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 down_write(&EXT4_I(inode)->i_mmap_sem); 14 truncate_inode_pages(inode->i_mapping, inode->i_size); 15 ext4_truncate(inode); 16 up_write(&EXT4_I(inode)->i_mmap_sem); 17 } 18 19 /* 20 * Work out how many blocks we need to proceed with the next chunk of a 21 * truncate transaction. 22 */ 23 static inline unsigned long ext4_blocks_for_truncate(struct inode *inode) 24 { 25 ext4_lblk_t needed; 26 27 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9); 28 29 /* Give ourselves just enough room to cope with inodes in which 30 * i_blocks is corrupt: we've seen disk corruptions in the past 31 * which resulted in random data in an inode which looked enough 32 * like a regular file for ext4 to try to delete it. Things 33 * will go a bit crazy if that happens, but at least we should 34 * try not to panic the whole kernel. */ 35 if (needed < 2) 36 needed = 2; 37 38 /* But we need to bound the transaction so we don't overflow the 39 * journal. */ 40 if (needed > EXT4_MAX_TRANS_DATA) 41 needed = EXT4_MAX_TRANS_DATA; 42 43 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed; 44 } 45 46