2 files changed, 20 insertions, 9 deletions

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 296160b8e78c..47a9daa7b4e6 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -258,14 +258,23 @@ xfs_bmapi_allocate_worker(
         struct xfs_bmalloca     *args = container_of(work,
                                                 struct xfs_bmalloca, work);
         unsigned long           pflags;
+        unsigned long           new_pflags = PF_FSTRANS;
 
-        /* we are in a transaction context here */
-        current_set_flags_nested(&pflags, PF_FSTRANS);
+        /*
+         * we are in a transaction context here, but may also be doing work
+         * in kswapd context, and hence we may need to inherit that state
+         * temporarily to ensure that we don't block waiting for memory reclaim
+         * in any way.
+         */
+        if (args->kswapd)
+                new_pflags |= PF_MEMALLOC | PF_SWAPWRITE | PF_KSWAPD;
+
+        current_set_flags_nested(&pflags, new_pflags);
 
         args->result = __xfs_bmapi_allocate(args);
         complete(args->done);
 
-        current_restore_flags_nested(&pflags, PF_FSTRANS);
+        current_restore_flags_nested(&pflags, new_pflags);
 }
 
 /*
@@ -284,6 +293,7 @@ xfs_bmapi_allocate(
 
 
         args->done = &done;
+        args->kswapd = current_is_kswapd();
         INIT_WORK_ONSTACK(&args->work, xfs_bmapi_allocate_worker);
         queue_work(xfs_alloc_wq, &args->work);
         wait_for_completion(&done);
diff --git a/fs/xfs/xfs_bmap_util.h b/fs/xfs/xfs_bmap_util.h
index 935ed2b24edf..075f72232a64 100644
--- a/fs/xfs/xfs_bmap_util.h
+++ b/fs/xfs/xfs_bmap_util.h
@@ -50,12 +50,13 @@ struct xfs_bmalloca {
         xfs_extlen_t            total;  /* total blocks needed for xaction */
         xfs_extlen_t            minlen; /* minimum allocation size (blocks) */
         xfs_extlen_t            minleft; /* amount must be left after alloc */
-        char                    eof;    /* set if allocating past last extent */
-        char                    wasdel; /* replacing a delayed allocation */
-        char                    userdata;/* set if is user data */
-        char                    aeof;   /* allocated space at eof */
-        char                    conv;   /* overwriting unwritten extents */
-        char                    stack_switch;
+        bool                    eof;    /* set if allocating past last extent */
+        bool                    wasdel; /* replacing a delayed allocation */
+        bool                    userdata;/* set if is user data */
+        bool                    aeof;   /* allocated space at eof */
+        bool                    conv;   /* overwriting unwritten extents */
+        bool                    stack_switch;
+        bool                    kswapd; /* allocation in kswapd context */
         int                     flags;
         struct completion       *done;
         struct work_struct      work;