Unix: Modify disk cache versioning

This change increments the disk cache version number, and adds a
structure size record to the disk cache header. All old disk caches
will be replaced when the client is started.

With the various changes made to unify our file handles, and to
support large file handles on Linux, the size of the 'fcache'
structure was modified earlier in the 1.5 series. However, fcache
is also the building block of the CacheItems file, so these changes
inadvertently broke users upgrading from 1.4. In addition, as the
disk cache inode is now a union of many different structures, the
structure size is now potentially volatile across both kernel, and
OpenAFS revisions.

Up the version number so old disk caches are invalidated and won't
crash users who are upgrading. Also take the opportunity to add an
item to the header which stores the size of struct fcache used
by the disk cache. If the size on disk doesn't match that expected
by the kernel module, truncate the cache and start again.

Change-Id: I2ee8863d0bfaaaba34272c9e139638e17669a53e
Reviewed-on: http://gerrit.openafs.org/1811
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Marc Dionne <marc.c.dionne@gmail.com>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>

diff --git a/src/afs/afs.h b/src/afs/afs.h
index 2a43b9e..5ff445e 100644 (file)
--- a/src/afs/afs.h
+++ b/src/afs/afs.h
@@ -1052,12 +1052,9 @@ struct afs_ioctl32 {
 struct afs_fheader {
 #define AFS_FHMAGIC        0x7635abaf  /* uses version number */
     afs_int32 magic;
-#if defined(AFS_SUN57_64BIT_ENV)
-#define AFS_CI_VERSION 3
-#else
-#define AFS_CI_VERSION 2
-#endif
+#define AFS_CI_VERSION 4
     afs_int32 version;
+    afs_uint32 dataSize;
     afs_int32 firstCSize;
     afs_int32 otherCSize;
 };

diff --git a/src/afs/afs_dcache.c b/src/afs/afs_dcache.c
index 03c8375..9d2bf48 100644 (file)
--- a/src/afs/afs_dcache.c
+++ b/src/afs/afs_dcache.c
@@ -2551,6 +2551,7 @@ afs_WriteThroughDSlots(void)
        theader.firstCSize = AFS_FIRSTCSIZE;
        theader.otherCSize = AFS_OTHERCSIZE;
        theader.version = AFS_CI_VERSION;
+       theader.dataSize = sizeof(struct fcache);
        afs_osi_Write(afs_cacheInodep, 0, &theader, sizeof(theader));
     }
     ReleaseWriteLock(&afs_xdcache);

diff --git a/src/afs/afs_init.c b/src/afs/afs_init.c
index 7039433..90f967a 100644 (file)
--- a/src/afs/afs_init.c
+++ b/src/afs/afs_init.c
@@ -488,6 +488,7 @@ afs_InitCacheInfo(register char *afile)
        if (theader.magic == AFS_FHMAGIC
            && theader.firstCSize == AFS_FIRSTCSIZE
            && theader.otherCSize == AFS_OTHERCSIZE
+           && theader.dataSize == sizeof(struct fcache)
            && theader.version == AFS_CI_VERSION)
            goodFile = 1;
     }
@@ -496,6 +497,7 @@ afs_InitCacheInfo(register char *afile)
        theader.magic = AFS_FHMAGIC;
        theader.firstCSize = AFS_FIRSTCSIZE;
        theader.otherCSize = AFS_OTHERCSIZE;
+       theader.dataSize = sizeof(struct fcache);
        theader.version = AFS_CI_VERSION;
        afs_osi_Write(tfile, 0, &theader, sizeof(theader));
        /*