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authorLukas Czerner <lczerner@redhat.com>2013-05-22 07:17:23 +0400
committerTheodore Ts'o <tytso@mit.edu>2013-05-22 07:17:23 +0400
commitd47992f86b307985b3215bcf141d56d1849d71df (patch)
treee1ae47bd19185371462c5a273c15276534447349 /mm/truncate.c
parentc7788792a5e7b0d5d7f96d0766b4cb6112d47d75 (diff)
downloadlinux-d47992f86b307985b3215bcf141d56d1849d71df.tar.xz
mm: change invalidatepage prototype to accept length
Currently there is no way to truncate partial page where the end truncate point is not at the end of the page. This is because it was not needed and the functionality was enough for file system truncate operation to work properly. However more file systems now support punch hole feature and it can benefit from mm supporting truncating page just up to the certain point. Specifically, with this functionality truncate_inode_pages_range() can be changed so it supports truncating partial page at the end of the range (currently it will BUG_ON() if 'end' is not at the end of the page). This commit changes the invalidatepage() address space operation prototype to accept range to be invalidated and update all the instances for it. We also change the block_invalidatepage() in the same way and actually make a use of the new length argument implementing range invalidation. Actual file system implementations will follow except the file systems where the changes are really simple and should not change the behaviour in any way .Implementation for truncate_page_range() which will be able to accept page unaligned ranges will follow as well. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com>
Diffstat (limited to 'mm/truncate.c')
-rw-r--r--mm/truncate.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/mm/truncate.c b/mm/truncate.c
index c75b736e54b7..fdba083f0d71 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -26,7 +26,8 @@
/**
* do_invalidatepage - invalidate part or all of a page
* @page: the page which is affected
- * @offset: the index of the truncation point
+ * @offset: start of the range to invalidate
+ * @length: length of the range to invalidate
*
* do_invalidatepage() is called when all or part of the page has become
* invalidated by a truncate operation.
@@ -37,16 +38,18 @@
* point. Because the caller is about to free (and possibly reuse) those
* blocks on-disk.
*/
-void do_invalidatepage(struct page *page, unsigned long offset)
+void do_invalidatepage(struct page *page, unsigned int offset,
+ unsigned int length)
{
- void (*invalidatepage)(struct page *, unsigned long);
+ void (*invalidatepage)(struct page *, unsigned int, unsigned int);
+
invalidatepage = page->mapping->a_ops->invalidatepage;
#ifdef CONFIG_BLOCK
if (!invalidatepage)
invalidatepage = block_invalidatepage;
#endif
if (invalidatepage)
- (*invalidatepage)(page, offset);
+ (*invalidatepage)(page, offset, length);
}
static inline void truncate_partial_page(struct page *page, unsigned partial)
@@ -54,7 +57,7 @@ static inline void truncate_partial_page(struct page *page, unsigned partial)
zero_user_segment(page, partial, PAGE_CACHE_SIZE);
cleancache_invalidate_page(page->mapping, page);
if (page_has_private(page))
- do_invalidatepage(page, partial);
+ do_invalidatepage(page, partial, PAGE_CACHE_SIZE - partial);
}
/*
@@ -103,7 +106,7 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
return -EIO;
if (page_has_private(page))
- do_invalidatepage(page, 0);
+ do_invalidatepage(page, 0, PAGE_CACHE_SIZE);
cancel_dirty_page(page, PAGE_CACHE_SIZE);