From eca0f91ef4283a65befd2c21cf8876713f8c8366 Mon Sep 17 00:00:00 2001
From: anserper <anserper>
Date: Mon, 17 Aug 2009 17:38:36 +0000
Subject: [PATCH] b=20008 i=Oleg Drokin i=Alex Tomas

pin the last page before starting transaction in setattr to avoid GFP_FS allocation under transaction
---
 lustre/doc/liblustreapi.7      | 11 +++++++++++
 lustre/doc/llapi_file_create.3 |  1 +
 lustre/obdfilter/filter.c      | 16 ++++++++++++++++
 3 files changed, 28 insertions(+)
 create mode 100644 lustre/doc/liblustreapi.7
 create mode 100644 lustre/doc/llapi_file_create.3

diff --git a/lustre/doc/liblustreapi.7 b/lustre/doc/liblustreapi.7
new file mode 100644
index 0000000..ebd86bf
--- /dev/null
+++ b/lustre/doc/liblustreapi.7
@@ -0,0 +1,11 @@
+.TH liblustreapi 7 "2009 Aug 10" Lustre liblustreapi
+.SH NAME
+liblustre \- The liblustre library
+.SH DESCRIPTION
+The liblustre library provides functions to access and/or modify settings specific to the Lustre filesystem (allocation policies, quotas, etc).
+.SH "SEE ALSO"
+.BR lustre (7),
+.BR llapi_file_create (3),
+.BR llapi_file_open (3),
+.BR llapi_file_get_stripe (3),
+.BR llapi_quotactl (3)
diff --git a/lustre/doc/llapi_file_create.3 b/lustre/doc/llapi_file_create.3
new file mode 100644
index 0000000..60dd263
--- /dev/null
+++ b/lustre/doc/llapi_file_create.3
@@ -0,0 +1 @@
+.so man3/llapi_file_open.3
diff --git a/lustre/obdfilter/filter.c b/lustre/obdfilter/filter.c
index df26397..eb6f1fb 100644
--- a/lustre/obdfilter/filter.c
+++ b/lustre/obdfilter/filter.c
@@ -2761,6 +2761,7 @@ int filter_setattr_internal(struct obd_export *exp, struct dentry *dentry,
         loff_t old_size = 0;
         unsigned int ia_valid;
         struct inode *inode;
+        struct page *page = NULL;
         struct iattr iattr;
         void *handle;
         ENTRY;
@@ -2796,6 +2797,17 @@ int filter_setattr_internal(struct obd_export *exp, struct dentry *dentry,
         if (rc)
                 GOTO(out_unlock, rc);
 
+        /* Let's pin the last page so that ldiskfs_truncate
+         * should not start GFP_FS allocation (20008). */
+        if (ia_valid & ATTR_SIZE) {
+                page = grab_cache_page(inode->i_mapping,
+                                       iattr.ia_size >> PAGE_CACHE_SHIFT);
+                if (page == NULL)
+                        GOTO(out_unlock, rc = -ENOMEM);
+
+                unlock_page(page);
+        }
+
         /* If the inode still has SUID+SGID bits set (see filter_precreate())
          * then we will accept the UID+GID sent by the client during write for
          * initializing the ownership of this inode.  We only allow this to
@@ -2886,7 +2898,11 @@ int filter_setattr_internal(struct obd_export *exp, struct dentry *dentry,
         }
 
         EXIT;
+
 out_unlock:
+        if (page)
+                page_cache_release(page);
+
         if (ia_valid & (ATTR_SIZE | ATTR_UID | ATTR_GID))
                 UNLOCK_INODE_MUTEX(inode);
         if (ia_valid & ATTR_SIZE)
-- 
1.8.3.1