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 down_write(&EXT4_I(inode)->i_mmap_sem); 15 truncate_inode_pages(inode->i_mapping, inode->i_size); 16 ext4_truncate(inode); 17 up_write(&EXT4_I(inode)->i_mmap_sem); 18 } 19 20 /* 21 * Work out how many blocks we need to proceed with the next chunk of a 22 * truncate transaction. 23 */ 24 static inline unsigned long ext4_blocks_for_truncate(struct inode *inode) 25 { 26 ext4_lblk_t needed; 27 28 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9); 29 30 /* Give ourselves just enough room to cope with inodes in which 31 * i_blocks is corrupt: we've seen disk corruptions in the past 32 * which resulted in random data in an inode which looked enough 33 * like a regular file for ext4 to try to delete it. Things 34 * will go a bit crazy if that happens, but at least we should 35 * try not to panic the whole kernel. */ 36 if (needed < 2) 37 needed = 2; 38 39 /* But we need to bound the transaction so we don't overflow the 40 * journal. */ 41 if (needed > EXT4_MAX_TRANS_DATA) 42 needed = EXT4_MAX_TRANS_DATA; 43 44 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed; 45 } 46 47