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* Copyright (c) 2008 Jakub Jermar
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* - The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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* @file vfs_register.c
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#include <ipc/services.h>
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#include <fibril_sync.h>
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FIBRIL_CONDVAR_INITIALIZE(fs_head_cv);
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FIBRIL_MUTEX_INITIALIZE(fs_head_lock);
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LIST_INITIALIZE(fs_head);
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atomic_t fs_handle_next = {
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/** Verify the VFS info structure.
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* @param info Info structure to be verified.
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* @return Non-zero if the info structure is sane, zero otherwise.
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static bool vfs_info_sane(vfs_info_t *info)
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* Check if the name is non-empty and is composed solely of ASCII
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* characters [a-z]+[a-z0-9_-]*.
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if (!islower(info->name[0])) {
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dprintf("The name doesn't start with a lowercase character.\n");
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for (i = 1; i < FS_NAME_MAXLEN; i++) {
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if (!(islower(info->name[i]) || isdigit(info->name[i])) &&
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(info->name[i] != '-') && (info->name[i] != '_')) {
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if (info->name[i] == '\0') {
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dprintf("The name contains illegal "
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* This check is not redundant. It ensures that the name is
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* NULL-terminated, even if FS_NAME_MAXLEN characters are used.
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if (info->name[i] != '\0') {
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dprintf("The name is not properly NULL-terminated.\n");
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/** VFS_REGISTER protocol function.
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* @param rid Hash of the call with the request.
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* @param request Call structure with the request.
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void vfs_register(ipc_callid_t rid, ipc_call_t *request)
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dprintf("Processing VFS_REGISTER request received from %p.\n",
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request->in_phone_hash);
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* The first call has to be IPC_M_DATA_SEND in which we receive the
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* VFS info structure from the client FS.
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if (!ipc_data_write_receive(&callid, &size)) {
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* The client doesn't obey the same protocol as we do.
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dprintf("Receiving of VFS info failed.\n");
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ipc_answer_0(callid, EINVAL);
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ipc_answer_0(rid, EINVAL);
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dprintf("VFS info received, size = %d\n", size);
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* We know the size of the VFS info structure. See if the client
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* understands this easy concept too.
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if (size != sizeof(vfs_info_t)) {
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* The client is sending us something, which cannot be
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* the info structure.
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dprintf("Received VFS info has bad size.\n");
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ipc_answer_0(callid, EINVAL);
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ipc_answer_0(rid, EINVAL);
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* Allocate and initialize a buffer for the fs_info structure.
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fs_info = (fs_info_t *) malloc(sizeof(fs_info_t));
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dprintf("Could not allocate memory for FS info.\n");
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ipc_answer_0(callid, ENOMEM);
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ipc_answer_0(rid, ENOMEM);
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link_initialize(&fs_info->fs_link);
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fibril_mutex_initialize(&fs_info->phone_lock);
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rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size);
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dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n",
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ipc_answer_0(callid, rc);
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ipc_answer_0(rid, rc);
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dprintf("VFS info delivered.\n");
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if (!vfs_info_sane(&fs_info->vfs_info)) {
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ipc_answer_0(callid, EINVAL);
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ipc_answer_0(rid, EINVAL);
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fibril_mutex_lock(&fs_head_lock);
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* Check for duplicit registrations.
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if (fs_name_to_handle(fs_info->vfs_info.name, false)) {
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* We already register a fs like this.
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dprintf("FS is already registered.\n");
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fibril_mutex_unlock(&fs_head_lock);
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ipc_answer_0(callid, EEXISTS);
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ipc_answer_0(rid, EEXISTS);
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* Add fs_info to the list of registered FS's.
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dprintf("Inserting FS into the list of registered file systems.\n");
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list_append(&fs_info->fs_link, &fs_head);
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* Now we want the client to send us the IPC_M_CONNECT_TO_ME call so
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* that a callback connection is created and we have a phone through
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* which to forward VFS requests to it.
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callid = async_get_call(&call);
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if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) {
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dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
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list_remove(&fs_info->fs_link);
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fibril_mutex_unlock(&fs_head_lock);
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ipc_answer_0(callid, EINVAL);
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ipc_answer_0(rid, EINVAL);
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fs_info->phone = IPC_GET_ARG5(call);
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ipc_answer_0(callid, EOK);
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dprintf("Callback connection to FS created.\n");
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* The client will want us to send him the address space area with PLB.
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if (!ipc_share_in_receive(&callid, &size)) {
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dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call));
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list_remove(&fs_info->fs_link);
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fibril_mutex_unlock(&fs_head_lock);
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ipc_hangup(fs_info->phone);
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ipc_answer_0(callid, EINVAL);
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ipc_answer_0(rid, EINVAL);
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* We can only send the client address space area PLB_SIZE bytes long.
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if (size != PLB_SIZE) {
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dprintf("Client suggests wrong size of PFB, size = %d\n", size);
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list_remove(&fs_info->fs_link);
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fibril_mutex_unlock(&fs_head_lock);
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ipc_hangup(fs_info->phone);
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ipc_answer_0(callid, EINVAL);
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ipc_answer_0(rid, EINVAL);
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* Commit to read-only sharing the PLB with the client.
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(void) ipc_share_in_finalize(callid, plb,
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AS_AREA_READ | AS_AREA_CACHEABLE);
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dprintf("Sharing PLB.\n");
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* That was it. The FS has been registered.
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* In reply to the VFS_REGISTER request, we assign the client file
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* system a global file system handle.
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fs_info->fs_handle = (fs_handle_t) atomic_postinc(&fs_handle_next);
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ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle);
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fibril_condvar_broadcast(&fs_head_cv);
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fibril_mutex_unlock(&fs_head_lock);
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dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n",
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FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle);
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/** For a given file system handle, implement policy for allocating a phone.
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* @param handle File system handle.
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* @return Phone over which a multi-call request can be safely
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* sent. Return 0 if no phone was found.
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int vfs_grab_phone(fs_handle_t handle)
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* For now, we don't try to be very clever and very fast. We simply
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* lookup the phone in the fs_head list and duplicate it. The duplicate
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* phone will be returned to the client and the client will use it for
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* communication. In the future, we should cache the connections so
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* that they do not have to be reestablished over and over again.
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fibril_mutex_lock(&fs_head_lock);
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for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
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fs = list_get_instance(cur, fs_info_t, fs_link);
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if (fs->fs_handle == handle) {
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fibril_mutex_unlock(&fs_head_lock);
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fibril_mutex_lock(&fs->phone_lock);
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phone = ipc_connect_me_to(fs->phone, 0, 0, 0);
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fibril_mutex_unlock(&fs->phone_lock);
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fibril_mutex_unlock(&fs_head_lock);
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/** Tell VFS that the phone is not needed anymore.
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* @param phone Phone to FS task.
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void vfs_release_phone(int phone)
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/* TODO: implement connection caching */
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/** Convert file system name to its handle.
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* @param name File system name.
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* @param lock If true, the function will lock and unlock the
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* @return File system handle or zero if file system not found.
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fs_handle_t fs_name_to_handle(char *name, bool lock)
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fibril_mutex_lock(&fs_head_lock);
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for (cur = fs_head.next; cur != &fs_head; cur = cur->next) {
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fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link);
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if (str_cmp(fs->vfs_info.name, name) == 0) {
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handle = fs->fs_handle;
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fibril_mutex_unlock(&fs_head_lock);