ocfs2: factor out write aops into nolock variants

ocfs2_mkwrite() will want this so that it can add some mmap specific checks
before asking for a write.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

1 files changed, 80 insertions, 40 deletions

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 3e5758ebd932..fc723fb9c981 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -849,7 +849,7 @@ static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc)
 
 static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp,
                                   struct ocfs2_super *osb, loff_t pos,
-                                  unsigned len)
+                                  unsigned len, struct buffer_head *di_bh)
 {
         struct ocfs2_write_ctxt *wc;
 
@@ -859,6 +859,8 @@ static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp,
 
         wc->w_cpos = pos >> osb->s_clustersize_bits;
         wc->w_clen = ocfs2_clusters_for_bytes(osb->sb, len);
+        get_bh(di_bh);
+        wc->w_di_bh = di_bh;
 
         if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits))
                 wc->w_large_pages = 1;
@@ -1211,9 +1213,10 @@ static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
         }
 }
 
-int ocfs2_write_begin(struct file *file, struct address_space *mapping,
-                      loff_t pos, unsigned len, unsigned flags,
-                      struct page **pagep, void **fsdata)
+static int ocfs2_write_begin_nolock(struct address_space *mapping,
+                                    loff_t pos, unsigned len, unsigned flags,
+                                    struct page **pagep, void **fsdata,
+                                    struct buffer_head *di_bh)
 {
         int ret, i, credits = OCFS2_INODE_UPDATE_CREDITS;
         unsigned int num_clusters = 0, clusters_to_alloc = 0;
@@ -1227,28 +1230,14 @@ int ocfs2_write_begin(struct file *file, struct address_space *mapping,
         handle_t *handle;
         struct ocfs2_write_cluster_desc *desc;
 
-        ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len);
+        ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len, di_bh);
         if (ret) {
                 mlog_errno(ret);
                 return ret;
         }
 
-        ret = ocfs2_meta_lock(inode, &wc->w_di_bh, 1);
-        if (ret) {
-                mlog_errno(ret);
-                goto out;
-        }
         di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
 
-        /*
-         * Take alloc sem here to prevent concurrent lookups. That way
-         * the mapping, zeroing and tree manipulation within
-         * ocfs2_write() will be safe against ->readpage(). This
-         * should also serve to lock out allocation from a shared
-         * writeable region.
-         */
-        down_write(&OCFS2_I(inode)->ip_alloc_sem);
-
         for (i = 0; i < wc->w_clen; i++) {
                 desc = &wc->w_desc[i];
                 desc->c_cpos = wc->w_cpos + i;
@@ -1258,7 +1247,7 @@ int ocfs2_write_begin(struct file *file, struct address_space *mapping,
                                                  &num_clusters, NULL);
                         if (ret) {
                                 mlog_errno(ret);
-                                goto out_meta;
+                                goto out;
                         }
                 } else if (phys) {
                         /*
@@ -1293,7 +1282,7 @@ int ocfs2_write_begin(struct file *file, struct address_space *mapping,
                                             &data_ac, &meta_ac);
                 if (ret) {
                         mlog_errno(ret);
-                        goto out_meta;
+                        goto out;
                 }
 
                 credits = ocfs2_calc_extend_credits(inode->i_sb, di,
@@ -1303,17 +1292,11 @@ int ocfs2_write_begin(struct file *file, struct address_space *mapping,
 
         ocfs2_set_target_boundaries(osb, wc, pos, len, clusters_to_alloc);
 
-        ret = ocfs2_data_lock(inode, 1);
-        if (ret) {
-                mlog_errno(ret);
-                goto out_meta;
-        }
-
         handle = ocfs2_start_trans(osb, credits);
         if (IS_ERR(handle)) {
                 ret = PTR_ERR(handle);
                 mlog_errno(ret);
-                goto out_data;
+                goto out;
         }
 
         wc->w_handle = handle;
@@ -1363,13 +1346,6 @@ int ocfs2_write_begin(struct file *file, struct address_space *mapping,
 out_commit:
         ocfs2_commit_trans(osb, handle);
 
-out_data:
-        ocfs2_data_unlock(inode, 1);
-
-out_meta:
-        up_write(&OCFS2_I(inode)->ip_alloc_sem);
-        ocfs2_meta_unlock(inode, 1);
-
 out:
         ocfs2_free_write_ctxt(wc);
 
@@ -1380,9 +1356,60 @@ out:
         return ret;
 }
 
-int ocfs2_write_end(struct file *file, struct address_space *mapping,
-                    loff_t pos, unsigned len, unsigned copied,
-                    struct page *page, void *fsdata)
+int ocfs2_write_begin(struct file *file, struct address_space *mapping,
+                      loff_t pos, unsigned len, unsigned flags,
+                      struct page **pagep, void **fsdata)
+{
+        int ret;
+        struct buffer_head *di_bh = NULL;
+        struct inode *inode = mapping->host;
+
+        ret = ocfs2_meta_lock(inode, &di_bh, 1);
+        if (ret) {
+                mlog_errno(ret);
+                return ret;
+        }
+
+        /*
+         * Take alloc sem here to prevent concurrent lookups. That way
+         * the mapping, zeroing and tree manipulation within
+         * ocfs2_write() will be safe against ->readpage(). This
+         * should also serve to lock out allocation from a shared
+         * writeable region.
+         */
+        down_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+        ret = ocfs2_data_lock(inode, 1);
+        if (ret) {
+                mlog_errno(ret);
+                goto out_fail;
+        }
+
+        ret = ocfs2_write_begin_nolock(mapping, pos, len, flags, pagep,
+                                       fsdata, di_bh);
+        if (ret) {
+                mlog_errno(ret);
+                goto out_fail_data;
+        }
+
+        brelse(di_bh);
+
+        return 0;
+
+out_fail_data:
+        ocfs2_data_unlock(inode, 1);
+out_fail:
+        up_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+        brelse(di_bh);
+        ocfs2_meta_unlock(inode, 1);
+
+        return ret;
+}
+
+static int ocfs2_write_end_nolock(struct address_space *mapping,
+                                  loff_t pos, unsigned len, unsigned copied,
+                                  struct page *page, void *fsdata)
 {
         int i;
         unsigned from, to, start = pos & (PAGE_CACHE_SIZE - 1);
@@ -1444,12 +1471,25 @@ int ocfs2_write_end(struct file *file, struct address_space *mapping,
         ocfs2_journal_dirty(handle, wc->w_di_bh);
 
         ocfs2_commit_trans(osb, handle);
+        ocfs2_free_write_ctxt(wc);
+
+        return copied;
+}
+
+int ocfs2_write_end(struct file *file, struct address_space *mapping,
+                    loff_t pos, unsigned len, unsigned copied,
+                    struct page *page, void *fsdata)
+{
+        int ret;
+        struct inode *inode = mapping->host;
+
+        ret = ocfs2_write_end_nolock(mapping, pos, len, copied, page, fsdata);
+
         ocfs2_data_unlock(inode, 1);
         up_write(&OCFS2_I(inode)->ip_alloc_sem);
         ocfs2_meta_unlock(inode, 1);
-        ocfs2_free_write_ctxt(wc);
 
-        return copied;
+        return ret;
 }
 
 const struct address_space_operations ocfs2_aops = {