path: root/include/linux/mm.h
diff options
authorHugh Dickins <hughd@google.com>2012-03-28 14:42:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-28 17:14:35 -0700
commit623e3db9f9b7d6e7b2a99180f9cf0825c936ab7a (patch)
treed8eaa8f1665a048c4318ccd0759775e057792823 /include/linux/mm.h
parentprocfs: fix /proc/statm (diff)
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/linux/mm.h')
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);