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-rw-r--r--fs/fat/cache.c79
-rw-r--r--fs/fat/dir.c2
-rw-r--r--fs/fat/fat.h5
-rw-r--r--fs/fat/inode.c31
4 files changed, 87 insertions, 30 deletions
diff --git a/fs/fat/cache.c b/fs/fat/cache.c
index 93fc622..5d38492 100644
--- a/fs/fat/cache.c
+++ b/fs/fat/cache.c
@@ -301,15 +301,59 @@ static int fat_bmap_cluster(struct inode *inode, int cluster)
return dclus;
}
-int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
- unsigned long *mapped_blocks, int create)
+int fat_get_mapped_cluster(struct inode *inode, sector_t sector,
+ sector_t last_block,
+ unsigned long *mapped_blocks, sector_t *bmap)
{
struct super_block *sb = inode->i_sb;
struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ int cluster, offset;
+
+ cluster = sector >> (sbi->cluster_bits - sb->s_blocksize_bits);
+ offset = sector & (sbi->sec_per_clus - 1);
+ cluster = fat_bmap_cluster(inode, cluster);
+ if (cluster < 0)
+ return cluster;
+ else if (cluster) {
+ *bmap = fat_clus_to_blknr(sbi, cluster) + offset;
+ *mapped_blocks = sbi->sec_per_clus - offset;
+ if (*mapped_blocks > last_block - sector)
+ *mapped_blocks = last_block - sector;
+ }
+
+ return 0;
+}
+
+static int is_exceed_eof(struct inode *inode, sector_t sector,
+ sector_t *last_block, int create)
+{
+ struct super_block *sb = inode->i_sb;
const unsigned long blocksize = sb->s_blocksize;
const unsigned char blocksize_bits = sb->s_blocksize_bits;
+
+ *last_block = (i_size_read(inode) + (blocksize - 1)) >> blocksize_bits;
+ if (sector >= *last_block) {
+ if (!create)
+ return 1;
+
+ /*
+ * ->mmu_private can access on only allocation path.
+ * (caller must hold ->i_mutex)
+ */
+ *last_block = (MSDOS_I(inode)->mmu_private + (blocksize - 1))
+ >> blocksize_bits;
+ if (sector >= *last_block)
+ return 1;
+ }
+
+ return 0;
+}
+
+int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
+ unsigned long *mapped_blocks, int create, bool from_bmap)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
sector_t last_block;
- int cluster, offset;
*phys = 0;
*mapped_blocks = 0;
@@ -321,31 +365,16 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
return 0;
}
- last_block = (i_size_read(inode) + (blocksize - 1)) >> blocksize_bits;
- if (sector >= last_block) {
- if (!create)
+ if (!from_bmap) {
+ if (is_exceed_eof(inode, sector, &last_block, create))
return 0;
-
- /*
- * ->mmu_private can access on only allocation path.
- * (caller must hold ->i_mutex)
- */
- last_block = (MSDOS_I(inode)->mmu_private + (blocksize - 1))
- >> blocksize_bits;
+ } else {
+ last_block = inode->i_blocks >>
+ (inode->i_sb->s_blocksize_bits - 9);
if (sector >= last_block)
return 0;
}
- cluster = sector >> (sbi->cluster_bits - sb->s_blocksize_bits);
- offset = sector & (sbi->sec_per_clus - 1);
- cluster = fat_bmap_cluster(inode, cluster);
- if (cluster < 0)
- return cluster;
- else if (cluster) {
- *phys = fat_clus_to_blknr(sbi, cluster) + offset;
- *mapped_blocks = sbi->sec_per_clus - offset;
- if (*mapped_blocks > last_block - sector)
- *mapped_blocks = last_block - sector;
- }
- return 0;
+ return fat_get_mapped_cluster(inode, sector, last_block, mapped_blocks,
+ phys);
}
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 8b2127f..7def96c 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -91,7 +91,7 @@ next:
*bh = NULL;
iblock = *pos >> sb->s_blocksize_bits;
- err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0);
+ err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0, false);
if (err || !phys)
return -1; /* beyond EOF or error */
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index eed04c0..4307cd4 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -285,8 +285,11 @@ static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
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_get_mapped_cluster(struct inode *inode, sector_t sector,
+ sector_t last_block,
+ unsigned long *mapped_blocks, sector_t *bmap);
extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
- unsigned long *mapped_blocks, int create);
+ unsigned long *mapped_blocks, int create, bool from_bmap);
/* fat/dir.c */
extern const struct file_operations fat_dir_operations;
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 0e5bc19..a559905 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -118,7 +118,7 @@ static inline int __fat_get_block(struct inode *inode, sector_t iblock,
sector_t phys, last_block;
int err, offset;
- err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
+ err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
if (err)
return err;
if (phys) {
@@ -154,7 +154,7 @@ static inline int __fat_get_block(struct inode *inode, sector_t iblock,
*max_blocks = min(mapped_blocks, *max_blocks);
MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
- err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
+ err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create, false);
if (err)
return err;
@@ -279,13 +279,38 @@ static ssize_t fat_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
return ret;
}
+static int fat_get_block_bmap(struct inode *inode, sector_t iblock,
+ struct buffer_head *bh_result, int create)
+{
+ struct super_block *sb = inode->i_sb;
+ unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
+ int err;
+ sector_t bmap;
+ unsigned long mapped_blocks;
+
+ BUG_ON(create != 0);
+
+ err = fat_bmap(inode, iblock, &bmap, &mapped_blocks, create, true);
+ if (err)
+ return err;
+
+ if (bmap) {
+ map_bh(bh_result, sb, bmap);
+ max_blocks = min(mapped_blocks, max_blocks);
+ }
+
+ bh_result->b_size = max_blocks << sb->s_blocksize_bits;
+
+ return 0;
+}
+
static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
{
sector_t blocknr;
/* fat_get_cluster() assumes the requested blocknr isn't truncated. */
down_read(&MSDOS_I(mapping->host)->truncate_lock);
- blocknr = generic_block_bmap(mapping, block, fat_get_block);
+ blocknr = generic_block_bmap(mapping, block, fat_get_block_bmap);
up_read(&MSDOS_I(mapping->host)->truncate_lock);
return blocknr;
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