hfsplus: switch to ->iterate_shared()
We need to protect the list of hfsplus_readdir_data against parallel
insertions (in readdir) and removals (in release). Add a spinlock
for that. Note that it has nothing to do with protection of
hfsplus_readdir_data->key - we have an exclusion between hfsplus_readdir()
and hfsplus_delete_cat() on directory lock and between several
hfsplus_readdir() for the same struct file on ->f_pos_lock. The spinlock
is strictly for list changes.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/hfsplus/catalog.c b/fs/hfsplus/catalog.c
index 022974a..fb707e8 100644
--- a/fs/hfsplus/catalog.c
+++ b/fs/hfsplus/catalog.c
@@ -374,12 +374,15 @@
hfsplus_free_fork(sb, cnid, &fork, HFSPLUS_TYPE_RSRC);
}
+ /* we only need to take spinlock for exclusion with ->release() */
+ spin_lock(&HFSPLUS_I(dir)->open_dir_lock);
list_for_each(pos, &HFSPLUS_I(dir)->open_dir_list) {
struct hfsplus_readdir_data *rd =
list_entry(pos, struct hfsplus_readdir_data, list);
if (fd.tree->keycmp(fd.search_key, (void *)&rd->key) < 0)
rd->file->f_pos--;
}
+ spin_unlock(&HFSPLUS_I(dir)->open_dir_lock);
err = hfs_brec_remove(&fd);
if (err)
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index a4e867e..42e1286 100644
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -271,8 +271,14 @@
}
file->private_data = rd;
rd->file = file;
+ spin_lock(&HFSPLUS_I(inode)->open_dir_lock);
list_add(&rd->list, &HFSPLUS_I(inode)->open_dir_list);
+ spin_unlock(&HFSPLUS_I(inode)->open_dir_lock);
}
+ /*
+ * Can be done after the list insertion; exclusion with
+ * hfsplus_delete_cat() is provided by directory lock.
+ */
memcpy(&rd->key, fd.key, sizeof(struct hfsplus_cat_key));
out:
kfree(strbuf);
@@ -284,9 +290,9 @@
{
struct hfsplus_readdir_data *rd = file->private_data;
if (rd) {
- inode_lock(inode);
+ spin_lock(&HFSPLUS_I(inode)->open_dir_lock);
list_del(&rd->list);
- inode_unlock(inode);
+ spin_unlock(&HFSPLUS_I(inode)->open_dir_lock);
kfree(rd);
}
return 0;
@@ -569,7 +575,7 @@
const struct file_operations hfsplus_dir_operations = {
.fsync = hfsplus_file_fsync,
.read = generic_read_dir,
- .iterate = hfsplus_readdir,
+ .iterate_shared = hfsplus_readdir,
.unlocked_ioctl = hfsplus_ioctl,
.llseek = generic_file_llseek,
.release = hfsplus_dir_release,
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index f91a1fa..fdc3446d 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -244,6 +244,7 @@
u8 userflags; /* BSD user file flags */
u32 subfolders; /* Subfolder count (HFSX only) */
struct list_head open_dir_list;
+ spinlock_t open_dir_lock;
loff_t phys_size;
struct inode vfs_inode;
diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c
index b28f398..037f738 100644
--- a/fs/hfsplus/inode.c
+++ b/fs/hfsplus/inode.c
@@ -374,6 +374,7 @@
hip = HFSPLUS_I(inode);
INIT_LIST_HEAD(&hip->open_dir_list);
+ spin_lock_init(&hip->open_dir_lock);
mutex_init(&hip->extents_lock);
atomic_set(&hip->opencnt, 0);
hip->extent_state = 0;
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index c359113..755bf30 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -67,6 +67,7 @@
return inode;
INIT_LIST_HEAD(&HFSPLUS_I(inode)->open_dir_list);
+ spin_lock_init(&HFSPLUS_I(inode)->open_dir_lock);
mutex_init(&HFSPLUS_I(inode)->extents_lock);
HFSPLUS_I(inode)->flags = 0;
HFSPLUS_I(inode)->extent_state = 0;
