truncate.h 1.5 KB

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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. * 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. /*
  14. * We don't need to call ext4_break_layouts() because the blocks we
  15. * are truncating were never visible to userspace.
  16. */
  17. down_write(&EXT4_I(inode)->i_mmap_sem);
  18. truncate_inode_pages(inode->i_mapping, inode->i_size);
  19. ext4_truncate(inode);
  20. up_write(&EXT4_I(inode)->i_mmap_sem);
  21. }
  22. /*
  23. * Work out how many blocks we need to proceed with the next chunk of a
  24. * truncate transaction.
  25. */
  26. static inline unsigned long ext4_blocks_for_truncate(struct inode *inode)
  27. {
  28. ext4_lblk_t needed;
  29. needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
  30. /* Give ourselves just enough room to cope with inodes in which
  31. * i_blocks is corrupt: we've seen disk corruptions in the past
  32. * which resulted in random data in an inode which looked enough
  33. * like a regular file for ext4 to try to delete it. Things
  34. * will go a bit crazy if that happens, but at least we should
  35. * try not to panic the whole kernel. */
  36. if (needed < 2)
  37. needed = 2;
  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. return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
  43. }