[GFS2] Fix change nlink deadlock

Bugzilla 215088

Fix deadlock in gfs2_change_nlink() while installing RHEL5 into GFS2
partition. The gfs2_rename() apparently needs block allocation for the
new name (into the directory) where it requires rg locks. At the same
time, while updating the nlink count for the replaced file,
gfs2_change_nlink() tries to return the inode meta-data back to resource
group where it needs rg locks too. Our logic doesn't allow process to
acquire these locks recursively by the same process  (RHEL installer)
that results a BUG call. This only happens within rename code path and
only if the destination file exists before the rename operation.

Signed-off-by: S. Wendy Cheng <wcheng@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index d122074c45e16d3163dd61d9e819b6c01ae652aa..6bc443644c3c5bd3f4e825c2db4bca5abf9df628 100644 (file)
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -281,16 +281,14 @@ out:
 }
 
 /**
- * gfs2_change_nlink - Change nlink count on inode
+ * gfs2_change_nlink_i - Change nlink count on inode
  * @ip: The GFS2 inode
  * @diff: The change in the nlink count required
  *
  * Returns: errno
  */
-
-int gfs2_change_nlink(struct gfs2_inode *ip, int diff)
+int gfs2_change_nlink_i(struct gfs2_inode *ip, int diff)
 {
-       struct gfs2_sbd *sdp = ip->i_inode.i_sb->s_fs_info;
        struct buffer_head *dibh;
        u32 nlink;
        int error;
@@ -322,6 +320,20 @@ int gfs2_change_nlink(struct gfs2_inode *ip, int diff)
        brelse(dibh);
        mark_inode_dirty(&ip->i_inode);
 
+       return error;
+}
+
+int gfs2_change_nlink(struct gfs2_inode *ip, int diff)
+{
+       struct gfs2_sbd *sdp = ip->i_inode.i_sb->s_fs_info;
+       int error;
+
+       /* update the nlink */
+       error = gfs2_change_nlink_i(ip, diff);
+       if (error)
+               return error;
+
+       /* return meta data block back to rg */
        if (ip->i_inode.i_nlink == 0) {
                struct gfs2_rgrpd *rgd;
                struct gfs2_holder ri_gh, rg_gh;

diff --git a/fs/gfs2/inode.h b/fs/gfs2/inode.h
index b57f448b15bc42e09c18c2889fe866bdc2efacc6..85c67cb568d185c296375e0b0cd6b542408d67fd 100644 (file)
--- a/fs/gfs2/inode.h
+++ b/fs/gfs2/inode.h
@@ -40,6 +40,7 @@ int gfs2_inode_refresh(struct gfs2_inode *ip);
 
 int gfs2_dinode_dealloc(struct gfs2_inode *inode);
 int gfs2_change_nlink(struct gfs2_inode *ip, int diff);
+int gfs2_change_nlink_i(struct gfs2_inode *ip, int diff);
 struct inode *gfs2_lookupi(struct inode *dir, const struct qstr *name,
                           int is_root, struct nameidata *nd);
 struct inode *gfs2_createi(struct gfs2_holder *ghs, const struct qstr *name,

diff --git a/fs/gfs2/ops_inode.c b/fs/gfs2/ops_inode.c
index 636dda4c7d38d688c76923c6289e130e8d4754ac..919e8947e710cd9e76a520d1ccfc3a13294e5f5f 100644 (file)
--- a/fs/gfs2/ops_inode.c
+++ b/fs/gfs2/ops_inode.c
@@ -553,6 +553,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
        int alloc_required;
        unsigned int x;
        int error;
+       struct gfs2_rgrpd *rgd;
 
        if (ndentry->d_inode) {
                nip = GFS2_I(ndentry->d_inode);
@@ -684,12 +685,12 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
                error = gfs2_trans_begin(sdp, sdp->sd_max_dirres +
                                         al->al_rgd->rd_ri.ri_length +
                                         4 * RES_DINODE + 4 * RES_LEAF +
-                                        RES_STATFS + RES_QUOTA, 0);
+                                        RES_STATFS + RES_QUOTA + 1, 0);
                if (error)
                        goto out_ipreserv;
        } else {
                error = gfs2_trans_begin(sdp, 4 * RES_DINODE +
-                                        5 * RES_LEAF, 0);
+                                        5 * RES_LEAF + 1, 0);
                if (error)
                        goto out_gunlock;
        }
@@ -703,7 +704,25 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
                        error = gfs2_dir_del(ndip, &ndentry->d_name);
                        if (error)
                                goto out_end_trans;
-                       error = gfs2_change_nlink(nip, -1);
+                       error = gfs2_change_nlink_i(nip, -1);
+                       if ((!error) && (nip->i_inode.i_nlink == 0)) {
+                               error = -EIO;
+                               rgd = gfs2_blk2rgrpd(sdp, nip->i_num.no_addr);
+                               if (rgd) {
+                                       struct gfs2_holder nlink_rg_gh;
+                                       if (rgd != nip->i_alloc.al_rgd)
+                                               error = gfs2_glock_nq_init(
+                                               rgd->rd_gl, LM_ST_EXCLUSIVE,
+                                               0, &nlink_rg_gh);
+                                       else
+                                               error = 0;
+                                       if (!error) {
+                                               gfs2_unlink_di(&nip->i_inode);
+                                               if (rgd != nip->i_alloc.al_rgd)
+                                                       gfs2_glock_dq_uninit(&nlink_rg_gh);
+                                       }
+                               }
+                       }
                }
                if (error)
                        goto out_end_trans;