diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c index 2f7951d67d16..cc1d01365905 100644 --- a/fs/autofs4/expire.c +++ b/fs/autofs4/expire.c @@ -295,7 +295,9 @@ struct dentry *autofs4_expire_direct(struct super_block *sb, struct autofs_info *ino = autofs4_dentry_ino(root); if (d_mountpoint(root)) { ino->flags |= AUTOFS_INF_MOUNTPOINT; - root->d_mounted--; + spin_lock(&root->d_lock); + root->d_flags &= ~DCACHE_MOUNTED; + spin_unlock(&root->d_lock); } ino->flags |= AUTOFS_INF_EXPIRING; init_completion(&ino->expire_complete); @@ -503,7 +505,14 @@ int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt, spin_lock(&sbi->fs_lock); if (ino->flags & AUTOFS_INF_MOUNTPOINT) { - sb->s_root->d_mounted++; + spin_lock(&sb->s_root->d_lock); + /* + * If we haven't been expired away, then reset + * mounted status. + */ + if (mnt->mnt_parent != mnt) + sb->s_root->d_flags |= DCACHE_MOUNTED; + spin_unlock(&sb->s_root->d_lock); ino->flags &= ~AUTOFS_INF_MOUNTPOINT; } ino->flags &= ~AUTOFS_INF_EXPIRING; diff --git a/fs/dcache.c b/fs/dcache.c index 187fea040108..1d5cf511e1c7 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1265,7 +1265,6 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) dentry->d_sb = NULL; dentry->d_op = NULL; dentry->d_fsdata = NULL; - dentry->d_mounted = 0; INIT_HLIST_NODE(&dentry->d_hash); INIT_LIST_HEAD(&dentry->d_lru); INIT_LIST_HEAD(&dentry->d_subdirs); diff --git a/fs/namespace.c b/fs/namespace.c index 3dbfc072ec70..39a7d507fba0 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -491,6 +491,27 @@ static void __touch_mnt_namespace(struct mnt_namespace *ns) } } +/* + * Clear dentry's mounted state if it has no remaining mounts. + * vfsmount_lock must be held for write. + */ +static void dentry_reset_mounted(struct vfsmount *mnt, struct dentry *dentry) +{ + unsigned u; + + for (u = 0; u < HASH_SIZE; u++) { + struct vfsmount *p; + + list_for_each_entry(p, &mount_hashtable[u], mnt_hash) { + if (p->mnt_mountpoint == dentry) + return; + } + } + spin_lock(&dentry->d_lock); + dentry->d_flags &= ~DCACHE_MOUNTED; + spin_unlock(&dentry->d_lock); +} + /* * vfsmount lock must be held for write */ @@ -502,7 +523,7 @@ static void detach_mnt(struct vfsmount *mnt, struct path *old_path) mnt->mnt_mountpoint = mnt->mnt_root; list_del_init(&mnt->mnt_child); list_del_init(&mnt->mnt_hash); - old_path->dentry->d_mounted--; + dentry_reset_mounted(old_path->mnt, old_path->dentry); } /* @@ -513,7 +534,9 @@ void mnt_set_mountpoint(struct vfsmount *mnt, struct dentry *dentry, { child_mnt->mnt_parent = mntget(mnt); child_mnt->mnt_mountpoint = dget(dentry); - dentry->d_mounted++; + spin_lock(&dentry->d_lock); + dentry->d_flags |= DCACHE_MOUNTED; + spin_unlock(&dentry->d_lock); } /* @@ -1073,7 +1096,7 @@ void umount_tree(struct vfsmount *mnt, int propagate, struct list_head *kill) list_del_init(&p->mnt_child); if (p->mnt_parent != p) { p->mnt_parent->mnt_ghosts++; - p->mnt_mountpoint->d_mounted--; + dentry_reset_mounted(p->mnt_parent, p->mnt_mountpoint); } change_mnt_propagation(p, MS_PRIVATE); } diff --git a/include/linux/dcache.h b/include/linux/dcache.h index c2e7390289cc..e4414693065e 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -92,7 +92,6 @@ struct dentry { unsigned int d_flags; /* protected by d_lock */ spinlock_t d_lock; /* per dentry lock */ seqcount_t d_seq; /* per dentry seqlock */ - int d_mounted; struct inode *d_inode; /* Where the name belongs to - NULL is * negative */ /* @@ -156,33 +155,34 @@ struct dentry_operations { /* d_flags entries */ #define DCACHE_AUTOFS_PENDING 0x0001 /* autofs: "under construction" */ -#define DCACHE_NFSFS_RENAMED 0x0002 /* this dentry has been "silly - * renamed" and has to be - * deleted on the last dput() - */ -#define DCACHE_DISCONNECTED 0x0004 - /* This dentry is possibly not currently connected to the dcache tree, - * in which case its parent will either be itself, or will have this - * flag as well. nfsd will not use a dentry with this bit set, but will - * first endeavour to clear the bit either by discovering that it is - * connected, or by performing lookup operations. Any filesystem which - * supports nfsd_operations MUST have a lookup function which, if it finds - * a directory inode with a DCACHE_DISCONNECTED dentry, will d_move - * that dentry into place and return that dentry rather than the passed one, - * typically using d_splice_alias. - */ +#define DCACHE_NFSFS_RENAMED 0x0002 + /* this dentry has been "silly renamed" and has to be deleted on the last + * dput() */ + +#define DCACHE_DISCONNECTED 0x0004 + /* This dentry is possibly not currently connected to the dcache tree, in + * which case its parent will either be itself, or will have this flag as + * well. nfsd will not use a dentry with this bit set, but will first + * endeavour to clear the bit either by discovering that it is connected, + * or by performing lookup operations. Any filesystem which supports + * nfsd_operations MUST have a lookup function which, if it finds a + * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that + * dentry into place and return that dentry rather than the passed one, + * typically using d_splice_alias. */ #define DCACHE_REFERENCED 0x0008 /* Recently used, don't discard. */ #define DCACHE_UNHASHED 0x0010 - -#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 /* Parent inode is watched by inotify */ +#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 + /* Parent inode is watched by inotify */ #define DCACHE_COOKIE 0x0040 /* For use by dcookie subsystem */ - -#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x0080 /* Parent inode is watched by some fsnotify listener */ +#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x0080 + /* Parent inode is watched by some fsnotify listener */ #define DCACHE_CANT_MOUNT 0x0100 #define DCACHE_GENOCIDE 0x0200 +#define DCACHE_MOUNTED 0x0400 /* is a mountpoint */ + extern spinlock_t dcache_inode_lock; extern seqlock_t rename_lock; @@ -372,7 +372,7 @@ extern void dput(struct dentry *); static inline int d_mountpoint(struct dentry *dentry) { - return dentry->d_mounted; + return dentry->d_flags & DCACHE_MOUNTED; } extern struct vfsmount *lookup_mnt(struct path *);