LXR linux/fs/ext4/truncate.h

   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 */
  12static 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 */
  30static 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