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-rw-r--r--fs/fat/cache.c2
-rw-r--r--fs/fat/dir.c4
-rw-r--r--fs/fat/fat.h30
-rw-r--r--fs/fat/fatent.c16
-rw-r--r--fs/fat/inode.c26
-rw-r--r--fs/fat/misc.c2
6 files changed, 55 insertions, 25 deletions
diff --git a/fs/fat/cache.c b/fs/fat/cache.c
index 78d501c1fb65..738e427e2d21 100644
--- a/fs/fat/cache.c
+++ b/fs/fat/cache.c
@@ -363,7 +363,7 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
*phys = 0;
*mapped_blocks = 0;
- if ((sbi->fat_bits != 32) && (inode->i_ino == MSDOS_ROOT_INO)) {
+ if (!is_fat32(sbi) && (inode->i_ino == MSDOS_ROOT_INO)) {
if (sector < (sbi->dir_entries >> sbi->dir_per_block_bits)) {
*phys = sector + sbi->dir_start;
*mapped_blocks = 1;
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 0295a095b920..9d01db37183f 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -57,7 +57,7 @@ static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
return;
/* root dir of FAT12/FAT16 */
- if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
+ if (!is_fat32(sbi) && (dir->i_ino == MSDOS_ROOT_INO))
return;
bh = sb_find_get_block(sb, phys);
@@ -1313,7 +1313,7 @@ int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
}
}
if (dir->i_ino == MSDOS_ROOT_INO) {
- if (sbi->fat_bits != 32)
+ if (!is_fat32(sbi))
goto error;
} else if (MSDOS_I(dir)->i_start == 0) {
fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 4e1b2f6df5e6..922a0c6ba46c 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -142,6 +142,34 @@ static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
return sb->s_fs_info;
}
+/*
+ * Functions that determine the variant of the FAT file system (i.e.,
+ * whether this is FAT12, FAT16 or FAT32.
+ */
+static inline bool is_fat12(const struct msdos_sb_info *sbi)
+{
+ return sbi->fat_bits == 12;
+}
+
+static inline bool is_fat16(const struct msdos_sb_info *sbi)
+{
+ return sbi->fat_bits == 16;
+}
+
+static inline bool is_fat32(const struct msdos_sb_info *sbi)
+{
+ return sbi->fat_bits == 32;
+}
+
+/* Maximum number of clusters */
+static inline u32 max_fat(struct super_block *sb)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+ return is_fat32(sbi) ? MAX_FAT32 :
+ is_fat16(sbi) ? MAX_FAT16 : MAX_FAT12;
+}
+
static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
{
return container_of(inode, struct msdos_inode_info, vfs_inode);
@@ -257,7 +285,7 @@ static inline int fat_get_start(const struct msdos_sb_info *sbi,
const struct msdos_dir_entry *de)
{
int cluster = le16_to_cpu(de->start);
- if (sbi->fat_bits == 32)
+ if (is_fat32(sbi))
cluster |= (le16_to_cpu(de->starthi) << 16);
return cluster;
}
diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
index f58c0cacc531..495edeafd60a 100644
--- a/fs/fat/fatent.c
+++ b/fs/fat/fatent.c
@@ -290,19 +290,17 @@ void fat_ent_access_init(struct super_block *sb)
mutex_init(&sbi->fat_lock);
- switch (sbi->fat_bits) {
- case 32:
+ if (is_fat32(sbi)) {
sbi->fatent_shift = 2;
sbi->fatent_ops = &fat32_ops;
- break;
- case 16:
+ } else if (is_fat16(sbi)) {
sbi->fatent_shift = 1;
sbi->fatent_ops = &fat16_ops;
- break;
- case 12:
+ } else if (is_fat12(sbi)) {
sbi->fatent_shift = -1;
sbi->fatent_ops = &fat12_ops;
- break;
+ } else {
+ fat_fs_error(sb, "invalid FAT variant, %u bits", sbi->fat_bits);
}
}
@@ -310,7 +308,7 @@ static void mark_fsinfo_dirty(struct super_block *sb)
{
struct msdos_sb_info *sbi = MSDOS_SB(sb);
- if (sb_rdonly(sb) || sbi->fat_bits != 32)
+ if (sb_rdonly(sb) || !is_fat32(sbi))
return;
__mark_inode_dirty(sbi->fsinfo_inode, I_DIRTY_SYNC);
@@ -327,7 +325,7 @@ static inline int fat_ent_update_ptr(struct super_block *sb,
/* Is this fatent's blocks including this entry? */
if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr)
return 0;
- if (sbi->fat_bits == 12) {
+ if (is_fat12(sbi)) {
if ((offset + 1) < sb->s_blocksize) {
/* This entry is on bhs[0]. */
if (fatent->nr_bhs == 2) {
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index c0b5b5c3373b..79bb0e73a65f 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -686,7 +686,7 @@ static void fat_set_state(struct super_block *sb,
b = (struct fat_boot_sector *) bh->b_data;
- if (sbi->fat_bits == 32) {
+ if (is_fat32(sbi)) {
if (set)
b->fat32.state |= FAT_STATE_DIRTY;
else
@@ -1396,7 +1396,7 @@ static int fat_read_root(struct inode *inode)
inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
inode->i_op = sbi->dir_ops;
inode->i_fop = &fat_dir_operations;
- if (sbi->fat_bits == 32) {
+ if (is_fat32(sbi)) {
MSDOS_I(inode)->i_start = sbi->root_cluster;
error = fat_calc_dir_size(inode);
if (error < 0)
@@ -1423,7 +1423,7 @@ static unsigned long calc_fat_clusters(struct super_block *sb)
struct msdos_sb_info *sbi = MSDOS_SB(sb);
/* Divide first to avoid overflow */
- if (sbi->fat_bits != 12) {
+ if (!is_fat12(sbi)) {
unsigned long ent_per_sec = sb->s_blocksize * 8 / sbi->fat_bits;
return ent_per_sec * sbi->fat_length;
}
@@ -1743,7 +1743,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
}
/* interpret volume ID as a little endian 32 bit integer */
- if (sbi->fat_bits == 32)
+ if (is_fat32(sbi))
sbi->vol_id = bpb.fat32_vol_id;
else /* fat 16 or 12 */
sbi->vol_id = bpb.fat16_vol_id;
@@ -1769,11 +1769,11 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
- if (sbi->fat_bits != 32)
+ if (!is_fat32(sbi))
sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
/* some OSes set FAT_STATE_DIRTY and clean it on unmount. */
- if (sbi->fat_bits == 32)
+ if (is_fat32(sbi))
sbi->dirty = bpb.fat32_state & FAT_STATE_DIRTY;
else /* fat 16 or 12 */
sbi->dirty = bpb.fat16_state & FAT_STATE_DIRTY;
@@ -1781,7 +1781,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
/* check that FAT table does not overflow */
fat_clusters = calc_fat_clusters(sb);
total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
- if (total_clusters > MAX_FAT(sb)) {
+ if (total_clusters > max_fat(sb)) {
if (!silent)
fat_msg(sb, KERN_ERR, "count of clusters too big (%u)",
total_clusters);
@@ -1803,11 +1803,15 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
fat_ent_access_init(sb);
/*
- * The low byte of FAT's first entry must have same value with
- * media-field. But in real world, too many devices is
- * writing wrong value. So, removed that validity check.
+ * The low byte of the first FAT entry must have the same value as
+ * the media field of the boot sector. But in real world, too many
+ * devices are writing wrong values. So, removed that validity check.
*
- * if (FAT_FIRST_ENT(sb, media) != first)
+ * The removed check compared the first FAT entry to a value dependent
+ * on the media field like this:
+ * == (0x0F00 | media), for FAT12
+ * == (0XFF00 | media), for FAT16
+ * == (0x0FFFFF | media), for FAT32
*/
error = -EINVAL;
diff --git a/fs/fat/misc.c b/fs/fat/misc.c
index fce0a76f3f1e..4fc950bb6433 100644
--- a/fs/fat/misc.c
+++ b/fs/fat/misc.c
@@ -64,7 +64,7 @@ int fat_clusters_flush(struct super_block *sb)
struct buffer_head *bh;
struct fat_boot_fsinfo *fsinfo;
- if (sbi->fat_bits != 32)
+ if (!is_fat32(sbi))
return 0;
bh = sb_bread(sb, sbi->fsinfo_sector);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-17 10:47:53 +0100