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--- docs:vserver [2015-04-14 19:02] – [Installing Vserver host on PLD Linux] glen
+++ docs:vserver [2015-10-05 15:07] (current) – syn on glen
@@ Line 713: / Line 713: @@
 You need ''CAP_AUDIT_CONTROL'' in ''bcapabilities'' and lower ''priority_boost'' to ''0'' in ''/etc/audit/auditd.conf''
+==== XFS filesystem - kernel upgrade causes xfs related oops (xfs_filestream_lookup_ag) ====
+After upgrading from 2.6-3.4 kernels (possibly other versions) to 3.18 (tested, possibly other versions) kernel ooppses
+almost immediately after accessing some files on xfs filesystem with ''xfs_filestream_lookup_ag'' visible in stack trace
+(or other filestream related function).
+That's because vserver patch for kernels earlier than 2.6.23 patched xfs filesystem to introduce new flag:
+<file c>
+#define XFS_XFLAG_BARRIER     0x00004000      /* chroot() barrier */
+</file>
+and files/dirs with such flag got saved on your filesystem.
+Starting with kernel 2.6.23 kernel introduced filestreams which are using 0x00004000 bit, thus causing conflict with vserver.
+<file c>
+#define XFS_XFLAG_FILESTREAM   0x00004000      /* use filestream allocator */
+</file>
+Vserver stopped adding such xfs xflag in 3.13 BUT your existing filesystem can still have XFS_XFLAG_BARRIER (0x00004000) set
+causing oops in newer kernels.
+How to find out if I'm affected?
+IIF you don't use filestream feature then modify http://oss.sgi.com/cgi-bin/gitweb.cgi?p=xfs/cmds/xfstests.git;a=blob_plain;f=src/bstat.c;hb=HEAD to show only files containing XFS_XFLAG_FILESTREAM
+<file diff>
+diff --git a/src/bstat.c b/src/bstat.c
+index 4e22ecd..887512f 100644
+--- a/src/bstat.c
++++ b/src/bstat.c
+@@ -34,19 +34,21 @@ dotime(void *ti, char *s)
+ void
+ printbstat(xfs_bstat_t *sp)
+ {
+-       printf("ino %lld mode %#o nlink %d uid %d gid %d rdev %#x\n",
+-               (long long)sp->bs_ino, sp->bs_mode, sp->bs_nlink,
+-               sp->bs_uid, sp->bs_gid, sp->bs_rdev);
+-       printf("\tblksize %d size %lld blocks %lld xflags %#x extsize %d\n",
+-               sp->bs_blksize, (long long)sp->bs_size, (long long)sp->bs_blocks,
+-               sp->bs_xflags, sp->bs_extsize);
+-       dotime(&sp->bs_atime, "atime");
+-       dotime(&sp->bs_mtime, "mtime");
+-       dotime(&sp->bs_ctime, "ctime");
+-       printf( "\textents %d %d gen %d\n",
+-               sp->bs_extents, sp->bs_aextents, sp->bs_gen);
+-       printf( "\tDMI: event mask 0x%08x state 0x%04x\n",
+-               sp->bs_dmevmask, sp->bs_dmstate);
++       if (sp->bs_xflags & XFS_XFLAG_FILESTREAM) {
++               printf("ino %lld mode %#o nlink %d uid %d gid %d rdev %#x\n",
++                               (long long)sp->bs_ino, sp->bs_mode, sp->bs_nlink,
++                               sp->bs_uid, sp->bs_gid, sp->bs_rdev);
++               printf("\tblksize %d size %lld blocks %lld xflags %#x extsize %d\n",
++                               sp->bs_blksize, (long long)sp->bs_size, (long long)sp->bs_blocks,
++                               sp->bs_xflags, sp->bs_extsize);
++               dotime(&sp->bs_atime, "atime");
++               dotime(&sp->bs_mtime, "mtime");
++               dotime(&sp->bs_ctime, "ctime");
++               printf( "\textents %d %d gen %d\n",
++                               sp->bs_extents, sp->bs_aextents, sp->bs_gen);
++               printf( "\tDMI: event mask 0x%08x state 0x%04x\n",
++                               sp->bs_dmevmask, sp->bs_dmstate);
++       }
+ }
+</file>
+and then run it with mounted directory of each filesystem (bstat /; bstat /home etc). It will print "ino ..." information for filestream files.
+How to clean up?
+rsync files to other partition, recreate problematic partition and then copy files back.
 ===== Debian or Ubuntu guest installation =====