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>

1 files changed, 26 insertions, 2 deletions

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index c9384f932975..fd9a10e4518d 100644
--- 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,