From: Bob Peterson <rpeterso@redhat.com>
Date: Mon, 7 Dec 2015 22:24:27 +0000 (-0600)
Subject: GFS2: Prevent delete work from occurring on glocks used for create
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=a4923865ea071b0bd708339df7a83c76732fa2db;p=linux-beck.git

GFS2: Prevent delete work from occurring on glocks used for create

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>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>
---

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 5788ebff716a..7f0257309b3e 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 845fb09cc606..a6a3389a07fc 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 3e94400d587c..95a914524a39 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)