diff options
| -rw-r--r-- | fs/exfat/inode.c | 159 |
1 files changed, 77 insertions, 82 deletions
diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c index a23677de4544..b22c02d6000f 100644 --- a/fs/exfat/inode.c +++ b/fs/exfat/inode.c @@ -274,9 +274,11 @@ static int exfat_get_block(struct inode *inode, sector_t iblock, sector_t last_block; sector_t phys = 0; sector_t valid_blks; + loff_t i_size; mutex_lock(&sbi->s_lock); - last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size_read(inode), sb); + i_size = i_size_read(inode); + last_block = EXFAT_B_TO_BLK_ROUND_UP(i_size, sb); if (iblock >= last_block && !create) goto done; @@ -305,102 +307,95 @@ static int exfat_get_block(struct inode *inode, sector_t iblock, if (buffer_delay(bh_result)) clear_buffer_delay(bh_result); - if (create) { + /* + * In most cases, we just need to set bh_result to mapped, unmapped + * or new status as follows: + * 1. i_size == valid_size + * 2. write case (create == 1) + * 3. direct_read (!bh_result->b_folio) + * -> the unwritten part will be zeroed in exfat_direct_IO() + * + * Otherwise, in the case of buffered read, it is necessary to take + * care the last nested block if valid_size is not equal to i_size. + */ + if (i_size == ei->valid_size || create || !bh_result->b_folio) valid_blks = EXFAT_B_TO_BLK_ROUND_UP(ei->valid_size, sb); + else + valid_blks = EXFAT_B_TO_BLK(ei->valid_size, sb); - if (iblock + max_blocks < valid_blks) { - /* The range has been written, map it */ - goto done; - } else if (iblock < valid_blks) { - /* - * The range has been partially written, - * map the written part. - */ - max_blocks = valid_blks - iblock; - goto done; - } + /* The range has been fully written, map it */ + if (iblock + max_blocks < valid_blks) + goto done; - /* The area has not been written, map and mark as new. */ - set_buffer_new(bh_result); + /* The range has been partially written, map the written part */ + if (iblock < valid_blks) { + max_blocks = valid_blks - iblock; + goto done; + } + /* The area has not been written, map and mark as new for create case */ + if (create) { + set_buffer_new(bh_result); ei->valid_size = EXFAT_BLK_TO_B(iblock + max_blocks, sb); mark_inode_dirty(inode); - } else { - valid_blks = EXFAT_B_TO_BLK(ei->valid_size, sb); + goto done; + } - if (iblock + max_blocks < valid_blks) { - /* The range has been written, map it */ - goto done; - } else if (iblock < valid_blks) { - /* - * The area has been partially written, - * map the written part. - */ - max_blocks = valid_blks - iblock; + /* + * The area has just one block partially written. + * In that case, we should read and fill the unwritten part of + * a block with zero. + */ + if (bh_result->b_folio && iblock == valid_blks && + (ei->valid_size & (sb->s_blocksize - 1))) { + loff_t size, pos; + void *addr; + + max_blocks = 1; + + /* + * No buffer_head is allocated. + * (1) bmap: It's enough to set blocknr without I/O. + * (2) read: The unwritten part should be filled with zero. + * If a folio does not have any buffers, + * let's returns -EAGAIN to fallback to + * block_read_full_folio() for per-bh IO. + */ + if (!folio_buffers(bh_result->b_folio)) { + err = -EAGAIN; goto done; - } else if (iblock == valid_blks && - (ei->valid_size & (sb->s_blocksize - 1))) { - /* - * The block has been partially written, - * zero the unwritten part and map the block. - */ - loff_t size, pos; - void *addr; - - max_blocks = 1; - - /* - * For direct read, the unwritten part will be zeroed in - * exfat_direct_IO() - */ - if (!bh_result->b_folio) - goto done; - - /* - * No buffer_head is allocated. - * (1) bmap: It's enough to fill bh_result without I/O. - * (2) read: The unwritten part should be filled with 0 - * If a folio does not have any buffers, - * let's returns -EAGAIN to fallback to - * per-bh IO like block_read_full_folio(). - */ - if (!folio_buffers(bh_result->b_folio)) { - err = -EAGAIN; - goto done; - } + } - pos = EXFAT_BLK_TO_B(iblock, sb); - size = ei->valid_size - pos; - addr = folio_address(bh_result->b_folio) + - offset_in_folio(bh_result->b_folio, pos); + pos = EXFAT_BLK_TO_B(iblock, sb); + size = ei->valid_size - pos; + addr = folio_address(bh_result->b_folio) + + offset_in_folio(bh_result->b_folio, pos); - /* Check if bh->b_data points to proper addr in folio */ - if (bh_result->b_data != addr) { - exfat_fs_error_ratelimit(sb, + /* Check if bh->b_data points to proper addr in folio */ + if (bh_result->b_data != addr) { + exfat_fs_error_ratelimit(sb, "b_data(%p) != folio_addr(%p)", bh_result->b_data, addr); - err = -EINVAL; - goto done; - } - - /* Read a block */ - err = bh_read(bh_result, 0); - if (err < 0) - goto done; + err = -EINVAL; + goto done; + } - /* Zero unwritten part of a block */ - memset(bh_result->b_data + size, 0, - bh_result->b_size - size); + /* Read a block */ + err = bh_read(bh_result, 0); + if (err < 0) + goto done; - err = 0; - } else { - /* - * The range has not been written, clear the mapped flag - * to only zero the cache and do not read from disk. - */ - clear_buffer_mapped(bh_result); - } + /* Zero unwritten part of a block */ + memset(bh_result->b_data + size, 0, bh_result->b_size - size); + err = 0; + goto done; } + + /* + * The area has not been written, clear mapped for read/bmap cases. + * If so, it will be filled with zero without reading from disk. + */ + clear_buffer_mapped(bh_result); done: bh_result->b_size = EXFAT_BLK_TO_B(max_blocks, sb); if (err < 0) |