Most walkers are interested only in positive dentries. Changes in simple_* libfs helpers are mostly cosmetic: it shouldn't cache negative dentries unless uses d_delete other than always_delete_dentry().
Signed-off-by: Konstantin Khlebnikov <[email protected]> --- fs/dcache.c | 10 ++++++++++ fs/libfs.c | 10 +++++++++- 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/fs/dcache.c b/fs/dcache.c index 44c6832d21d6..0fd2e02e507b 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1442,6 +1442,9 @@ static enum d_walk_ret path_check_mount(void *data, struct dentry *dentry) struct check_mount *info = data; struct path path = { .mnt = info->mnt, .dentry = dentry }; + if (d_is_tail_negative(dentry)) + return D_WALK_SKIP_SIBLINGS; + if (likely(!d_mountpoint(dentry))) return D_WALK_CONTINUE; if (__path_is_mountpoint(&path)) { @@ -1688,6 +1691,10 @@ void shrink_dcache_for_umount(struct super_block *sb) static enum d_walk_ret find_submount(void *_data, struct dentry *dentry) { struct dentry **victim = _data; + + if (d_is_tail_negative(dentry)) + return D_WALK_SKIP_SIBLINGS; + if (d_mountpoint(dentry)) { __dget_dlock(dentry); *victim = dentry; @@ -3159,6 +3166,9 @@ static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry) { struct dentry *root = data; if (dentry != root) { + if (d_is_tail_negative(dentry)) + return D_WALK_SKIP_SIBLINGS; + if (d_unhashed(dentry) || !dentry->d_inode) return D_WALK_SKIP; diff --git a/fs/libfs.c b/fs/libfs.c index 3759fbacf522..de944c241cf0 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -106,6 +106,10 @@ static struct dentry *scan_positives(struct dentry *cursor, spin_lock(&dentry->d_lock); while ((p = p->next) != &dentry->d_subdirs) { struct dentry *d = list_entry(p, struct dentry, d_child); + + if (d_is_tail_negative(d)) + break; + // we must at least skip cursors, to avoid livelocks if (d->d_flags & DCACHE_DENTRY_CURSOR) continue; @@ -255,7 +259,8 @@ static struct dentry *find_next_child(struct dentry *parent, struct dentry *prev spin_unlock(&d->d_lock); if (likely(child)) break; - } + } else if (d_is_tail_negative(d)) + break; } spin_unlock(&parent->d_lock); dput(prev); @@ -408,6 +413,9 @@ int simple_empty(struct dentry *dentry) spin_lock(&dentry->d_lock); list_for_each_entry(child, &dentry->d_subdirs, d_child) { + if (d_is_tail_negative(child)) + break; + spin_lock_nested(&child->d_lock, DENTRY_D_LOCK_NESTED); if (simple_positive(child)) { spin_unlock(&child->d_lock);
