ocfs2: Small refactor of truncate zeroing code

We'll want to reuse most of this when pushing inline data back out to an
extent. Keeping this part as a seperate patch helps to keep the upcoming
changes for write support uncluttered.

The core portion of ocfs2_zero_cluster_pages() responsible for making sure a
page is mapped and properly dirtied is abstracted out into it's own
function, ocfs2_map_and_dirty_page(). Actual functionality doesn't change,
though zeroing becomes optional.

We also turn part of ocfs2_free_write_ctxt() into  a common function for
unlocking and freeing a page array. This operation is very common (and
uniform) for Ocfs2 cluster sizes greater than page size, so it makes sense
to keep the code in one place.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Reviewed-by: Joel Becker <joel.becker@oracle.com>

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index c91706f949ffdcf3426e3ac3b885b867d79c0925..c81bfdfb992979c0defc1ca456d7391e31be2758 100644 (file)
--- a/fs/ocfs2/alloc.c
+++ b/fs/ocfs2/alloc.c
@@ -5633,12 +5633,50 @@ static int ocfs2_ordered_zero_func(handle_t *handle, struct buffer_head *bh)
        return ocfs2_journal_dirty_data(handle, bh);
 }
 
+static void ocfs2_map_and_dirty_page(struct inode *inode, handle_t *handle,
+                                    unsigned int from, unsigned int to,
+                                    struct page *page, int zero, u64 *phys)
+{
+       int ret, partial = 0;
+
+       ret = ocfs2_map_page_blocks(page, phys, inode, from, to, 0);
+       if (ret)
+               mlog_errno(ret);
+
+       if (zero)
+               zero_user_page(page, from, to - from, KM_USER0);
+
+       /*
+        * Need to set the buffers we zero'd into uptodate
+        * here if they aren't - ocfs2_map_page_blocks()
+        * might've skipped some
+        */
+       if (ocfs2_should_order_data(inode)) {
+               ret = walk_page_buffers(handle,
+                                       page_buffers(page),
+                                       from, to, &partial,
+                                       ocfs2_ordered_zero_func);
+               if (ret < 0)
+                       mlog_errno(ret);
+       } else {
+               ret = walk_page_buffers(handle, page_buffers(page),
+                                       from, to, &partial,
+                                       ocfs2_writeback_zero_func);
+               if (ret < 0)
+                       mlog_errno(ret);
+       }
+
+       if (!partial)
+               SetPageUptodate(page);
+
+       flush_dcache_page(page);
+}
+
 static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t start,
                                     loff_t end, struct page **pages,
                                     int numpages, u64 phys, handle_t *handle)
 {
-       int i, ret, partial = 0;
-       void *kaddr;
+       int i;
        struct page *page;
        unsigned int from, to = PAGE_CACHE_SIZE;
        struct super_block *sb = inode->i_sb;
@@ -5659,87 +5697,31 @@ static void ocfs2_zero_cluster_pages(struct inode *inode, loff_t start,
                BUG_ON(from > PAGE_CACHE_SIZE);
                BUG_ON(to > PAGE_CACHE_SIZE);
 
-               ret = ocfs2_map_page_blocks(page, &phys, inode, from, to, 0);
-               if (ret)
-                       mlog_errno(ret);
-
-               kaddr = kmap_atomic(page, KM_USER0);
-               memset(kaddr + from, 0, to - from);
-               kunmap_atomic(kaddr, KM_USER0);
-
-               /*
-                * Need to set the buffers we zero'd into uptodate
-                * here if they aren't - ocfs2_map_page_blocks()
-                * might've skipped some
-                */
-               if (ocfs2_should_order_data(inode)) {
-                       ret = walk_page_buffers(handle,
-                                               page_buffers(page),
-                                               from, to, &partial,
-                                               ocfs2_ordered_zero_func);
-                       if (ret < 0)
-                               mlog_errno(ret);
-               } else {
-                       ret = walk_page_buffers(handle, page_buffers(page),
-                                               from, to, &partial,
-                                               ocfs2_writeback_zero_func);
-                       if (ret < 0)
-                               mlog_errno(ret);
-               }
-
-               if (!partial)
-                       SetPageUptodate(page);
-
-               flush_dcache_page(page);
+               ocfs2_map_and_dirty_page(inode, handle, from, to, page, 1,
+                                        &phys);
 
                start = (page->index + 1) << PAGE_CACHE_SHIFT;
        }
 out:
-       if (pages) {
-               for (i = 0; i < numpages; i++) {
-                       page = pages[i];
-                       unlock_page(page);
-                       mark_page_accessed(page);
-                       page_cache_release(page);
-               }
-       }
+       if (pages)
+               ocfs2_unlock_and_free_pages(pages, numpages);
 }
 
 static int ocfs2_grab_eof_pages(struct inode *inode, loff_t start, loff_t end,
-                               struct page **pages, int *num, u64 *phys)
+                               struct page **pages, int *num)
 {
-       int i, numpages = 0, ret = 0;
-       unsigned int ext_flags;
+       int numpages, ret = 0;
        struct super_block *sb = inode->i_sb;
        struct address_space *mapping = inode->i_mapping;
        unsigned long index;
        loff_t last_page_bytes;
 
-       BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(sb)));
        BUG_ON(start > end);
 
-       if (start == end)
-               goto out;
-
        BUG_ON(start >> OCFS2_SB(sb)->s_clustersize_bits !=
               (end - 1) >> OCFS2_SB(sb)->s_clustersize_bits);
 
-       ret = ocfs2_extent_map_get_blocks(inode, start >> sb->s_blocksize_bits,
-                                         phys, NULL, &ext_flags);
-       if (ret) {
-               mlog_errno(ret);
-               goto out;
-       }
-
-       /* Tail is a hole. */
-       if (*phys == 0)
-               goto out;
-
-       /* Tail is marked as unwritten, we can count on write to zero
-        * in that case. */
-       if (ext_flags & OCFS2_EXT_UNWRITTEN)
-               goto out;
-
+       numpages = 0;
        last_page_bytes = PAGE_ALIGN(end);
        index = start >> PAGE_CACHE_SHIFT;
        do {
@@ -5756,14 +5738,8 @@ static int ocfs2_grab_eof_pages(struct inode *inode, loff_t start, loff_t end,
 
 out:
        if (ret != 0) {
-               if (pages) {
-                       for (i = 0; i < numpages; i++) {
-                               if (pages[i]) {
-                                       unlock_page(pages[i]);
-                                       page_cache_release(pages[i]);
-                               }
-                       }
-               }
+               if (pages)
+                       ocfs2_unlock_and_free_pages(pages, numpages);
                numpages = 0;
        }
 
@@ -5784,18 +5760,20 @@ out:
 int ocfs2_zero_range_for_truncate(struct inode *inode, handle_t *handle,
                                  u64 range_start, u64 range_end)
 {
-       int ret, numpages;
+       int ret = 0, numpages;
        struct page **pages = NULL;
        u64 phys;
+       unsigned int ext_flags;
+       struct super_block *sb = inode->i_sb;
 
        /*
         * File systems which don't support sparse files zero on every
         * extend.
         */
-       if (!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
+       if (!ocfs2_sparse_alloc(OCFS2_SB(sb)))
                return 0;
 
-       pages = kcalloc(ocfs2_pages_per_cluster(inode->i_sb),
+       pages = kcalloc(ocfs2_pages_per_cluster(sb),
                        sizeof(struct page *), GFP_NOFS);
        if (pages == NULL) {
                ret = -ENOMEM;
@@ -5803,15 +5781,30 @@ int ocfs2_zero_range_for_truncate(struct inode *inode, handle_t *handle,
                goto out;
        }
 
-       ret = ocfs2_grab_eof_pages(inode, range_start, range_end, pages,
-                                  &numpages, &phys);
+       if (range_start == range_end)
+               goto out;
+
+       ret = ocfs2_extent_map_get_blocks(inode,
+                                         range_start >> sb->s_blocksize_bits,
+                                         &phys, NULL, &ext_flags);
        if (ret) {
                mlog_errno(ret);
                goto out;
        }
 
-       if (numpages == 0)
+       /*
+        * Tail is a hole, or is marked unwritten. In either case, we
+        * can count on read and write to return/push zero's.
+        */
+       if (phys == 0 || ext_flags & OCFS2_EXT_UNWRITTEN)
+               goto out;
+
+       ret = ocfs2_grab_eof_pages(inode, range_start, range_end, pages,
+                                  &numpages);
+       if (ret) {
+               mlog_errno(ret);
                goto out;
+       }
 
        ocfs2_zero_cluster_pages(inode, range_start, range_end, pages,
                                 numpages, phys, handle);

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index fae07672eb189c7b3b3e80e5e9562df03cd0ad8e..8416e383197cbf8291f1b697b3d4b457f2d7d1c9 100644 (file)
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -830,18 +830,22 @@ struct ocfs2_write_ctxt {
        struct ocfs2_cached_dealloc_ctxt w_dealloc;
 };
 
-static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc)
+void ocfs2_unlock_and_free_pages(struct page **pages, int num_pages)
 {
        int i;
 
-       for(i = 0; i < wc->w_num_pages; i++) {
-               if (wc->w_pages[i] == NULL)
-                       continue;
-
-               unlock_page(wc->w_pages[i]);
-               mark_page_accessed(wc->w_pages[i]);
-               page_cache_release(wc->w_pages[i]);
+       for(i = 0; i < num_pages; i++) {
+               if (pages[i]) {
+                       unlock_page(pages[i]);
+                       mark_page_accessed(pages[i]);
+                       page_cache_release(pages[i]);
+               }
        }
+}
+
+static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc)
+{
+       ocfs2_unlock_and_free_pages(wc->w_pages, wc->w_num_pages);
 
        brelse(wc->w_di_bh);
        kfree(wc);

diff --git a/fs/ocfs2/aops.h b/fs/ocfs2/aops.h
index 389579bd64e372e8294858d63d5b0d913fee648a..b4fa37d40db4a6f9fac05683fabc8e5076b28318 100644 (file)
--- a/fs/ocfs2/aops.h
+++ b/fs/ocfs2/aops.h
@@ -34,6 +34,8 @@ int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
                          struct inode *inode, unsigned int from,
                          unsigned int to, int new);
 
+void ocfs2_unlock_and_free_pages(struct page **pages, int num_pages);
+
 int walk_page_buffers( handle_t *handle,
                        struct buffer_head *head,
                        unsigned from,