1 /* 2 * linux/fs/ext4/truncate.h 3 * 4 * Common inline functions needed for truncate support 5 */ 6 7 /* 8 * Truncate blocks that were not used by write. We have to truncate the 9 * pagecache as well so that corresponding buffers get properly unmapped. 10 */ 11 static inline void ext4_truncate_failed_write(struct inode *inode) 12 { 13 truncate_inode_pages(inode->i_mapping, inode->i_size); 14 ext4_truncate(inode); 15 } 16 17 /* 18 * Work out how many blocks we need to proceed with the next chunk of a 19 * truncate transaction. 20 */ 21 static inline unsigned long ext4_blocks_for_truncate(struct inode *inode) 22 { 23 ext4_lblk_t needed; 24 25 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9); 26 27 /* Give ourselves just enough room to cope with inodes in which 28 * i_blocks is corrupt: we've seen disk corruptions in the past 29 * which resulted in random data in an inode which looked enough 30 * like a regular file for ext4 to try to delete it. Things 31 * will go a bit crazy if that happens, but at least we should 32 * try not to panic the whole kernel. */ 33 if (needed < 2) 34 needed = 2; 35 36 /* But we need to bound the transaction so we don't overflow the 37 * journal. */ 38 if (needed > EXT4_MAX_TRANS_DATA) 39 needed = EXT4_MAX_TRANS_DATA; 40 41 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed; 42 } 43 44