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| author | Hugh Dickins <hughd@google.com> | 2012-03-28 14:42:40 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-28 17:14:35 -0700 |
| commit | 623e3db9f9b7d6e7b2a99180f9cf0825c936ab7a (patch) | |
| tree | d8eaa8f1665a048c4318ccd0759775e057792823 /include | |
| parent | 3748b2f15b06ea1861df39d5e9693dcd6e9542b1 (diff) | |
| download | linux-exynos-623e3db9f9b7d6e7b2a99180f9cf0825c936ab7a.tar.gz linux-exynos-623e3db9f9b7d6e7b2a99180f9cf0825c936ab7a.tar.bz2 linux-exynos-623e3db9f9b7d6e7b2a99180f9cf0825c936ab7a.zip | |
mm for fs: add truncate_pagecache_range()
Holepunching filesystems ext4 and xfs are using truncate_inode_pages_range
but forgetting to unmap pages first (ocfs2 remembers). This is not really
a bug, since races already require truncate_inode_page() to handle that
case once the page is locked; but it can be very inefficient if the file
being punched happens to be mapped into many vmas.
Provide a drop-in replacement truncate_pagecache_range() which does the
unmapping pass first, handling the awkward mismatch between arguments to
truncate_inode_pages_range() and arguments to unmap_mapping_range().
Note that holepunching does not unmap privately COWed pages in the range:
POSIX requires that we do so when truncating, but it's hard to justify,
difficult to implement without an i_size cutoff, and no filesystem is
attempting to implement it.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Ben Myers <bpm@sgi.com>
Cc: Alex Elder <elder@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/mm.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index cf7982336103..630068184265 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -954,7 +954,7 @@ extern void truncate_pagecache(struct inode *inode, loff_t old, loff_t new); extern void truncate_setsize(struct inode *inode, loff_t newsize); extern int vmtruncate(struct inode *inode, loff_t offset); extern int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end); - +void truncate_pagecache_range(struct inode *inode, loff_t offset, loff_t end); int truncate_inode_page(struct address_space *mapping, struct page *page); int generic_error_remove_page(struct address_space *mapping, struct page *page); |