diff options
| -rw-r--r-- | fs/mount.h | 4 | ||||
| -rw-r--r-- | fs/namespace.c | 38 | ||||
| -rw-r--r-- | fs/super.c | 3 | ||||
| -rw-r--r-- | include/linux/fs.h | 4 |
4 files changed, 36 insertions, 13 deletions
diff --git a/fs/mount.h b/fs/mount.h index 04d0eadc4c10..b208f69f69d7 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -64,7 +64,9 @@ struct mount { #endif struct list_head mnt_mounts; /* list of children, anchored here */ struct list_head mnt_child; /* and going through their mnt_child */ - struct list_head mnt_instance; /* mount instance on sb->s_mounts */ + struct mount *mnt_next_for_sb; /* the next two fields are hlist_node, */ + struct mount * __aligned(1) *mnt_pprev_for_sb; + /* except that LSB of pprev will be stolen */ const char *mnt_devname; /* Name of device e.g. /dev/dsk/hda1 */ struct list_head mnt_list; struct list_head mnt_expire; /* link in fs-specific expiry list */ diff --git a/fs/namespace.c b/fs/namespace.c index 4e9ed4edd854..342dfd882b13 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -730,6 +730,27 @@ static inline void mnt_unhold_writers(struct mount *mnt) mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD; } +static inline void mnt_del_instance(struct mount *m) +{ + struct mount **p = m->mnt_pprev_for_sb; + struct mount *next = m->mnt_next_for_sb; + + if (next) + next->mnt_pprev_for_sb = p; + *p = next; +} + +static inline void mnt_add_instance(struct mount *m, struct super_block *s) +{ + struct mount *first = s->s_mounts; + + if (first) + first->mnt_pprev_for_sb = &m->mnt_next_for_sb; + m->mnt_next_for_sb = first; + m->mnt_pprev_for_sb = &s->s_mounts; + s->s_mounts = m; +} + static int mnt_make_readonly(struct mount *mnt) { int ret; @@ -743,7 +764,6 @@ static int mnt_make_readonly(struct mount *mnt) int sb_prepare_remount_readonly(struct super_block *sb) { - struct mount *mnt; int err = 0; /* Racy optimization. Recheck the counter under MNT_WRITE_HOLD */ @@ -751,9 +771,9 @@ int sb_prepare_remount_readonly(struct super_block *sb) return -EBUSY; lock_mount_hash(); - list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) { - if (!(mnt->mnt.mnt_flags & MNT_READONLY)) { - err = mnt_hold_writers(mnt); + for (struct mount *m = sb->s_mounts; m; m = m->mnt_next_for_sb) { + if (!(m->mnt.mnt_flags & MNT_READONLY)) { + err = mnt_hold_writers(m); if (err) break; } @@ -763,9 +783,9 @@ int sb_prepare_remount_readonly(struct super_block *sb) if (!err) sb_start_ro_state_change(sb); - list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) { - if (mnt->mnt.mnt_flags & MNT_WRITE_HOLD) - mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD; + for (struct mount *m = sb->s_mounts; m; m = m->mnt_next_for_sb) { + if (m->mnt.mnt_flags & MNT_WRITE_HOLD) + m->mnt.mnt_flags &= ~MNT_WRITE_HOLD; } unlock_mount_hash(); @@ -1207,7 +1227,7 @@ static void setup_mnt(struct mount *m, struct dentry *root) m->mnt_parent = m; lock_mount_hash(); - list_add_tail(&m->mnt_instance, &s->s_mounts); + mnt_add_instance(m, s); unlock_mount_hash(); } @@ -1425,7 +1445,7 @@ static void mntput_no_expire(struct mount *mnt) mnt->mnt.mnt_flags |= MNT_DOOMED; rcu_read_unlock(); - list_del(&mnt->mnt_instance); + mnt_del_instance(mnt); if (unlikely(!list_empty(&mnt->mnt_expire))) list_del(&mnt->mnt_expire); diff --git a/fs/super.c b/fs/super.c index 7f876f32343a..3b0f49e1b817 100644 --- a/fs/super.c +++ b/fs/super.c @@ -323,7 +323,6 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags, if (!s) return NULL; - INIT_LIST_HEAD(&s->s_mounts); s->s_user_ns = get_user_ns(user_ns); init_rwsem(&s->s_umount); lockdep_set_class(&s->s_umount, &type->s_umount_key); @@ -408,7 +407,7 @@ static void __put_super(struct super_block *s) list_del_init(&s->s_list); WARN_ON(s->s_dentry_lru.node); WARN_ON(s->s_inode_lru.node); - WARN_ON(!list_empty(&s->s_mounts)); + WARN_ON(s->s_mounts); call_rcu(&s->rcu, destroy_super_rcu); } } diff --git a/include/linux/fs.h b/include/linux/fs.h index d7ab4f96d705..0e9c7f1460dc 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1324,6 +1324,8 @@ struct sb_writers { struct percpu_rw_semaphore rw_sem[SB_FREEZE_LEVELS]; }; +struct mount; + struct super_block { struct list_head s_list; /* Keep this first */ dev_t s_dev; /* search index; _not_ kdev_t */ @@ -1358,7 +1360,7 @@ struct super_block { __u16 s_encoding_flags; #endif struct hlist_bl_head s_roots; /* alternate root dentries for NFS */ - struct list_head s_mounts; /* list of mounts; _not_ for fs use */ + struct mount *s_mounts; /* list of mounts; _not_ for fs use */ struct block_device *s_bdev; /* can go away once we use an accessor for @s_bdev_file */ struct file *s_bdev_file; struct backing_dev_info *s_bdi; |