[PATCH 12/13] FAT: reserved clusters cleanup

From: OGAWA Hirofumi
Date: Mon Jan 17 2005 - 13:15:24 EST

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- Replaces the "number of reserved clusters" by FAT_START_ENT.

- The ->clusters is total number of clusters. Instead of it, use the
maximum cluster number (->max_cluster).

By this change, removes the some "->clusters + 2" calculation.

- Adds inline function for cluster to block number conversion. And
replaces the open-coding for it.

Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
---

fs/fat/cache.c | 8 +++-----
fs/fat/dir.c | 2 +-
fs/fat/inode.c | 25 +++++++++++++------------
fs/fat/misc.c | 27 ++++++++++++++-------------
include/linux/msdos_fs.h | 11 ++++++++++-
5 files changed, 41 insertions(+), 32 deletions(-)

diff -puN fs/fat/cache.c~fat_max-clusters-cleanup fs/fat/cache.c
--- linux-2.6.11-rc1/fs/fat/cache.c~fat_max-clusters-cleanup 2005-01-15 16:49:08.000000000 +0900
+++ linux-2.6.11-rc1-hirofumi/fs/fat/cache.c 2005-01-15 16:49:08.000000000 +0900
@@ -305,7 +305,7 @@ int fat_access(struct super_block *sb, i
int next;

next = -EIO;
- if (nr < 2 || MSDOS_SB(sb)->clusters + 2 <= nr) {
+ if (nr < FAT_START_ENT || MSDOS_SB(sb)->max_cluster <= nr) {
fat_fs_panic(sb, "invalid access to FAT (entry 0x%08x)", nr);
goto out;
}
@@ -431,9 +431,7 @@ int fat_bmap(struct inode *inode, sector
cluster = fat_bmap_cluster(inode, cluster);
if (cluster < 0)
return cluster;
- else if (cluster) {
- *phys = ((sector_t)cluster - 2) * sbi->sec_per_clus
- + sbi->data_start + offset;
- }
+ else if (cluster)
+ *phys = fat_clus_to_blknr(sbi, cluster) + offset;
return 0;
}
diff -puN fs/fat/dir.c~fat_max-clusters-cleanup fs/fat/dir.c
--- linux-2.6.11-rc1/fs/fat/dir.c~fat_max-clusters-cleanup 2005-01-15 16:49:08.000000000 +0900
+++ linux-2.6.11-rc1-hirofumi/fs/fat/dir.c 2005-01-15 16:49:08.000000000 +0900
@@ -767,7 +767,7 @@ static struct buffer_head *fat_extend_di
if (nr < 0)
return ERR_PTR(nr);

- sector = ((sector_t)nr - 2) * sec_per_clus + MSDOS_SB(sb)->data_start;
+ sector = fat_clus_to_blknr(MSDOS_SB(sb), nr);
last_sector = sector + sec_per_clus;
for ( ; sector < last_sector; sector++) {
if ((bh = sb_getblk(sb, sector))) {
diff -puN fs/fat/inode.c~fat_max-clusters-cleanup fs/fat/inode.c
--- linux-2.6.11-rc1/fs/fat/inode.c~fat_max-clusters-cleanup 2005-01-15 16:49:08.000000000 +0900
+++ linux-2.6.11-rc1-hirofumi/fs/fat/inode.c 2005-01-15 16:49:08.000000000 +0900
@@ -419,17 +419,18 @@ static int fat_remount(struct super_bloc

static int fat_statfs(struct super_block *sb, struct kstatfs *buf)
{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
int free, nr, ret;

- if (MSDOS_SB(sb)->free_clusters != -1)
- free = MSDOS_SB(sb)->free_clusters;
+ if (sbi->free_clusters != -1)
+ free = sbi->free_clusters;
else {
lock_fat(sb);
- if (MSDOS_SB(sb)->free_clusters != -1)
- free = MSDOS_SB(sb)->free_clusters;
+ if (sbi->free_clusters != -1)
+ free = sbi->free_clusters;
else {
free = 0;
- for (nr = 2; nr < MSDOS_SB(sb)->clusters + 2; nr++) {
+ for (nr = FAT_START_ENT; nr < sbi->max_cluster; nr++) {
ret = fat_access(sb, nr, -1);
if (ret < 0) {
unlock_fat(sb);
@@ -437,17 +438,17 @@ static int fat_statfs(struct super_block
} else if (ret == FAT_ENT_FREE)
free++;
}
- MSDOS_SB(sb)->free_clusters = free;
+ sbi->free_clusters = free;
}
unlock_fat(sb);
}

buf->f_type = sb->s_magic;
- buf->f_bsize = MSDOS_SB(sb)->cluster_size;
- buf->f_blocks = MSDOS_SB(sb)->clusters;
+ buf->f_bsize = sbi->cluster_size;
+ buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
buf->f_bfree = free;
buf->f_bavail = free;
- buf->f_namelen = MSDOS_SB(sb)->options.isvfat ? 260 : 12;
+ buf->f_namelen = sbi->options.isvfat ? 260 : 12;

return 0;
}
@@ -1232,7 +1233,7 @@ int fat_fill_super(struct super_block *s

/* check that FAT table does not overflow */
fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
- total_clusters = min(total_clusters, fat_clusters - 2);
+ total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
if (total_clusters > MAX_FAT(sb)) {
if (!silent)
printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
@@ -1241,9 +1242,9 @@ int fat_fill_super(struct super_block *s
goto out_invalid;
}

- sbi->clusters = total_clusters;
+ sbi->max_cluster = total_clusters + FAT_START_ENT;
/* check the free_clusters, it's not necessarily correct */
- if (sbi->free_clusters != -1 && sbi->free_clusters > sbi->clusters)
+ if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
sbi->free_clusters = -1;

brelse(bh);
diff -puN fs/fat/misc.c~fat_max-clusters-cleanup fs/fat/misc.c
--- linux-2.6.11-rc1/fs/fat/misc.c~fat_max-clusters-cleanup 2005-01-15 16:49:08.000000000 +0900
+++ linux-2.6.11-rc1-hirofumi/fs/fat/misc.c 2005-01-15 16:49:08.000000000 +0900
@@ -86,8 +86,9 @@ void fat_clusters_flush(struct super_blo
int fat_add_cluster(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
int ret, count, limit, new_dclus, new_fclus, last;
- int cluster_bits = MSDOS_SB(sb)->cluster_bits;
+ int cluster_bits = sbi->cluster_bits;

/*
* We must locate the last cluster of the file to add this new
@@ -110,17 +111,17 @@ int fat_add_cluster(struct inode *inode)
/* find free FAT entry */
lock_fat(sb);

- if (MSDOS_SB(sb)->free_clusters == 0) {
+ if (sbi->free_clusters == 0) {
unlock_fat(sb);
return -ENOSPC;
}

- limit = MSDOS_SB(sb)->clusters + 2;
- new_dclus = MSDOS_SB(sb)->prev_free + 1;
- for (count = 0; count < MSDOS_SB(sb)->clusters; count++, new_dclus++) {
+ limit = sbi->max_cluster;
+ new_dclus = sbi->prev_free + 1;
+ for (count = FAT_START_ENT; count < limit; count++, new_dclus++) {
new_dclus = new_dclus % limit;
- if (new_dclus < 2)
- new_dclus = 2;
+ if (new_dclus < FAT_START_ENT)
+ new_dclus = FAT_START_ENT;

ret = fat_access(sb, new_dclus, -1);
if (ret < 0) {
@@ -129,8 +130,8 @@ int fat_add_cluster(struct inode *inode)
} else if (ret == FAT_ENT_FREE)
break;
}
- if (count >= MSDOS_SB(sb)->clusters) {
- MSDOS_SB(sb)->free_clusters = 0;
+ if (count >= limit) {
+ sbi->free_clusters = 0;
unlock_fat(sb);
return -ENOSPC;
}
@@ -141,9 +142,9 @@ int fat_add_cluster(struct inode *inode)
return ret;
}

- MSDOS_SB(sb)->prev_free = new_dclus;
- if (MSDOS_SB(sb)->free_clusters != -1)
- MSDOS_SB(sb)->free_clusters--;
+ sbi->prev_free = new_dclus;
+ if (sbi->free_clusters != -1)
+ sbi->free_clusters--;
fat_clusters_flush(sb);

unlock_fat(sb);
@@ -164,7 +165,7 @@ int fat_add_cluster(struct inode *inode)
new_fclus, inode->i_blocks >> (cluster_bits - 9));
fat_cache_inval_inode(inode);
}
- inode->i_blocks += MSDOS_SB(sb)->cluster_size >> 9;
+ inode->i_blocks += sbi->cluster_size >> 9;

return new_dclus;
}
diff -puN include/linux/msdos_fs.h~fat_max-clusters-cleanup include/linux/msdos_fs.h
--- linux-2.6.11-rc1/include/linux/msdos_fs.h~fat_max-clusters-cleanup 2005-01-15 16:49:08.000000000 +0900
+++ linux-2.6.11-rc1-hirofumi/include/linux/msdos_fs.h 2005-01-15 16:49:08.000000000 +0900
@@ -64,6 +64,9 @@
#define FAT_FIRST_ENT(s, x) ((MSDOS_SB(s)->fat_bits == 32 ? 0x0FFFFF00 : \
MSDOS_SB(s)->fat_bits == 16 ? 0xFF00 : 0xF00) | (x))

+/* start of data cluster's entry (number of reserved clusters) */
+#define FAT_START_ENT 2
+
/* maximum number of clusters */
#define MAX_FAT12 0xFF4
#define MAX_FAT16 0xFFF4
@@ -221,7 +224,7 @@ struct msdos_sb_info {
unsigned long dir_start;
unsigned short dir_entries; /* root dir start & entries */
unsigned long data_start; /* first data sector */
- unsigned long clusters; /* number of clusters */
+ unsigned long max_cluster; /* maximum cluster number */
unsigned long root_cluster; /* first cluster of the root directory */
unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
struct semaphore fat_lock;
@@ -270,6 +273,12 @@ static inline struct msdos_inode_info *M
return container_of(inode, struct msdos_inode_info, vfs_inode);
}

+static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
+{
+ return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
+ + sbi->data_start;
+}
+
static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
{
#ifdef __BIG_ENDIAN
_
-
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Next message: John Richard Moser: "Re: Linux Kernel Audit Project?"
Previous message: Luca Falavigna: "Re: [PATCH] Kprobes /proc entry"
In reply to: OGAWA Hirofumi: "[PATCH 11/13] FAT: fs/fat/* cleanup"
Next in thread: OGAWA Hirofumi: "[PATCH 13/13] FAT: show current nls config even if it's default."
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]