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-rw-r--r--source3/include/locking.h8
-rw-r--r--source3/locking/brlock.c95
-rw-r--r--source3/locking/locking.c6
-rw-r--r--source3/smbd/blocking.c2
4 files changed, 77 insertions, 34 deletions
diff --git a/source3/include/locking.h b/source3/include/locking.h
index 9e70411fa6..a09e7d1aff 100644
--- a/source3/include/locking.h
+++ b/source3/include/locking.h
@@ -23,11 +23,15 @@
#define _LOCKING_H
/* passed to br lock code - the UNLOCK_LOCK should never be stored into the tdb
- and is used in calculating POSIX unlock ranges only. */
+ and is used in calculating POSIX unlock ranges only. We differentiate between
+ PENDING read and write locks to allow posix lock downgrades to trigger a lock
+ re-evaluation. */
-enum brl_type {READ_LOCK, WRITE_LOCK, PENDING_LOCK, UNLOCK_LOCK};
+enum brl_type {READ_LOCK, WRITE_LOCK, PENDING_READ_LOCK, PENDING_WRITE_LOCK, UNLOCK_LOCK};
enum brl_flavour {WINDOWS_LOCK = 0, POSIX_LOCK = 1};
+#define IS_PENDING_LOCK(type) ((type) == PENDING_READ_LOCK || (type) == PENDING_WRITE_LOCK)
+
/* This contains elements that differentiate locks. The smbpid is a
client supplied pid, and is essentially the locking context for
this client */
diff --git a/source3/locking/brlock.c b/source3/locking/brlock.c
index 4a36d938ad..568c80f3ee 100644
--- a/source3/locking/brlock.c
+++ b/source3/locking/brlock.c
@@ -98,7 +98,7 @@ static BOOL brl_conflict(const struct lock_struct *lck1,
const struct lock_struct *lck2)
{
/* Ignore PENDING locks. */
- if (lck1->lock_type == PENDING_LOCK || lck2->lock_type == PENDING_LOCK )
+ if (IS_PENDING_LOCK(lck1->lock_type) || IS_PENDING_LOCK(lck2->lock_type))
return False;
/* Read locks never conflict. */
@@ -129,7 +129,7 @@ static BOOL brl_conflict_posix(const struct lock_struct *lck1,
#endif
/* Ignore PENDING locks. */
- if (lck1->lock_type == PENDING_LOCK || lck2->lock_type == PENDING_LOCK )
+ if (IS_PENDING_LOCK(lck1->lock_type) || IS_PENDING_LOCK(lck2->lock_type))
return False;
/* Read locks never conflict. */
@@ -151,7 +151,7 @@ static BOOL brl_conflict_posix(const struct lock_struct *lck1,
static BOOL brl_conflict1(const struct lock_struct *lck1,
const struct lock_struct *lck2)
{
- if (lck1->lock_type == PENDING_LOCK || lck2->lock_type == PENDING_LOCK )
+ if (IS_PENDING_LOCK(lck1->lock_type) || IS_PENDING_LOCK(lck2->lock_type))
return False;
if (lck1->lock_type == READ_LOCK && lck2->lock_type == READ_LOCK) {
@@ -184,7 +184,7 @@ static BOOL brl_conflict1(const struct lock_struct *lck1,
static BOOL brl_conflict_other(const struct lock_struct *lck1, const struct lock_struct *lck2)
{
- if (lck1->lock_type == PENDING_LOCK || lck2->lock_type == PENDING_LOCK )
+ if (IS_PENDING_LOCK(lck1->lock_type) || IS_PENDING_LOCK(lck2->lock_type))
return False;
if (lck1->lock_type == READ_LOCK && lck2->lock_type == READ_LOCK)
@@ -211,6 +211,19 @@ static BOOL brl_conflict_other(const struct lock_struct *lck1, const struct lock
}
/****************************************************************************
+ Check if an unlock overlaps a pending lock.
+****************************************************************************/
+
+static BOOL brl_pending_overlap(const struct lock_struct *lock, const struct lock_struct *pend_lock)
+{
+ if ((lock->start <= pend_lock->start) && (lock->start + lock->size > pend_lock->start))
+ return True;
+ if ((lock->start >= pend_lock->start) && (lock->start <= pend_lock->start + pend_lock->size))
+ return True;
+ return False;
+}
+
+/****************************************************************************
Amazingly enough, w2k3 "remembers" whether the last lock failure on a fnum
is the same as this one and changes its error code. I wonder if any
app depends on this ?
@@ -320,7 +333,7 @@ static NTSTATUS brl_lock_windows(struct byte_range_lock *br_lck,
be mapped into a lower level POSIX one, and if so can
we get it ? */
- if ((plock->lock_type != PENDING_LOCK) && lp_posix_locking(SNUM(fsp->conn))) {
+ if (!IS_PENDING_LOCK(plock->lock_type) && lp_posix_locking(SNUM(fsp->conn))) {
int errno_ret;
if (!set_posix_lock_windows_flavour(fsp,
plock->start,
@@ -575,6 +588,7 @@ static NTSTATUS brl_lock_posix(struct byte_range_lock *br_lck,
struct lock_struct *locks = (struct lock_struct *)br_lck->lock_data;
struct lock_struct *tp;
BOOL lock_was_added = False;
+ BOOL signal_pending_read = False;
/* No zero-zero locks for POSIX. */
if (plock->start == 0 && plock->size == 0) {
@@ -598,19 +612,28 @@ static NTSTATUS brl_lock_posix(struct byte_range_lock *br_lck,
count = 0;
for (i=0; i < br_lck->num_locks; i++) {
- if (locks[i].lock_flav == WINDOWS_LOCK) {
+ struct lock_struct *curr_lock = &locks[i];
+
+ /* If we have a pending read lock, a lock downgrade should
+ trigger a lock re-evaluation. */
+ if (curr_lock->lock_type == PENDING_READ_LOCK &&
+ brl_pending_overlap(plock, curr_lock)) {
+ signal_pending_read = True;
+ }
+
+ if (curr_lock->lock_flav == WINDOWS_LOCK) {
/* Do any Windows flavour locks conflict ? */
- if (brl_conflict(&locks[i], plock)) {
+ if (brl_conflict(curr_lock, plock)) {
/* No games with error messages. */
SAFE_FREE(tp);
return NT_STATUS_FILE_LOCK_CONFLICT;
}
/* Just copy the Windows lock into the new array. */
- memcpy(&tp[count], &locks[i], sizeof(struct lock_struct));
+ memcpy(&tp[count], curr_lock, sizeof(struct lock_struct));
count++;
} else {
/* POSIX conflict semantics are different. */
- if (brl_conflict_posix(&locks[i], plock)) {
+ if (brl_conflict_posix(curr_lock, plock)) {
/* Can't block ourselves with POSIX locks. */
/* No games with error messages. */
SAFE_FREE(tp);
@@ -618,7 +641,7 @@ static NTSTATUS brl_lock_posix(struct byte_range_lock *br_lck,
}
/* Work out overlaps. */
- count += brlock_posix_split_merge(&tp[count], &locks[i], plock, &lock_was_added);
+ count += brlock_posix_split_merge(&tp[count], curr_lock, plock, &lock_was_added);
}
}
@@ -631,7 +654,7 @@ static NTSTATUS brl_lock_posix(struct byte_range_lock *br_lck,
be mapped into a lower level POSIX one, and if so can
we get it ? */
- if ((plock->lock_type != PENDING_LOCK) && lp_posix_locking(SNUM(br_lck->fsp->conn))) {
+ if (!IS_PENDING_LOCK(plock->lock_type) && lp_posix_locking(SNUM(br_lck->fsp->conn))) {
int errno_ret;
/* The lower layer just needs to attempt to
@@ -661,7 +684,34 @@ static NTSTATUS brl_lock_posix(struct byte_range_lock *br_lck,
br_lck->num_locks = count;
SAFE_FREE(br_lck->lock_data);
br_lck->lock_data = (void *)tp;
+ locks = tp;
br_lck->modified = True;
+
+ /* A successful downgrade from write to read lock can trigger a lock
+ re-evalutation where waiting readers can now proceed. */
+
+ if (signal_pending_read) {
+ /* Send unlock messages to any pending read waiters that overlap. */
+ for (i=0; i < br_lck->num_locks; i++) {
+ struct lock_struct *pend_lock = &locks[i];
+
+ /* Ignore non-pending locks. */
+ if (!IS_PENDING_LOCK(pend_lock->lock_type)) {
+ continue;
+ }
+
+ if (pend_lock->lock_type == PENDING_READ_LOCK &&
+ brl_pending_overlap(plock, pend_lock)) {
+ DEBUG(10,("brl_lock_posix: sending unlock message to pid %s\n",
+ procid_str_static(&pend_lock->context.pid )));
+
+ message_send_pid(pend_lock->context.pid,
+ MSG_SMB_UNLOCK,
+ NULL, 0, True);
+ }
+ }
+ }
+
return NT_STATUS_OK;
}
@@ -711,19 +761,6 @@ NTSTATUS brl_lock(struct byte_range_lock *br_lck,
}
/****************************************************************************
- Check if an unlock overlaps a pending lock.
-****************************************************************************/
-
-static BOOL brl_pending_overlap(const struct lock_struct *lock, const struct lock_struct *pend_lock)
-{
- if ((lock->start <= pend_lock->start) && (lock->start + lock->size > pend_lock->start))
- return True;
- if ((lock->start >= pend_lock->start) && (lock->start <= pend_lock->start + pend_lock->size))
- return True;
- return False;
-}
-
-/****************************************************************************
Unlock a range of bytes - Windows semantics.
****************************************************************************/
@@ -807,7 +844,7 @@ static BOOL brl_unlock_windows(struct byte_range_lock *br_lck, const struct lock
struct lock_struct *pend_lock = &locks[j];
/* Ignore non-pending locks. */
- if (pend_lock->lock_type != PENDING_LOCK) {
+ if (!IS_PENDING_LOCK(pend_lock->lock_type)) {
continue;
}
@@ -866,7 +903,7 @@ static BOOL brl_unlock_posix(struct byte_range_lock *br_lck, const struct lock_s
unsigned int tmp_count;
/* Only remove our own locks - ignore fnum. */
- if (lock->lock_type == PENDING_LOCK ||
+ if (IS_PENDING_LOCK(lock->lock_type) ||
!brl_same_context(&lock->context, &plock->context)) {
memcpy(&tp[count], lock, sizeof(struct lock_struct));
count++;
@@ -974,7 +1011,7 @@ static BOOL brl_unlock_posix(struct byte_range_lock *br_lck, const struct lock_s
struct lock_struct *pend_lock = &locks[j];
/* Ignore non-pending locks. */
- if (pend_lock->lock_type != PENDING_LOCK) {
+ if (!IS_PENDING_LOCK(pend_lock->lock_type)) {
continue;
}
@@ -1173,7 +1210,7 @@ BOOL brl_lock_cancel(struct byte_range_lock *br_lck,
/* For pending locks we *always* care about the fnum. */
if (brl_same_context(&lock->context, &context) &&
lock->fnum == br_lck->fsp->fnum &&
- lock->lock_type == PENDING_LOCK &&
+ IS_PENDING_LOCK(lock->lock_type) &&
lock->lock_flav == lock_flav &&
lock->start == start &&
lock->size == size) {
@@ -1288,7 +1325,7 @@ void brl_close_fnum(struct byte_range_lock *br_lck)
struct lock_struct *pend_lock = &locks[j];
/* Ignore our own or non-pending locks. */
- if (pend_lock->lock_type != PENDING_LOCK) {
+ if (!IS_PENDING_LOCK(pend_lock->lock_type)) {
continue;
}
diff --git a/source3/locking/locking.c b/source3/locking/locking.c
index 3879d40cba..4cd6b436c3 100644
--- a/source3/locking/locking.c
+++ b/source3/locking/locking.c
@@ -55,8 +55,10 @@ const char *lock_type_name(enum brl_type lock_type)
return "READ";
case WRITE_LOCK:
return "WRITE";
- case PENDING_LOCK:
- return "PENDING";
+ case PENDING_READ_LOCK:
+ return "PENDING_READ";
+ case PENDING_WRITE_LOCK:
+ return "PENDING_WRITE";
default:
return "other";
}
diff --git a/source3/smbd/blocking.c b/source3/smbd/blocking.c
index ed57c9f621..0304a6559f 100644
--- a/source3/smbd/blocking.c
+++ b/source3/smbd/blocking.c
@@ -137,7 +137,7 @@ BOOL push_blocking_lock_request( struct byte_range_lock *br_lck,
procid_self(),
offset,
count,
- PENDING_LOCK,
+ lock_type == READ_LOCK ? PENDING_READ_LOCK : PENDING_WRITE_LOCK,
blr->lock_flav,
lock_timeout ? True : False); /* blocking_lock. */
generated by cgit (git 2.34.1) at 2024-12-01 18:01:33 +0000