From 796a6b521d0eadb338adf8cf7e482351c3a8a7b4 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 16 Jan 2010 13:28:47 -0500 Subject: [PATCH] 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 --- fs/namespace.c | 2 +- fs/pnode.c | 28 +++++++++++++++++----------- fs/pnode.h | 3 +-- 3 files changed, 19 insertions(+), 14 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index c768f733c8d6..25c1dcf9e9eb 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -573,7 +573,7 @@ static struct vfsmount *clone_mnt(struct vfsmount *old, struct dentry *root, mnt->mnt_master = old; CLEAR_MNT_SHARED(mnt); } 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); if (IS_MNT_SLAVE(old)) list_add(&mnt->mnt_slave, &old->mnt_slave); diff --git a/fs/pnode.c b/fs/pnode.c index 8d5f392ec3d3..5cc564a83149 100644 --- a/fs/pnode.c +++ b/fs/pnode.c @@ -86,7 +86,7 @@ static int do_make_slave(struct vfsmount *mnt) /* * 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. */ 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. * @m: the mount seen last * @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, 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_dest = NULL; - *type = CL_PROPAGATION; - - if (IS_MNT_SHARED(dest)) - *type |= CL_MAKE_SHARED; while (last_dest != dest->mnt_master) { p_last_dest = last_dest; @@ -202,13 +203,18 @@ static struct vfsmount *get_source(struct vfsmount *dest, do { p_last_dest = next_peer(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; + } } - - if (dest != p_last_dest) { - *type |= CL_SLAVE; - return last_src; - } else - return p_last_src; + /* slave of the earlier, then */ + *type = CL_SLAVE; + /* beginning of peer group among the slaves? */ + if (IS_MNT_SHARED(dest)) + *type |= CL_MAKE_SHARED; + return last_src; } /* diff --git a/fs/pnode.h b/fs/pnode.h index 958665d662af..6c7ef3252a26 100644 --- a/fs/pnode.h +++ b/fs/pnode.h @@ -21,8 +21,7 @@ #define CL_SLAVE 0x02 #define CL_COPY_ALL 0x04 #define CL_MAKE_SHARED 0x08 -#define CL_PROPAGATION 0x10 -#define CL_PRIVATE 0x20 +#define CL_PRIVATE 0x10 static inline void set_mnt_shared(struct vfsmount *mnt) { -- 2.20.1