From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: Linus Torvalds <torvalds@osdl.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] adds fat_get_cluster (7/11)
Date: Tue, 22 Jul 2003 00:55:38 +0900 [thread overview]
Message-ID: <87wuebvpqd.fsf@devron.myhome.or.jp> (raw)
This adds the fat_get_cluster() for generic reads of FAT
cluster-chains, and old fat_get_cluster() is renamed to
fat_bmap_cluster().
fs/fat/cache.c | 46 ++++++++++++++++++++++++++++++++++++++++++++--
include/linux/msdos_fs.h | 2 ++
2 files changed, 46 insertions(+), 2 deletions(-)
diff -puN fs/fat/cache.c~fat_add-get_cluster fs/fat/cache.c
--- linux-2.6.0-test1/fs/fat/cache.c~fat_add-get_cluster 2003-07-21 02:48:24.000000000 +0900
+++ linux-2.6.0-test1-hirofumi/fs/fat/cache.c 2003-07-21 02:48:24.000000000 +0900
@@ -287,7 +287,49 @@ out:
spin_unlock(&sbi->cache_lock);
}
-static int fat_get_cluster(struct inode *inode, int cluster)
+int fat_get_cluster(struct inode *inode, int cluster, int *fclus, int *dclus)
+{
+ struct super_block *sb = inode->i_sb;
+ const int limit = sb->s_maxbytes >> MSDOS_SB(sb)->cluster_bits;
+ int nr;
+
+ BUG_ON(MSDOS_I(inode)->i_start == 0);
+
+ *fclus = 0;
+ *dclus = MSDOS_I(inode)->i_start;
+ if (cluster == 0)
+ return 0;
+
+ fat_cache_lookup(inode, cluster, fclus, dclus);
+ while (*fclus < cluster) {
+ /* prevent the infinite loop of cluster chain */
+ if (*fclus > limit) {
+ fat_fs_panic(sb, "%s: detected the cluster chain loop"
+ " (i_pos %llu)", __FUNCTION__,
+ MSDOS_I(inode)->i_pos);
+ return -EIO;
+ }
+
+ nr = fat_access(sb, *dclus, -1);
+ if (nr < 0)
+ return nr;
+ else if (nr == FAT_ENT_FREE) {
+ fat_fs_panic(sb, "%s: invalid cluster chain"
+ " (i_pos %llu)", __FUNCTION__,
+ MSDOS_I(inode)->i_pos);
+ return -EIO;
+ } else if (nr == FAT_ENT_EOF) {
+ fat_cache_add(inode, *fclus, *dclus);
+ return FAT_ENT_EOF;
+ }
+ (*fclus)++;
+ *dclus = nr;
+ }
+ fat_cache_add(inode, *fclus, *dclus);
+ return 0;
+}
+
+static int fat_bmap_cluster(struct inode *inode, int cluster)
{
struct super_block *sb = inode->i_sb;
int nr,count;
@@ -336,7 +378,7 @@ int fat_bmap(struct inode *inode, sector
cluster = sector >> (sbi->cluster_bits - sb->s_blocksize_bits);
offset = sector & (sbi->cluster_size - 1);
- cluster = fat_get_cluster(inode, cluster);
+ cluster = fat_bmap_cluster(inode, cluster);
if (cluster < 0)
return cluster;
else if (cluster) {
diff -puN include/linux/msdos_fs.h~fat_add-get_cluster include/linux/msdos_fs.h
--- linux-2.6.0-test1/include/linux/msdos_fs.h~fat_add-get_cluster 2003-07-21 02:48:24.000000000 +0900
+++ linux-2.6.0-test1-hirofumi/include/linux/msdos_fs.h 2003-07-21 02:48:24.000000000 +0900
@@ -237,6 +237,8 @@ extern void fat_cache_lookup(struct inod
int *d_clu);
extern void fat_cache_add(struct inode *inode, int f_clu, int d_clu);
extern void fat_cache_inval_inode(struct inode *inode);
+extern int fat_get_cluster(struct inode *inode, int cluster,
+ int *fclus, int *dclus);
extern int fat_free(struct inode *inode, int skip);
/* fat/dir.c */
_
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
reply other threads:[~2003-07-21 15:41 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87wuebvpqd.fsf@devron.myhome.or.jp \
--to=hirofumi@mail.parknet.co.jp \
--cc=linux-kernel@vger.kernel.org \
--cc=torvalds@osdl.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.