1310,9 @@
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 --git a/include/linux/msdos_fs.h b/include/linux/msdos_fs.h
index fa253fa..0e09c00 100644
--- a/include/linux/msdos_fs.h
+++ b/include/linux/msdos_fs.h
@@ -205,7 +205,8 @@
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