/*
* 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 (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright 2013 Nexenta Systems, Inc. All rights reserved.
*/
/*
* This module provides range lock functionality for CIFS/SMB clients.
* Lock range service functions process SMB lock and and unlock
* requests for a file by applying lock rules and marks file range
* as locked if the lock is successful otherwise return proper
* error code.
*/
#include <smbsrv/smb_kproto.h>
#include <smbsrv/smb_fsops.h>
#include <sys/nbmlock.h>
#include <sys/param.h>
extern caller_context_t smb_ct;
static void smb_lock_posix_unlock(smb_node_t *, smb_lock_t *, cred_t *);
static boolean_t smb_is_range_unlocked(uint64_t, uint64_t, uint32_t,
smb_llist_t *, uint64_t *);
static int smb_lock_range_overlap(smb_lock_t *, uint64_t, uint64_t);
static uint32_t smb_lock_range_lckrules(smb_request_t *, smb_ofile_t *,
smb_node_t *, smb_lock_t *, smb_lock_t **);
static clock_t smb_lock_wait(smb_request_t *, smb_lock_t *, smb_lock_t *);
static uint32_t smb_lock_range_ulckrules(smb_request_t *, smb_node_t *,
uint64_t, uint64_t, smb_lock_t **nodelock);
static smb_lock_t *smb_lock_create(smb_request_t *, uint64_t, uint64_t,
uint32_t, uint32_t);
static void smb_lock_destroy(smb_lock_t *);
static void smb_lock_free(smb_lock_t *);
/*
* Return the number of range locks on the specified ofile.
*/
uint32_t
smb_lock_get_lock_count(smb_node_t *node, smb_ofile_t *of)
{
smb_lock_t *lock;
smb_llist_t *llist;
uint32_t count = 0;
SMB_NODE_VALID(node);
SMB_OFILE_VALID(of);
llist = &node->n_lock_list;
smb_llist_enter(llist, RW_READER);
for (lock = smb_llist_head(llist);
lock != NULL;
lock = smb_llist_next(llist, lock)) {
if (lock->l_file == of)
++count;
}
smb_llist_exit(llist);
return (count);
}
/*
* smb_unlock_range
*
* locates lock range performed for corresponding to unlock request.
*
* NT_STATUS_SUCCESS - Lock range performed successfully.
* !NT_STATUS_SUCCESS - Error in unlock range operation.
*/
uint32_t
smb_unlock_range(
smb_request_t *sr,
smb_node_t *node,
uint64_t start,
uint64_t length)
{
smb_lock_t *lock = NULL;
uint32_t status;
/* Apply unlocking rules */
smb_llist_enter(&node->n_lock_list, RW_WRITER);
status = smb_lock_range_ulckrules(sr, node, start, length, &lock);
if (status != NT_STATUS_SUCCESS) {
/*
* If lock range is not matching in the list
* return error.
*/
ASSERT(lock == NULL);
smb_llist_exit(&node->n_lock_list);
return (status);
}
smb_llist_remove(&node->n_lock_list, lock);
smb_lock_posix_unlock(node, lock, sr->user_cr);
smb_llist_exit(&node->n_lock_list);
smb_lock_destroy(lock);
return (status);
}
/*
* smb_lock_range
*
* Checks for integrity of file lock operation for the given range of file data.
* This is performed by applying lock rules with all the elements of the node
* lock list.
*
* Break shared (levelII) oplocks. If there is an exclusive oplock, it is
* owned by this ofile and therefore should not be broken.
*
* The function returns with new lock added if lock request is non-conflicting
* with existing range lock for the file. Otherwise smb request is filed
* without returning.
*
* NT_STATUS_SUCCESS - Lock range performed successfully.
* !NT_STATUS_SUCCESS - Error in lock range operation.
*/
uint32_t
smb_lock_range(
smb_request_t *sr,
uint64_t start,
uint64_t length,
uint32_t timeout,
uint32_t locktype)
{
smb_ofile_t *file = sr->fid_ofile;
smb_node_t *node = file->f_node;
smb_lock_t *lock;
smb_lock_t *clock = NULL;
uint32_t result = NT_STATUS_SUCCESS;
boolean_t lock_has_timeout =
(timeout != 0 && timeout != UINT_MAX);
lock = smb_lock_create(sr, start, length, locktype, timeout);
smb_llist_enter(&node->n_lock_list, RW_WRITER);
for (;;) {
clock_t rc;
/* Apply locking rules */
result = smb_lock_range_lckrules(sr, file, node, lock, &clock);
if ((result == NT_STATUS_CANCELLED) ||
(result == NT_STATUS_SUCCESS) ||
(result == NT_STATUS_RANGE_NOT_LOCKED)) {
ASSERT(clock == NULL);
break;
} else if (timeout == 0) {
break;
}
ASSERT(result == NT_STATUS_LOCK_NOT_GRANTED);
ASSERT(clock);
/*
* Call smb_lock_wait holding write lock for
* node lock list. smb_lock_wait will release
* this lock if it blocks.
*/
ASSERT(node == clock->l_file->f_node);
rc = smb_lock_wait(sr, lock, clock);
if (rc == 0) {
result = NT_STATUS_CANCELLED;
break;
}
if (rc == -1)
timeout = 0;
clock = NULL;
}
lock->l_blocked_by = NULL;
if (result != NT_STATUS_SUCCESS) {
/*
* Under certain conditions NT_STATUS_FILE_LOCK_CONFLICT
* should be returned instead of NT_STATUS_LOCK_NOT_GRANTED.
* All of this appears to be specific to SMB1
*/
if (sr->session->dialect <= NT_LM_0_12 &&
result == NT_STATUS_LOCK_NOT_GRANTED) {
/*
* Locks with timeouts always return
* NT_STATUS_FILE_LOCK_CONFLICT
*/
if (lock_has_timeout)
result = NT_STATUS_FILE_LOCK_CONFLICT;
/*
* Locks starting higher than 0xef000000 that do not
* have the MSB set always return
* NT_STATUS_FILE_LOCK_CONFLICT
*/
if ((lock->l_start >= 0xef000000) &&
!(lock->l_start & (1ULL << 63))) {
result = NT_STATUS_FILE_LOCK_CONFLICT;
}
/*
* If the last lock attempt to fail on this file handle
* started at the same offset as this one then return
* NT_STATUS_FILE_LOCK_CONFLICT
*/
mutex_enter(&file->f_mutex);
if ((file->f_flags & SMB_OFLAGS_LLF_POS_VALID) &&
(lock->l_start == file->f_llf_pos)) {
result = NT_STATUS_FILE_LOCK_CONFLICT;
}
mutex_exit(&file->f_mutex);
}
/* Update last lock failed offset */
mutex_enter(&file->f_mutex);
file->f_llf_pos = lock->l_start;
file->f_flags |= SMB_OFLAGS_LLF_POS_VALID;
mutex_exit(&file->f_mutex);
smb_lock_free(lock);
} else {
/*
* don't insert into the CIFS lock list unless the
* posix lock worked
*/
if (smb_fsop_frlock(node, lock, B_FALSE, sr->user_cr))
result = NT_STATUS_FILE_LOCK_CONFLICT;
else
smb_llist_insert_tail(&node->n_lock_list, lock);
}
smb_llist_exit(&node->n_lock_list);
if (result == NT_STATUS_SUCCESS)
smb_oplock_break_levelII(node);
return (result);
}
/*
* smb_lock_range_access
*
* scans node lock list
* to check if there is any overlapping lock. Overlapping
* lock is allowed only under same session and client pid.
*
* Return values
* NT_STATUS_SUCCESS lock access granted.
* NT_STATUS_FILE_LOCK_CONFLICT access denied due to lock conflict.
*/
int
smb_lock_range_access(
smb_request_t *sr,
smb_node_t *node,
uint64_t start,
uint64_t length, /* zero means to EoF */
boolean_t will_write)
{
smb_lock_t *lock;
smb_llist_t *llist;
int status = NT_STATUS_SUCCESS;
llist = &node->n_lock_list;
smb_llist_enter(llist, RW_READER);
/* Search for any applicable lock */
for (lock = smb_llist_head(llist);
lock != NULL;
lock = smb_llist_next(llist, lock)) {
if (!smb_lock_range_overlap(lock, start, length))
/* Lock does not overlap */
continue;
if (lock->l_type == SMB_LOCK_TYPE_READONLY && !will_write)
continue;
if (lock->l_type == SMB_LOCK_TYPE_READWRITE &&
lock->l_session_kid == sr->session->s_kid &&
lock->l_pid == sr->smb_pid)
continue;
status = NT_STATUS_FILE_LOCK_CONFLICT;
break;
}
smb_llist_exit(llist);
return (status);
}
void
smb_node_destroy_lock_by_ofile(smb_node_t *node, smb_ofile_t *file)
{
smb_lock_t *lock;
smb_lock_t *nxtl;
list_t destroy_list;
SMB_NODE_VALID(node);
ASSERT(node->n_refcnt);
/*
* Move locks matching the specified file from the node->n_lock_list
* to a temporary list (holding the lock the entire time) then
* destroy all the matching locks. We can't call smb_lock_destroy
* while we are holding the lock for node->n_lock_list because we will
* deadlock and we can't drop the lock because the list contents might
* change (for example nxtl might get removed on another thread).
*/
list_create(&destroy_list, sizeof (smb_lock_t),
offsetof(smb_lock_t, l_lnd));
smb_llist_enter(&node->n_lock_list, RW_WRITER);
lock = smb_llist_head(&node->n_lock_list);
while (lock) {
nxtl = smb_llist_next(&node->n_lock_list, lock);
if (lock->l_file == file) {
smb_llist_remove(&node->n_lock_list, lock);
smb_lock_posix_unlock(node, lock, file->f_user->u_cred);
list_insert_tail(&destroy_list, lock);
}
lock = nxtl;
}
smb_llist_exit(&node->n_lock_list);
lock = list_head(&destroy_list);
while (lock) {
nxtl = list_next(&destroy_list, lock);
list_remove(&destroy_list, lock);
smb_lock_destroy(lock);
lock = nxtl;
}
list_destroy(&destroy_list);
}
void
smb_lock_range_error(smb_request_t *sr, uint32_t status32)
{
uint16_t errcode;
if (status32 == NT_STATUS_CANCELLED)
errcode = ERROR_OPERATION_ABORTED;
else
errcode = ERRlock;
smbsr_error(sr, status32, ERRDOS, errcode);
}
/*
* An SMB variant of nbl_conflict().
*
* SMB prevents remove or rename when conflicting locks exist
* (unlike NFS, which is why we can't just use nbl_conflict).
*
* Returns:
* NT_STATUS_SHARING_VIOLATION - nbl_share_conflict
* NT_STATUS_FILE_LOCK_CONFLICT - nbl_lock_conflict
* NT_STATUS_SUCCESS - operation can proceed
*
* NB: This function used to also check the list of ofiles,
* via: smb_lock_range_access() but we _can't_ do that here
* due to lock order constraints between node->n_lock_list
* and node->vp->vnbllock (taken via nvl_start_crit).
* They must be taken in that order, and in here, we
* already hold vp->vnbllock.
*/
DWORD
smb_nbl_conflict(smb_node_t *node, uint64_t off, uint64_t len, nbl_op_t op)
{
int svmand;
SMB_NODE_VALID(node);
ASSERT(smb_node_in_crit(node));
ASSERT(op == NBL_READ || op == NBL_WRITE || op == NBL_READWRITE ||
op == NBL_REMOVE || op == NBL_RENAME);
if (smb_node_is_dir(node))
return (NT_STATUS_SUCCESS);
if (nbl_share_conflict(node->vp, op, &smb_ct))
return (NT_STATUS_SHARING_VIOLATION);
/*
* When checking for lock conflicts, rename and remove
* are not allowed, so treat those as read/write.
*/
if (op == NBL_RENAME || op == NBL_REMOVE)
op = NBL_READWRITE;
if (nbl_svmand(node->vp, zone_kcred(), &svmand))
svmand = 1;
if (nbl_lock_conflict(node->vp, op, off, len, svmand, &smb_ct))
return (NT_STATUS_FILE_LOCK_CONFLICT);
return (NT_STATUS_SUCCESS);
}
/*
* smb_lock_posix_unlock
*
* checks if the current unlock request is in another lock and repeatedly calls
* smb_is_range_unlocked on a sliding basis to unlock all bits of the lock
* that are not in other locks
*
*/
static void
smb_lock_posix_unlock(smb_node_t *node, smb_lock_t *lock, cred_t *cr)
{
uint64_t new_mark;
uint64_t unlock_start;
uint64_t unlock_end;
smb_lock_t new_unlock;
smb_llist_t *llist;
boolean_t can_unlock;
new_mark = 0;
unlock_start = lock->l_start;
unlock_end = unlock_start + lock->l_length;
llist = &node->n_lock_list;
for (;;) {
can_unlock = smb_is_range_unlocked(unlock_start, unlock_end,
lock->l_file->f_uniqid, llist, &new_mark);
if (can_unlock) {
if (new_mark) {
new_unlock = *lock;
new_unlock.l_start = unlock_start;
new_unlock.l_length = new_mark - unlock_start;
(void) smb_fsop_frlock(node, &new_unlock,
B_TRUE, cr);
unlock_start = new_mark;
} else {
new_unlock = *lock;
new_unlock.l_start = unlock_start;
new_unlock.l_length = unlock_end - unlock_start;
(void) smb_fsop_frlock(node, &new_unlock,
B_TRUE, cr);
break;
}
} else if (new_mark) {
unlock_start = new_mark;
} else {
break;
}
}
}
/*
* smb_lock_range_overlap
*
* Checks if lock range(start, length) overlaps range in lock structure.
*
* Zero-length byte range locks actually affect no single byte of the stream,
* meaning they can still be accessed even with such locks in place. However,
* they do conflict with other ranges in the following manner:
* conflict will only exist if the positive-length range contains the
* zero-length range's offset but doesn't start at it
*
* return values:
* 0 - Lock range doesn't overlap
* 1 - Lock range overlaps.
*/
#define RANGE_NO_OVERLAP 0
#define RANGE_OVERLAP 1
static int
smb_lock_range_overlap(struct smb_lock *lock, uint64_t start, uint64_t length)
{
if (length == 0) {
if ((lock->l_start < start) &&
((lock->l_start + lock->l_length) > start))
return (RANGE_OVERLAP);
return (RANGE_NO_OVERLAP);
}
/* The following test is intended to catch roll over locks. */
if ((start == lock->l_start) && (length == lock->l_length))
return (RANGE_OVERLAP);
if (start < lock->l_start) {
if (start + length > lock->l_start)
return (RANGE_OVERLAP);
} else if (start < lock->l_start + lock->l_length)
return (RANGE_OVERLAP);
return (RANGE_NO_OVERLAP);
}
/*
* smb_lock_range_lckrules
*
* Lock range rules:
* 1. Overlapping read locks are allowed if the
* current locks in the region are only read locks
* irrespective of pid of smb client issuing lock request.
*
* 2. Read lock in the overlapped region of write lock
* are allowed if the pervious lock is performed by the
* same pid and connection.
*
* return status:
* NT_STATUS_SUCCESS - Input lock range adapts to lock rules.
* NT_STATUS_LOCK_NOT_GRANTED - Input lock conflicts lock rules.
* NT_STATUS_CANCELLED - Error in processing lock rules
*/
static uint32_t
smb_lock_range_lckrules(
smb_request_t *sr,
smb_ofile_t *file,
smb_node_t *node,
smb_lock_t *dlock,
smb_lock_t **clockp)
{
smb_lock_t *lock;
uint32_t status = NT_STATUS_SUCCESS;
/* Check if file is closed */
if (!smb_ofile_is_open(file)) {
return (NT_STATUS_RANGE_NOT_LOCKED);
}
/* Caller must hold lock for node->n_lock_list */
for (lock = smb_llist_head(&node->n_lock_list);
lock != NULL;
lock = smb_llist_next(&node->n_lock_list, lock)) {
if (!smb_lock_range_overlap(lock, dlock->l_start,
dlock->l_length))
continue;
/*
* Check to see if lock in the overlapping record
* is only read lock. Current finding is read
* locks can overlapped irrespective of pids.
*/
if ((lock->l_type == SMB_LOCK_TYPE_READONLY) &&
(dlock->l_type == SMB_LOCK_TYPE_READONLY)) {
continue;
}
/*
* When the read lock overlaps write lock, check if
* allowed.
*/
if ((dlock->l_type == SMB_LOCK_TYPE_READONLY) &&
!(lock->l_type == SMB_LOCK_TYPE_READONLY)) {
if (lock->l_file == sr->fid_ofile &&
lock->l_session_kid == sr->session->s_kid &&
lock->l_pid == sr->smb_pid &&
lock->l_uid == sr->smb_uid) {
continue;
}
}
/* Conflict in overlapping lock element */
*clockp = lock;
status = NT_STATUS_LOCK_NOT_GRANTED;
break;
}
return (status);
}
/*
* smb_lock_wait
*
* Wait operation for smb overlapping lock to be released. Caller must hold
* write lock for node->n_lock_list so that the set of active locks can't
* change unexpectedly. The lock for node->n_lock_list will be released
* within this function during the sleep after the lock dependency has
* been recorded.
*
* return value
*
* 0 The request was canceled.
* -1 The timeout was reached.
* >0 Condition met.
*/
static clock_t
smb_lock_wait(smb_request_t *sr, smb_lock_t *b_lock, smb_lock_t *c_lock)
{
clock_t rc = 0;
ASSERT(sr->sr_awaiting == NULL);
mutex_enter(&sr->sr_mutex);
switch (sr->sr_state) {
case SMB_REQ_STATE_ACTIVE:
/*
* Wait up till the timeout time keeping track of actual
* time waited for possible retry failure.
*/
sr->sr_state = SMB_REQ_STATE_WAITING_LOCK;
sr->sr_awaiting = c_lock;
mutex_exit(&sr->sr_mutex);
mutex_enter(&c_lock->l_mutex);
/*
* The conflict list (l_conflict_list) for a lock contains
* all the locks that are blocked by and in conflict with
* that lock. Add the new lock to the conflict list for the
* active lock.
*
* l_conflict_list is currently a fancy way of representing
* the references/dependencies on a lock. It could be
* replaced with a reference count but this approach
* has the advantage that MDB can display the lock
* dependencies at any point in time. In the future
* we should be able to leverage the list to implement
* an asynchronous locking model.
*
* l_blocked_by is the reverse of the conflict list. It
* points to the lock that the new lock conflicts with.
* As currently implemented this value is purely for
* debug purposes -- there are windows of time when
* l_blocked_by may be non-NULL even though there is no
* conflict list
*/
b_lock->l_blocked_by = c_lock;
smb_slist_insert_tail(&c_lock->l_conflict_list, b_lock);
smb_llist_exit(&c_lock->l_file->f_node->n_lock_list);
if (SMB_LOCK_INDEFINITE_WAIT(b_lock)) {
cv_wait(&c_lock->l_cv, &c_lock->l_mutex);
} else {
rc = cv_timedwait(&c_lock->l_cv,
&c_lock->l_mutex, b_lock->l_end_time);
}
mutex_exit(&c_lock->l_mutex);
smb_llist_enter(&c_lock->l_file->f_node->n_lock_list,
RW_WRITER);
smb_slist_remove(&c_lock->l_conflict_list, b_lock);
mutex_enter(&sr->sr_mutex);
sr->sr_awaiting = NULL;
if (sr->sr_state == SMB_REQ_STATE_CANCELED) {
rc = 0;
} else {
sr->sr_state = SMB_REQ_STATE_ACTIVE;
}
break;
default:
ASSERT(sr->sr_state == SMB_REQ_STATE_CANCELED);
rc = 0;
break;
}
mutex_exit(&sr->sr_mutex);
return (rc);
}
/*
* smb_lock_range_ulckrules
*
* 1. Unlock should be performed at exactly matching ends.
* This has been changed because overlapping ends is
* allowed and there is no other precise way of locating
* lock entity in node lock list.
*
* 2. Unlock is failed if there is no corresponding lock exists.
*
* Return values
*
* NT_STATUS_SUCCESS Unlock request matches lock record
* pointed by 'nodelock' lock structure.
*
* NT_STATUS_RANGE_NOT_LOCKED Unlock request doen't match any
* of lock record in node lock request or
* error in unlock range processing.
*/
static uint32_t
smb_lock_range_ulckrules(
smb_request_t *sr,
smb_node_t *node,
uint64_t start,
uint64_t length,
smb_lock_t **nodelock)
{
smb_lock_t *lock;
uint32_t status = NT_STATUS_RANGE_NOT_LOCKED;
/* Caller must hold lock for node->n_lock_list */
for (lock = smb_llist_head(&node->n_lock_list);
lock != NULL;
lock = smb_llist_next(&node->n_lock_list, lock)) {
if ((start == lock->l_start) &&
(length == lock->l_length) &&
lock->l_file == sr->fid_ofile &&
lock->l_session_kid == sr->session->s_kid &&
lock->l_pid == sr->smb_pid &&
lock->l_uid == sr->smb_uid) {
*nodelock = lock;
status = NT_STATUS_SUCCESS;
break;
}
}
return (status);
}
static smb_lock_t *
smb_lock_create(
smb_request_t *sr,
uint64_t start,
uint64_t length,
uint32_t locktype,
uint32_t timeout)
{
smb_lock_t *lock;
ASSERT(locktype == SMB_LOCK_TYPE_READWRITE ||
locktype == SMB_LOCK_TYPE_READONLY);
lock = kmem_zalloc(sizeof (smb_lock_t), KM_SLEEP);
lock->l_magic = SMB_LOCK_MAGIC;
lock->l_sr = sr; /* Invalid after lock is active */
lock->l_session_kid = sr->session->s_kid;
lock->l_session = sr->session;
lock->l_file = sr->fid_ofile;
lock->l_uid = sr->smb_uid;
lock->l_pid = sr->smb_pid;
lock->l_type = locktype;
lock->l_start = start;
lock->l_length = length;
/*
* Calculate the absolute end time so that we can use it
* in cv_timedwait.
*/
lock->l_end_time = ddi_get_lbolt() + MSEC_TO_TICK(timeout);
if (timeout == UINT_MAX)
lock->l_flags |= SMB_LOCK_FLAG_INDEFINITE;
mutex_init(&lock->l_mutex, NULL, MUTEX_DEFAULT, NULL);
cv_init(&lock->l_cv, NULL, CV_DEFAULT, NULL);
smb_slist_constructor(&lock->l_conflict_list, sizeof (smb_lock_t),
offsetof(smb_lock_t, l_conflict_lnd));
return (lock);
}
static void
smb_lock_free(smb_lock_t *lock)
{
smb_slist_destructor(&lock->l_conflict_list);
cv_destroy(&lock->l_cv);
mutex_destroy(&lock->l_mutex);
kmem_free(lock, sizeof (smb_lock_t));
}
/*
* smb_lock_destroy
*
* Caller must hold node->n_lock_list
*/
static void
smb_lock_destroy(smb_lock_t *lock)
{
/*
* Caller must hold node->n_lock_list lock.
*/
mutex_enter(&lock->l_mutex);
cv_broadcast(&lock->l_cv);
mutex_exit(&lock->l_mutex);
/*
* The cv_broadcast above should wake up any locks that previous
* had conflicts with this lock. Wait for the locking threads
* to remove their references to this lock.
*/
smb_slist_wait_for_empty(&lock->l_conflict_list);
smb_lock_free(lock);
}
/*
* smb_is_range_unlocked
*
* Checks if the current unlock byte range request overlaps another lock
* This function is used to determine where POSIX unlocks should be
* applied.
*
* The return code and the value of new_mark must be interpreted as
* follows:
*
* B_TRUE and (new_mark == 0):
* This is the last or only lock left to be unlocked
*
* B_TRUE and (new_mark > 0):
* The range from start to new_mark can be unlocked
*
* B_FALSE and (new_mark == 0):
* The unlock can't be performed and we are done
*
* B_FALSE and (new_mark > 0),
* The range from start to new_mark can't be unlocked
* Start should be reset to new_mark for the next pass
*/
static boolean_t
smb_is_range_unlocked(uint64_t start, uint64_t end, uint32_t uniqid,
smb_llist_t *llist_head, uint64_t *new_mark)
{
struct smb_lock *lk = NULL;
uint64_t low_water_mark = MAXOFFSET_T;
uint64_t lk_start;
uint64_t lk_end;
*new_mark = 0;
lk = smb_llist_head(llist_head);
while (lk) {
if (lk->l_length == 0) {
lk = smb_llist_next(llist_head, lk);
continue;
}
if (lk->l_file->f_uniqid != uniqid) {
lk = smb_llist_next(llist_head, lk);
continue;
}
lk_end = lk->l_start + lk->l_length - 1;
lk_start = lk->l_start;
/*
* there is no overlap for the first 2 cases
* check next node
*/
if (lk_end < start) {
lk = smb_llist_next(llist_head, lk);
continue;
}
if (lk_start > end) {
lk = smb_llist_next(llist_head, lk);
continue;
}
/* this range is completely locked */
if ((lk_start <= start) && (lk_end >= end)) {
return (B_FALSE);
}
/* the first part of this range is locked */
if ((start >= lk_start) && (start <= lk_end)) {
if (end > lk_end)
*new_mark = lk_end + 1;
return (B_FALSE);
}
/* this piece is unlocked */
if ((lk_start >= start) && (lk_start <= end)) {
if (low_water_mark > lk_start)
low_water_mark = lk_start;
}
lk = smb_llist_next(llist_head, lk);
}
if (low_water_mark != MAXOFFSET_T) {
*new_mark = low_water_mark;
return (B_TRUE);
}
/* the range is completely unlocked */
return (B_TRUE);
}