ocfs2: CoW a reflinked cluster when it is truncated.
When we truncate a file to a specific size which resides in a reflinked
cluster, we need to CoW it since ocfs2_zero_range_for_truncate will
zero the space after the size(just another type of write).
So we add a "max_cpos" in ocfs2_refcount_cow so that it will stop when
it hit the max cluster offset.
Signed-off-by: Tao Ma <tao.ma@oracle.com>
diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c
index 0a924365..37aa0c8 100644
--- a/fs/ocfs2/refcounttree.c
+++ b/fs/ocfs2/refcounttree.c
@@ -2482,6 +2482,7 @@
*
* cpos is vitual start cluster position we want to do CoW in a
* file and write_len is the cluster length.
+ * max_cpos is the place where we want to stop CoW intentionally.
*
* Normal we will start CoW from the beginning of extent record cotaining cpos.
* We try to break up extents on boundaries of MAX_CONTIG_BYTES so that we
@@ -2491,6 +2492,7 @@
struct buffer_head *di_bh,
u32 cpos,
u32 write_len,
+ u32 max_cpos,
u32 *cow_start,
u32 *cow_len)
{
@@ -2505,6 +2507,8 @@
int contig_clusters = ocfs2_cow_contig_clusters(inode->i_sb);
int leaf_clusters;
+ BUG_ON(cpos + write_len > max_cpos);
+
if (tree_height > 0) {
ret = ocfs2_find_leaf(INODE_CACHE(inode), el, cpos, &eb_bh);
if (ret) {
@@ -2549,15 +2553,20 @@
}
/*
- * If we encounter a hole or a non-refcounted record,
- * stop the search.
+ * If we encounter a hole, a non-refcounted record or
+ * pass the max_cpos, stop the search.
*/
if ((!(rec->e_flags & OCFS2_EXT_REFCOUNTED)) ||
- (*cow_len && rec_end != le32_to_cpu(rec->e_cpos)))
+ (*cow_len && rec_end != le32_to_cpu(rec->e_cpos)) ||
+ (max_cpos <= le32_to_cpu(rec->e_cpos)))
break;
leaf_clusters = le16_to_cpu(rec->e_leaf_clusters);
rec_end = le32_to_cpu(rec->e_cpos) + leaf_clusters;
+ if (rec_end > max_cpos) {
+ rec_end = max_cpos;
+ leaf_clusters = rec_end - le32_to_cpu(rec->e_cpos);
+ }
/*
* How many clusters do we actually need from
@@ -3184,12 +3193,13 @@
}
/*
- * Starting at cpos, try to CoW write_len clusters.
- * This will stop when it runs into a hole or an unrefcounted extent.
+ * Starting at cpos, try to CoW write_len clusters. Don't CoW
+ * past max_cpos. This will stop when it runs into a hole or an
+ * unrefcounted extent.
*/
static int ocfs2_refcount_cow_hunk(struct inode *inode,
struct buffer_head *di_bh,
- u32 cpos, u32 write_len)
+ u32 cpos, u32 write_len, u32 max_cpos)
{
int ret;
u32 cow_start = 0, cow_len = 0;
@@ -3201,12 +3211,14 @@
BUG_ON(!(oi->ip_dyn_features & OCFS2_HAS_REFCOUNT_FL));
- ret = ocfs2_refcount_cal_cow_clusters(inode, di_bh, cpos, write_len,
+ ret = ocfs2_refcount_cal_cow_clusters(inode, di_bh,
+ cpos, write_len, max_cpos,
&cow_start, &cow_len);
if (ret) {
mlog_errno(ret);
goto out;
}
+
mlog(0, "CoW inode %lu, cpos %u, write_len %u, cow_start %u, "
"cow_len %u\n", inode->i_ino,
cpos, write_len, cow_start, cow_len);
@@ -3233,12 +3245,12 @@
/*
* CoW any and all clusters between cpos and cpos+write_len.
- * If this returns successfully, all clusters between cpos and
- * cpos+write_len are safe to modify.
+ * Don't CoW past max_cpos. If this returns successfully, all
+ * clusters between cpos and cpos+write_len are safe to modify.
*/
int ocfs2_refcount_cow(struct inode *inode,
struct buffer_head *di_bh,
- u32 cpos, u32 write_len)
+ u32 cpos, u32 write_len, u32 max_cpos)
{
int ret = 0;
u32 p_cluster, num_clusters;
@@ -3257,7 +3269,7 @@
if (ext_flags & OCFS2_EXT_REFCOUNTED) {
ret = ocfs2_refcount_cow_hunk(inode, di_bh, cpos,
- num_clusters);
+ num_clusters, max_cpos);
if (ret) {
mlog_errno(ret);
break;