/* Unix SMB/CIFS implementation. POSIX NTVFS backend - locking Copyright (C) Andrew Tridgell 2004 This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>. */ #include "includes.h" #include "vfs_posix.h" #include "system/time.h" #include "../lib/util/dlinklist.h" #include "messaging/messaging.h" /* check if we can perform IO on a range that might be locked */ NTSTATUS pvfs_check_lock(struct pvfs_state *pvfs, struct pvfs_file *f, uint32_t smbpid, uint64_t offset, uint64_t count, enum brl_type rw) { if (!(pvfs->flags & PVFS_FLAG_STRICT_LOCKING)) { return NT_STATUS_OK; } return brl_locktest(pvfs->brl_context, f->brl_handle, smbpid, offset, count, rw); } /* this state structure holds information about a lock we are waiting on */ struct pvfs_pending_lock { struct pvfs_pending_lock *next, *prev; struct pvfs_state *pvfs; union smb_lock *lck; struct pvfs_file *f; struct ntvfs_request *req; int pending_lock; struct pvfs_wait *wait_handle; struct timeval end_time; }; /* a secondary attempt to setup a lock has failed - back out the locks we did get and send an error */ static void pvfs_lock_async_failed(struct pvfs_state *pvfs, struct ntvfs_request *req, struct pvfs_file *f, struct smb_lock_entry *locks, int i, NTSTATUS status) { /* undo the locks we just did */ for (i--;i>=0;i--) { brl_unlock(pvfs->brl_context, f->brl_handle, locks[i].pid, locks[i].offset, locks[i].count); f->lock_count--; } req->async_states->status = status; req->async_states->send_fn(req); } /* called when we receive a pending lock notification. It means that either our lock timed out or someone else has unlocked a overlapping range, so we should try the lock again. Note that on timeout we do retry the lock, giving it a last chance. */ static void pvfs_pending_lock_continue(void *private, enum pvfs_wait_notice reason) { struct pvfs_pending_lock *pending = private; struct pvfs_state *pvfs = pending->pvfs; struct pvfs_file *f = pending->f; struct ntvfs_request *req = pending->req; union smb_lock *lck = pending->lck; struct smb_lock_entry *locks; enum brl_type rw; NTSTATUS status; int i; bool timed_out; timed_out = (reason != PVFS_WAIT_EVENT); locks = lck->lockx.in.locks + lck->lockx.in.ulock_cnt; if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) { rw = READ_LOCK; } else { rw = WRITE_LOCK; } DLIST_REMOVE(f->pending_list, pending); /* we don't retry on a cancel */ if (reason == PVFS_WAIT_CANCEL) { status = NT_STATUS_FILE_LOCK_CONFLICT; } else { /* * here it's important to pass the pending pointer * because with this we'll get the correct error code * FILE_LOCK_CONFLICT in the error case */ status = brl_lock(pvfs->brl_context, f->brl_handle, locks[pending->pending_lock].pid, locks[pending->pending_lock].offset, locks[pending->pending_lock].count, rw, pending); } if (NT_STATUS_IS_OK(status)) { f->lock_count++; timed_out = false; } /* if we have failed and timed out, or succeeded, then we don't need the pending lock any more */ if (NT_STATUS_IS_OK(status) || timed_out) { NTSTATUS status2; status2 = brl_remove_pending(pvfs->brl_context, f->brl_handle, pending); if (!NT_STATUS_IS_OK(status2)) { DEBUG(0,("pvfs_lock: failed to remove pending lock - %s\n", nt_errstr(status2))); } talloc_free(pending->wait_handle); } if (!NT_STATUS_IS_OK(status)) { if (timed_out) { /* no more chances */ pvfs_lock_async_failed(pvfs, req, f, locks, pending->pending_lock, status); talloc_free(pending); } else { /* we can try again */ DLIST_ADD(f->pending_list, pending); } return; } /* if we haven't timed out yet, then we can do more pending locks */ if (rw == READ_LOCK) { rw = PENDING_READ_LOCK; } else { rw = PENDING_WRITE_LOCK; } /* we've now got the pending lock. try and get the rest, which might lead to more pending locks */ for (i=pending->pending_lock+1;i<lck->lockx.in.lock_cnt;i++) { if (pending) { pending->pending_lock = i; } status = brl_lock(pvfs->brl_context, f->brl_handle, locks[i].pid, locks[i].offset, locks[i].count, rw, pending); if (!NT_STATUS_IS_OK(status)) { if (pending) { /* a timed lock failed - setup a wait message to handle the pending lock notification or a timeout */ pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY, pending->end_time, pvfs_pending_lock_continue, pending); if (pending->wait_handle == NULL) { pvfs_lock_async_failed(pvfs, req, f, locks, i, NT_STATUS_NO_MEMORY); talloc_free(pending); } else { talloc_steal(pending, pending->wait_handle); DLIST_ADD(f->pending_list, pending); } return; } pvfs_lock_async_failed(pvfs, req, f, locks, i, status); talloc_free(pending); return; } f->lock_count++; } /* we've managed to get all the locks. Tell the client */ req->async_states->status = NT_STATUS_OK; req->async_states->send_fn(req); talloc_free(pending); } /* called when we close a file that might have locks */ void pvfs_lock_close(struct pvfs_state *pvfs, struct pvfs_file *f) { struct pvfs_pending_lock *p, *next; if (f->lock_count || f->pending_list) { DEBUG(5,("pvfs_lock: removing %.0f locks on close\n", (double)f->lock_count)); brl_close(f->pvfs->brl_context, f->brl_handle); f->lock_count = 0; } /* reply to all the pending lock requests, telling them the lock failed */ for (p=f->pending_list;p;p=next) { next = p->next; DLIST_REMOVE(f->pending_list, p); p->req->async_states->status = NT_STATUS_RANGE_NOT_LOCKED; p->req->async_states->send_fn(p->req); } } /* cancel a set of locks */ static NTSTATUS pvfs_lock_cancel(struct pvfs_state *pvfs, struct ntvfs_request *req, union smb_lock *lck, struct pvfs_file *f) { struct pvfs_pending_lock *p; for (p=f->pending_list;p;p=p->next) { /* check if the lock request matches exactly - you can only cancel with exact matches */ if (p->lck->lockx.in.ulock_cnt == lck->lockx.in.ulock_cnt && p->lck->lockx.in.lock_cnt == lck->lockx.in.lock_cnt && p->lck->lockx.in.file.ntvfs== lck->lockx.in.file.ntvfs && p->lck->lockx.in.mode == (lck->lockx.in.mode & ~LOCKING_ANDX_CANCEL_LOCK)) { int i; for (i=0;i<lck->lockx.in.ulock_cnt + lck->lockx.in.lock_cnt;i++) { if (p->lck->lockx.in.locks[i].pid != lck->lockx.in.locks[i].pid || p->lck->lockx.in.locks[i].offset != lck->lockx.in.locks[i].offset || p->lck->lockx.in.locks[i].count != lck->lockx.in.locks[i].count) { break; } } if (i < lck->lockx.in.ulock_cnt) continue; /* an exact match! we can cancel it, which is equivalent to triggering the timeout early */ pvfs_pending_lock_continue(p, PVFS_WAIT_TIMEOUT); return NT_STATUS_OK; } } return NT_STATUS_DOS(ERRDOS, ERRcancelviolation); } /* lock or unlock a byte range */ NTSTATUS pvfs_lock(struct ntvfs_module_context *ntvfs, struct ntvfs_request *req, union smb_lock *lck) { struct pvfs_state *pvfs = ntvfs->private_data; struct pvfs_file *f; struct smb_lock_entry *locks; int i; enum brl_type rw; struct pvfs_pending_lock *pending = NULL; NTSTATUS status; if (lck->generic.level != RAW_LOCK_GENERIC) { return ntvfs_map_lock(ntvfs, req, lck); } if (lck->lockx.in.mode & LOCKING_ANDX_OPLOCK_RELEASE) { return pvfs_oplock_release(ntvfs, req, lck); } f = pvfs_find_fd(pvfs, req, lck->lockx.in.file.ntvfs); if (!f) { return NT_STATUS_INVALID_HANDLE; } if (f->handle->fd == -1) { return NT_STATUS_FILE_IS_A_DIRECTORY; } status = pvfs_break_level2_oplocks(f); NT_STATUS_NOT_OK_RETURN(status); if (lck->lockx.in.timeout != 0 && (req->async_states->state & NTVFS_ASYNC_STATE_MAY_ASYNC)) { pending = talloc(f, struct pvfs_pending_lock); if (pending == NULL) { return NT_STATUS_NO_MEMORY; } pending->pvfs = pvfs; pending->lck = lck; pending->f = f; pending->req = req; pending->end_time = timeval_current_ofs(lck->lockx.in.timeout/1000, 1000*(lck->lockx.in.timeout%1000)); } if (lck->lockx.in.mode & LOCKING_ANDX_SHARED_LOCK) { rw = pending? PENDING_READ_LOCK : READ_LOCK; } else { rw = pending? PENDING_WRITE_LOCK : WRITE_LOCK; } if (lck->lockx.in.mode & LOCKING_ANDX_CANCEL_LOCK) { talloc_free(pending); return pvfs_lock_cancel(pvfs, req, lck, f); } if (lck->lockx.in.mode & LOCKING_ANDX_CHANGE_LOCKTYPE) { /* this seems to not be supported by any windows server, or used by any clients */ talloc_free(pending); return NT_STATUS_DOS(ERRDOS, ERRnoatomiclocks); } /* the unlocks happen first */ locks = lck->lockx.in.locks; for (i=0;i<lck->lockx.in.ulock_cnt;i++) { status = brl_unlock(pvfs->brl_context, f->brl_handle, locks[i].pid, locks[i].offset, locks[i].count); if (!NT_STATUS_IS_OK(status)) { talloc_free(pending); return status; } f->lock_count--; } locks += i; for (i=0;i<lck->lockx.in.lock_cnt;i++) { if (pending) { pending->pending_lock = i; } status = brl_lock(pvfs->brl_context, f->brl_handle, locks[i].pid, locks[i].offset, locks[i].count, rw, pending); if (!NT_STATUS_IS_OK(status)) { if (pending) { /* a timed lock failed - setup a wait message to handle the pending lock notification or a timeout */ pending->wait_handle = pvfs_wait_message(pvfs, req, MSG_BRL_RETRY, pending->end_time, pvfs_pending_lock_continue, pending); if (pending->wait_handle == NULL) { talloc_free(pending); return NT_STATUS_NO_MEMORY; } talloc_steal(pending, pending->wait_handle); DLIST_ADD(f->pending_list, pending); return NT_STATUS_OK; } /* undo the locks we just did */ for (i--;i>=0;i--) { brl_unlock(pvfs->brl_context, f->brl_handle, locks[i].pid, locks[i].offset, locks[i].count); f->lock_count--; } talloc_free(pending); return status; } f->lock_count++; } talloc_free(pending); return NT_STATUS_OK; }