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Diffstat (limited to 'fs/xfs/xfs_btree.c')
-rw-r--r--fs/xfs/xfs_btree.c82
1 files changed, 81 insertions, 1 deletions
diff --git a/fs/xfs/xfs_btree.c b/fs/xfs/xfs_btree.c
index bf810c6baf2b..cf893bc1e373 100644
--- a/fs/xfs/xfs_btree.c
+++ b/fs/xfs/xfs_btree.c
@@ -33,6 +33,7 @@
#include "xfs_error.h"
#include "xfs_trace.h"
#include "xfs_cksum.h"
+#include "xfs_alloc.h"
/*
* Cursor allocation zone.
@@ -2323,7 +2324,7 @@ error1:
* record (to be inserted into parent).
*/
STATIC int /* error */
-xfs_btree_split(
+__xfs_btree_split(
struct xfs_btree_cur *cur,
int level,
union xfs_btree_ptr *ptrp,
@@ -2503,6 +2504,85 @@ error0:
return error;
}
+struct xfs_btree_split_args {
+ struct xfs_btree_cur *cur;
+ int level;
+ union xfs_btree_ptr *ptrp;
+ union xfs_btree_key *key;
+ struct xfs_btree_cur **curp;
+ int *stat; /* success/failure */
+ int result;
+ bool kswapd; /* allocation in kswapd context */
+ struct completion *done;
+ struct work_struct work;
+};
+
+/*
+ * Stack switching interfaces for allocation
+ */
+static void
+xfs_btree_split_worker(
+ struct work_struct *work)
+{
+ struct xfs_btree_split_args *args = container_of(work,
+ struct xfs_btree_split_args, work);
+ unsigned long pflags;
+ unsigned long new_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_btree_split(args->cur, args->level, args->ptrp,
+ args->key, args->curp, args->stat);
+ complete(args->done);
+
+ current_restore_flags_nested(&pflags, new_pflags);
+}
+
+/*
+ * BMBT split requests often come in with little stack to work on. Push
+ * them off to a worker thread so there is lots of stack to use. For the other
+ * btree types, just call directly to avoid the context switch overhead here.
+ */
+STATIC int /* error */
+xfs_btree_split(
+ struct xfs_btree_cur *cur,
+ int level,
+ union xfs_btree_ptr *ptrp,
+ union xfs_btree_key *key,
+ struct xfs_btree_cur **curp,
+ int *stat) /* success/failure */
+{
+ struct xfs_btree_split_args args;
+ DECLARE_COMPLETION_ONSTACK(done);
+
+ if (cur->bc_btnum != XFS_BTNUM_BMAP)
+ return __xfs_btree_split(cur, level, ptrp, key, curp, stat);
+
+ args.cur = cur;
+ args.level = level;
+ args.ptrp = ptrp;
+ args.key = key;
+ args.curp = curp;
+ args.stat = stat;
+ args.done = &done;
+ args.kswapd = current_is_kswapd();
+ INIT_WORK_ONSTACK(&args.work, xfs_btree_split_worker);
+ queue_work(xfs_alloc_wq, &args.work);
+ wait_for_completion(&done);
+ destroy_work_on_stack(&args.work);
+ return args.result;
+}
+
+
/*
* Copy the old inode root contents into a real block and make the
* broot point to it.