diff options
| -rw-r--r-- | fs/dcache.c | 60 | ||||
| -rw-r--r-- | fs/namei.c | 12 |
2 files changed, 39 insertions, 33 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index 8150e4e..484114a 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1343,36 +1343,39 @@ void shrink_dcache_for_umount(struct super_block *sb) } } -static enum d_walk_ret check_and_collect(void *_data, struct dentry *dentry) +struct detach_data { + struct select_data select; + struct dentry *mountpoint; +}; +static enum d_walk_ret detach_and_collect(void *_data, struct dentry *dentry) { - struct select_data *data = _data; + struct detach_data *data = _data; if (d_mountpoint(dentry)) { - data->found = -EBUSY; + __dget_dlock(dentry); + data->mountpoint = dentry; return D_WALK_QUIT; } - return select_collect(_data, dentry); + return select_collect(&data->select, dentry); } static void check_and_drop(void *_data) { - struct select_data *data = _data; + struct detach_data *data = _data; - if (d_mountpoint(data->start)) - data->found = -EBUSY; - if (!data->found) - __d_drop(data->start); + if (!data->mountpoint && !data->select.found) + __d_drop(data->select.start); } /** - * check_submounts_and_drop - prune dcache, check for submounts and drop + * check_submounts_and_drop - detach submounts, prune dcache, and drop * - * All done as a single atomic operation relative to has_unlinked_ancestor(). - * Returns 0 if successfully unhashed @parent. If there were submounts then - * return -EBUSY. + * The final d_drop is done as an atomic operation relative to + * rename_lock ensuring there are no races with d_set_mounted. This + * ensures there are no unhashed dentries on the path to a mountpoint. * - * @dentry: dentry to prune and drop + * @dentry: dentry to detach, prune and drop */ int check_submounts_and_drop(struct dentry *dentry) { @@ -1385,19 +1388,24 @@ int check_submounts_and_drop(struct dentry *dentry) } for (;;) { - struct select_data data; + struct detach_data data; - INIT_LIST_HEAD(&data.dispose); - data.start = dentry; - data.found = 0; + data.mountpoint = NULL; + INIT_LIST_HEAD(&data.select.dispose); + data.select.start = dentry; + data.select.found = 0; + + d_walk(dentry, &data, detach_and_collect, check_and_drop); - d_walk(dentry, &data, check_and_collect, check_and_drop); - ret = data.found; + if (data.select.found) + shrink_dentry_list(&data.select.dispose); - if (!list_empty(&data.dispose)) - shrink_dentry_list(&data.dispose); + if (data.mountpoint) { + detach_mounts(data.mountpoint); + dput(data.mountpoint); + } - if (ret <= 0) + if (!data.mountpoint && !data.select.found) break; cond_resched(); @@ -2639,10 +2647,8 @@ static struct dentry *__d_unalias(struct inode *inode, goto out_err; m2 = &alias->d_parent->d_inode->i_mutex; out_unalias: - if (likely(!d_mountpoint(alias))) { - __d_move(alias, dentry, false); - ret = alias; - } + __d_move(alias, dentry, false); + ret = alias; out_err: spin_unlock(&inode->i_lock); if (m2) @@ -3567,8 +3567,6 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry) error = -EBUSY; if (is_local_mountpoint(dentry)) goto out; - if (d_mountpoint(dentry)) - goto out; error = security_inode_rmdir(dir, dentry); if (error) @@ -3581,6 +3579,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry) dentry->d_inode->i_flags |= S_DEAD; dont_mount(dentry); + detach_mounts(dentry); out: mutex_unlock(&dentry->d_inode->i_mutex); @@ -3683,7 +3682,7 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegate return -EPERM; mutex_lock(&target->i_mutex); - if (is_local_mountpoint(dentry) || d_mountpoint(dentry)) + if (is_local_mountpoint(dentry)) error = -EBUSY; else { error = security_inode_unlink(dir, dentry); @@ -3692,8 +3691,10 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegate if (error) goto out; error = dir->i_op->unlink(dir, dentry); - if (!error) + if (!error) { dont_mount(dentry); + detach_mounts(dentry); + } } } out: @@ -4130,8 +4131,6 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, error = -EBUSY; if (is_local_mountpoint(old_dentry) || is_local_mountpoint(new_dentry)) goto out; - if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry)) - goto out; if (max_links && new_dir != old_dir) { error = -EMLINK; @@ -4168,6 +4167,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (is_dir) target->i_flags |= S_DEAD; dont_mount(new_dentry); + detach_mounts(new_dentry); } if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) { if (!(flags & RENAME_EXCHANGE)) |
