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             :         /*
      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         193 : static inline unsigned long ext4_blocks_for_truncate(struct inode *inode)
      29             : {
      30         193 :         ext4_lblk_t needed;
      31             : 
      32         193 :         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         193 :         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         193 :         return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
      49             : }
      50             :