From: Felix Frank <Felix.Frank@Desy.de>
Date: Tue, 12 May 2009 18:56:30 +0000 (+0000)
Subject: linux-mmap-antirecursion-fix-20090512
X-Git-Tag: openafs-devel-1_5_61~330
X-Git-Url: https://git.michaelhowe.org/gitweb/?a=commitdiff_plain;h=5e0e1ea2540d0cb7d7274350eb1fadfd41733ea4;p=packages%2Fo%2Fopenafs.git

linux-mmap-antirecursion-fix-20090512

LICENSE IPL10
FIXES 124627

fix the mmap anti-recursion protection to set and mask CPageWrite appropriately
and with the correct lock protection. this leaves us with an issue to handle
when the mmap'd file is larger (possibly considerably larger) than the
cache
---

diff --git a/src/afs/LINUX/osi_vm.c b/src/afs/LINUX/osi_vm.c
index c96babd66..55a3737e7 100644
--- a/src/afs/LINUX/osi_vm.c
+++ b/src/afs/LINUX/osi_vm.c
@@ -102,9 +102,7 @@ osi_VM_StoreAllSegments(struct vcache *avc)
 {
     struct inode *ip = AFSTOV(avc);
 
-    if (!avc->f.states & CPageWrite)
-	avc->f.states |= CPageWrite;
-    else 
+    if (avc->f.states & CPageWrite)
 	return; /* someone already writing */
 
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,4,5)
@@ -120,7 +118,6 @@ osi_VM_StoreAllSegments(struct vcache *avc)
     AFS_GLOCK();
     ObtainWriteLock(&avc->lock, 121);
 #endif
-    avc->f.states &= ~CPageWrite;
 }
 
 /* Purge VM for a file when its callback is revoked.
diff --git a/src/afs/LINUX/osi_vnodeops.c b/src/afs/LINUX/osi_vnodeops.c
index 67e7bad36..39bd08151 100644
--- a/src/afs/LINUX/osi_vnodeops.c
+++ b/src/afs/LINUX/osi_vnodeops.c
@@ -1188,7 +1188,7 @@ afs_linux_lookup(struct inode *dip, struct dentry *dp)
     if (code == ENOENT)
 	return ERR_PTR(0);
 #endif
-    else if ((code >= 0) && (code <= MAX_ERRNO))
+    else if ((code > 0) && (code <= MAX_ERRNO))
         return ERR_PTR(-code);
     else 
 	return ERR_PTR(-EIO);
@@ -1895,9 +1895,9 @@ afs_linux_writepage_sync(struct inode *ip, struct page *pp,
 	       ICL_TYPE_POINTER, pp, ICL_TYPE_INT32, page_count(pp),
 	       ICL_TYPE_INT32, 99999);
 
-    ObtainReadLock(&vcp->lock);
+    ObtainWriteLock(&vcp->lock, 532);
     if (vcp->f.states & CPageWrite) {
-	ReleaseReadLock(&vcp->lock);
+	ReleaseWriteLock(&vcp->lock);
 	AFS_GUNLOCK();
 	maybe_unlock_kernel();
 	crfree(credp);
@@ -1913,7 +1913,8 @@ afs_linux_writepage_sync(struct inode *ip, struct page *pp,
 	return(0); 
 #endif
     }
-    ReleaseReadLock(&vcp->lock);
+    vcp->states |= CPageWrite;
+    ReleaseWriteLock(&vcp->lock);
 
     setup_uio(&tuio, &iovec, buffer, base, count, UIO_WRITE, AFS_UIOSYS);
 
@@ -1922,16 +1923,18 @@ afs_linux_writepage_sync(struct inode *ip, struct page *pp,
     i_size_write(ip, vcp->f.m.Length);
     ip->i_blocks = ((vcp->f.m.Length + 1023) >> 10) << 1;
 
+    ObtainWriteLock(&vcp->lock, 533);
     if (!code) {
 	struct vrequest treq;
 
-	ObtainWriteLock(&vcp->lock, 533);
 	if (!afs_InitReq(&treq, credp))
 	    code = afs_DoPartialWrite(vcp, &treq);
-	ReleaseWriteLock(&vcp->lock);
     }
     code = code ? -code : count - tuio.uio_resid;
 
+    vcp->states &= ~CPageWrite;
+    ReleaseWriteLock(&vcp->lock);
+
     afs_Trace4(afs_iclSetp, CM_TRACE_UPDATEPAGE, ICL_TYPE_POINTER, vcp,
 	       ICL_TYPE_POINTER, pp, ICL_TYPE_INT32, page_count(pp),
 	       ICL_TYPE_INT32, code);
@@ -1986,7 +1989,12 @@ afs_linux_writepage(struct page *pp)
   do_it:
     status = afs_linux_writepage_sync(inode, pp, 0, offset);
     SetPageUptodate(pp);
-    UnlockPage(pp);
+#if defined(WRITEPAGE_ACTIVATE)
+    if ( status != WRITEPAGE_ACTIVATE )
+#else
+    if ( status != AOP_WRITEPAGE_ACTIVATE )
+#endif
+	UnlockPage(pp);
     if (status == offset)
 	return 0;
     else