/trunk/uspace/srv/vfs/vfs_unlink.c |
---|
40,9 → 40,9 |
/** |
* This futex prevents the race between a triplet-to-VFS-node resolution and a |
* concurrent VFS_UNLINK or VFS_RMDIR operation. |
* concurrent VFS operation which modifies the file system namespace. |
*/ |
atomic_t unlink_futex = FUTEX_INITIALIZER; |
atomic_t namespace_futex = FUTEX_INITIALIZER; |
/** |
* @} |
/trunk/uspace/srv/vfs/vfs_open.c |
---|
93,7 → 93,7 |
* find/create-and-lock the VFS node corresponding to the looked-up |
* triplet. |
*/ |
futex_down(&unlink_futex); |
futex_down(&namespace_futex); |
/* |
* The path is now populated and we can call vfs_lookup_internal(). |
101,7 → 101,7 |
vfs_triplet_t triplet; |
rc = vfs_lookup_internal(path, size, &triplet, NULL); |
if (rc) { |
futex_up(&unlink_futex); |
futex_up(&namespace_futex); |
ipc_answer_0(rid, rc); |
free(path); |
return; |
113,7 → 113,7 |
free(path); |
vfs_node_t *node = vfs_node_get(&triplet); |
futex_up(&unlink_futex); |
futex_up(&namespace_futex); |
/* |
* Get ourselves a file descriptor and the corresponding vfs_file_t |
/trunk/uspace/srv/vfs/vfs_mount.c |
---|
154,9 → 154,9 |
/* |
* Lookup the root node of the filesystem being mounted. |
* In this case, we don't need to take the unlink_futex as the root node |
* cannot be removed. However, we do take a reference to it so that |
* we can track how many times it has been mounted. |
* In this case, we don't need to take the namespace_futex as the root |
* node cannot be removed. However, we do take a reference to it so |
* that we can track how many times it has been mounted. |
*/ |
int rc; |
vfs_triplet_t mounted_root; |
182,13 → 182,13 |
/* |
* We already have the root FS. |
*/ |
futex_down(&unlink_futex); |
futex_down(&namespace_futex); |
rc = vfs_lookup_internal(buf, size, &mp, NULL); |
if (rc != EOK) { |
/* |
* The lookup failed for some reason. |
*/ |
futex_up(&unlink_futex); |
futex_up(&namespace_futex); |
futex_up(&rootfs_futex); |
vfs_node_put(mr_node); /* failed -> drop reference */ |
free(buf); |
197,7 → 197,7 |
} |
mp_node = vfs_node_get(&mp); |
if (!mp_node) { |
futex_up(&unlink_futex); |
futex_up(&namespace_futex); |
futex_up(&rootfs_futex); |
vfs_node_put(mr_node); /* failed -> drop reference */ |
free(buf); |
209,7 → 209,7 |
* It will be dropped upon the corresponding VFS_UNMOUNT. |
* This prevents the mount point from being deleted. |
*/ |
futex_up(&unlink_futex); |
futex_up(&namespace_futex); |
} else { |
/* |
* We still don't have the root file system mounted. |
/trunk/uspace/srv/vfs/vfs.h |
---|
134,6 → 134,9 |
VFS_TRIPLET; /**< Identity of the node. */ |
unsigned refcnt; /**< Usage counter. */ |
link_t nh_link; /**< Node hash-table link. */ |
/** Holding this futex prevents modifications of the node's contents. */ |
atomic_t contents_futex; |
} vfs_node_t; |
/** |
169,7 → 172,8 |
extern uint8_t *plb; /**< Path Lookup Buffer */ |
extern link_t plb_head; /**< List of active PLB entries. */ |
extern atomic_t unlink_futex; /**< VFS_{CREATE|OPEN|UNLINK} serialization. */ |
/** Holding this futex prevents extern changes in file system namespace. */ |
atomic_t namespace_futex; |
extern int vfs_grab_phone(int); |
extern void vfs_release_phone(int); |
/trunk/uspace/srv/vfs/vfs_node.c |
---|
146,6 → 146,7 |
node->dev_handle = triplet->fs_handle; |
node->index = triplet->index; |
link_initialize(&node->nh_link); |
futex_initialize(&node->contents_futex, 1); |
hash_table_insert(&nodes, key, &node->nh_link); |
} else { |
node = hash_table_get_instance(tmp, vfs_node_t, nh_link); |
/trunk/uspace/srv/vfs/vfs_rdwr.c |
---|
39,6 → 39,7 |
#include <ipc/ipc.h> |
#include <async.h> |
#include <errno.h> |
#include <futex.h> |
static void vfs_rdwr(ipc_callid_t rid, ipc_call_t *request, bool read) |
{ |
80,6 → 81,12 |
return; |
} |
/* |
* Lock the file's node so that no other client can read/write to it at |
* the same time. |
*/ |
futex_down(&file->node->contents_futex); |
int fs_phone = vfs_grab_phone(file->node->fs_handle); |
/* |
108,6 → 115,11 |
size_t bytes = IPC_GET_ARG1(answer); |
/* |
* Unlock the VFS node. |
*/ |
futex_up(&file->node->contents_futex); |
/* |
* Update the position pointer. |
*/ |
file->pos += bytes; |