4 files changed, 67 insertions, 38 deletions

diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
index 098890357659..52b2b5da566e 100644
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -708,6 +708,27 @@ xfs_buf_get_empty(
         return bp;
 }
 
+/*
+ * Return a buffer allocated as an empty buffer and associated to external
+ * memory via xfs_buf_associate_memory() back to it's empty state.
+ */
+void
+xfs_buf_set_empty(
+        struct xfs_buf          *bp,
+        size_t                  len)
+{
+        if (bp->b_pages)
+                _xfs_buf_free_pages(bp);
+
+        bp->b_pages = NULL;
+        bp->b_page_count = 0;
+        bp->b_addr = NULL;
+        bp->b_file_offset = 0;
+        bp->b_buffer_length = bp->b_count_desired = len;
+        bp->b_bn = XFS_BUF_DADDR_NULL;
+        bp->b_flags &= ~XBF_MAPPED;
+}
+
 static inline struct page *
 mem_to_page(
         void                    *addr)
diff --git a/fs/xfs/linux-2.6/xfs_buf.h b/fs/xfs/linux-2.6/xfs_buf.h
index a9a1c4512645..50a7d5fb3b73 100644
--- a/fs/xfs/linux-2.6/xfs_buf.h
+++ b/fs/xfs/linux-2.6/xfs_buf.h
@@ -178,6 +178,7 @@ extern xfs_buf_t *xfs_buf_read(xfs_buftarg_t *, xfs_off_t, size_t,
                                 xfs_buf_flags_t);
 
 extern xfs_buf_t *xfs_buf_get_empty(size_t, xfs_buftarg_t *);
+extern void xfs_buf_set_empty(struct xfs_buf *bp, size_t len);
 extern xfs_buf_t *xfs_buf_get_uncached(struct xfs_buftarg *, size_t, int);
 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t);
 extern void xfs_buf_hold(xfs_buf_t *);
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 18fd4beffcc3..211930246f20 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1449,6 +1449,13 @@ xlog_dealloc_log(xlog_t *log)
 
         xlog_cil_destroy(log);
 
+        /*
+         * always need to ensure that the extra buffer does not point to memory
+         * owned by another log buffer before we free it.
+         */
+        xfs_buf_set_empty(log->l_xbuf, log->l_iclog_size);
+        xfs_buf_free(log->l_xbuf);
+
         iclog = log->l_iclog;
         for (i=0; i<log->l_iclog_bufs; i++) {
                 xfs_buf_free(iclog->ic_bp);
@@ -1458,7 +1465,6 @@ xlog_dealloc_log(xlog_t *log)
         }
         spinlock_destroy(&log->l_icloglock);
 
-        xfs_buf_free(log->l_xbuf);
         log->l_mp->m_log = NULL;
         kmem_free(log);
 }       /* xlog_dealloc_log */
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 5cc464a17c93..04142caedb2b 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -205,6 +205,35 @@ xlog_bread(
 }
 
 /*
+ * Read at an offset into the buffer. Returns with the buffer in it's original
+ * state regardless of the result of the read.
+ */
+STATIC int
+xlog_bread_offset(
+        xlog_t          *log,
+        xfs_daddr_t     blk_no,         /* block to read from */
+        int             nbblks,         /* blocks to read */
+        xfs_buf_t       *bp,
+        xfs_caddr_t     offset)
+{
+        xfs_caddr_t     orig_offset = XFS_BUF_PTR(bp);
+        int             orig_len = bp->b_buffer_length;
+        int             error, error2;
+
+        error = XFS_BUF_SET_PTR(bp, offset, BBTOB(nbblks));
+        if (error)
+                return error;
+
+        error = xlog_bread_noalign(log, blk_no, nbblks, bp);
+
+        /* must reset buffer pointer even on error */
+        error2 = XFS_BUF_SET_PTR(bp, orig_offset, orig_len);
+        if (error)
+                return error;
+        return error2;
+}
+
+/*
  * Write out the buffer at the given block for the given number of blocks.
  * The buffer is kept locked across the write and is returned locked.
  * This can only be used for synchronous log writes.
@@ -1229,20 +1258,12 @@ xlog_write_log_records(
                  */
                 ealign = round_down(end_block, sectbb);
                 if (j == 0 && (start_block + endcount > ealign)) {
-                        offset = XFS_BUF_PTR(bp);
-                        balign = BBTOB(ealign - start_block);
-                        error = XFS_BUF_SET_PTR(bp, offset + balign,
-                                                BBTOB(sectbb));
+                        offset = XFS_BUF_PTR(bp) + BBTOB(ealign - start_block);
+                        error = xlog_bread_offset(log, ealign, sectbb,
+                                                        bp, offset);
                         if (error)
                                 break;
 
-                        error = xlog_bread_noalign(log, ealign, sectbb, bp);
-                        if (error)
-                                break;
-
-                        error = XFS_BUF_SET_PTR(bp, offset, bufblks);
-                        if (error)
-                                break;
                 }
 
                 offset = xlog_align(log, start_block, endcount, bp);
@@ -3448,19 +3469,9 @@ xlog_do_recovery_pass(
                                  *   - order is important.
                                  */
                                 wrapped_hblks = hblks - split_hblks;
-                                error = XFS_BUF_SET_PTR(hbp,
-                                                offset + BBTOB(split_hblks),
-                                                BBTOB(hblks - split_hblks));
-                                if (error)
-                                        goto bread_err2;
-
-                                error = xlog_bread_noalign(log, 0,
-                                                           wrapped_hblks, hbp);
-                                if (error)
-                                        goto bread_err2;
-
-                                error = XFS_BUF_SET_PTR(hbp, offset,
-                                                        BBTOB(hblks));
+                                error = xlog_bread_offset(log, 0,
+                                                wrapped_hblks, hbp,
+                                                offset + BBTOB(split_hblks));
                                 if (error)
                                         goto bread_err2;
                         }
@@ -3511,19 +3522,9 @@ xlog_do_recovery_pass(
                                  *   _first_, then the log start (LR header end)
                                  *   - order is important.
                                  */
-                                error = XFS_BUF_SET_PTR(dbp,
-                                                offset + BBTOB(split_bblks),
-                                                BBTOB(bblks - split_bblks));
-                                if (error)
-                                        goto bread_err2;
-
-                                error = xlog_bread_noalign(log, wrapped_hblks,
-                                                bblks - split_bblks,
-                                                dbp);
-                                if (error)
-                                        goto bread_err2;
-
-                                error = XFS_BUF_SET_PTR(dbp, offset, h_size);
+                                error = xlog_bread_offset(log, 0,
+                                                bblks - split_bblks, hbp,
+                                                offset + BBTOB(split_bblks));
                                 if (error)
                                         goto bread_err2;
                         }