[GFS2] filesystem consistency error from do_strip

This patch fixes a GFS2 filesystem consistency error reported from
function do_strip.  The problem was caused by a timing window
that allowed two vfs inodes to be created in memory that point
to the same file.  The problem is fixed by making the vfs's
iget_test, iget_set mechanism check and set a new bit in the
in-core gfs2_inode structure while the vfs inode spin_lock is held.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

5 files changed, 20 insertions, 15 deletions

diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index d31badadef8f..07d84d16cda4 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -249,7 +249,7 @@ static int inode_go_lock(struct gfs2_holder *gh)
         struct gfs2_inode *ip = gl->gl_object;
         int error = 0;
 
-        if (!ip)
+        if (!ip || (gh->gh_flags & GL_SKIP))
                 return 0;
 
         if (test_bit(GIF_INVALID, &ip->i_flags)) {
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 9c2c0b90b22a..eabe5eac41da 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -236,6 +236,7 @@ enum {
         GIF_INVALID             = 0,
         GIF_QD_LOCKED           = 1,
         GIF_SW_PAGED            = 3,
+        GIF_USER                = 4, /* user inode, not metadata addr space */
 };
 
 struct gfs2_dinode_host {
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 3a9ef526c308..09453d057e41 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -47,8 +47,7 @@ static int iget_test(struct inode *inode, void *opaque)
         struct gfs2_inode *ip = GFS2_I(inode);
         u64 *no_addr = opaque;
 
-        if (ip->i_no_addr == *no_addr &&
-            inode->i_private != NULL)
+        if (ip->i_no_addr == *no_addr && test_bit(GIF_USER, &ip->i_flags))
                 return 1;
 
         return 0;
@@ -61,6 +60,7 @@ static int iget_set(struct inode *inode, void *opaque)
 
         inode->i_ino = (unsigned long)*no_addr;
         ip->i_no_addr = *no_addr;
+        set_bit(GIF_USER, &ip->i_flags);
         return 0;
 }
 
@@ -86,7 +86,7 @@ static int iget_skip_test(struct inode *inode, void *opaque)
         struct gfs2_inode *ip = GFS2_I(inode);
         struct gfs2_skip_data *data = opaque;
 
-        if (ip->i_no_addr == data->no_addr && inode->i_private != NULL){
+        if (ip->i_no_addr == data->no_addr && test_bit(GIF_USER, &ip->i_flags)){
                 if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)){
                         data->skipped = 1;
                         return 0;
@@ -105,6 +105,7 @@ static int iget_skip_set(struct inode *inode, void *opaque)
                 return 1;
         inode->i_ino = (unsigned long)(data->no_addr);
         ip->i_no_addr = data->no_addr;
+        set_bit(GIF_USER, &ip->i_flags);
         return 0;
 }
 
@@ -166,7 +167,7 @@ void gfs2_set_iop(struct inode *inode)
  * Returns: A VFS inode, or an error
  */
 
-struct inode *gfs2_inode_lookup(struct super_block *sb, 
+struct inode *gfs2_inode_lookup(struct super_block *sb,
                                 unsigned int type,
                                 u64 no_addr,
                                 u64 no_formal_ino, int skip_freeing)
@@ -187,7 +188,6 @@ struct inode *gfs2_inode_lookup(struct super_block *sb,
 
         if (inode->i_state & I_NEW) {
                 struct gfs2_sbd *sdp = GFS2_SB(inode);
-                inode->i_private = ip;
                 ip->i_no_formal_ino = no_formal_ino;
 
                 error = gfs2_glock_get(sdp, no_addr, &gfs2_inode_glops, CREATE, &ip->i_gl);
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 85aea27b4a86..78d75f892f82 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
- * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
  *
  * This copyrighted material is made available to anyone wishing to use,
  * modify, copy, or redistribute it subject to the terms and conditions
@@ -69,13 +69,15 @@ static const struct address_space_operations aspace_aops = {
 struct inode *gfs2_aspace_get(struct gfs2_sbd *sdp)
 {
         struct inode *aspace;
+        struct gfs2_inode *ip;
 
         aspace = new_inode(sdp->sd_vfs);
         if (aspace) {
                 mapping_set_gfp_mask(aspace->i_mapping, GFP_NOFS);
                 aspace->i_mapping->a_ops = &aspace_aops;
                 aspace->i_size = ~0ULL;
-                aspace->i_private = NULL;
+                ip = GFS2_I(aspace);
+                clear_bit(GIF_USER, &ip->i_flags);
                 insert_inode_hash(aspace);
         }
         return aspace;
diff --git a/fs/gfs2/ops_super.c b/fs/gfs2/ops_super.c
index 2278c68b7e35..0b7cc920eb89 100644
--- a/fs/gfs2/ops_super.c
+++ b/fs/gfs2/ops_super.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
- * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
  *
  * This copyrighted material is made available to anyone wishing to use,
  * modify, copy, or redistribute it subject to the terms and conditions
@@ -52,7 +52,7 @@ static int gfs2_write_inode(struct inode *inode, int sync)
         struct gfs2_inode *ip = GFS2_I(inode);
 
         /* Check this is a "normal" inode */
-        if (inode->i_private) {
+        if (test_bit(GIF_USER, &ip->i_flags)) {
                 if (current->flags & PF_MEMALLOC)
                         return 0;
                 if (sync)
@@ -297,8 +297,9 @@ static int gfs2_remount_fs(struct super_block *sb, int *flags, char *data)
  */
 static void gfs2_drop_inode(struct inode *inode)
 {
-        if (inode->i_private && inode->i_nlink) {
-                struct gfs2_inode *ip = GFS2_I(inode);
+        struct gfs2_inode *ip = GFS2_I(inode);
+
+        if (test_bit(GIF_USER, &ip->i_flags) && inode->i_nlink) {
                 struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
                 if (gl && test_bit(GLF_DEMOTE, &gl->gl_flags))
                         clear_nlink(inode);
@@ -314,12 +315,13 @@ static void gfs2_drop_inode(struct inode *inode)
 
 static void gfs2_clear_inode(struct inode *inode)
 {
+        struct gfs2_inode *ip = GFS2_I(inode);
+
         /* This tells us its a "real" inode and not one which only
          * serves to contain an address space (see rgrp.c, meta_io.c)
          * which therefore doesn't have its own glocks.
          */
-        if (inode->i_private) {
-                struct gfs2_inode *ip = GFS2_I(inode);
+        if (test_bit(GIF_USER, &ip->i_flags)) {
                 ip->i_gl->gl_object = NULL;
                 gfs2_glock_schedule_for_reclaim(ip->i_gl);
                 gfs2_glock_put(ip->i_gl);
@@ -419,7 +421,7 @@ static void gfs2_delete_inode(struct inode *inode)
         struct gfs2_holder gh;
         int error;
 
-        if (!inode->i_private)
+        if (!test_bit(GIF_USER, &ip->i_flags))
                 goto out;
 
         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);