diff options
Diffstat (limited to 'fs/fat')
| -rw-r--r-- | fs/fat/cache.c | 14 | ||||
| -rw-r--r-- | fs/fat/dir.c | 6 | ||||
| -rw-r--r-- | fs/fat/inode.c | 82 |
3 files changed, 87 insertions, 15 deletions
diff --git a/fs/fat/cache.c b/fs/fat/cache.c index 77c24fcf712..1acc941245f 100644 --- a/fs/fat/cache.c +++ b/fs/fat/cache.c @@ -295,7 +295,8 @@ static int fat_bmap_cluster(struct inode *inode, int cluster) return dclus; } -int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys) +int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys, + unsigned long *mapped_blocks) { struct super_block *sb = inode->i_sb; struct msdos_sb_info *sbi = MSDOS_SB(sb); @@ -303,9 +304,12 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys) int cluster, offset; *phys = 0; + *mapped_blocks = 0; if ((sbi->fat_bits != 32) && (inode->i_ino == MSDOS_ROOT_INO)) { - if (sector < (sbi->dir_entries >> sbi->dir_per_block_bits)) + if (sector < (sbi->dir_entries >> sbi->dir_per_block_bits)) { *phys = sector + sbi->dir_start; + *mapped_blocks = 1; + } return 0; } last_block = (MSDOS_I(inode)->mmu_private + (sb->s_blocksize - 1)) @@ -318,7 +322,11 @@ int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys) cluster = fat_bmap_cluster(inode, cluster); if (cluster < 0) return cluster; - else if (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; } diff --git a/fs/fat/dir.c b/fs/fat/dir.c index 4ce77475aed..eef1b81aa29 100644 --- a/fs/fat/dir.c +++ b/fs/fat/dir.c @@ -68,8 +68,8 @@ static int fat__get_entry(struct inode *dir, loff_t *pos, { struct super_block *sb = dir->i_sb; sector_t phys, iblock; - int offset; - int err; + unsigned long mapped_blocks; + int err, offset; next: if (*bh) @@ -77,7 +77,7 @@ next: *bh = NULL; iblock = *pos >> sb->s_blocksize_bits; - err = fat_bmap(dir, iblock, &phys); + err = fat_bmap(dir, iblock, &phys, &mapped_blocks); if (err || !phys) return -1; /* beyond EOF or error */ diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 932c8d6d1f5..e7f4aa7fc68 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -23,6 +23,7 @@ #include <linux/mount.h> #include <linux/vfs.h> #include <linux/parser.h> +#include <linux/uio.h> #include <asm/unaligned.h> #ifndef CONFIG_FAT_DEFAULT_IOCHARSET @@ -49,43 +50,77 @@ static int fat_add_cluster(struct inode *inode) return err; } -static int fat_get_block(struct inode *inode, sector_t iblock, - struct buffer_head *bh_result, int create) +static int __fat_get_blocks(struct inode *inode, sector_t iblock, + unsigned long *max_blocks, + struct buffer_head *bh_result, int create) { struct super_block *sb = inode->i_sb; + struct msdos_sb_info *sbi = MSDOS_SB(sb); sector_t phys; - int err; + unsigned long mapped_blocks; + int err, offset; - err = fat_bmap(inode, iblock, &phys); + err = fat_bmap(inode, iblock, &phys, &mapped_blocks); if (err) return err; if (phys) { map_bh(bh_result, sb, phys); + *max_blocks = min(mapped_blocks, *max_blocks); return 0; } if (!create) return 0; + if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) { fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)", MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private); return -EIO; } - if (!((unsigned long)iblock & (MSDOS_SB(sb)->sec_per_clus - 1))) { + + offset = (unsigned long)iblock & (sbi->sec_per_clus - 1); + if (!offset) { + /* TODO: multiple cluster allocation would be desirable. */ err = fat_add_cluster(inode); if (err) return err; } - MSDOS_I(inode)->mmu_private += sb->s_blocksize; - err = fat_bmap(inode, iblock, &phys); + /* available blocks on this cluster */ + mapped_blocks = sbi->sec_per_clus - offset; + + *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); if (err) return err; - if (!phys) - BUG(); + BUG_ON(!phys); + BUG_ON(*max_blocks != mapped_blocks); set_buffer_new(bh_result); map_bh(bh_result, sb, phys); return 0; } +static int fat_get_blocks(struct inode *inode, sector_t iblock, + unsigned long max_blocks, + struct buffer_head *bh_result, int create) +{ + struct super_block *sb = inode->i_sb; + int err; + + err = __fat_get_blocks(inode, iblock, &max_blocks, bh_result, create); + if (err) + return err; + bh_result->b_size = max_blocks << sb->s_blocksize_bits; + return 0; +} + +static int fat_get_block(struct inode *inode, sector_t iblock, + struct buffer_head *bh_result, int create) +{ + unsigned long max_blocks = 1; + return __fat_get_blocks(inode, iblock, &max_blocks, bh_result, create); +} + static int fat_writepage(struct page *page, struct writeback_control *wbc) { return block_write_full_page(page, fat_get_block, wbc); @@ -128,6 +163,34 @@ static int fat_commit_write(struct file *file, struct page *page, return err; } +static ssize_t fat_direct_IO(int rw, struct kiocb *iocb, + const struct iovec *iov, + loff_t offset, unsigned long nr_segs) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file->f_mapping->host; + + if (rw == WRITE) { + /* + * FIXME: blockdev_direct_IO() doesn't use ->prepare_write(), + * so we need to update the ->mmu_private to block boundary. + * + * But we must fill the remaining area or hole by nul for + * updating ->mmu_private. + */ + loff_t size = offset + iov_length(iov, nr_segs); + if (MSDOS_I(inode)->mmu_private < size) + return -EINVAL; + } + + /* + * FAT need to use the DIO_LOCKING for avoiding the race + * condition of fat_get_block() and ->truncate(). + */ + return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, + offset, nr_segs, fat_get_blocks, NULL); +} + static sector_t _fat_bmap(struct address_space *mapping, sector_t block) { return generic_block_bmap(mapping, block, fat_get_block); @@ -141,6 +204,7 @@ static struct address_space_operations fat_aops = { .sync_page = block_sync_page, .prepare_write = fat_prepare_write, .commit_write = fat_commit_write, + .direct_IO = fat_direct_IO, .bmap = _fat_bmap }; |