ocfs2: Initialize the cluster we're writing to in a non-sparse extend

In a non-sparse extend, we correctly allocate (and zero) the clusters between
the old_i_size and pos, but we don't zero the portions of the cluster we're
writing to outside of pos<->len.

It handles clustersize > pagesize and blocksize < pagesize.

[Cleaned up by Joel Becker.]

Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Signed-off-by: Joel Becker <joel.becker@oracle.com>

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index e511df10145181a03e4e95352b56bb444d9a9ab2..b401654011a2b64c4e55f87c7916e3badc07f68e 100644 (file)
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -895,18 +895,17 @@ struct ocfs2_write_cluster_desc {
         */
        unsigned        c_new;
        unsigned        c_unwritten;
+       unsigned        c_needs_zero;
 };
 
-static inline int ocfs2_should_zero_cluster(struct ocfs2_write_cluster_desc *d)
-{
-       return d->c_new || d->c_unwritten;
-}
-
 struct ocfs2_write_ctxt {
        /* Logical cluster position / len of write */
        u32                             w_cpos;
        u32                             w_clen;
 
+       /* First cluster allocated in a nonsparse extend */
+       u32                             w_first_new_cpos;
+
        struct ocfs2_write_cluster_desc w_desc[OCFS2_MAX_CLUSTERS_PER_PAGE];
 
        /*
@@ -984,6 +983,7 @@ static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp,
                return -ENOMEM;
 
        wc->w_cpos = pos >> osb->s_clustersize_bits;
+       wc->w_first_new_cpos = UINT_MAX;
        cend = (pos + len - 1) >> osb->s_clustersize_bits;
        wc->w_clen = cend - wc->w_cpos + 1;
        get_bh(di_bh);
@@ -1218,20 +1218,18 @@ out:
  */
 static int ocfs2_write_cluster(struct address_space *mapping,
                               u32 phys, unsigned int unwritten,
+                              unsigned int should_zero,
                               struct ocfs2_alloc_context *data_ac,
                               struct ocfs2_alloc_context *meta_ac,
                               struct ocfs2_write_ctxt *wc, u32 cpos,
                               loff_t user_pos, unsigned user_len)
 {
-       int ret, i, new, should_zero = 0;
+       int ret, i, new;
        u64 v_blkno, p_blkno;
        struct inode *inode = mapping->host;
        struct ocfs2_extent_tree et;
 
        new = phys == 0 ? 1 : 0;
-       if (new || unwritten)
-               should_zero = 1;
-
        if (new) {
                u32 tmp_pos;
 
@@ -1342,7 +1340,9 @@ static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
                        local_len = osb->s_clustersize - cluster_off;
 
                ret = ocfs2_write_cluster(mapping, desc->c_phys,
-                                         desc->c_unwritten, data_ac, meta_ac,
+                                         desc->c_unwritten,
+                                         desc->c_needs_zero,
+                                         data_ac, meta_ac,
                                          wc, desc->c_cpos, pos, local_len);
                if (ret) {
                        mlog_errno(ret);
@@ -1392,14 +1392,14 @@ static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
                 * newly allocated cluster.
                 */
                desc = &wc->w_desc[0];
-               if (ocfs2_should_zero_cluster(desc))
+               if (desc->c_needs_zero)
                        ocfs2_figure_cluster_boundaries(osb,
                                                        desc->c_cpos,
                                                        &wc->w_target_from,
                                                        NULL);
 
                desc = &wc->w_desc[wc->w_clen - 1];
-               if (ocfs2_should_zero_cluster(desc))
+               if (desc->c_needs_zero)
                        ocfs2_figure_cluster_boundaries(osb,
                                                        desc->c_cpos,
                                                        NULL,
@@ -1467,13 +1467,28 @@ static int ocfs2_populate_write_desc(struct inode *inode,
                        phys++;
                }
 
+               /*
+                * If w_first_new_cpos is < UINT_MAX, we have a non-sparse
+                * file that got extended.  w_first_new_cpos tells us
+                * where the newly allocated clusters are so we can
+                * zero them.
+                */
+               if (desc->c_cpos >= wc->w_first_new_cpos) {
+                       BUG_ON(phys == 0);
+                       desc->c_needs_zero = 1;
+               }
+
                desc->c_phys = phys;
                if (phys == 0) {
                        desc->c_new = 1;
+                       desc->c_needs_zero = 1;
                        *clusters_to_alloc = *clusters_to_alloc + 1;
                }
-               if (ext_flags & OCFS2_EXT_UNWRITTEN)
+
+               if (ext_flags & OCFS2_EXT_UNWRITTEN) {
                        desc->c_unwritten = 1;
+                       desc->c_needs_zero = 1;
+               }
 
                num_clusters--;
        }
@@ -1633,10 +1648,13 @@ static int ocfs2_expand_nonsparse_inode(struct inode *inode, loff_t pos,
        if (newsize <= i_size_read(inode))
                return 0;
 
-       ret = ocfs2_extend_no_holes(inode, newsize, newsize - len);
+       ret = ocfs2_extend_no_holes(inode, newsize, pos);
        if (ret)
                mlog_errno(ret);
 
+       wc->w_first_new_cpos =
+               ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
+
        return ret;
 }
 
@@ -1645,7 +1663,7 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
                             struct page **pagep, void **fsdata,
                             struct buffer_head *di_bh, struct page *mmap_page)
 {
-       int ret, credits = OCFS2_INODE_UPDATE_CREDITS;
+       int ret, cluster_of_pages, credits = OCFS2_INODE_UPDATE_CREDITS;
        unsigned int clusters_to_alloc, extents_to_split;
        struct ocfs2_write_ctxt *wc;
        struct inode *inode = mapping->host;
@@ -1723,8 +1741,19 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
 
        }
 
-       ocfs2_set_target_boundaries(osb, wc, pos, len,
-                                   clusters_to_alloc + extents_to_split);
+       /*
+        * We have to zero sparse allocated clusters, unwritten extent clusters,
+        * and non-sparse clusters we just extended.  For non-sparse writes,
+        * we know zeros will only be needed in the first and/or last cluster.
+        */
+       if (clusters_to_alloc || extents_to_split ||
+           wc->w_desc[0].c_needs_zero ||
+           wc->w_desc[wc->w_clen - 1].c_needs_zero)
+               cluster_of_pages = 1;
+       else
+               cluster_of_pages = 0;
+
+       ocfs2_set_target_boundaries(osb, wc, pos, len, cluster_of_pages);
 
        handle = ocfs2_start_trans(osb, credits);
        if (IS_ERR(handle)) {
@@ -1757,8 +1786,7 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
         * extent.
         */
        ret = ocfs2_grab_pages_for_write(mapping, wc, wc->w_cpos, pos,
-                                        clusters_to_alloc + extents_to_split,
-                                        mmap_page);
+                                        cluster_of_pages, mmap_page);
        if (ret) {
                mlog_errno(ret);
                goto out_quota;