GFS2: Increase i_writecount during gfs2_setattr_size

This patch calls get_write_access in a few functions. This
merely increases inode->i_writecount for the duration of the function.
That will ensure that any file closes won't delete the inode's
multi-block reservation while the function is running.

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

3 files changed, 29 insertions, 11 deletions

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 1dc9a13ce6bb..93b5809c20bb 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -1286,17 +1286,26 @@ int gfs2_setattr_size(struct inode *inode, u64 newsize)
         if (ret)
                 return ret;
 
+        ret = get_write_access(inode);
+        if (ret)
+                return ret;
+
         inode_dio_wait(inode);
 
         ret = gfs2_rs_alloc(GFS2_I(inode));
         if (ret)
-                return ret;
+                goto out;
 
         oldsize = inode->i_size;
-        if (newsize >= oldsize)
-                return do_grow(inode, newsize);
+        if (newsize >= oldsize) {
+                ret = do_grow(inode, newsize);
+                goto out;
+        }
 
-        return do_shrink(inode, oldsize, newsize);
+        ret = do_shrink(inode, oldsize, newsize);
+out:
+        put_write_access(inode);
+        return ret;
 }
 
 int gfs2_truncatei_resume(struct gfs2_inode *ip)
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index acd16764b133..ad0dc38d87ab 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -402,16 +402,20 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
         /* Update file times before taking page lock */
         file_update_time(vma->vm_file);
 
+        ret = get_write_access(inode);
+        if (ret)
+                goto out;
+
         ret = gfs2_rs_alloc(ip);
         if (ret)
-                return ret;
+                goto out_write_access;
 
         gfs2_size_hint(vma->vm_file, pos, PAGE_CACHE_SIZE);
 
         gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
         ret = gfs2_glock_nq(&gh);
         if (ret)
-                goto out;
+                goto out_uninit;
 
         set_bit(GLF_DIRTY, &ip->i_gl->gl_flags);
         set_bit(GIF_SW_PAGED, &ip->i_flags);
@@ -480,12 +484,15 @@ out_quota_unlock:
         gfs2_quota_unlock(ip);
 out_unlock:
         gfs2_glock_dq(&gh);
-out:
+out_uninit:
         gfs2_holder_uninit(&gh);
         if (ret == 0) {
                 set_page_dirty(page);
                 wait_for_stable_page(page);
         }
+out_write_access:
+        put_write_access(inode);
+out:
         sb_end_pagefault(inode->i_sb);
         return block_page_mkwrite_return(ret);
 }
@@ -594,10 +601,10 @@ static int gfs2_release(struct inode *inode, struct file *file)
         kfree(file->private_data);
         file->private_data = NULL;
 
-        if ((file->f_mode & FMODE_WRITE) &&
-            (atomic_read(&inode->i_writecount) == 1))
-                gfs2_rs_delete(ip);
+        if (!(file->f_mode & FMODE_WRITE))
+                return 0;
 
+        gfs2_rs_delete(ip);
         return 0;
 }
 
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 5232525934ae..9809156e3d04 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -638,8 +638,10 @@ void gfs2_rs_deltree(struct gfs2_blkreserv *rs)
  */
 void gfs2_rs_delete(struct gfs2_inode *ip)
 {
+        struct inode *inode = &ip->i_inode;
+
         down_write(&ip->i_rw_mutex);
-        if (ip->i_res) {
+        if (ip->i_res && atomic_read(&inode->i_writecount) <= 1) {
                 gfs2_rs_deltree(ip->i_res);
                 BUG_ON(ip->i_res->rs_free);
                 kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);