gfs2: Use gfs2 wrapper to sync inode before calling generic_file_splice_read()

gfs2_file_splice_read() f_op grabs and releases the cluster-wide
inode glock to sync the inode size to the latest.

Without this, generic_file_splice_read() uses an older i_size value
and can return EOF for valid offsets in the inode.

Signed-off-by: Abhi Das <adas@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index c9384f932975efb8075d2fd2013116e8be9f055a..fd9a10e4518d00aaa98840583d4310a1b51901ab 100644 (file)
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -950,6 +950,30 @@ out_uninit:
        return ret;
 }
 
+static ssize_t gfs2_file_splice_read(struct file *in, loff_t *ppos,
+                                    struct pipe_inode_info *pipe, size_t len,
+                                    unsigned int flags)
+{
+       struct inode *inode = in->f_mapping->host;
+       struct gfs2_inode *ip = GFS2_I(inode);
+       struct gfs2_holder gh;
+       int ret;
+
+       mutex_lock(&inode->i_mutex);
+
+       ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
+       if (ret) {
+               mutex_unlock(&inode->i_mutex);
+               return ret;
+       }
+
+       gfs2_glock_dq_uninit(&gh);
+       mutex_unlock(&inode->i_mutex);
+
+       return generic_file_splice_read(in, ppos, pipe, len, flags);
+}
+
+
 static ssize_t gfs2_file_splice_write(struct pipe_inode_info *pipe,
                                      struct file *out, loff_t *ppos,
                                      size_t len, unsigned int flags)
@@ -1112,7 +1136,7 @@ const struct file_operations gfs2_file_fops = {
        .fsync          = gfs2_fsync,
        .lock           = gfs2_lock,
        .flock          = gfs2_flock,
-       .splice_read    = generic_file_splice_read,
+       .splice_read    = gfs2_file_splice_read,
        .splice_write   = gfs2_file_splice_write,
        .setlease       = simple_nosetlease,
        .fallocate      = gfs2_fallocate,
@@ -1140,7 +1164,7 @@ const struct file_operations gfs2_file_fops_nolock = {
        .open           = gfs2_open,
        .release        = gfs2_release,
        .fsync          = gfs2_fsync,
-       .splice_read    = generic_file_splice_read,
+       .splice_read    = gfs2_file_splice_read,
        .splice_write   = gfs2_file_splice_write,
        .setlease       = generic_setlease,
        .fallocate      = gfs2_fallocate,