xfs: introduce the CoW fork
Introduce a new in-core fork for storing copy-on-write delalloc
reservations and allocated extents that are in the process of being
written out.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
index 7699a03..5dd56d3 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.c
+++ b/fs/xfs/libxfs/xfs_inode_fork.c
@@ -206,9 +206,14 @@
XFS_ERROR_REPORT("xfs_iformat(7)", XFS_ERRLEVEL_LOW, ip->i_mount);
return -EFSCORRUPTED;
}
- if (error) {
+ if (error)
return error;
+
+ if (xfs_is_reflink_inode(ip)) {
+ ASSERT(ip->i_cowfp == NULL);
+ xfs_ifork_init_cow(ip);
}
+
if (!XFS_DFORK_Q(dip))
return 0;
@@ -247,6 +252,9 @@
if (error) {
kmem_zone_free(xfs_ifork_zone, ip->i_afp);
ip->i_afp = NULL;
+ if (ip->i_cowfp)
+ kmem_zone_free(xfs_ifork_zone, ip->i_cowfp);
+ ip->i_cowfp = NULL;
xfs_idestroy_fork(ip, XFS_DATA_FORK);
}
return error;
@@ -761,6 +769,9 @@
if (whichfork == XFS_ATTR_FORK) {
kmem_zone_free(xfs_ifork_zone, ip->i_afp);
ip->i_afp = NULL;
+ } else if (whichfork == XFS_COW_FORK) {
+ kmem_zone_free(xfs_ifork_zone, ip->i_cowfp);
+ ip->i_cowfp = NULL;
}
}
@@ -948,6 +959,19 @@
}
}
+/* Convert bmap state flags to an inode fork. */
+struct xfs_ifork *
+xfs_iext_state_to_fork(
+ struct xfs_inode *ip,
+ int state)
+{
+ if (state & BMAP_COWFORK)
+ return ip->i_cowfp;
+ else if (state & BMAP_ATTRFORK)
+ return ip->i_afp;
+ return &ip->i_df;
+}
+
/*
* Insert new item(s) into the extent records for incore inode
* fork 'ifp'. 'count' new items are inserted at index 'idx'.
@@ -960,7 +984,7 @@
xfs_bmbt_irec_t *new, /* items to insert */
int state) /* type of extent conversion */
{
- xfs_ifork_t *ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df;
+ xfs_ifork_t *ifp = xfs_iext_state_to_fork(ip, state);
xfs_extnum_t i; /* extent record index */
trace_xfs_iext_insert(ip, idx, new, state, _RET_IP_);
@@ -1210,7 +1234,7 @@
int ext_diff, /* number of extents to remove */
int state) /* type of extent conversion */
{
- xfs_ifork_t *ifp = (state & BMAP_ATTRFORK) ? ip->i_afp : &ip->i_df;
+ xfs_ifork_t *ifp = xfs_iext_state_to_fork(ip, state);
xfs_extnum_t nextents; /* number of extents in file */
int new_size; /* size of extents after removal */
@@ -1955,3 +1979,20 @@
ifp->if_u1.if_ext_irec[i].er_extoff += ext_diff;
}
}
+
+/*
+ * Initialize an inode's copy-on-write fork.
+ */
+void
+xfs_ifork_init_cow(
+ struct xfs_inode *ip)
+{
+ if (ip->i_cowfp)
+ return;
+
+ ip->i_cowfp = kmem_zone_zalloc(xfs_ifork_zone,
+ KM_SLEEP | KM_NOFS);
+ ip->i_cowfp->if_flags = XFS_IFEXTENTS;
+ ip->i_cformat = XFS_DINODE_FMT_EXTENTS;
+ ip->i_cnextents = 0;
+}