Line data    Source code

       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           0 :         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           0 :         filemap_invalidate_lock(mapping);
      21           0 :         truncate_inode_pages(mapping, inode->i_size);
      22           0 :         ext4_truncate(inode);
      23           0 :         filemap_invalidate_unlock(mapping);
      24           0 : }
      25             : 
      26             : /*
      27             :  * Work out how many blocks we need to proceed with the next chunk of a
      28             :  * truncate transaction.
      29             :  */
      30           0 : static inline unsigned long ext4_blocks_for_truncate(struct inode *inode)
      31             : {
      32           0 :         ext4_lblk_t needed;
      33             : 
      34           0 :         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           0 :         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           0 :         return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
      51             : }
      52             :