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OpenCloudOS-Kernel
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Kill CL_PROPAGATION, sanitize fs/pnode.c:get_source() 

First of all, get_source() never results in CL_PROPAGATION
alone.  We either get CL_MAKE_SHARED (for the continuation
of peer group) or CL_SLAVE (slave that is not shared) or both
(beginning of peer group among slaves).  Massage the code to
make that explicit, kill CL_PROPAGATION test in clone_mnt()
(nothing sets CL_MAKE_SHARED without CL_PROPAGATION and in
clone_mnt() we are checking CL_PROPAGATION after we'd found
that there's no CL_SLAVE, so the check for CL_MAKE_SHARED
would do just as well).

Fix comments, while we are at it...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2010-01-16 13:28:47 -05:00
parent c177c2ac8c
commit 796a6b521d
3 changed files with 19 additions and 14 deletions
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2
fs/namespace.c
View File

@ -573,7 +573,7 @@ static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root,
mnt->mnt_master = old; mnt->mnt_master = old;
CLEAR_MNT_SHARED(mnt); CLEAR_MNT_SHARED(mnt);
} else if (!(flag & CL_PRIVATE)) { } else if (!(flag & CL_PRIVATE)) {
if ((flag & CL_PROPAGATION) || IS_MNT_SHARED(old)) if ((flag & CL_MAKE_SHARED) || IS_MNT_SHARED(old))
list_add(&mnt->mnt_share, &old->mnt_share); list_add(&mnt->mnt_share, &old->mnt_share);
if (IS_MNT_SLAVE(old)) if (IS_MNT_SLAVE(old))
list_add(&mnt->mnt_slave, &old->mnt_slave); list_add(&mnt->mnt_slave, &old->mnt_slave);

28
fs/pnode.c
View File

@ -86,7 +86,7 @@ static int do_make_slave(struct vfsmount *mnt)
/* /*
* slave 'mnt' to a peer mount that has the * slave 'mnt' to a peer mount that has the
* same root dentry. If none is available than * same root dentry. If none is available then
* slave it to anything that is available. * slave it to anything that is available.
*/ */
while ((peer_mnt = next_peer(peer_mnt)) != mnt && while ((peer_mnt = next_peer(peer_mnt)) != mnt &&
@ -147,6 +147,11 @@ void change_mnt_propagation(struct vfsmount *mnt, int type)
* get the next mount in the propagation tree. * get the next mount in the propagation tree.
* @m: the mount seen last * @m: the mount seen last
* @origin: the original mount from where the tree walk initiated * @origin: the original mount from where the tree walk initiated
*
* Note that peer groups form contiguous segments of slave lists.
* We rely on that in get_source() to be able to find out if
* vfsmount found while iterating with propagation_next() is
* a peer of one we'd found earlier.
*/ */
static struct vfsmount *propagation_next(struct vfsmount *m, static struct vfsmount *propagation_next(struct vfsmount *m,
struct vfsmount *origin) struct vfsmount *origin)
@ -186,10 +191,6 @@ static struct vfsmount *get_source(struct vfsmount *dest,
{ {
struct vfsmount *p_last_src = NULL; struct vfsmount *p_last_src = NULL;
struct vfsmount *p_last_dest = NULL; struct vfsmount *p_last_dest = NULL;
*type = CL_PROPAGATION;
if (IS_MNT_SHARED(dest))
*type |= CL_MAKE_SHARED;
while (last_dest != dest->mnt_master) { while (last_dest != dest->mnt_master) {
p_last_dest = last_dest; p_last_dest = last_dest;
@ -202,13 +203,18 @@ static struct vfsmount *get_source(struct vfsmount *dest,
do { do {
p_last_dest = next_peer(p_last_dest); p_last_dest = next_peer(p_last_dest);
} while (IS_MNT_NEW(p_last_dest)); } while (IS_MNT_NEW(p_last_dest));
/* is that a peer of the earlier? */
if (dest == p_last_dest) {
*type = CL_MAKE_SHARED;
return p_last_src;
}
} }
/* slave of the earlier, then */
if (dest != p_last_dest) { *type = CL_SLAVE;
*type |= CL_SLAVE; /* beginning of peer group among the slaves? */
return last_src; if (IS_MNT_SHARED(dest))
} else *type |= CL_MAKE_SHARED;
return p_last_src; return last_src;
} }
/* /*

3
fs/pnode.h
View File

@ -21,8 +21,7 @@
#define CL_SLAVE 0x02 #define CL_SLAVE 0x02
#define CL_COPY_ALL 0x04 #define CL_COPY_ALL 0x04
#define CL_MAKE_SHARED 0x08 #define CL_MAKE_SHARED 0x08
#define CL_PROPAGATION 0x10 #define CL_PRIVATE 0x10
#define CL_PRIVATE 0x20
static inline void set_mnt_shared(struct vfsmount *mnt) static inline void set_mnt_shared(struct vfsmount *mnt)
{ {