GFS2: Improve resource group error handling

This patch improves the error handling in the case where we
discover that the summary information in the resource group
doesn't match the bitmap information while in the process of
allocating blocks. Originally this resulted in a kernel bug,
but this patch changes that so that we return -EIO and print
some messages explaining what went wrong, and how to fix it.

We also remember locally not to try and allocate from the
same rgrp again, so that a subsequent allocation in a
different rgrp should succeed.

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

1 files changed, 43 insertions, 15 deletions

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 565038243fa2..fbacf09ee34e 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -701,10 +701,7 @@ static void gfs2_rgrp_in(struct gfs2_rgrpd *rgd, const void *buf)
         u32 rg_flags;
 
         rg_flags = be32_to_cpu(str->rg_flags);
-        if (rg_flags & GFS2_RGF_NOALLOC)
-                rgd->rd_flags |= GFS2_RDF_NOALLOC;
-        else
-                rgd->rd_flags &= ~GFS2_RDF_NOALLOC;
+        rg_flags &= ~GFS2_RDF_MASK;
         rgd->rd_free = be32_to_cpu(str->rg_free);
         rgd->rd_dinodes = be32_to_cpu(str->rg_dinodes);
         rgd->rd_igeneration = be64_to_cpu(str->rg_igeneration);
@@ -713,11 +710,8 @@ static void gfs2_rgrp_in(struct gfs2_rgrpd *rgd, const void *buf)
 static void gfs2_rgrp_out(struct gfs2_rgrpd *rgd, void *buf)
 {
         struct gfs2_rgrp *str = buf;
-        u32 rg_flags = 0;
 
-        if (rgd->rd_flags & GFS2_RDF_NOALLOC)
-                rg_flags |= GFS2_RGF_NOALLOC;
-        str->rg_flags = cpu_to_be32(rg_flags);
+        str->rg_flags = cpu_to_be32(rgd->rd_flags & ~GFS2_RDF_MASK);
         str->rg_free = cpu_to_be32(rgd->rd_free);
         str->rg_dinodes = cpu_to_be32(rgd->rd_dinodes);
         str->__pad = cpu_to_be32(0);
@@ -942,7 +936,7 @@ static int try_rgrp_fit(struct gfs2_rgrpd *rgd, struct gfs2_alloc *al)
         struct gfs2_sbd *sdp = rgd->rd_sbd;
         int ret = 0;
 
-        if (rgd->rd_flags & GFS2_RDF_NOALLOC)
+        if (rgd->rd_flags & (GFS2_RGF_NOALLOC | GFS2_RDF_ERROR))
                 return 0;
 
         spin_lock(&sdp->sd_rindex_spin);
@@ -1435,13 +1429,33 @@ static struct gfs2_rgrpd *rgblk_free(struct gfs2_sbd *sdp, u64 bstart,
 }
 
 /**
- * gfs2_alloc_block - Allocate a block
+ * gfs2_rgrp_dump - print out an rgrp
+ * @seq: The iterator
+ * @gl: The glock in question
+ *
+ */
+
+int gfs2_rgrp_dump(struct seq_file *seq, const struct gfs2_glock *gl)
+{
+        const struct gfs2_rgrpd *rgd = gl->gl_object;
+        if (rgd == NULL)
+                return 0;
+        gfs2_print_dbg(seq, " R: n:%llu f:%02x b:%u/%u i:%u\n",
+                       (unsigned long long)rgd->rd_addr, rgd->rd_flags,
+                       rgd->rd_free, rgd->rd_free_clone, rgd->rd_dinodes);
+        return 0;
+}
+
+/**
+ * gfs2_alloc_block - Allocate one or more blocks
  * @ip: the inode to allocate the block for
+ * @bn: Used to return the starting block number
+ * @n: requested number of blocks/extent length (value/result)
  *
- * Returns: the allocated block
+ * Returns: 0 or error
  */
 
-u64 gfs2_alloc_block(struct gfs2_inode *ip, unsigned int *n)
+int gfs2_alloc_block(struct gfs2_inode *ip, u64 *bn, unsigned int *n)
 {
         struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
         struct buffer_head *dibh;
@@ -1457,7 +1471,10 @@ u64 gfs2_alloc_block(struct gfs2_inode *ip, unsigned int *n)
                 goal = rgd->rd_last_alloc;
 
         blk = rgblk_search(rgd, goal, GFS2_BLKST_FREE, GFS2_BLKST_USED, n);
-        BUG_ON(blk == BFITNOENT);
+
+        /* Since all blocks are reserved in advance, this shouldn't happen */
+        if (blk == BFITNOENT)
+                goto rgrp_error;
 
         rgd->rd_last_alloc = blk;
         block = rgd->rd_data0 + blk;
@@ -1469,7 +1486,9 @@ u64 gfs2_alloc_block(struct gfs2_inode *ip, unsigned int *n)
                 di->di_goal_meta = di->di_goal_data = cpu_to_be64(ip->i_goal);
                 brelse(dibh);
         }
-        gfs2_assert_withdraw(sdp, rgd->rd_free >= *n);
+        if (rgd->rd_free < *n)
+                goto rgrp_error;
+
         rgd->rd_free -= *n;
 
         gfs2_trans_add_bh(rgd->rd_gl, rgd->rd_bits[0].bi_bh, 1);
@@ -1484,7 +1503,16 @@ u64 gfs2_alloc_block(struct gfs2_inode *ip, unsigned int *n)
         rgd->rd_free_clone -= *n;
         spin_unlock(&sdp->sd_rindex_spin);
 
-        return block;
+        *bn = block;
+        return 0;
+
+rgrp_error:
+        fs_warn(sdp, "rgrp %llu has an error, marking it readonly until umount\n",
+                (unsigned long long)rgd->rd_addr);
+        fs_warn(sdp, "umount on all nodes and run fsck.gfs2 to fix the error\n");
+        gfs2_rgrp_dump(NULL, rgd->rd_gl);
+        rgd->rd_flags |= GFS2_RDF_ERROR;
+        return -EIO;
 }
 
 /**