ocfs2: Integrate CoW in file write.

When we use mmap, we CoW the refcountd clusters in
ocfs2_write_begin_nolock. While for normal file
io(including directio), we do CoW in
ocfs2_prepare_inode_for_write.

Signed-off-by: Tao Ma <tao.ma@oracle.com>

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index fdad075..9db9d64 100644 (file)
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -44,6 +44,7 @@
 #include "suballoc.h"
 #include "super.h"
 #include "symlink.h"
+#include "refcounttree.h"
 
 #include "buffer_head_io.h"
 
@@ -590,6 +591,8 @@ static int ocfs2_direct_IO_get_blocks(struct inode *inode, sector_t iblock,
                goto bail;
        }
 
+       /* We should already CoW the refcounted extent. */
+       BUG_ON(ext_flags & OCFS2_EXT_REFCOUNTED);
        /*
         * get_more_blocks() expects us to describe a hole by clearing
         * the mapped bit on bh_result().
@@ -1449,6 +1452,9 @@ static int ocfs2_populate_write_desc(struct inode *inode,
                                goto out;
                        }
 
+                       /* We should already CoW the refcountd extent. */
+                       BUG_ON(ext_flags & OCFS2_EXT_REFCOUNTED);
+
                        /*
                         * Assume worst case - that we're writing in
                         * the middle of the extent.
@@ -1700,6 +1706,19 @@ int ocfs2_write_begin_nolock(struct address_space *mapping,
                goto out;
        }
 
+       ret = ocfs2_check_range_for_refcount(inode, pos, len);
+       if (ret < 0) {
+               mlog_errno(ret);
+               goto out;
+       } else if (ret == 1) {
+               ret = ocfs2_refcount_cow(inode, di_bh,
+                                        wc->w_cpos, wc->w_clen);
+               if (ret) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+       }
+
        ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc,
                                        &extents_to_split);
        if (ret) {

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 4921b4e..6ee20e8 100644 (file)
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -59,6 +59,7 @@
 #include "xattr.h"
 #include "acl.h"
 #include "quota.h"
+#include "refcounttree.h"
 
 #include "buffer_head_io.h"
 
@@ -1656,6 +1657,70 @@ static long ocfs2_fallocate(struct inode *inode, int mode, loff_t offset,
                                         OCFS2_IOC_RESVSP64, &sr, change_size);
 }
 
+int ocfs2_check_range_for_refcount(struct inode *inode, loff_t pos,
+                                  size_t count)
+{
+       int ret = 0;
+       unsigned int extent_flags;
+       u32 cpos, clusters, extent_len, phys_cpos;
+       struct super_block *sb = inode->i_sb;
+
+       if (!ocfs2_refcount_tree(OCFS2_SB(inode->i_sb)) ||
+           !(OCFS2_I(inode)->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL))
+               return 0;
+
+       cpos = pos >> OCFS2_SB(sb)->s_clustersize_bits;
+       clusters = ocfs2_clusters_for_bytes(sb, pos + count) - cpos;
+
+       while (clusters) {
+               ret = ocfs2_get_clusters(inode, cpos, &phys_cpos, &extent_len,
+                                        &extent_flags);
+               if (ret < 0) {
+                       mlog_errno(ret);
+                       goto out;
+               }
+
+               if (phys_cpos && (extent_flags & OCFS2_EXT_REFCOUNTED)) {
+                       ret = 1;
+                       break;
+               }
+
+               if (extent_len > clusters)
+                       extent_len = clusters;
+
+               clusters -= extent_len;
+               cpos += extent_len;
+       }
+out:
+       return ret;
+}
+
+static int ocfs2_prepare_inode_for_refcount(struct inode *inode,
+                                           loff_t pos, size_t count,
+                                           int *meta_level)
+{
+       int ret;
+       struct buffer_head *di_bh = NULL;
+       u32 cpos = pos >> OCFS2_SB(inode->i_sb)->s_clustersize_bits;
+       u32 clusters =
+               ocfs2_clusters_for_bytes(inode->i_sb, pos + count) - cpos;
+
+       ret = ocfs2_inode_lock(inode, &di_bh, 1);
+       if (ret) {
+               mlog_errno(ret);
+               goto out;
+       }
+
+       *meta_level = 1;
+
+       ret = ocfs2_refcount_cow(inode, di_bh, cpos, clusters);
+       if (ret)
+               mlog_errno(ret);
+out:
+       brelse(di_bh);
+       return ret;
+}
+
 static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
                                         loff_t *ppos,
                                         size_t count,
@@ -1712,6 +1777,22 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
 
                end = saved_pos + count;
 
+               ret = ocfs2_check_range_for_refcount(inode, saved_pos, count);
+               if (ret == 1) {
+                       ocfs2_inode_unlock(inode, meta_level);
+                       meta_level = -1;
+
+                       ret = ocfs2_prepare_inode_for_refcount(inode,
+                                                              saved_pos,
+                                                              count,
+                                                              &meta_level);
+               }
+
+               if (ret < 0) {
+                       mlog_errno(ret);
+                       goto out_unlock;
+               }
+
                /*
                 * Skip the O_DIRECT checks if we don't need
                 * them.
@@ -1758,7 +1839,8 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry,
                *ppos = saved_pos;
 
 out_unlock:
-       ocfs2_inode_unlock(inode, meta_level);
+       if (meta_level >= 0)
+               ocfs2_inode_unlock(inode, meta_level);
 
 out:
        return ret;

diff --git a/fs/ocfs2/file.h b/fs/ocfs2/file.h
index 172f9fb..d66cf4f 100644 (file)
--- a/fs/ocfs2/file.h
+++ b/fs/ocfs2/file.h
@@ -69,4 +69,6 @@ int ocfs2_update_inode_atime(struct inode *inode,
 int ocfs2_change_file_space(struct file *file, unsigned int cmd,
                            struct ocfs2_space_resv *sr);
 
+int ocfs2_check_range_for_refcount(struct inode *inode, loff_t pos,
+                                  size_t count);
 #endif /* OCFS2_FILE_H */