1 files changed, 10 insertions, 0 deletions

diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c
index a64dfbd565a5..aad8c5da38af 100644
--- a/fs/xfs/xfs_ialloc.c
+++ b/fs/xfs/xfs_ialloc.c
@@ -147,6 +147,7 @@ xfs_ialloc_ag_alloc(
         int             version;        /* inode version number to use */
         int             isaligned = 0;  /* inode allocation at stripe unit */
                                         /* boundary */
+        unsigned int    gen;
 
         args.tp = tp;
         args.mp = tp->t_mountp;
@@ -290,6 +291,14 @@ xfs_ialloc_ag_alloc(
         else
                 version = XFS_DINODE_VERSION_1;
 
+        /*
+         * Seed the new inode cluster with a random generation number. This
+         * prevents short-term reuse of generation numbers if a chunk is
+         * freed and then immediately reallocated. We use random numbers
+         * rather than a linear progression to prevent the next generation
+         * number from being easily guessable.
+         */
+        gen = random32();
         for (j = 0; j < nbufs; j++) {
                 /*
                  * Get the block.
@@ -309,6 +318,7 @@ xfs_ialloc_ag_alloc(
                         free = XFS_MAKE_IPTR(args.mp, fbuf, i);
                         free->di_core.di_magic = cpu_to_be16(XFS_DINODE_MAGIC);
                         free->di_core.di_version = version;
+                        free->di_core.di_gen = cpu_to_be32(gen);
                         free->di_next_unlinked = cpu_to_be32(NULLAGINO);
                         xfs_ialloc_log_di(tp, fbuf, i,
                                 XFS_DI_CORE_BITS | XFS_DI_NEXT_UNLINKED);