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From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 7/29] FAT: Use "unsigned int" for ->free_clusters and ->prev_free
Date: Sun, 06 Mar 2005 03:47:04 +0900	[thread overview]
Message-ID: <87r7iuq6af.fsf_-_@devron.myhome.or.jp> (raw)
In-Reply-To: <87vf86q6d2.fsf_-_@devron.myhome.or.jp> (OGAWA Hirofumi's message of "Sun, 06 Mar 2005 03:45:29 +0900")


This changes ->free_clusters and ->prev_free from "int" to "unsigned int".
These value should be never negative value (but it's using 0xffffffff(-1)
as undefined state).

With this changes, fatfs would handle the corruption of free_clusters
more proper.

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
---

 fs/fat/fatent.c          |    3 +--
 fs/fat/inode.c           |    6 +++++-
 include/linux/msdos_fs.h |    4 ++--
 3 files changed, 8 insertions(+), 5 deletions(-)

diff -puN fs/fat/fatent.c~sync05-fat_free-unsigned fs/fat/fatent.c
--- linux-2.6.11/fs/fat/fatent.c~sync05-fat_free-unsigned	2005-03-06 02:36:19.000000000 +0900
+++ linux-2.6.11-hirofumi/fs/fat/fatent.c	2005-03-06 02:36:19.000000000 +0900
@@ -453,8 +453,7 @@ int fat_alloc_clusters(struct inode *ino
 	fatent_init(&fatent);
 	fatent_set_entry(&fatent, sbi->prev_free + 1);
 	while (count < sbi->max_cluster) {
-		fatent.entry %= sbi->max_cluster;
-		if (fatent.entry < FAT_START_ENT)
+		if (fatent.entry >= sbi->max_cluster)
 			fatent.entry = FAT_START_ENT;
 		fatent_set_entry(&fatent, fatent.entry);
 		err = fat_ent_read_block(sb, &fatent);
diff -puN fs/fat/inode.c~sync05-fat_free-unsigned fs/fat/inode.c
--- linux-2.6.11/fs/fat/inode.c~sync05-fat_free-unsigned	2005-03-06 02:36:19.000000000 +0900
+++ linux-2.6.11-hirofumi/fs/fat/inode.c	2005-03-06 02:36:19.000000000 +0900
@@ -1163,7 +1163,7 @@ int fat_fill_super(struct super_block *s
 	sbi->fat_length = le16_to_cpu(b->fat_length);
 	sbi->root_cluster = 0;
 	sbi->free_clusters = -1;	/* Don't know yet */
-	sbi->prev_free = -1;
+	sbi->prev_free = FAT_START_ENT;
 
 	if (!sbi->fat_length && b->fat32_length) {
 		struct fat_boot_fsinfo *fsinfo;
@@ -1247,6 +1247,10 @@ int fat_fill_super(struct super_block *s
 	/* check the free_clusters, it's not necessarily correct */
 	if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
 		sbi->free_clusters = -1;
+	/* check the prev_free, it's not necessarily correct */
+	sbi->prev_free %= sbi->max_cluster;
+	if (sbi->prev_free < FAT_START_ENT)
+		sbi->prev_free = FAT_START_ENT;
 
 	brelse(bh);
 
diff -puN include/linux/msdos_fs.h~sync05-fat_free-unsigned include/linux/msdos_fs.h
--- linux-2.6.11/include/linux/msdos_fs.h~sync05-fat_free-unsigned	2005-03-06 02:36:19.000000000 +0900
+++ linux-2.6.11-hirofumi/include/linux/msdos_fs.h	2005-03-06 02:36:19.000000000 +0900
@@ -225,8 +225,8 @@ struct msdos_sb_info {
 	unsigned long root_cluster;  /* first cluster of the root directory */
 	unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
 	struct semaphore fat_lock;
-	int prev_free;               /* previously allocated cluster number */
-	int free_clusters;           /* -1 if undefined */
+	unsigned int prev_free;      /* previously allocated cluster number */
+	unsigned int free_clusters;  /* -1 if undefined */
 	struct fat_mount_options options;
 	struct nls_table *nls_disk;  /* Codepage used on disk */
 	struct nls_table *nls_io;    /* Charset used for input and display */
_

  reply	other threads:[~2005-03-05 19:12 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <87ll92rl6a.fsf@devron.myhome.or.jp>
2005-03-05 18:41 ` [PATCH 1/29] fat: fix writev(), add aio support OGAWA Hirofumi
2005-03-05 18:42   ` [PATCH 2/29] FAT: Updated FAT attributes patch OGAWA Hirofumi
2005-03-05 18:43     ` [PATCH 3/29] FAT: fat_readdirx() with dotOK=yes fix OGAWA Hirofumi
2005-03-05 18:43       ` [PATCH 4/29] let fat handle MS_SYNCHRONOUS flag OGAWA Hirofumi
2005-03-06 22:38         ` Christoph Hellwig
2005-03-07 14:56           ` OGAWA Hirofumi
2005-03-05 18:44       ` [PATCH 5/29] FAT: Rewrite the FAT (File Allocation Table) access stuff OGAWA Hirofumi
2005-03-05 18:45         ` [PATCH 6/29] FAT: add debugging code to fatent.c OGAWA Hirofumi
2005-03-05 18:47           ` OGAWA Hirofumi [this message]
2005-03-05 18:47             ` [PATCH 8/29] FAT: "struct vfat_slot_info" cleanup OGAWA Hirofumi
2005-03-05 18:48               ` [PATCH 9/29] FAT: Use "struct fat_slot_info" for fat_search_long() OGAWA Hirofumi
2005-03-05 18:49                 ` [PATCH 10/29] FAT: Add fat_remove_entries() OGAWA Hirofumi
2005-03-05 18:49                   ` [PATCH 11/29] FAT: fat_build_inode() cleanup OGAWA Hirofumi
2005-03-05 18:50                     ` [PATCH 12/29] FAT: Use "struct fat_slot_info" for fat_scan() OGAWA Hirofumi
2005-03-05 18:50                       ` [PATCH 13/29] FAT: Use "struct fat_slot_info" for msdos_find() OGAWA Hirofumi
2005-03-05 18:51                         ` [PATCH 14/29] FAT: vfat_build_slots() cleanup OGAWA Hirofumi
2005-03-05 18:52                           ` [PATCH 15/29] FAT: Use a same timestamp on some operations path OGAWA Hirofumi
2005-03-05 18:52                             ` [PATCH 16/29] FAT: msdos_rename() cleanup OGAWA Hirofumi
2005-03-05 18:53                               ` [PATCH 17/29] FAT: msdos_add_entry() cleanup OGAWA Hirofumi
2005-03-05 18:53                                 ` [PATCH 18/29] FAT: Allocate the cluster before adding the directory entry OGAWA Hirofumi
2005-03-05 18:54                                   ` [PATCH 19/29] FAT: Rewrite fat_add_entries() OGAWA Hirofumi
2005-03-05 18:55                                     ` [PATCH 20/29] FAT: Use fat_remove_entries() for msdos OGAWA Hirofumi
2005-03-05 18:55                                       ` [PATCH 21/29] FAT: make the fat_get_entry()/fat__get_entry() the static OGAWA Hirofumi
2005-03-05 18:56                                         ` [PATCH 22/29] FAT: "i_pos" cleanup OGAWA Hirofumi
2005-03-05 18:56                                           ` [PATCH 23/29] FAT: Remove the multiple MSDOS_SB() call OGAWA Hirofumi
2005-03-05 18:57                                             ` [PATCH 24/29] FAT: Remove unneed mark_inode_dirty() OGAWA Hirofumi
2005-03-05 18:57                                               ` [PATCH 25/29] FAT: Fix fat_truncate() OGAWA Hirofumi
2005-03-05 18:58                                                 ` [PATCH 26/29] FAT: Fix fat_write_inode() OGAWA Hirofumi
2005-03-05 18:58                                                   ` [PATCH 27/29] FAT: Use synchronous update for {vfat,msdos}_add_entry() OGAWA Hirofumi
2005-03-05 18:59                                                     ` [PATCH 28/29] FAT: Update ->rename() path OGAWA Hirofumi
2005-03-05 19:00                                                       ` [PATCH 29/29] FAT: Fix typo OGAWA Hirofumi
2005-03-06 22:44                                             ` [PATCH 23/29] FAT: Remove the multiple MSDOS_SB() call Christoph Hellwig
2005-03-07 22:01                                             ` Adrian Bunk
2005-03-08 13:48                                               ` OGAWA Hirofumi
2005-03-06 15:53     ` [PATCH 2/29] FAT: Updated FAT attributes patch Michael Geng
2005-03-06 17:02       ` OGAWA Hirofumi
2005-03-06 22:45       ` Christoph Hellwig
2005-03-06  0:07   ` [PATCH] FAT: Support synchronous updates OGAWA Hirofumi
2005-03-07  1:10 ` [PATCH] FAT: Support synchronous update Andrew Morton
2005-03-07 15:02   ` OGAWA Hirofumi

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