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DEVEL15-windows-interlocked-volume-refcount-20080306

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LICENSE MIT

Switch cm_volume_t objects to InterlockedIncrement/InterlockedDecrement
for reference counting.

Remove protections against null pointers being passed into cm_GetVolume()
Instead, do not call cm_GetVolume() if the pointer is NULL.

Fix a buffer data version comparison that should be bad version number
instead of <= 0.


(cherry picked from commit fb154e60e3cb6cf9e934f9a75c5ca67473ac36a2)
This commit is contained in:
Jeffrey Altman 2008-03-07 01:14:13 +00:00
parent 42c527deab
commit efcef7c17f
4 changed files with 21 additions and 24 deletions
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2
src/WINNT/afsd/cm_buf.c
View File

@ -1188,7 +1188,7 @@ long buf_CountFreeList(void)
* has been invalidate (by having its DV stomped upon), then
* count it as free, since it isn't really being utilized.
*/
if (!(bufp->flags & CM_BUF_INHASH) || bufp->dataVersion <= 0)
if (!(bufp->flags & CM_BUF_INHASH) || bufp->dataVersion == CM_BUF_VERSION_BAD)
count++;
}
lock_ReleaseRead(&buf_globalLock);

3
src/WINNT/afsd/cm_scache.c
View File

@ -746,7 +746,8 @@ long cm_GetSCache(cm_fid_t *fidp, cm_scache_t **outScpp, cm_user_t *userp,
#endif
scp->fid = *fidp;
scp->volp = cm_data.rootSCachep->volp;
cm_GetVolume(scp->volp); /* grab an additional reference */
if (scp->volp)
cm_GetVolume(scp->volp); /* grab an additional reference */
scp->dotdotFid.cell=AFS_FAKE_ROOT_CELL_ID;
scp->dotdotFid.volume=AFS_FAKE_ROOT_VOL_ID;
scp->dotdotFid.unique=1;

36
src/WINNT/afsd/cm_volume.c
View File

@ -553,11 +553,7 @@ long cm_UpdateVolume(struct cm_cell *cellp, cm_user_t *userp, cm_req_t *reqp,
void cm_GetVolume(cm_volume_t *volp)
{
if (volp) {
lock_ObtainWrite(&cm_volumeLock);
volp->refCount++;
lock_ReleaseWrite(&cm_volumeLock);
}
InterlockedIncrement(&volp->refCount);
}
@ -782,12 +778,12 @@ long cm_GetVolumeByName(struct cm_cell *cellp, char *volumeNamep,
}
else {
lock_ReleaseRead(&cm_volumeLock);
if (volp) {
cm_GetVolume(volp);
lock_ObtainMutex(&volp->mx);
} else {
if (!volp)
return CM_ERROR_NOSUCHVOLUME;
}
cm_GetVolume(volp);
lock_ObtainMutex(&volp->mx);
}
/* if we get here we are holding the mutex */
@ -803,15 +799,15 @@ long cm_GetVolumeByName(struct cm_cell *cellp, char *volumeNamep,
code = CM_ERROR_NOSUCHVOLUME;
if (code == 0) {
*outVolpp = volp;
*outVolpp = volp;
if (!(flags & CM_GETVOL_FLAG_NO_LRU_UPDATE)) {
lock_ObtainWrite(&cm_volumeLock);
cm_AdjustVolumeLRU(volp);
lock_ReleaseWrite(&cm_volumeLock);
}
if (!(flags & CM_GETVOL_FLAG_NO_LRU_UPDATE)) {
lock_ObtainWrite(&cm_volumeLock);
cm_AdjustVolumeLRU(volp);
lock_ReleaseWrite(&cm_volumeLock);
}
} else
cm_PutVolume(volp);
cm_PutVolume(volp);
return code;
}
@ -869,7 +865,6 @@ void cm_ForceUpdateVolume(cm_fid_t *fidp, cm_user_t *userp, cm_req_t *reqp)
#ifdef SEARCH_ALL_VOLUMES
osi_assertx(volp == volp2, "unexpected cm_vol_t");
#endif
lock_ReleaseRead(&cm_volumeLock);
/* hold the volume if we found it */
@ -927,9 +922,8 @@ cm_serverRef_t **cm_GetVolServers(cm_volume_t *volp, afs_uint32 volume)
void cm_PutVolume(cm_volume_t *volp)
{
lock_ObtainWrite(&cm_volumeLock);
osi_assertx(volp->refCount-- > 0, "cm_volume_t refCount 0");
lock_ReleaseWrite(&cm_volumeLock);
afs_int32 refCount = InterlockedDecrement(&volp->refCount);
osi_assertx(refCount >= 0, "cm_volume_t refCount underflow has occurred");
}
/* return the read-only volume, if there is one, or the read-write volume if

4
src/WINNT/afsd/cm_volume.h
View File

@ -36,7 +36,7 @@ typedef struct cm_volume {
struct cm_fid dotdotFid; /* parent of volume root */
osi_mutex_t mx;
afs_uint32 flags; /* by mx */
afs_uint32 refCount; /* by cm_volumeLock */
afs_int32 refCount; /* by Interlocked operations */
time_t cbExpiresRO; /* latest RO expiration time; by cm_scacheLock */
} cm_volume_t;
@ -121,4 +121,6 @@ extern void cm_VolumeStatusNotification(cm_volume_t * volp, afs_uint32 volID, en
extern enum volstatus cm_GetVolumeStatus(cm_volume_t *volp, afs_uint32 volID);
extern void cm_VolumeRenewROCallbacks(void);
extern osi_rwlock_t cm_volumeLock;
#endif /* __CM_VOLUME_H_ENV__ */