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 struct address_space *mapping = inode->i_mapping; 15 16 /* 17 * We don't need to call ext4_break_layouts() because the blocks we 18 * are truncating were never visible to userspace. 19 */ 20 filemap_invalidate_lock(mapping); 21 truncate_inode_pages(mapping, inode->i_size); 22 ext4_truncate(inode); 23 filemap_invalidate_unlock(mapping); 24 } 25 26 /* 27 * Work out how many blocks we need to proceed with the next chunk of a 28 * truncate transaction. 29 */ 30 static inline unsigned long ext4_blocks_for_truncate(struct inode *inode) 31 { 32 ext4_lblk_t needed; 33 34 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9); 35 36 /* Give ourselves just enough room to cope with inodes in which 37 * i_blocks is corrupt: we've seen disk corruptions in the past 38 * which resulted in random data in an inode which looked enough 39 * like a regular file for ext4 to try to delete it. Things 40 * will go a bit crazy if that happens, but at least we should 41 * try not to panic the whole kernel. */ 42 if (needed < 2) 43 needed = 2; 44 45 /* But we need to bound the transaction so we don't overflow the 46 * journal. */ 47 if (needed > EXT4_MAX_TRANS_DATA) 48 needed = EXT4_MAX_TRANS_DATA; 49 50 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed; 51 } 52 53