Commit 48c4565e authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs fixes from Al Viro:
 "Tmpfs readdir throughput regression fix (this cycle) + some -stable
  fodder all over the place.

  One missing bit is Miklos' tonight locks.c fix - NFS folks had already
  grabbed that one by the time I woke up ;-)"

[ The locks.c fix came through the nfsd tree just moments ago ]

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  namespace: update event counter when umounting a deleted dentry
  9p: use file_dentry()
  ceph: fix d_obtain_alias() misuses
  lockless next_positive()
  libfs.c: new helper - next_positive()
  dcache_{readdir,dir_lseek}(): don't bother with nested ->d_lock
parents 2728c57f e06b933e
......@@ -74,7 +74,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
v9fs_proto_dotu(v9ses));
fid = file->private_data;
if (!fid) {
fid = v9fs_fid_clone(file->f_path.dentry);
fid = v9fs_fid_clone(file_dentry(file));
if (IS_ERR(fid))
return PTR_ERR(fid);
......@@ -100,7 +100,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
* because we want write after unlink usecase
* to work.
*/
fid = v9fs_writeback_fid(file->f_path.dentry);
fid = v9fs_writeback_fid(file_dentry(file));
if (IS_ERR(fid)) {
err = PTR_ERR(fid);
mutex_unlock(&v9inode->v_mutex);
......@@ -516,7 +516,7 @@ v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma)
* because we want write after unlink usecase
* to work.
*/
fid = v9fs_writeback_fid(filp->f_path.dentry);
fid = v9fs_writeback_fid(file_dentry(filp));
if (IS_ERR(fid)) {
retval = PTR_ERR(fid);
mutex_unlock(&v9inode->v_mutex);
......
......@@ -95,10 +95,8 @@ static struct dentry *__fh_to_dentry(struct super_block *sb, u64 ino)
}
dentry = d_obtain_alias(inode);
if (IS_ERR(dentry)) {
iput(inode);
if (IS_ERR(dentry))
return dentry;
}
err = ceph_init_dentry(dentry);
if (err < 0) {
dput(dentry);
......@@ -167,10 +165,8 @@ static struct dentry *__get_parent(struct super_block *sb,
return ERR_PTR(-ENOENT);
dentry = d_obtain_alias(inode);
if (IS_ERR(dentry)) {
iput(inode);
if (IS_ERR(dentry))
return dentry;
}
err = ceph_init_dentry(dentry);
if (err < 0) {
dput(dentry);
......@@ -210,7 +206,7 @@ static struct dentry *ceph_fh_to_parent(struct super_block *sb,
dout("fh_to_parent %llx\n", cfh->parent_ino);
dentry = __get_parent(sb, NULL, cfh->ino);
if (IS_ERR(dentry) && PTR_ERR(dentry) == -ENOENT)
if (unlikely(dentry == ERR_PTR(-ENOENT)))
dentry = __fh_to_dentry(sb, cfh->parent_ino);
return dentry;
}
......
......@@ -84,6 +84,61 @@ int dcache_dir_close(struct inode *inode, struct file *file)
}
EXPORT_SYMBOL(dcache_dir_close);
/* parent is locked at least shared */
static struct dentry *next_positive(struct dentry *parent,
struct list_head *from,
int count)
{
unsigned *seq = &parent->d_inode->i_dir_seq, n;
struct dentry *res;
struct list_head *p;
bool skipped;
int i;
retry:
i = count;
skipped = false;
n = smp_load_acquire(seq) & ~1;
res = NULL;
rcu_read_lock();
for (p = from->next; p != &parent->d_subdirs; p = p->next) {
struct dentry *d = list_entry(p, struct dentry, d_child);
if (!simple_positive(d)) {
skipped = true;
} else if (!--i) {
res = d;
break;
}
}
rcu_read_unlock();
if (skipped) {
smp_rmb();
if (unlikely(*seq != n))
goto retry;
}
return res;
}
static void move_cursor(struct dentry *cursor, struct list_head *after)
{
struct dentry *parent = cursor->d_parent;
unsigned n, *seq = &parent->d_inode->i_dir_seq;
spin_lock(&parent->d_lock);
for (;;) {
n = *seq;
if (!(n & 1) && cmpxchg(seq, n, n + 1) == n)
break;
cpu_relax();
}
__list_del(cursor->d_child.prev, cursor->d_child.next);
if (after)
list_add(&cursor->d_child, after);
else
list_add_tail(&cursor->d_child, &parent->d_subdirs);
smp_store_release(seq, n + 2);
spin_unlock(&parent->d_lock);
}
loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
{
struct dentry *dentry = file->f_path.dentry;
......@@ -99,25 +154,14 @@ loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
if (offset != file->f_pos) {
file->f_pos = offset;
if (file->f_pos >= 2) {
struct list_head *p;
struct dentry *cursor = file->private_data;
struct dentry *to;
loff_t n = file->f_pos - 2;
spin_lock(&dentry->d_lock);
/* d_lock not required for cursor */
list_del(&cursor->d_child);
p = dentry->d_subdirs.next;
while (n && p != &dentry->d_subdirs) {
struct dentry *next;
next = list_entry(p, struct dentry, d_child);
spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
if (simple_positive(next))
n--;
spin_unlock(&next->d_lock);
p = p->next;
}
list_add_tail(&cursor->d_child, p);
spin_unlock(&dentry->d_lock);
inode_lock_shared(dentry->d_inode);
to = next_positive(dentry, &dentry->d_subdirs, n);
move_cursor(cursor, to ? &to->d_child : NULL);
inode_unlock_shared(dentry->d_inode);
}
}
return offset;
......@@ -140,36 +184,25 @@ int dcache_readdir(struct file *file, struct dir_context *ctx)
{
struct dentry *dentry = file->f_path.dentry;
struct dentry *cursor = file->private_data;
struct list_head *p, *q = &cursor->d_child;
struct list_head *p = &cursor->d_child;
struct dentry *next;
bool moved = false;
if (!dir_emit_dots(file, ctx))
return 0;
spin_lock(&dentry->d_lock);
if (ctx->pos == 2)
list_move(q, &dentry->d_subdirs);
for (p = q->next; p != &dentry->d_subdirs; p = p->next) {
struct dentry *next = list_entry(p, struct dentry, d_child);
spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
if (!simple_positive(next)) {
spin_unlock(&next->d_lock);
continue;
}
spin_unlock(&next->d_lock);
spin_unlock(&dentry->d_lock);
if (ctx->pos == 2)
p = &dentry->d_subdirs;
while ((next = next_positive(dentry, p, 1)) != NULL) {
if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
d_inode(next)->i_ino, dt_type(d_inode(next))))
return 0;
spin_lock(&dentry->d_lock);
spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
/* next is still alive */
list_move(q, p);
spin_unlock(&next->d_lock);
p = q;
break;
moved = true;
p = &next->d_child;
ctx->pos++;
}
spin_unlock(&dentry->d_lock);
if (moved)
move_cursor(cursor, p);
return 0;
}
EXPORT_SYMBOL(dcache_readdir);
......
......@@ -1562,6 +1562,7 @@ void __detach_mounts(struct dentry *dentry)
goto out_unlock;
lock_mount_hash();
event++;
while (!hlist_empty(&mp->m_list)) {
mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
if (mnt->mnt.mnt_flags & MNT_UMOUNT) {
......
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