/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END */ /* * Copyright 2008 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ #pragma ident "@(#)smb_oplock.c 1.5 08/08/07 SMI" /* * SMB Locking library functions. */ #include #include /* * Oplock functionality enable/disable */ /* * Magic 0xFF 'S' 'M' 'B' * smb_com a byte, the "first" command * Error a 4-byte union, ignored in a request * smb_flg a one byte set of eight flags * smb_flg2 a two byte set of 16 flags * . twelve reserved bytes, have a role * in connectionless transports (IPX, UDP?) * smb_tid a 16-bit tree ID, a mount point sorta, * 0xFFFF is this command does not have * or require a tree context * smb_pid a 16-bit process ID * smb_uid a 16-bit user ID, specific to this "session" * and mapped to a system (bona-fide) UID * smb_mid a 16-bit multiplex ID, used to differentiate * multiple simultaneous requests from the same * process (pid) (ref RPC "xid") * * SMB_COM_LOCKING_ANDX allows both locking and/or unlocking of file range(s). * * Client Request Description * ================================== ================================= * * UCHAR WordCount; Count of parameter words = 8 * UCHAR AndXCommand; Secondary (X) command; 0xFF = none * UCHAR AndXReserved; Reserved (must be 0) * USHORT AndXOffset; Offset to next command WordCount * USHORT Fid; File handle * UCHAR LockType; See LockType table below * UCHAR OplockLevel; The new oplock level * ULONG Timeout; Milliseconds to wait for unlock * USHORT NumberOfUnlocks; Num. unlock range structs following * USHORT NumberOfLocks; Num. lock range structs following * USHORT ByteCount; Count of data bytes * LOCKING_ANDX_RANGE Unlocks[]; Unlock ranges * LOCKING_ANDX_RANGE Locks[]; Lock ranges * * LockType Flag Name Value Description * ============================ ===== ================================ * * LOCKING_ANDX_SHARED_LOCK 0x01 Read-only lock * LOCKING_ANDX_OPLOCK_RELEASE 0x02 Oplock break notification * LOCKING_ANDX_CHANGE_LOCKTYPE 0x04 Change lock type * LOCKING_ANDX_CANCEL_LOCK 0x08 Cancel outstanding request * LOCKING_ANDX_LARGE_FILES 0x10 Large file locking format * * LOCKING_ANDX_RANGE Format * ===================================================================== * * USHORT Pid; PID of process "owning" lock * ULONG Offset; Offset to bytes to [un]lock * ULONG Length; Number of bytes to [un]lock * * Large File LOCKING_ANDX_RANGE Format * ===================================================================== * * USHORT Pid; PID of process "owning" lock * USHORT Pad; Pad to DWORD align (mbz) * ULONG OffsetHigh; Offset to bytes to [un]lock * (high) * ULONG OffsetLow; Offset to bytes to [un]lock (low) * ULONG LengthHigh; Number of bytes to [un]lock * (high) * ULONG LengthLow; Number of bytes to [un]lock (low) * * Server Response Description * ================================== ================================= * * UCHAR WordCount; Count of parameter words = 2 * UCHAR AndXCommand; Secondary (X) command; 0xFF = * none * UCHAR AndXReserved; Reserved (must be 0) * USHORT AndXOffset; Offset to next command WordCount * USHORT ByteCount; Count of data bytes = 0 * */ /* * smb_oplock_acquire * * Attempt to acquire an oplock. Note that the oplock granted may be * none, i.e. the oplock was not granted. * * Grant an oplock to the requestor if this session is the only one * that has the file open, regardless of the number of instances of * the file opened by this session. * * However, if there is no oplock on this file and there is already * at least one open, we will not grant an oplock, even if the only * existing opens are from the same client. This is "server discretion." * * An oplock may need to be broken in order for one to be granted, and * depending on what action is taken by the other client (unlock or close), * an oplock may or may not be granted. (The breaking of an oplock is * done earlier in the calling path.) * * XXX: Node synchronization is not yet implemented. However, racing * opens are handled thus: * * A racing oplock acquire can happen in the open path between * smb_oplock_break() and smb_fsop_open(), but no later. (Once * the file is open via smb_fsop_open()/VOP_OPEN, * smb_fsop_oplock_install() will not be able to install an oplock, * which requires an open count of 1.) * * Hence, we can safely break any oplock that came in after the * smb_oplock_break() done previously in the open path, knowing that * no other racing oplock acquisitions should be able to succeed * because we already have the file open (see above). * * The type of oplock being requested is passed in op->my_flags. The result * is also returned in op->my_flags. * * (Note that exclusive and batch oplocks are treated interchangeably.) * * The Returns NT status codes: * NT_STATUS_SUCCESS * NT_STATUS_CONNECTION_DISCONNECTED */ DWORD smb_oplock_acquire( smb_request_t *sr, smb_ofile_t *of, struct open_param *op) { smb_node_t *node; unsigned int level; ASSERT(sr); ASSERT(of); ASSERT(op); ASSERT(op->fqi.last_attr.sa_vattr.va_type == VREG); level = op->my_flags & MYF_OPLOCK_MASK; op->my_flags &= ~MYF_OPLOCK_MASK; if ((sr->sr_cfg->skc_oplock_enable == 0) || smb_tree_has_feature(of->f_tree, SMB_TREE_NO_OPLOCKS)) return (NT_STATUS_SUCCESS); if (!((MYF_IS_EXCLUSIVE_OPLOCK(level)) || (MYF_IS_BATCH_OPLOCK(level)))) return (NT_STATUS_SUCCESS); node = of->f_node; smb_rwx_rwenter(&node->n_lock, RW_WRITER); if (EXCLUSIVE_OPLOCK_IN_FORCE(node) || BATCH_OPLOCK_IN_FORCE(node)) { smb_rwx_rwexit(&node->n_lock); if (SMB_SAME_SESSION(sr->session, node->n_oplock.op_ofile->f_session)) { op->my_flags |= level; return (NT_STATUS_SUCCESS); } else if (SMB_ATTR_ONLY_OPEN(op)) { ASSERT(!(op->my_flags & MYF_OPLOCK_MASK)); return (NT_STATUS_SUCCESS); } smb_oplock_break(node); smb_rwx_rwenter(&node->n_lock, RW_WRITER); } if (smb_fsop_oplock_install(node, of->f_mode) != 0) { smb_rwx_rwexit(&node->n_lock); return (NT_STATUS_SUCCESS); } node->n_oplock.op_ofile = of; node->n_oplock.op_ipaddr = sr->session->ipaddr; node->n_oplock.op_kid = sr->session->s_kid; node->flags &= ~NODE_OPLOCKS_IN_FORCE; if (MYF_IS_EXCLUSIVE_OPLOCK(level)) node->flags |= NODE_EXCLUSIVE_OPLOCK; if (MYF_IS_BATCH_OPLOCK(level)) node->flags |= NODE_BATCH_OPLOCK; op->my_flags |= level; smb_rwx_rwexit(&node->n_lock); return (NT_STATUS_SUCCESS); } /* * smb_oplock_break * * The oplock break may succeed for multiple reasons: file close, oplock * release, holder connection dropped, requesting client disconnect etc. * Whatever the reason, the oplock should be broken when this function * returns. The exceptions are when the client making this request gets * disconnected or when another client is handling the break and it gets * disconnected. * * Returns NT status codes: * NT_STATUS_SUCCESS No oplock in force, i.e. the * oplock has been broken. * NT_STATUS_CONNECTION_DISCONNECTED Requesting client disconnected. * NT_STATUS_INTERNAL_ERROR */ void smb_oplock_break(smb_node_t *node) { smb_session_t *oplock_session; smb_ofile_t *oplock_ofile; struct mbuf_chain mbc; int retries = 0; clock_t elapsed_time; clock_t max_time; boolean_t flag; smb_rwx_rwenter(&node->n_lock, RW_WRITER); if (!OPLOCKS_IN_FORCE(node)) { smb_rwx_rwexit(&node->n_lock); return; } if (node->n_oplock.op_flags & OPLOCK_FLAG_BREAKING) { elapsed_time = 0; max_time = MSEC_TO_TICK(smb_oplock_timeout * OPLOCK_RETRIES); /* * Another client is already attempting to break the oplock. * We wait for it to finish. If the caller was trying to * acquire an oplock, he should retry in case the client's * connection was dropped while trying to break the oplock. * * If the holder's connection has been dropped, we yield to * allow the thread handling the break to detect it and set * the flags. */ while ((node->n_oplock.op_flags & OPLOCK_FLAG_BREAKING) && (elapsed_time < max_time)) { clock_t timeleft; timeleft = smb_rwx_rwwait(&node->n_lock, max_time); if (timeleft == -1) { elapsed_time = max_time; } else { elapsed_time += max_time - timeleft; } } /* * If there are no oplocks in force we're done. */ if (!OPLOCKS_IN_FORCE(node)) { smb_rwx_rwexit(&node->n_lock); return; } else { /* * This is an anomalous condition. * Cancel/release the oplock. */ smb_oplock_release(node, B_TRUE); smb_rwx_rwexit(&node->n_lock); return; } } oplock_ofile = node->n_oplock.op_ofile; ASSERT(oplock_ofile); oplock_session = oplock_ofile->f_session; ASSERT(oplock_session); /* * Start oplock break. */ node->n_oplock.op_flags |= OPLOCK_FLAG_BREAKING; smb_rwx_rwexit(&node->n_lock); max_time = MSEC_TO_TICK(smb_oplock_timeout); do { MBC_INIT(&mbc, MLEN); (void) smb_mbc_encodef(&mbc, "Mb19.wwwwbb3.ww10.", SMB_COM_LOCKING_ANDX, oplock_ofile->f_tree->t_tid, 0xffff, 0, 0xffff, 8, 0xff, oplock_ofile->f_fid, LOCKING_ANDX_OPLOCK_RELEASE); flag = B_TRUE; smb_rwx_rwenter(&oplock_session->s_lock, RW_WRITER); while (flag) { switch (oplock_session->s_state) { case SMB_SESSION_STATE_DISCONNECTED: case SMB_SESSION_STATE_TERMINATED: smb_rwx_rwexit(&oplock_session->s_lock); smb_rwx_rwenter(&node->n_lock, RW_WRITER); node->flags &= ~NODE_OPLOCKS_IN_FORCE; node->n_oplock.op_flags &= ~OPLOCK_FLAG_BREAKING; node->n_oplock.op_ofile = NULL; node->n_oplock.op_ipaddr = 0; node->n_oplock.op_kid = 0; smb_rwx_rwexit(&node->n_lock); return; case SMB_SESSION_STATE_OPLOCK_BREAKING: flag = B_FALSE; break; case SMB_SESSION_STATE_NEGOTIATED: oplock_session->s_state = SMB_SESSION_STATE_OPLOCK_BREAKING; flag = B_FALSE; break; default: (void) smb_rwx_rwwait(&oplock_session->s_lock, -1); break; } } smb_rwx_rwexit(&oplock_session->s_lock); (void) smb_session_send(oplock_session, 0, &mbc); elapsed_time = 0; smb_rwx_rwenter(&node->n_lock, RW_WRITER); while ((node->n_oplock.op_flags & OPLOCK_FLAG_BREAKING) && (elapsed_time < max_time)) { clock_t timeleft; timeleft = smb_rwx_rwwait(&node->n_lock, max_time); if (timeleft == -1) { elapsed_time = max_time; } else { elapsed_time += max_time - timeleft; } } if (!OPLOCKS_IN_FORCE(node)) { /* * smb_oplock_release() was called */ smb_rwx_rwexit(&node->n_lock); return; } } while (++retries < OPLOCK_RETRIES); /* * Retries exhausted and timed out. * Cancel the oplock and continue. */ smb_oplock_release(node, B_TRUE); smb_rwx_rwexit(&node->n_lock); } /* * smb_oplock_release * * This function uninstalls the FEM oplock monitors and * clears all flags in relation to an oplock on the * given node. * * The function can be called with the node->n_lock held * or not held. */ void /*ARGSUSED*/ smb_oplock_release(smb_node_t *node, boolean_t have_rwx) { if (!have_rwx) smb_rwx_rwenter(&node->n_lock, RW_WRITER); if (!OPLOCKS_IN_FORCE(node)) { if (!have_rwx) smb_rwx_rwexit(&node->n_lock); return; } smb_fsop_oplock_uninstall(node); node->flags &= ~NODE_OPLOCKS_IN_FORCE; node->n_oplock.op_flags &= ~OPLOCK_FLAG_BREAKING; node->n_oplock.op_ofile = NULL; node->n_oplock.op_ipaddr = 0; node->n_oplock.op_kid = 0; if (!have_rwx) smb_rwx_rwexit(&node->n_lock); } /* * smb_oplock_conflict * * The two checks on "session" and "op" are primarily for the open path. * Other CIFS functions may call smb_oplock_conflict() with a session * pointer so as to do the session check. */ boolean_t smb_oplock_conflict(smb_node_t *node, smb_session_t *session, struct open_param *op) { smb_session_t *oplock_session; smb_ofile_t *oplock_ofile; smb_rwx_rwenter(&node->n_lock, RW_READER); if (!OPLOCKS_IN_FORCE(node)) { smb_rwx_rwexit(&node->n_lock); return (B_FALSE); } oplock_ofile = node->n_oplock.op_ofile; ASSERT(oplock_ofile); oplock_session = oplock_ofile->f_session; ASSERT(oplock_session); if (SMB_SAME_SESSION(session, oplock_session)) { smb_rwx_rwexit(&node->n_lock); return (B_FALSE); } if (SMB_ATTR_ONLY_OPEN(op)) { smb_rwx_rwexit(&node->n_lock); return (B_FALSE); } smb_rwx_rwexit(&node->n_lock); return (B_TRUE); }