[PATCH 57/58] xfs: support XFS_XFLAG_REFLINK (and FS_NOCOW_FL) on reflink filesystems

Darrick J. Wong
2015-10-07T05:01:35Z

Report the reflink/nocow flags as appropriate in the XFS-specific and
"standard" getattr ioctls.

Allow the user to clear the reflink flag (or set the nocow flag) if the
size is zero.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
fs/xfs/libxfs/xfs_fs.h | 1 +
fs/xfs/xfs_inode.c | 10 +++++++--
fs/xfs/xfs_ioctl.c | 15 +++++++++++++-
fs/xfs/xfs_reflink.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/xfs/xfs_reflink.h | 4 ++++
5 files changed, 77 insertions(+), 4 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index c63afd4..0dcffc8 100644
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -67,6 +67,7 @@ struct fsxattr {
#define XFS_XFLAG_EXTSZINHERIT 0x00001000 /* inherit inode extent size */
#define XFS_XFLAG_NODEFRAG 0x00002000 /* do not defragment */
#define XFS_XFLAG_FILESTREAM 0x00004000 /* use filestream allocator */
+#define XFS_XFLAG_REFLINK 0x00008000 /* file is reflinked */
#define XFS_XFLAG_HASATTR 0x80000000 /* no DIFLAG for this */

/*
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 61a468b..297151a 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -610,7 +610,8 @@ __xfs_iflock(

STATIC uint
_xfs_dic2xflags(
- __uint16_t di_flags)
+ __uint16_t di_flags,
+ __uint64_t di_flags2)
{
uint flags = 0;

@@ -643,6 +644,8 @@ _xfs_dic2xflags(
flags |= XFS_XFLAG_NODEFRAG;
if (di_flags & XFS_DIFLAG_FILESTREAM)
flags |= XFS_XFLAG_FILESTREAM;
+ if (di_flags2 & XFS_DIFLAG2_REFLINK)
+ flags |= XFS_XFLAG_REFLINK;
}

return flags;
@@ -654,7 +657,7 @@ xfs_ip2xflags(
{
xfs_icdinode_t *dic = &ip->i_d;

- return _xfs_dic2xflags(dic->di_flags) |
+ return _xfs_dic2xflags(dic->di_flags, dic->di_flags2) |
(XFS_IFORK_Q(ip) ? XFS_XFLAG_HASATTR : 0);
}

@@ -662,7 +665,8 @@ uint
xfs_dic2xflags(
xfs_dinode_t *dip)
{
- return _xfs_dic2xflags(be16_to_cpu(dip->di_flags)) |
+ return _xfs_dic2xflags(be16_to_cpu(dip->di_flags),
+ be64_to_cpu(dip->di_flags2)) |
(XFS_DFORK_Q(dip) ? XFS_XFLAG_HASATTR : 0);
}

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 92aaca0..1dba30b 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -870,6 +870,10 @@ xfs_merge_ioc_xflags(
xflags |= XFS_XFLAG_NODUMP;
else
xflags &= ~XFS_XFLAG_NODUMP;
+ if (flags & FS_NOCOW_FL)
+ xflags &= ~XFS_XFLAG_REFLINK;
+ else
+ xflags |= XFS_XFLAG_REFLINK;

return xflags;
}
@@ -1181,6 +1185,10 @@ xfs_ioctl_setattr(

trace_xfs_ioctl_setattr(ip);

+ code = xfs_reflink_check_flag_adjust(ip, &fa->fsx_xflags);
+ if (code)
+ return code;
+
code = xfs_ioctl_setattr_check_projid(ip, fa);
if (code)
return code;
@@ -1303,6 +1311,7 @@ xfs_ioc_getxflags(
unsigned int flags;

flags = xfs_di2lxflags(ip->i_d.di_flags);
+ xfs_reflink_get_lxflags(ip, &flags);
if (copy_to_user(arg, &flags, sizeof(flags)))
return -EFAULT;
return 0;
@@ -1324,11 +1333,15 @@ xfs_ioc_setxflags(

if (flags & ~(FS_IMMUTABLE_FL | FS_APPEND_FL | \
FS_NOATIME_FL | FS_NODUMP_FL | \
- FS_SYNC_FL))
+ FS_SYNC_FL | FS_NOCOW_FL))
return -EOPNOTSUPP;

fa.fsx_xflags = xfs_merge_ioc_xflags(flags, xfs_ip2xflags(ip));

+ error = xfs_reflink_check_flag_adjust(ip, &fa.fsx_xflags);
+ if (error)
+ return error;
+
error = mnt_want_write_file(filp);
if (error)
return error;
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 92d8345..99635aa 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1892,3 +1892,54 @@ out:
trace_xfs_reflink_unshare_error(ip, error, _RET_IP_);
return error;
}
+
+/**
+ * xfs_reflink_get_lxflags() - set reflink-related linux inode flags
+ *
+ * @ip: XFS inode
+ * @flags: Pointer to the user-visible inode flags
+ */
+void
+xfs_reflink_get_lxflags(
+ struct xfs_inode *ip, /* XFS inode */
+ unsigned int *flags) /* user flags */
+{
+ /*
+ * If this is a reflink-capable filesystem and there are no shared
+ * blocks, then this is a "nocow" file.
+ */
+ if (!xfs_sb_version_hasreflink(&ip->i_mount->m_sb) ||
+ xfs_is_reflink_inode(ip))
+ return;
+ *flags |= FS_NOCOW_FL;
+}
+
+/**
+ * xfs_reflink_check_flag_adjust() - The only change we allow to the inode
+ * reflink flag is to clear it when the
+ * fs supports reflink and the size is zero.
+ *
+ * @ip: XFS inode
+ * @xflags: XFS in-core inode flags
+ */
+int
+xfs_reflink_check_flag_adjust(
+ struct xfs_inode *ip,
+ unsigned int *xflags)
+{
+ unsigned int chg;
+
+ chg = !!(*xflags & XFS_XFLAG_REFLINK) ^ !!xfs_is_reflink_inode(ip);
+
+ if (!chg)
+ return 0;
+ if (!xfs_sb_version_hasreflink(&ip->i_mount->m_sb))
+ return -EOPNOTSUPP;
+ if (i_size_read(VFS_I(ip)) != 0)
+ return -EINVAL;
+ if (*xflags & XFS_XFLAG_REFLINK) {
+ *xflags &= ~XFS_XFLAG_REFLINK;
+ return 0;
+ }
+ return 0;
+}
diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
index 4ce2cba6..4733bf1 100644
--- a/fs/xfs/xfs_reflink.h
+++ b/fs/xfs/xfs_reflink.h
@@ -54,4 +54,8 @@ extern int xfs_reflink(struct xfs_inode *src, xfs_off_t srcoff,
extern int xfs_reflink_unshare(struct xfs_inode *ip, struct file *filp,
xfs_off_t offset, xfs_off_t len);

+extern void xfs_reflink_get_lxflags(struct xfs_inode *ip, unsigned int *flags);
+extern int xfs_reflink_check_flag_adjust(struct xfs_inode *ip,
+ unsigned int *xflags);
+
#endif /* __XFS_REFLINK_H */