ext4: force inode writes when nfsd calls commit_metadata()

BugLink: https://bugs.launchpad.net/bugs/1837257
commit fde872682e175743e0c3ef939c89e3c6008a1529 upstream.

Some time back, nfsd switched from calling vfs_fsync() to using a new
commit_metadata() hook in export_operations().  If the file system did
not provide a commit_metadata() hook, it fell back to using
sync_inode_metadata().  Unfortunately doesn't work on all file
systems.  In particular, it doesn't work on ext4 due to how the inode
gets journalled --- the VFS writeback code will not always call
ext4_write_inode().

So we need to provide our own ext4_nfs_commit_metdata() method which
calls ext4_write_inode() directly.

Google-Bug-Id: 121195940
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index cd76885f48d13507842d28eac0da46b4f7d288f4..7bf6e5886011b7f4fc851b41f8a186f82199a5fd 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1158,6 +1158,16 @@ static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
                                    ext4_nfs_get_inode);
 }
 
+static int ext4_nfs_commit_metadata(struct inode *inode)
+{
+       struct writeback_control wbc = {
+               .sync_mode = WB_SYNC_ALL
+       };
+
+       trace_ext4_nfs_commit_metadata(inode);
+       return ext4_write_inode(inode, &wbc);
+}
+
 /*
  * Try to release metadata pages (indirect blocks, directories) which are
  * mapped via the block device.  Since these pages could have journal heads
@@ -1368,6 +1378,7 @@ static const struct export_operations ext4_export_ops = {
        .fh_to_dentry = ext4_fh_to_dentry,
        .fh_to_parent = ext4_fh_to_parent,
        .get_parent = ext4_get_parent,
+       .commit_metadata = ext4_nfs_commit_metadata,
 };
 
 enum {

diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 4d0e3af4e56174192c3d70a8e698e1b11b89c3b4..3902b6960db2a4599cb98d313c2fcd670b8d05db 100644 (file)
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -225,6 +225,26 @@ TRACE_EVENT(ext4_drop_inode,
                  (unsigned long) __entry->ino, __entry->drop)
 );
 
+TRACE_EVENT(ext4_nfs_commit_metadata,
+       TP_PROTO(struct inode *inode),
+
+       TP_ARGS(inode),
+
+       TP_STRUCT__entry(
+               __field(        dev_t,  dev                     )
+               __field(        ino_t,  ino                     )
+       ),
+
+       TP_fast_assign(
+               __entry->dev    = inode->i_sb->s_dev;
+               __entry->ino    = inode->i_ino;
+       ),
+
+       TP_printk("dev %d,%d ino %lu",
+                 MAJOR(__entry->dev), MINOR(__entry->dev),
+                 (unsigned long) __entry->ino)
+);
+
 TRACE_EVENT(ext4_mark_inode_dirty,
        TP_PROTO(struct inode *inode, unsigned long IP),