gfs2: Grab glock reference sooner in gfs2_add_revoke

This patch rearranges gfs2_add_revoke so that the extra glock
reference is added earlier on in the function to avoid races in which
the glock is freed before the new reference is taken.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
This commit is contained in:
Andreas Gruenbacher 2020-05-05 11:56:46 -05:00
parent c9cb9e3819
commit f4e2f5e1a5

View File

@ -669,13 +669,13 @@ void gfs2_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
struct buffer_head *bh = bd->bd_bh;
struct gfs2_glock *gl = bd->bd_gl;
sdp->sd_log_num_revoke++;
if (atomic_inc_return(&gl->gl_revokes) == 1)
gfs2_glock_hold(gl);
bh->b_private = NULL;
bd->bd_blkno = bh->b_blocknr;
gfs2_remove_from_ail(bd); /* drops ref on bh */
bd->bd_bh = NULL;
sdp->sd_log_num_revoke++;
if (atomic_inc_return(&gl->gl_revokes) == 1)
gfs2_glock_hold(gl);
set_bit(GLF_LFLUSH, &gl->gl_flags);
list_add(&bd->bd_list, &sdp->sd_log_revokes);
}