Nobody ever dereferences an XFS mount point's m_dm_ops vector
pointer any more unless the XFS_MOUNT_DMAPI mount flag is set. So
leverage that to just use a null pointer there in that case, and
drop the whole xfs_dmcore_stub variable.
Change it so that once the m_dm_ops vector has had a chance to be
assigned at mount time, a non-null m_vm_ops pointer is always used
to indicate DMAPI is active on a file system rather than looking at
the mount flag.
Also rearrange the logic in xfs_dmops_get() a bit to avoid
including much of the code in the case DMAPI isn't supported
at build time.
Signed-off-by: Alex Elder <aelder@xxxxxxx>
---
fs/xfs/linux-2.6/xfs_file.c | 6 ++----
fs/xfs/xfs_dmapi.h | 10 +++++-----
fs/xfs/xfs_dmops.c | 37 +++++++++++++++++++++----------------
3 files changed, 28 insertions(+), 25 deletions(-)
Index: b/fs/xfs/linux-2.6/xfs_file.c
===================================================================
--- a/fs/xfs/linux-2.6/xfs_file.c
+++ b/fs/xfs/linux-2.6/xfs_file.c
@@ -674,8 +674,7 @@ start:
goto out_unlock_mutex;
}
- if (mp->m_flags & XFS_MOUNT_DMAPI && !(ioflags & IO_INVIS) &&
- !eventsent) {
+ if (mp->m_dm_ops && !(ioflags & IO_INVIS) && !eventsent) {
int dmflags = FILP_DELAY_FLAG(file);
if (need_i_mutex)
@@ -830,8 +829,7 @@ write_retry:
xfs_iunlock(ip, XFS_ILOCK_EXCL);
}
- if (ret == -ENOSPC && mp->m_flags & XFS_MOUNT_DMAPI &&
- !(ioflags & IO_INVIS)) {
+ if (ret == -ENOSPC && mp->m_dm_ops && !(ioflags & IO_INVIS)) {
xfs_iunlock(ip, iolock);
if (need_i_mutex)
mutex_unlock(&inode->i_mutex);
Index: b/fs/xfs/xfs_dmapi.h
===================================================================
--- a/fs/xfs/xfs_dmapi.h
+++ b/fs/xfs/xfs_dmapi.h
@@ -201,7 +201,7 @@ xfs_dmapi_event_enabled(struct xfs_inode
#ifdef XFS_DMAPI
unsigned int event_mask = 1 << event;
- return ip->i_mount->m_flags & XFS_MOUNT_DMAPI &&
+ return ip->i_mount->m_dm_ops &&
(ip->i_mount->m_dmevmask & event_mask ||
ip->i_d.di_dmevmask & event_mask);
#else /* ! XFS_DMAPI */
@@ -235,7 +235,7 @@ xfs_dmapi_send_mmap(
struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
struct xfs_mount *mp = XFS_M(inode->i_sb);
- if (mp->m_flags & XFS_MOUNT_DMAPI) {
+ if (mp->m_dm_ops) {
xfs_send_mmap_t send_mmap = mp->m_dm_ops->xfs_send_mmap;
return send_mmap(vma, vm_flags);
@@ -319,7 +319,7 @@ xfs_dmapi_send_mount(
struct xfs_mount *mp,
char *path)
{
- if (mp->m_flags & XFS_MOUNT_DMAPI) {
+ if (mp->m_dm_ops) {
xfs_send_mount_t send_mount = mp->m_dm_ops->xfs_send_mount;
return send_mount(mp, DM_RIGHT_NULL, path, mp->m_fsname);
@@ -333,7 +333,7 @@ static inline void
xfs_dmapi_send_preunmount(
struct xfs_mount *mp)
{
- if (mp->m_flags & XFS_MOUNT_DMAPI)
+ if (mp->m_dm_ops)
(void) xfs_dmapi_send_namesp(mp->m_rootip, DM_RIGHT_NULL, NULL,
DM_EVENT_PREUNMOUNT,
mp->m_rootip, DM_RIGHT_NULL, NULL,
@@ -344,7 +344,7 @@ static inline void
xfs_dmapi_send_unmount(
struct xfs_mount *mp)
{
- if (mp->m_flags & XFS_MOUNT_DMAPI) {
+ if (mp->m_dm_ops) {
xfs_send_unmount_t send_unmount =
mp->m_dm_ops->xfs_send_unmount;
Index: b/fs/xfs/xfs_dmops.c
===================================================================
--- a/fs/xfs/xfs_dmops.c
+++ b/fs/xfs/xfs_dmops.c
@@ -28,30 +28,35 @@
#include "xfs_inode.h"
#include "xfs_dmapi.h"
-
-static struct xfs_dmops xfs_dmcore_stub = {
- .xfs_send_data = (xfs_send_data_t)fs_nosys,
- .xfs_send_mmap = (xfs_send_mmap_t)fs_noerr,
- .xfs_send_destroy = (xfs_send_destroy_t)fs_nosys,
- .xfs_send_namesp = (xfs_send_namesp_t)fs_nosys,
- .xfs_send_mount = (xfs_send_mount_t)fs_nosys,
- .xfs_send_unmount = (xfs_send_unmount_t)fs_noerr,
-};
-
int
xfs_dmops_get(struct xfs_mount *mp)
{
- if (mp->m_flags & XFS_MOUNT_DMAPI) {
- cmn_err(CE_WARN,
- "XFS: dmapi support not available in this kernel.");
- return EINVAL;
+ ASSERT(!mp->m_dm_ops);
+ if (!(mp->m_flags & XFS_MOUNT_DMAPI))
+ return 0;
+
+#ifdef XFS_DMAPI
+ mp->m_dm_ops = symbol_get(xfs_dmcore_xfs);
+ if (!mp->m_dm_ops) {
+ request_module("xfs_dmapi");
+ mp->m_dm_ops = symbol_get(xfs_dmcore_xfs);
}
+ if (mp->m_dm_ops)
+ return 0;
+#endif /* XFS_DMAPI */
- mp->m_dm_ops = &xfs_dmcore_stub;
- return 0;
+ /* Turn off the flag, since it won't be operative */
+ mp->m_flags &= ~XFS_MOUNT_DMAPI;
+ cmn_err(CE_WARN, "XFS: dmapi support not available in this kernel.");
+
+ return EINVAL;
}
void
xfs_dmops_put(struct xfs_mount *mp)
{
+ if (mp->m_dm_ops) {
+ symbol_put(xfs_dmcore_xfs);
+ mp->m_dm_ops = NULL;
+ }
}
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