[Cluster-devel] [PATCH 1/4] GFS2: Prevent delete work from occurring on glocks used for create

[Bob Peterson <rpeterso@redhat.com>]

This patch tries to prevent delete work (queued via iopen callback)
from executing if the glock is currently being used to create
a new inode.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
 fs/gfs2/glock.c  | 7 +++++++
 fs/gfs2/incore.h | 1 +
 fs/gfs2/inode.c  | 7 ++++++-
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index a4ff7b5..cb5ed3a 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -572,6 +572,12 @@ static void delete_work_func(struct work_struct *work)
 	struct inode *inode;
 	u64 no_addr = gl->gl_name.ln_number;
 
+	/* If someone's using this glock to create a new dinode, the block must
+	   have been freed by another node, then re-used, in which case our
+	   iopen callback is too late after the fact. Ignore it. */
+	if (test_bit(GLF_INODE_CREATING, &gl->gl_flags))
+		goto out;
+
 	ip = gl->gl_object;
 	/* Note: Unsafe to dereference ip as we don't hold right refs/locks */
 
@@ -583,6 +589,7 @@ static void delete_work_func(struct work_struct *work)
 		d_prune_aliases(inode);
 		iput(inode);
 	}
+out:
 	gfs2_glock_put(gl);
 }
 
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 845fb09..a6a3389 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -328,6 +328,7 @@ enum {
 	GLF_LRU				= 13,
 	GLF_OBJECT			= 14, /* Used only for tracing */
 	GLF_BLOCKING			= 15,
+	GLF_INODE_CREATING		= 16, /* Inode creation occurring */
 };
 
 struct gfs2_glock {
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 009b551..6cdafed 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -592,7 +592,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 	struct inode *inode = NULL;
 	struct gfs2_inode *dip = GFS2_I(dir), *ip;
 	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
-	struct gfs2_glock *io_gl;
+	struct gfs2_glock *io_gl = NULL;
 	int error, free_vfs_inode = 1;
 	u32 aflags = 0;
 	unsigned blocks = 1;
@@ -729,6 +729,8 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 	if (error)
 		goto fail_gunlock2;
 
+	BUG_ON(test_and_set_bit(GLF_INODE_CREATING, &io_gl->gl_flags));
+
 	error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, GL_EXACT, &ip->i_iopen_gh);
 	if (error)
 		goto fail_gunlock2;
@@ -771,12 +773,15 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 	}
 	gfs2_glock_dq_uninit(ghs);
 	gfs2_glock_dq_uninit(ghs + 1);
+	clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags);
 	return error;
 
 fail_gunlock3:
 	gfs2_glock_dq_uninit(&ip->i_iopen_gh);
 	gfs2_glock_put(io_gl);
 fail_gunlock2:
+	if (io_gl)
+		clear_bit(GLF_INODE_CREATING, &io_gl->gl_flags);
 	gfs2_glock_dq_uninit(ghs + 1);
 fail_free_inode:
 	if (ip->i_gl)
-- 
2.5.0