diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 96 |
1 files changed, 74 insertions, 22 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 5be02a0635be..4aad64ad9ad0 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -577,6 +577,7 @@ int sb_prepare_remount_readonly(struct super_block *sb) static void free_vfsmnt(struct mount *mnt) { + kfree(mnt->mnt.data); kfree_const(mnt->mnt_devname); #ifdef CONFIG_SMP free_percpu(mnt->mnt_pcp); @@ -743,26 +744,50 @@ static struct mountpoint *lookup_mountpoint(struct dentry *dentry) return NULL; } -static struct mountpoint *new_mountpoint(struct dentry *dentry) +static struct mountpoint *get_mountpoint(struct dentry *dentry) { - struct hlist_head *chain = mp_hash(dentry); - struct mountpoint *mp; + struct mountpoint *mp, *new = NULL; int ret; - mp = kmalloc(sizeof(struct mountpoint), GFP_KERNEL); - if (!mp) + if (d_mountpoint(dentry)) { +mountpoint: + read_seqlock_excl(&mount_lock); + mp = lookup_mountpoint(dentry); + read_sequnlock_excl(&mount_lock); + if (mp) + goto done; + } + + if (!new) + new = kmalloc(sizeof(struct mountpoint), GFP_KERNEL); + if (!new) return ERR_PTR(-ENOMEM); + + /* Exactly one processes may set d_mounted */ ret = d_set_mounted(dentry); - if (ret) { - kfree(mp); - return ERR_PTR(ret); - } - mp->m_dentry = dentry; - mp->m_count = 1; - hlist_add_head(&mp->m_hash, chain); - INIT_HLIST_HEAD(&mp->m_list); + /* Someone else set d_mounted? */ + if (ret == -EBUSY) + goto mountpoint; + + /* The dentry is not available as a mountpoint? */ + mp = ERR_PTR(ret); + if (ret) + goto done; + + /* Add the new mountpoint to the hash table */ + read_seqlock_excl(&mount_lock); + new->m_dentry = dentry; + new->m_count = 1; + hlist_add_head(&new->m_hash, mp_hash(dentry)); + INIT_HLIST_HEAD(&new->m_list); + read_sequnlock_excl(&mount_lock); + + mp = new; + new = NULL; +done: + kfree(new); return mp; } @@ -942,11 +967,21 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void if (!mnt) return ERR_PTR(-ENOMEM); + mnt->mnt.data = NULL; + if (type->alloc_mnt_data) { + mnt->mnt.data = type->alloc_mnt_data(); + if (!mnt->mnt.data) { + mnt_free_id(mnt); + free_vfsmnt(mnt); + return ERR_PTR(-ENOMEM); + } + } if (flags & MS_KERNMOUNT) mnt->mnt.mnt_flags = MNT_INTERNAL; - root = mount_fs(type, flags, name, data); + root = mount_fs(type, flags, name, &mnt->mnt, data); if (IS_ERR(root)) { + kfree(mnt->mnt.data); mnt_free_id(mnt); free_vfsmnt(mnt); return ERR_CAST(root); @@ -974,6 +1009,14 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root, if (!mnt) return ERR_PTR(-ENOMEM); + if (sb->s_op->clone_mnt_data) { + mnt->mnt.data = sb->s_op->clone_mnt_data(old->mnt.data); + if (!mnt->mnt.data) { + err = -ENOMEM; + goto out_free; + } + } + if (flag & (CL_SLAVE | CL_PRIVATE | CL_SHARED_TO_SLAVE)) mnt->mnt_group_id = 0; /* not a peer of original */ else @@ -1042,6 +1085,7 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root, return mnt; out_free: + kfree(mnt->mnt.data); mnt_free_id(mnt); free_vfsmnt(mnt); return ERR_PTR(err); @@ -1557,11 +1601,11 @@ void __detach_mounts(struct dentry *dentry) struct mount *mnt; namespace_lock(); + lock_mount_hash(); mp = lookup_mountpoint(dentry); if (IS_ERR_OR_NULL(mp)) goto out_unlock; - lock_mount_hash(); event++; while (!hlist_empty(&mp->m_list)) { mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list); @@ -1571,9 +1615,9 @@ void __detach_mounts(struct dentry *dentry) } else umount_tree(mnt, UMOUNT_CONNECTED); } - unlock_mount_hash(); put_mountpoint(mp); out_unlock: + unlock_mount_hash(); namespace_unlock(); } @@ -1962,9 +2006,7 @@ retry: namespace_lock(); mnt = lookup_mnt(path); if (likely(!mnt)) { - struct mountpoint *mp = lookup_mountpoint(dentry); - if (!mp) - mp = new_mountpoint(dentry); + struct mountpoint *mp = get_mountpoint(dentry); if (IS_ERR(mp)) { namespace_unlock(); mutex_unlock(&dentry->d_inode->i_mutex); @@ -1983,7 +2025,11 @@ retry: static void unlock_mount(struct mountpoint *where) { struct dentry *dentry = where->m_dentry; + + read_seqlock_excl(&mount_lock); put_mountpoint(where); + read_sequnlock_excl(&mount_lock); + namespace_unlock(); mutex_unlock(&dentry->d_inode->i_mutex); } @@ -2208,8 +2254,14 @@ static int do_remount(struct path *path, int flags, int mnt_flags, err = change_mount_flags(path->mnt, flags); else if (!capable(CAP_SYS_ADMIN)) err = -EPERM; - else - err = do_remount_sb(sb, flags, data, 0); + else { + err = do_remount_sb2(path->mnt, sb, flags, data, 0); + namespace_lock(); + lock_mount_hash(); + propagate_remount(mnt); + unlock_mount_hash(); + namespace_unlock(); + } if (!err) { lock_mount_hash(); mnt_flags |= mnt->mnt.mnt_flags & ~MNT_USER_SETTABLE_MASK; @@ -3055,9 +3107,9 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, touch_mnt_namespace(current->nsproxy->mnt_ns); /* A moved mount should not expire automatically */ list_del_init(&new_mnt->mnt_expire); + put_mountpoint(root_mp); unlock_mount_hash(); chroot_fs_refs(&root, &new); - put_mountpoint(root_mp); error = 0; out4: unlock_mount(old_mp); |