GFS2: Rework reclaiming unlinked dinodes

The previous patch I wrote for reclaiming unlinked dinodes
had some shortcomings and did not prevent all hangs.
This version is much cleaner and more logical, and has
passed very difficult testing.  Sorry for the churn.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 29 insertions, 25 deletions

diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 51d8061fa07a..b5612cbb62a5 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -242,34 +242,38 @@ fail:
 }
 
 /**
- * gfs2_unlinked_inode_lookup - Lookup an unlinked inode for reclamation
+ * gfs2_process_unlinked_inode - Lookup an unlinked inode for reclamation
+ *                               and try to reclaim it by doing iput.
+ *
+ * This function assumes no rgrp locks are currently held.
+ *
  * @sb: The super block
  * no_addr: The inode number
- * @@inode: A pointer to the inode found, if any
  *
- * Returns: 0 and *inode if no errors occurred.  If an error occurs,
- *          the resulting *inode may or may not be NULL.
  */
 
-int gfs2_unlinked_inode_lookup(struct super_block *sb, u64 no_addr,
-                               struct inode **inode)
+void gfs2_process_unlinked_inode(struct super_block *sb, u64 no_addr)
 {
         struct gfs2_sbd *sdp;
         struct gfs2_inode *ip;
         struct gfs2_glock *io_gl;
         int error;
         struct gfs2_holder gh;
+        struct inode *inode;
 
-        *inode = gfs2_iget_skip(sb, no_addr);
+        inode = gfs2_iget_skip(sb, no_addr);
 
-        if (!(*inode))
-                return -ENOBUFS;
+        if (!inode)
+                return;
 
-        if (!((*inode)->i_state & I_NEW))
-                return -ENOBUFS;
+        /* If it's not a new inode, someone's using it, so leave it alone. */
+        if (!(inode->i_state & I_NEW)) {
+                iput(inode);
+                return;
+        }
 
-        ip = GFS2_I(*inode);
-        sdp = GFS2_SB(*inode);
+        ip = GFS2_I(inode);
+        sdp = GFS2_SB(inode);
         ip->i_no_formal_ino = -1;
 
         error = gfs2_glock_get(sdp, no_addr, &gfs2_inode_glops, CREATE, &ip->i_gl);
@@ -284,15 +288,13 @@ int gfs2_unlinked_inode_lookup(struct super_block *sb, u64 no_addr,
         set_bit(GIF_INVALID, &ip->i_flags);
         error = gfs2_glock_nq_init(io_gl, LM_ST_SHARED, LM_FLAG_TRY | GL_EXACT,
                                    &ip->i_iopen_gh);
-        if (unlikely(error)) {
-                if (error == GLR_TRYFAILED)
-                        error = 0;
+        if (unlikely(error))
                 goto fail_iopen;
-        }
+
         ip->i_iopen_gh.gh_gl->gl_object = ip;
         gfs2_glock_put(io_gl);
 
-        (*inode)->i_mode = DT2IF(DT_UNKNOWN);
+        inode->i_mode = DT2IF(DT_UNKNOWN);
 
         /*
          * We must read the inode in order to work out its type in
@@ -303,16 +305,17 @@ int gfs2_unlinked_inode_lookup(struct super_block *sb, u64 no_addr,
          */
         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, LM_FLAG_TRY,
                                    &gh);
-        if (unlikely(error)) {
-                if (error == GLR_TRYFAILED)
-                        error = 0;
+        if (unlikely(error))
                 goto fail_glock;
-        }
+
         /* Inode is now uptodate */
         gfs2_glock_dq_uninit(&gh);
-        gfs2_set_iop(*inode);
+        gfs2_set_iop(inode);
+
+        /* The iput will cause it to be deleted. */
+        iput(inode);
+        return;
 
-        return 0;
 fail_glock:
         gfs2_glock_dq(&ip->i_iopen_gh);
 fail_iopen:
@@ -321,7 +324,8 @@ fail_put:
         ip->i_gl->gl_object = NULL;
         gfs2_glock_put(ip->i_gl);
 fail:
-        return error;
+        iget_failed(inode);
+        return;
 }
 
 static int gfs2_dinode_in(struct gfs2_inode *ip, const void *buf)