[Cluster-devel] [GFS2 PATCH v2] [PATCH 2/4] GFS2: Set gl_object in inode lookup only after block type check
Bob Peterson
rpeterso at redhat.com
Tue Jul 18 19:21:51 UTC 2017
Hi,
Here is the new improved version of patch #2:
Patch description:
---
GFS2: Set gl_object in inode lookup only after block type check
Before this patch, the inode glock's gl_object was set after a
reference was acquired, but before the block type was verified.
In cases where the block was unlinked, then freed and reused on
another node, a residule delete callback (delete_work) would try
to look up the inode, eventually failing the block check, but
only after it overwrites gl_object with a pointer to the wrong
inode. This patch moves the assignment of gl_object after the
block check so it won't be improperly overwritten.
Likewise, at the end of the function, gfs2_inode_lookup was
clearing gl_object after it unlocked the glock, which meant
another process might free the glock in the meantime. This
patch guards against that case.
Signed-off-by: Bob Peterson <rpeterso at redhat.com>
---
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 608e4bf60754..5e4f045e992a 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -145,7 +145,6 @@ struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type,
if (unlikely(error))
goto fail;
flush_delayed_work(&ip->i_gl->gl_work);
- glock_set_object(ip->i_gl, ip);
error = gfs2_glock_get(sdp, no_addr, &gfs2_iopen_glops, CREATE, &io_gl);
if (unlikely(error))
@@ -170,6 +169,7 @@ struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type,
}
}
+ glock_set_object(ip->i_gl, ip);
set_bit(GIF_INVALID, &ip->i_flags);
error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, GL_EXACT, &ip->i_iopen_gh);
if (unlikely(error))
@@ -207,9 +207,9 @@ struct inode *gfs2_inode_lookup(struct super_block *sb, unsigned int type,
fail_put:
if (io_gl)
gfs2_glock_put(io_gl);
+ glock_clear_object(ip->i_gl, ip);
if (gfs2_holder_initialized(&i_gh))
gfs2_glock_dq_uninit(&i_gh);
- glock_clear_object(ip->i_gl, ip);
fail:
iget_failed(inode);
return ERR_PTR(error);
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