diff options
| -rw-r--r-- | fs/mount.h | 13 | ||||
| -rw-r--r-- | fs/namespace.c | 17 | ||||
| -rw-r--r-- | tools/testing/selftests/filesystems/statmount/Makefile | 2 | ||||
| -rw-r--r-- | tools/testing/selftests/filesystems/statmount/listmount_test.c | 66 |
4 files changed, 91 insertions, 7 deletions
diff --git a/fs/mount.h b/fs/mount.h index e9f48e563c0f..ffb613cdfeee 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -8,7 +8,11 @@ struct mnt_namespace { struct ns_common ns; struct mount * root; - struct rb_root mounts; /* Protected by namespace_sem */ + struct { + struct rb_root mounts; /* Protected by namespace_sem */ + struct rb_node *mnt_last_node; /* last (rightmost) mount in the rbtree */ + struct rb_node *mnt_first_node; /* first (leftmost) mount in the rbtree */ + }; struct user_namespace *user_ns; struct ucounts *ucounts; u64 seq; /* Sequence number to prevent loops */ @@ -154,8 +158,13 @@ static inline bool mnt_ns_attached(const struct mount *mnt) static inline void move_from_ns(struct mount *mnt, struct list_head *dt_list) { + struct mnt_namespace *ns = mnt->mnt_ns; WARN_ON(!mnt_ns_attached(mnt)); - rb_erase(&mnt->mnt_node, &mnt->mnt_ns->mounts); + if (ns->mnt_last_node == &mnt->mnt_node) + ns->mnt_last_node = rb_prev(&mnt->mnt_node); + if (ns->mnt_first_node == &mnt->mnt_node) + ns->mnt_first_node = rb_next(&mnt->mnt_node); + rb_erase(&mnt->mnt_node, &ns->mounts); RB_CLEAR_NODE(&mnt->mnt_node); list_add_tail(&mnt->mnt_list, dt_list); } diff --git a/fs/namespace.c b/fs/namespace.c index a382be402f62..5336e5f09996 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1155,16 +1155,25 @@ static void mnt_add_to_ns(struct mnt_namespace *ns, struct mount *mnt) { struct rb_node **link = &ns->mounts.rb_node; struct rb_node *parent = NULL; + bool mnt_first_node = true, mnt_last_node = true; WARN_ON(mnt_ns_attached(mnt)); mnt->mnt_ns = ns; while (*link) { parent = *link; - if (mnt->mnt_id_unique < node_to_mount(parent)->mnt_id_unique) + if (mnt->mnt_id_unique < node_to_mount(parent)->mnt_id_unique) { link = &parent->rb_left; - else + mnt_last_node = false; + } else { link = &parent->rb_right; + mnt_first_node = false; + } } + + if (mnt_last_node) + ns->mnt_last_node = &mnt->mnt_node; + if (mnt_first_node) + ns->mnt_first_node = &mnt->mnt_node; rb_link_node(&mnt->mnt_node, parent, link); rb_insert_color(&mnt->mnt_node, &ns->mounts); } @@ -5563,9 +5572,9 @@ static ssize_t do_listmount(struct mnt_namespace *ns, u64 mnt_parent_id, if (!last_mnt_id) { if (reverse) - first = node_to_mount(rb_last(&ns->mounts)); + first = node_to_mount(ns->mnt_last_node); else - first = node_to_mount(rb_first(&ns->mounts)); + first = node_to_mount(ns->mnt_first_node); } else { if (reverse) first = mnt_find_id_at_reverse(ns, last_mnt_id - 1); diff --git a/tools/testing/selftests/filesystems/statmount/Makefile b/tools/testing/selftests/filesystems/statmount/Makefile index 3af3136e35a4..14ee91a41650 100644 --- a/tools/testing/selftests/filesystems/statmount/Makefile +++ b/tools/testing/selftests/filesystems/statmount/Makefile @@ -1,6 +1,6 @@ # SPDX-License-Identifier: GPL-2.0-or-later CFLAGS += -Wall -O2 -g $(KHDR_INCLUDES) -TEST_GEN_PROGS := statmount_test statmount_test_ns +TEST_GEN_PROGS := statmount_test statmount_test_ns listmount_test include ../../lib.mk diff --git a/tools/testing/selftests/filesystems/statmount/listmount_test.c b/tools/testing/selftests/filesystems/statmount/listmount_test.c new file mode 100644 index 000000000000..15f0834f7557 --- /dev/null +++ b/tools/testing/selftests/filesystems/statmount/listmount_test.c @@ -0,0 +1,66 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +// Copyright (c) 2024 Christian Brauner <brauner@kernel.org> + +#define _GNU_SOURCE +#include <fcntl.h> +#include <sched.h> +#include <stdio.h> +#include <string.h> +#include <sys/stat.h> +#include <sys/mount.h> +#include <unistd.h> + +#include "statmount.h" +#include "../../kselftest_harness.h" + +#ifndef LISTMOUNT_REVERSE +#define LISTMOUNT_REVERSE (1 << 0) /* List later mounts first */ +#endif + +#define LISTMNT_BUFFER 10 + +/* Check that all mount ids are in increasing order. */ +TEST(listmount_forward) +{ + uint64_t list[LISTMNT_BUFFER], last_mnt_id = 0; + + for (;;) { + ssize_t nr_mounts; + + nr_mounts = listmount(LSMT_ROOT, 0, last_mnt_id, + list, LISTMNT_BUFFER, 0); + ASSERT_GE(nr_mounts, 0); + if (nr_mounts == 0) + break; + + for (size_t cur = 0; cur < nr_mounts; cur++) { + if (cur < nr_mounts - 1) + ASSERT_LT(list[cur], list[cur + 1]); + last_mnt_id = list[cur]; + } + } +} + +/* Check that all mount ids are in decreasing order. */ +TEST(listmount_backward) +{ + uint64_t list[LISTMNT_BUFFER], last_mnt_id = 0; + + for (;;) { + ssize_t nr_mounts; + + nr_mounts = listmount(LSMT_ROOT, 0, last_mnt_id, + list, LISTMNT_BUFFER, LISTMOUNT_REVERSE); + ASSERT_GE(nr_mounts, 0); + if (nr_mounts == 0) + break; + + for (size_t cur = 0; cur < nr_mounts; cur++) { + if (cur < nr_mounts - 1) + ASSERT_GT(list[cur], list[cur + 1]); + last_mnt_id = list[cur]; + } + } +} + +TEST_HARNESS_MAIN |