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https://github.com/torvalds/linux
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d4f5258eae
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>
53 lines
1.5 KiB
C
53 lines
1.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/ext4/truncate.h
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*
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* Common inline functions needed for truncate support
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*/
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/*
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* Truncate blocks that were not used by write. We have to truncate the
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* pagecache as well so that corresponding buffers get properly unmapped.
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*/
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static inline void ext4_truncate_failed_write(struct inode *inode)
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{
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struct address_space *mapping = inode->i_mapping;
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/*
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* We don't need to call ext4_break_layouts() because the blocks we
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* are truncating were never visible to userspace.
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*/
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filemap_invalidate_lock(mapping);
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truncate_inode_pages(mapping, inode->i_size);
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ext4_truncate(inode);
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filemap_invalidate_unlock(mapping);
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}
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/*
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* Work out how many blocks we need to proceed with the next chunk of a
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* truncate transaction.
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*/
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static inline unsigned long ext4_blocks_for_truncate(struct inode *inode)
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{
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ext4_lblk_t needed;
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needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
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/* Give ourselves just enough room to cope with inodes in which
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* i_blocks is corrupt: we've seen disk corruptions in the past
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* which resulted in random data in an inode which looked enough
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* like a regular file for ext4 to try to delete it. Things
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* will go a bit crazy if that happens, but at least we should
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* try not to panic the whole kernel. */
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if (needed < 2)
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needed = 2;
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/* But we need to bound the transaction so we don't overflow the
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* journal. */
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if (needed > EXT4_MAX_TRANS_DATA)
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needed = EXT4_MAX_TRANS_DATA;
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return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
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}
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