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* Fixed a dead lock when drivers were scanned: we must not hold the devfs lock

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when scanning for drivers, as that reverts the standard locking order with
  locks like the device manager lock. There is now a dedicated scan_lock for
  each directory.
* get_device_name() now locks itself which also adds a missing lock in the
  B_GET_PATH_FOR_DEVICE ioctl().
* Minor refactoring; the directory init code was duplicated over several places
  in the source file.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@33465 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler
2009-10-06 12:56:21 +00:00
parent 852e81f6cb
commit ab7516c8f3
1 changed files with 52 additions and 47 deletions
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src/system/kernel/device_manager/devfs.cpp
+52 -47
View File
@@ -69,6 +69,7 @@ struct devfs_stream {
struct stream_dir {
struct devfs_vnode* dir_head;
struct list cookies;
mutex scan_lock;
int32 scanned;
} dir;
struct stream_dev {
@@ -177,8 +178,15 @@ scan_mode(void)
static status_t
scan_for_drivers(devfs_vnode* dir)
scan_for_drivers_if_needed(devfs_vnode* dir)
{
ASSERT(S_ISDIR(dir->stream.type));
MutexLocker _(dir->stream.u.dir.scan_lock);
if (dir->stream.u.dir.scanned >= scan_mode())
return B_OK;
KPath path;
if (path.InitCheck() != B_OK)
return B_NO_MEMORY;
@@ -186,7 +194,8 @@ scan_for_drivers(devfs_vnode* dir)
get_device_name(dir, path.LockBuffer(), path.BufferSize());
path.UnlockBuffer();
TRACE(("scan_for_drivers: mode %ld: %s\n", scan_mode(), path.Path()));
TRACE(("scan_for_drivers_if_needed: mode %ld: %s\n", scan_mode(),
path.Path()));
// scan for drivers at this path
static int32 updateCycle = 1;
@@ -224,6 +233,16 @@ devfs_vnode_compare(void* _vnode, const void* _key)
}
static void
init_directory_vnode(struct devfs_vnode* vnode, int permissions)
{
vnode->stream.type = S_IFDIR | permissions;
mutex_init(&vnode->stream.u.dir.scan_lock, "devfs scan");
vnode->stream.u.dir.dir_head = NULL;
list_init(&vnode->stream.u.dir.cookies);
}
static struct devfs_vnode*
devfs_create_vnode(struct devfs* fs, devfs_vnode* parent, const char* name)
{
@@ -275,6 +294,8 @@ devfs_delete_vnode(struct devfs* fs, struct devfs_vnode* vnode,
// device and is still in use there
put_vnode(fs->volume, vnode->stream.u.dev.partition->raw_device->id);
}
} else if (S_ISDIR(vnode->stream.type)) {
mutex_destroy(&vnode->stream.u.dir.scan_lock);
}
free(vnode->name);
@@ -511,6 +532,14 @@ out:
}
static void
publish_node(devfs* fs, devfs_vnode* dirNode, struct devfs_vnode* node)
{
hash_insert(fs->vnode_hash, node);
devfs_insert_in_dir(dirNode, node);
}
static status_t
publish_directory(struct devfs *fs, const char *path)
{
@@ -564,12 +593,8 @@ publish_directory(struct devfs *fs, const char *path)
}
// set up the new directory
vnode->stream.type = S_IFDIR | 0755;
vnode->stream.u.dir.dir_head = NULL;
list_init(&vnode->stream.u.dir.cookies);
hash_insert(sDeviceFileSystem->vnode_hash, vnode);
devfs_insert_in_dir(dir, vnode);
init_directory_vnode(vnode, 0755);
publish_node(sDeviceFileSystem, dir, vnode);
last = i;
dir = vnode;
@@ -643,12 +668,8 @@ new_node(struct devfs *fs, const char *path, struct devfs_vnode **_node,
// set up the new vnode
if (!atLeaf) {
// this is a dir
vnode->stream.type = S_IFDIR | 0755;
vnode->stream.u.dir.dir_head = NULL;
list_init(&vnode->stream.u.dir.cookies);
hash_insert(fs->vnode_hash, vnode);
devfs_insert_in_dir(dir, vnode);
init_directory_vnode(vnode, 0755);
publish_node(fs, dir, vnode);
} else {
// this is the last component
// Note: We do not yet insert the node into the directory, as it
@@ -670,14 +691,6 @@ out:
}
static void
publish_node(devfs* fs, devfs_vnode* dirNode, struct devfs_vnode* node)
{
hash_insert(fs->vnode_hash, node);
devfs_insert_in_dir(dirNode, node);
}
static status_t
publish_device(struct devfs* fs, const char* path, BaseDevice* device)
{
@@ -729,7 +742,9 @@ publish_device(struct devfs* fs, const char* path, BaseDevice* device)
static void
get_device_name(struct devfs_vnode* vnode, char* buffer, size_t size)
{
struct devfs_vnode *leaf = vnode;
RecursiveLocker _(sDeviceFileSystem->lock);
struct devfs_vnode* leaf = vnode;
size_t offset = 0;
// count levels
@@ -878,9 +893,7 @@ devfs_mount(fs_volume *volume, const char *devfs, uint32 flags,
vnode->parent = vnode;
// create a dir stream for it to hold
vnode->stream.type = S_IFDIR | 0755;
vnode->stream.u.dir.dir_head = NULL;
list_init(&vnode->stream.u.dir.cookies);
init_directory_vnode(vnode, 0755);
fs->root_vnode = vnode;
hash_insert(fs->vnode_hash, vnode);
@@ -951,10 +964,10 @@ devfs_lookup(fs_volume *_volume, fs_vnode *_dir, const char *name, ino_t *_id)
if (!S_ISDIR(dir->stream.type))
return B_NOT_A_DIRECTORY;
RecursiveLocker locker(&fs->lock);
// Make sure the directory contents are up to date
scan_for_drivers_if_needed(dir);
if (dir->stream.u.dir.scanned < scan_mode())
scan_for_drivers(dir);
RecursiveLocker locker(&fs->lock);
// look it up
vnode = devfs_find_in_dir(dir, name);
@@ -1088,10 +1101,8 @@ devfs_create(fs_volume* _volume, fs_vnode* _dir, const char* name, int openMode,
if (status < B_OK)
return status;
locker.Lock();
char path[B_FILE_NAME_LENGTH];
get_device_name(vnode, path, sizeof(path));
locker.Unlock();
status = device->Open(path, openMode, &cookie->device_cookie);
if (status != B_OK)
@@ -1116,7 +1127,6 @@ devfs_open(fs_volume* _volume, fs_vnode* _vnode, int openMode,
void** _cookie)
{
struct devfs_vnode* vnode = (struct devfs_vnode*)_vnode->private_node;
struct devfs* fs = (struct devfs*)_volume->private_volume;
struct devfs_cookie* cookie;
status_t status = B_OK;
@@ -1124,26 +1134,26 @@ devfs_open(fs_volume* _volume, fs_vnode* _vnode, int openMode,
if (cookie == NULL)
return B_NO_MEMORY;
TRACE(("devfs_open: vnode %p, openMode 0x%x, cookie %p\n", vnode, openMode, cookie));
TRACE(("devfs_open: vnode %p, openMode 0x%x, cookie %p\n", vnode, openMode,
cookie));
cookie->device_cookie = NULL;
if (S_ISCHR(vnode->stream.type)) {
BaseDevice* device = vnode->stream.u.dev.device;
status = device->InitDevice();
if (status < B_OK)
if (status != B_OK)
return status;
RecursiveLocker locker(fs->lock);
char path[B_FILE_NAME_LENGTH];
get_device_name(vnode, path, sizeof(path));
locker.Unlock();
status = device->Open(path, openMode, &cookie->device_cookie);
if (status != B_OK)
device->UninitDevice();
}
if (status < B_OK)
if (status != B_OK)
free(cookie);
else
*_cookie = cookie;
@@ -1293,12 +1303,8 @@ devfs_create_dir(fs_volume *_volume, fs_vnode *_dir, const char *name,
}
// set up the new directory
vnode->stream.type = S_IFDIR | perms;
vnode->stream.u.dir.dir_head = NULL;
list_init(&vnode->stream.u.dir.cookies);
hash_insert(sDeviceFileSystem->vnode_hash, vnode);
devfs_insert_in_dir(dir, vnode);
init_directory_vnode(vnode, perms);
publish_node(sDeviceFileSystem, dir, vnode);
return B_OK;
}
@@ -1320,11 +1326,10 @@ devfs_open_dir(fs_volume *_volume, fs_vnode *_vnode, void **_cookie)
if (cookie == NULL)
return B_NO_MEMORY;
RecursiveLocker locker(&fs->lock);
// make sure the directory has up-to-date contents
if (vnode->stream.u.dir.scanned < scan_mode())
scan_for_drivers(vnode);
scan_for_drivers_if_needed(vnode);
RecursiveLocker locker(&fs->lock);
cookie->current = vnode->stream.u.dir.dir_head;
cookie->state = ITERATION_STATE_BEGIN;