Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
+78
-48
+3
-3
fs/9p/vfs_file.c
+3
-3
fs/9p/vfs_file.c
···
74
74
v9fs_proto_dotu(v9ses));
75
75
fid = file->private_data;
76
76
if (!fid) {
77
-
fid = v9fs_fid_clone(file->f_path.dentry);
77
+
fid = v9fs_fid_clone(file_dentry(file));
78
78
if (IS_ERR(fid))
79
79
return PTR_ERR(fid);
80
80
···
100
100
* because we want write after unlink usecase
101
101
* to work.
102
102
*/
103
-
fid = v9fs_writeback_fid(file->f_path.dentry);
103
+
fid = v9fs_writeback_fid(file_dentry(file));
104
104
if (IS_ERR(fid)) {
105
105
err = PTR_ERR(fid);
106
106
mutex_unlock(&v9inode->v_mutex);
···
516
516
* because we want write after unlink usecase
517
517
* to work.
518
518
*/
519
-
fid = v9fs_writeback_fid(filp->f_path.dentry);
519
+
fid = v9fs_writeback_fid(file_dentry(filp));
520
520
if (IS_ERR(fid)) {
521
521
retval = PTR_ERR(fid);
522
522
mutex_unlock(&v9inode->v_mutex);
+3
-7
fs/ceph/export.c
+3
-7
fs/ceph/export.c
···
95
95
}
96
96
97
97
dentry = d_obtain_alias(inode);
98
-
if (IS_ERR(dentry)) {
99
-
iput(inode);
98
+
if (IS_ERR(dentry))
100
99
return dentry;
101
-
}
102
100
err = ceph_init_dentry(dentry);
103
101
if (err < 0) {
104
102
dput(dentry);
···
165
167
return ERR_PTR(-ENOENT);
166
168
167
169
dentry = d_obtain_alias(inode);
168
-
if (IS_ERR(dentry)) {
169
-
iput(inode);
170
+
if (IS_ERR(dentry))
170
171
return dentry;
171
-
}
172
172
err = ceph_init_dentry(dentry);
173
173
if (err < 0) {
174
174
dput(dentry);
···
206
210
207
211
dout("fh_to_parent %llx\n", cfh->parent_ino);
208
212
dentry = __get_parent(sb, NULL, cfh->ino);
209
-
if (IS_ERR(dentry) && PTR_ERR(dentry) == -ENOENT)
213
+
if (unlikely(dentry == ERR_PTR(-ENOENT)))
210
214
dentry = __fh_to_dentry(sb, cfh->parent_ino);
211
215
return dentry;
212
216
}
+71
-38
fs/libfs.c
+71
-38
fs/libfs.c
···
84
84
}
85
85
EXPORT_SYMBOL(dcache_dir_close);
86
86
87
+
/* parent is locked at least shared */
88
+
static struct dentry *next_positive(struct dentry *parent,
89
+
struct list_head *from,
90
+
int count)
91
+
{
92
+
unsigned *seq = &parent->d_inode->i_dir_seq, n;
93
+
struct dentry *res;
94
+
struct list_head *p;
95
+
bool skipped;
96
+
int i;
97
+
98
+
retry:
99
+
i = count;
100
+
skipped = false;
101
+
n = smp_load_acquire(seq) & ~1;
102
+
res = NULL;
103
+
rcu_read_lock();
104
+
for (p = from->next; p != &parent->d_subdirs; p = p->next) {
105
+
struct dentry *d = list_entry(p, struct dentry, d_child);
106
+
if (!simple_positive(d)) {
107
+
skipped = true;
108
+
} else if (!--i) {
109
+
res = d;
110
+
break;
111
+
}
112
+
}
113
+
rcu_read_unlock();
114
+
if (skipped) {
115
+
smp_rmb();
116
+
if (unlikely(*seq != n))
117
+
goto retry;
118
+
}
119
+
return res;
120
+
}
121
+
122
+
static void move_cursor(struct dentry *cursor, struct list_head *after)
123
+
{
124
+
struct dentry *parent = cursor->d_parent;
125
+
unsigned n, *seq = &parent->d_inode->i_dir_seq;
126
+
spin_lock(&parent->d_lock);
127
+
for (;;) {
128
+
n = *seq;
129
+
if (!(n & 1) && cmpxchg(seq, n, n + 1) == n)
130
+
break;
131
+
cpu_relax();
132
+
}
133
+
__list_del(cursor->d_child.prev, cursor->d_child.next);
134
+
if (after)
135
+
list_add(&cursor->d_child, after);
136
+
else
137
+
list_add_tail(&cursor->d_child, &parent->d_subdirs);
138
+
smp_store_release(seq, n + 2);
139
+
spin_unlock(&parent->d_lock);
140
+
}
141
+
87
142
loff_t dcache_dir_lseek(struct file *file, loff_t offset, int whence)
88
143
{
89
144
struct dentry *dentry = file->f_path.dentry;
···
154
99
if (offset != file->f_pos) {
155
100
file->f_pos = offset;
156
101
if (file->f_pos >= 2) {
157
-
struct list_head *p;
158
102
struct dentry *cursor = file->private_data;
103
+
struct dentry *to;
159
104
loff_t n = file->f_pos - 2;
160
105
161
-
spin_lock(&dentry->d_lock);
162
-
/* d_lock not required for cursor */
163
-
list_del(&cursor->d_child);
164
-
p = dentry->d_subdirs.next;
165
-
while (n && p != &dentry->d_subdirs) {
166
-
struct dentry *next;
167
-
next = list_entry(p, struct dentry, d_child);
168
-
spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
169
-
if (simple_positive(next))
170
-
n--;
171
-
spin_unlock(&next->d_lock);
172
-
p = p->next;
173
-
}
174
-
list_add_tail(&cursor->d_child, p);
175
-
spin_unlock(&dentry->d_lock);
106
+
inode_lock_shared(dentry->d_inode);
107
+
to = next_positive(dentry, &dentry->d_subdirs, n);
108
+
move_cursor(cursor, to ? &to->d_child : NULL);
109
+
inode_unlock_shared(dentry->d_inode);
176
110
}
177
111
}
178
112
return offset;
···
184
140
{
185
141
struct dentry *dentry = file->f_path.dentry;
186
142
struct dentry *cursor = file->private_data;
187
-
struct list_head *p, *q = &cursor->d_child;
143
+
struct list_head *p = &cursor->d_child;
144
+
struct dentry *next;
145
+
bool moved = false;
188
146
189
147
if (!dir_emit_dots(file, ctx))
190
148
return 0;
191
-
spin_lock(&dentry->d_lock);
149
+
192
150
if (ctx->pos == 2)
193
-
list_move(q, &dentry->d_subdirs);
194
-
195
-
for (p = q->next; p != &dentry->d_subdirs; p = p->next) {
196
-
struct dentry *next = list_entry(p, struct dentry, d_child);
197
-
spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
198
-
if (!simple_positive(next)) {
199
-
spin_unlock(&next->d_lock);
200
-
continue;
201
-
}
202
-
203
-
spin_unlock(&next->d_lock);
204
-
spin_unlock(&dentry->d_lock);
151
+
p = &dentry->d_subdirs;
152
+
while ((next = next_positive(dentry, p, 1)) != NULL) {
205
153
if (!dir_emit(ctx, next->d_name.name, next->d_name.len,
206
154
d_inode(next)->i_ino, dt_type(d_inode(next))))
207
-
return 0;
208
-
spin_lock(&dentry->d_lock);
209
-
spin_lock_nested(&next->d_lock, DENTRY_D_LOCK_NESTED);
210
-
/* next is still alive */
211
-
list_move(q, p);
212
-
spin_unlock(&next->d_lock);
213
-
p = q;
155
+
break;
156
+
moved = true;
157
+
p = &next->d_child;
214
158
ctx->pos++;
215
159
}
216
-
spin_unlock(&dentry->d_lock);
160
+
if (moved)
161
+
move_cursor(cursor, p);
217
162
return 0;
218
163
}
219
164
EXPORT_SYMBOL(dcache_readdir);