[RFC][PATCH 2/5] introduce simple_set_mnt_no_get() helper for NFS

From: Dave Hansen
Date: Tue Apr 29 2008 - 15:01:52 EST



The next patch will introduce a list of all mounts for a given
superblock. In order to keep the list, we need to make sure
all filesystems attaching a mount to a superblock get added
to this list.

NFS currently bypasses the simple_set_mnt() function, and sets
mnt_sb directly. This patch makes it use a helper function,
instead.

Signed-off-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
---

linux-2.6.git-dave/fs/namespace.c | 11 +++++++++--
linux-2.6.git-dave/fs/nfs/super.c | 10 +++++-----
linux-2.6.git-dave/include/linux/fs.h | 1 +
3 files changed, 15 insertions(+), 7 deletions(-)

diff -puN fs/namespace.c~introduce_simple_set_mnt_no_get_helper_for_NFS fs/namespace.c
--- linux-2.6.git/fs/namespace.c~introduce_simple_set_mnt_no_get_helper_for_NFS 2008-04-29 11:56:39.000000000 -0700
+++ linux-2.6.git-dave/fs/namespace.c 2008-04-29 11:56:39.000000000 -0700
@@ -402,12 +402,19 @@ static void __mnt_unmake_readonly(struct
spin_unlock(&vfsmount_lock);
}

-int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
+int simple_set_mnt_no_get(struct vfsmount *mnt, struct super_block *sb)
{
mnt->mnt_sb = sb;
- mnt->mnt_root = dget(sb->s_root);
+ add_mount_to_sb_list(mnt, sb);
return 0;
}
+EXPORT_SYMBOL(simple_set_mnt_no_get);
+
+int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
+{
+ mnt->mnt_root = dget(sb->s_root);
+ return simple_set_mnt_no_get(mnt, sb);
+}

EXPORT_SYMBOL(simple_set_mnt);

diff -puN fs/nfs/super.c~introduce_simple_set_mnt_no_get_helper_for_NFS fs/nfs/super.c
--- linux-2.6.git/fs/nfs/super.c~introduce_simple_set_mnt_no_get_helper_for_NFS 2008-04-29 11:56:39.000000000 -0700
+++ linux-2.6.git-dave/fs/nfs/super.c 2008-04-29 11:56:39.000000000 -0700
@@ -1635,7 +1635,7 @@ static int nfs_get_sb(struct file_system
goto error_splat_root;

s->s_flags |= MS_ACTIVE;
- mnt->mnt_sb = s;
+ simple_set_mnt_no_get(mnt, s);
mnt->mnt_root = mntroot;
error = 0;

@@ -1727,7 +1727,7 @@ static int nfs_xdev_get_sb(struct file_s
}

s->s_flags |= MS_ACTIVE;
- mnt->mnt_sb = s;
+ simple_set_mnt_no_get(mnt, s);
mnt->mnt_root = mntroot;

/* clone any lsm security options from the parent to the new sb */
@@ -1998,7 +1998,7 @@ static int nfs4_get_sb(struct file_syste
}

s->s_flags |= MS_ACTIVE;
- mnt->mnt_sb = s;
+ simple_set_mnt_no_get(mnt, s);
mnt->mnt_root = mntroot;
error = 0;

@@ -2089,7 +2089,7 @@ static int nfs4_xdev_get_sb(struct file_
}

s->s_flags |= MS_ACTIVE;
- mnt->mnt_sb = s;
+ simple_set_mnt_no_get(mnt, s);
mnt->mnt_root = mntroot;

dprintk("<-- nfs4_xdev_get_sb() = 0\n");
@@ -2168,7 +2168,7 @@ static int nfs4_referral_get_sb(struct f
}

s->s_flags |= MS_ACTIVE;
- mnt->mnt_sb = s;
+ simple_set_mnt_no_get(mnt, s);
mnt->mnt_root = mntroot;

dprintk("<-- nfs4_referral_get_sb() = 0\n");
diff -puN include/linux/fs.h~introduce_simple_set_mnt_no_get_helper_for_NFS include/linux/fs.h
--- linux-2.6.git/include/linux/fs.h~introduce_simple_set_mnt_no_get_helper_for_NFS 2008-04-29 11:56:39.000000000 -0700
+++ linux-2.6.git-dave/include/linux/fs.h 2008-04-29 11:56:39.000000000 -0700
@@ -1521,6 +1521,7 @@ extern int get_sb_pseudo(struct file_sys
const struct super_operations *ops, unsigned long,
struct vfsmount *mnt);
extern int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb);
+extern int simple_set_mnt_no_get(struct vfsmount *mnt, struct super_block *sb);
int __put_super(struct super_block *sb);
int __put_super_and_need_restart(struct super_block *sb);
void unnamed_dev_init(void);
_
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