1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/ext4/truncate.h 4 * 5 * Common inline functions needed for truncate support 6 */ 7 8 /* 9 * Truncate blocks that were not used by write. We have to truncate the 10 * pagecache as well so that corresponding buffers get properly unmapped. 11 */ 12 static inline void ext4_truncate_failed_write(struct inode *inode) 13 { 14 /* 15 * We don't need to call ext4_break_layouts() because the blocks we 16 * are truncating were never visible to userspace. 17 */ 18 down_write(&EXT4_I(inode)->i_mmap_sem); 19 truncate_inode_pages(inode->i_mapping, inode->i_size); 20 ext4_truncate(inode); 21 up_write(&EXT4_I(inode)->i_mmap_sem); 22 } 23 24 /* 25 * Work out how many blocks we need to proceed with the next chunk of a 26 * truncate transaction. 27 */ 28 static inline unsigned long ext4_blocks_for_truncate(struct inode *inode) 29 { 30 ext4_lblk_t needed; 31 32 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9); 33 34 /* Give ourselves just enough room to cope with inodes in which 35 * i_blocks is corrupt: we've seen disk corruptions in the past 36 * which resulted in random data in an inode which looked enough 37 * like a regular file for ext4 to try to delete it. Things 38 * will go a bit crazy if that happens, but at least we should 39 * try not to panic the whole kernel. */ 40 if (needed < 2) 41 needed = 2; 42 43 /* But we need to bound the transaction so we don't overflow the 44 * journal. */ 45 if (needed > EXT4_MAX_TRANS_DATA) 46 needed = EXT4_MAX_TRANS_DATA; 47 48 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed; 49 } 50 51