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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 : 0 : 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 : 0 : down_write(&EXT4_I(inode)->i_mmap_sem); 19 : 0 : truncate_inode_pages(inode->i_mapping, inode->i_size); 20 : 0 : ext4_truncate(inode); 21 : 0 : up_write(&EXT4_I(inode)->i_mmap_sem); 22 : 0 : } 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 : :