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authorBoaz Harrosh <bharrosh@panasas.com>2010-01-12 15:13:47 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2010-03-03 13:00:16 -0500
commitad2a722f196d2b014f49e6c37e072df71eb3695f (patch)
tree5f643dc85181e1f2a63a906de316c3091c93c360
parent4b1ae27a96d9860e6c4348673e8fb6a0322511fe (diff)
downloadlinux-ad2a722f196d2b014f49e6c37e072df71eb3695f.tar.bz2
libfs: Open code simple_commit_write into only user
* simple_commit_write was only called by simple_write_end. Open coding it makes it tiny bit less heavy on the arithmetic and much more readable. * While at it use zero_user() for clearing a partial page. * While at it add a docbook comment for simple_write_end. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/libfs.c59
1 files changed, 35 insertions, 24 deletions
diff --git a/fs/libfs.c b/fs/libfs.c
index 6e8d17e1dc4c..cd88abdcb436 100644
--- a/fs/libfs.c
+++ b/fs/libfs.c
@@ -370,40 +370,51 @@ int simple_write_begin(struct file *file, struct address_space *mapping,
return simple_prepare_write(file, page, from, from+len);
}
-static int simple_commit_write(struct file *file, struct page *page,
- unsigned from, unsigned to)
-{
- struct inode *inode = page->mapping->host;
- loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
-
- if (!PageUptodate(page))
- SetPageUptodate(page);
- /*
- * No need to use i_size_read() here, the i_size
- * cannot change under us because we hold the i_mutex.
- */
- if (pos > inode->i_size)
- i_size_write(inode, pos);
- set_page_dirty(page);
- return 0;
-}
-
+/**
+ * simple_write_end - .write_end helper for non-block-device FSes
+ * @available: See .write_end of address_space_operations
+ * @file: "
+ * @mapping: "
+ * @pos: "
+ * @len: "
+ * @copied: "
+ * @page: "
+ * @fsdata: "
+ *
+ * simple_write_end does the minimum needed for updating a page after writing is
+ * done. It has the same API signature as the .write_end of
+ * address_space_operations vector. So it can just be set onto .write_end for
+ * FSes that don't need any other processing. i_mutex is assumed to be held.
+ * Block based filesystems should use generic_write_end().
+ * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
+ * is not called, so a filesystem that actually does store data in .write_inode
+ * should extend on what's done here with a call to mark_inode_dirty() in the
+ * case that i_size has changed.
+ */
int simple_write_end(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata)
{
- unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+ struct inode *inode = page->mapping->host;
+ loff_t last_pos = pos + copied;
/* zero the stale part of the page if we did a short copy */
if (copied < len) {
- void *kaddr = kmap_atomic(page, KM_USER0);
- memset(kaddr + from + copied, 0, len - copied);
- flush_dcache_page(page);
- kunmap_atomic(kaddr, KM_USER0);
+ unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+
+ zero_user(page, from + copied, len - copied);
}
- simple_commit_write(file, page, from, from+copied);
+ if (!PageUptodate(page))
+ SetPageUptodate(page);
+ /*
+ * No need to use i_size_read() here, the i_size
+ * cannot change under us because we hold the i_mutex.
+ */
+ if (last_pos > inode->i_size)
+ i_size_write(inode, last_pos);
+ set_page_dirty(page);
unlock_page(page);
page_cache_release(page);