DEVEL15-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

(cherry picked from commit 5e0e1ea2540d0cb7d7274350eb1fadfd41733ea4)

diff --git a/src/afs/LINUX/osi_vm.c b/src/afs/LINUX/osi_vm.c
index c96babd6683721d7be6a24a415baca1764d7eec6..55a3737e78e7e49a15f98f6c7d35f482be2416c9 100644 (file)
--- 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 a65af8a4e85bb471fa1a4be3f5e55762ad74bba7..6081ab0a18295550e41c89939ba583200ff2c5dc 100644 (file)
--- 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