linux-stable/fs/ext4/truncate.h
Jan Kara d4f5258eae ext4: Convert to use mapping->invalidate_lock
Convert ext4 to use mapping->invalidate_lock instead of its private
EXT4_I(inode)->i_mmap_sem. This is mostly search-and-replace. By this
conversion we fix a long standing race between hole punching and read(2)
/ readahead(2) paths that can lead to stale page cache contents.

CC: <linux-ext4@vger.kernel.org>
CC: Ted Tso <tytso@mit.edu>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
2021-07-13 14:29:00 +02:00

52 lines
1.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/ext4/truncate.h
*
* Common inline functions needed for truncate support
*/
/*
* Truncate blocks that were not used by write. We have to truncate the
* pagecache as well so that corresponding buffers get properly unmapped.
*/
static inline void ext4_truncate_failed_write(struct inode *inode)
{
struct address_space *mapping = inode->i_mapping;
/*
* We don't need to call ext4_break_layouts() because the blocks we
* are truncating were never visible to userspace.
*/
filemap_invalidate_lock(mapping);
truncate_inode_pages(mapping, inode->i_size);
ext4_truncate(inode);
filemap_invalidate_unlock(mapping);
}
/*
* Work out how many blocks we need to proceed with the next chunk of a
* truncate transaction.
*/
static inline unsigned long ext4_blocks_for_truncate(struct inode *inode)
{
ext4_lblk_t needed;
needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
/* Give ourselves just enough room to cope with inodes in which
* i_blocks is corrupt: we've seen disk corruptions in the past
* which resulted in random data in an inode which looked enough
* like a regular file for ext4 to try to delete it. Things
* will go a bit crazy if that happens, but at least we should
* try not to panic the whole kernel. */
if (needed < 2)
needed = 2;
/* But we need to bound the transaction so we don't overflow the
* journal. */
if (needed > EXT4_MAX_TRANS_DATA)
needed = EXT4_MAX_TRANS_DATA;
return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
}