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From 7fefbc7487f55b0edaa7a85f0e5b9fea68d5ff15 Mon Sep 17 00:00:00 2001
From: Liu Xuezhao <xuezhao.liu@emc.com>
Date: Thu, 9 Aug 2012 10:31:10 +0800
Subject: [PATCH 06/13] LU-1337 vfs: kernel 3.2 protects inode->i_nlink
Kernel 3.2 protects inode->i_nlink from direct modification.
Filesystems may only read i_nlink directly. They shall use the
(set|clear|inc|drop)_nlink for modification.
See kernel commit a78ef704a8dd430225955f0709b22d4a6ba21deb.
This patch adds LC_HAVE_PROTECT_I_NLINK checking and implements
set_nlink for old kernel, clear/inc/drop_nlink exists after 2.6.18
so need not to be re-implemented.
Signed-off-by: Liu Xuezhao <xuezhao.liu@emc.com>
Change-Id: Ie958cb308291ecc48d409a1282fed7ea3549a561
---
lustre/autoconf/lustre-core.m4 | 22 ++++++++++++++++++++++
lustre/include/linux/lustre_compat25.h | 8 ++++++++
lustre/llite/dcache.c | 4 ++--
lustre/llite/file.c | 2 +-
lustre/llite/llite_lib.c | 4 ++--
lustre/osd-ldiskfs/osd_handler.c | 12 ++++++------
6 files changed, 41 insertions(+), 11 deletions(-)
diff --git a/lustre/autoconf/lustre-core.m4 b/lustre/autoconf/lustre-core.m4
index 420d81e..84f1678 100644
--- a/lustre/autoconf/lustre-core.m4
+++ b/lustre/autoconf/lustre-core.m4
@@ -1895,6 +1895,27 @@ LB_LINUX_TRY_COMPILE([
])
#
+# 3.2 protects inode->i_nlink from direct modification
+# see kernel commit a78ef704a8dd430225955f0709b22d4a6ba21deb
+# at the same time, add set_nlink()
+#
+AC_DEFUN([LC_HAVE_PROTECT_I_NLINK],
+[AC_MSG_CHECKING([if inode->i_nlink is protected from direct modification])
+LB_LINUX_TRY_COMPILE([
+ #include <linux/fs.h>
+],[
+ struct inode i;
+ i.i_nlink = 0;
+],[
+ AC_MSG_RESULT([no])
+],[
+ AC_DEFINE(HAVE_PROTECT_I_NLINK, 1,
+ [inode->i_nlink is protected from direct modification])
+ AC_MSG_RESULT([yes])
+])
+])
+
+#
# 3.3 introduces migrate_mode.h and migratepage has 4 args
#
AC_DEFUN([LC_HAVE_MIGRATE_HEADER],
@@ -2084,6 +2105,7 @@ AC_DEFUN([LC_PROG_LINUX],
# 3.2
LC_HAVE_VOID_MAKE_REQUEST_FN
+ LC_HAVE_PROTECT_I_NLINK
# 3.3
LC_HAVE_MIGRATE_HEADER
diff --git a/lustre/include/linux/lustre_compat25.h b/lustre/include/linux/lustre_compat25.h
index 2d0dd0e..7ead133 100644
--- a/lustre/include/linux/lustre_compat25.h
+++ b/lustre/include/linux/lustre_compat25.h
@@ -839,5 +839,13 @@ static inline int ll_namei_to_lookup_intent_flag(int flag)
# define LL_MRF_RETURN(rc) RETURN(rc)
#endif
+#include <linux/fs.h>
+#ifndef HAVE_PROTECT_I_NLINK
+static inline void set_nlink(struct inode *inode, unsigned int nlink)
+{
+ inode->i_nlink = nlink;
+}
+#endif
+
#endif /* __KERNEL__ */
#endif /* _COMPAT25_H */
diff --git a/lustre/llite/dcache.c b/lustre/llite/dcache.c
index 14fb634..b507408 100644
--- a/lustre/llite/dcache.c
+++ b/lustre/llite/dcache.c
@@ -187,7 +187,7 @@ static int ll_ddelete(HAVE_D_DELETE_CONST struct dentry *de)
/* if not ldlm lock for this inode, set i_nlink to 0 so that
* this inode can be recycled later b=20433 */
if (de->d_inode && !find_cbdata(de->d_inode))
- de->d_inode->i_nlink = 0;
+ clear_nlink(de->d_inode);
#endif
if (d_lustre_invalid((struct dentry *)de))
@@ -687,7 +687,7 @@ void ll_d_iput(struct dentry *de, struct inode *inode)
{
LASSERT(inode);
if (!find_cbdata(inode))
- inode->i_nlink = 0;
+ clear_nlink(inode);
iput(inode);
}
diff --git a/lustre/llite/file.c b/lustre/llite/file.c
index bf9ba2f..8840295 100644
--- a/lustre/llite/file.c
+++ b/lustre/llite/file.c
@@ -2315,7 +2315,7 @@ ldlm_mode_t ll_take_md_lock(struct inode *inode, __u64 bits,
static int ll_inode_revalidate_fini(struct inode *inode, int rc) {
if (rc == -ENOENT) { /* Already unlinked. Just update nlink
* and return success */
- inode->i_nlink = 0;
+ clear_nlink(inode);
/* This path cannot be hit for regular files unless in
* case of obscure races, so no need to to validate
* size. */
diff --git a/lustre/llite/llite_lib.c b/lustre/llite/llite_lib.c
index 7f3ac28..07efcfc 100644
--- a/lustre/llite/llite_lib.c
+++ b/lustre/llite/llite_lib.c
@@ -1218,7 +1218,7 @@ int ll_md_setattr(struct dentry *dentry, struct md_op_data *op_data,
if (rc) {
ptlrpc_req_finished(request);
if (rc == -ENOENT) {
- inode->i_nlink = 0;
+ clear_nlink(inode);
/* Unlinked special device node? Or just a race?
* Pretend we done everything. */
if (!S_ISREG(inode->i_mode) &&
@@ -1724,7 +1724,7 @@ void ll_update_inode(struct inode *inode, struct lustre_md *md)
if (body->valid & OBD_MD_FLFLAGS)
inode->i_flags = ll_ext_to_inode_flags(body->flags);
if (body->valid & OBD_MD_FLNLINK)
- inode->i_nlink = body->nlink;
+ set_nlink(inode, body->nlink);
if (body->valid & OBD_MD_FLRDEV)
inode->i_rdev = old_decode_dev(body->rdev);
diff --git a/lustre/osd-ldiskfs/osd_handler.c b/lustre/osd-ldiskfs/osd_handler.c
index 1c37bd9..ec9dfb6 100644
--- a/lustre/osd-ldiskfs/osd_handler.c
+++ b/lustre/osd-ldiskfs/osd_handler.c
@@ -1518,7 +1518,7 @@ static int osd_inode_setattr(const struct lu_env *env,
if (bits & LA_GID)
inode->i_gid = attr->la_gid;
if (bits & LA_NLINK)
- inode->i_nlink = attr->la_nlink;
+ set_nlink(inode, attr->la_nlink);
if (bits & LA_RDEV)
inode->i_rdev = attr->la_rdev;
@@ -2076,7 +2076,7 @@ static int osd_object_destroy(const struct lu_env *env,
LASSERT(osd_inode_unlinked(inode) ||
inode->i_nlink == 1);
cfs_spin_lock(&obj->oo_guard);
- inode->i_nlink = 0;
+ clear_nlink(inode);
cfs_spin_unlock(&obj->oo_guard);
inode->i_sb->s_op->dirty_inode(inode);
} else {
@@ -2283,11 +2283,11 @@ static int osd_object_ref_add(const struct lu_env *env,
* do not actually care whether this flag is set or not.
*/
cfs_spin_lock(&obj->oo_guard);
- inode->i_nlink++;
+ inc_nlink(inode);
if (S_ISDIR(inode->i_mode) && inode->i_nlink > 1) {
if (inode->i_nlink >= LDISKFS_LINK_MAX ||
inode->i_nlink == 2)
- inode->i_nlink = 1;
+ set_nlink(inode, 1);
}
LASSERT(inode->i_nlink <= LDISKFS_LINK_MAX);
cfs_spin_unlock(&obj->oo_guard);
@@ -2333,12 +2333,12 @@ static int osd_object_ref_del(const struct lu_env *env, struct dt_object *dt,
cfs_spin_lock(&obj->oo_guard);
LASSERT(inode->i_nlink > 0);
- inode->i_nlink--;
+ drop_nlink(inode);
/* If this is/was a many-subdir directory (nlink > LDISKFS_LINK_MAX)
* then the nlink count is 1. Don't let it be set to 0 or the directory
* inode will be deleted incorrectly. */
if (S_ISDIR(inode->i_mode) && inode->i_nlink == 0)
- inode->i_nlink++;
+ inc_nlink(inode);
cfs_spin_unlock(&obj->oo_guard);
inode->i_sb->s_op->dirty_inode(inode);
LINVRNT(osd_invariant(obj));
--
1.7.12
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