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/file.c b/fs/ocfs2/file.c
index 4921b4e..6ee20e8 100644
--- 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 @@
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 @@
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 @@
*ppos = saved_pos;
out_unlock:
- ocfs2_inode_unlock(inode, meta_level);
+ if (meta_level >= 0)
+ ocfs2_inode_unlock(inode, meta_level);
out:
return ret;
