Merge tag 'v3.15-rc6' into patchwork

Linux 3.15-rc6

* tag 'v3.15-rc6': (1314 commits)
  Linux 3.15-rc6
  Btrfs: send, fix incorrect ref access when using extrefs
  Btrfs: fix EIO on reading file after ioctl clone works on it
  scripts/checksyscalls.sh: Make renameat optional
  asm-generic: Add renameat2 syscall
  ia64: add renameat2 syscall
  parisc: add renameat2 syscall
  m68k: add renameat2 syscall
  sysfs: make sure read buffer is zeroed
  ahci: imx: PLL clock needs 100us to settle down
  PCI: Wrong register used to check pending traffic
  target: fix memory leak on XCOPY
  random: fix BUG_ON caused by accounting simplification
  clk: tegra: Fix wrong value written to PLLE_AUX
  staging: rtl8723au: Do not reset wdev->iftype in netdev_close()
  ACPI / video: Revert native brightness quirk for ThinkPad T530
  staging: rtl8723au: Use correct pipe type for USB interrupts
  crush: decode and initialize chooseleaf_vary_r
  libceph: fix corruption when using page_count 0 page in rbd
  arm64: fix pud_huge() for 2-level pagetables
  ...

1 files changed, 28 insertions, 22 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index a82fbe4c9e8e..000a220e2a41 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -906,8 +906,8 @@ EXPORT_SYMBOL(page_cache_prev_hole);
  * Looks up the page cache slot at @mapping & @offset.  If there is a
  * page cache page, it is returned with an increased refcount.
  *
- * If the slot holds a shadow entry of a previously evicted page, it
- * is returned.
+ * If the slot holds a shadow entry of a previously evicted page, or a
+ * swap entry from shmem/tmpfs, it is returned.
  *
  * Otherwise, %NULL is returned.
  */
@@ -928,9 +928,9 @@ repeat:
 			if (radix_tree_deref_retry(page))
 				goto repeat;
 			/*
-			 * Otherwise, shmem/tmpfs must be storing a swap entry
-			 * here as an exceptional entry: so return it without
-			 * attempting to raise page count.
+			 * A shadow entry of a recently evicted page,
+			 * or a swap entry from shmem/tmpfs.  Return
+			 * it without attempting to raise page count.
 			 */
 			goto out;
 		}
@@ -983,8 +983,8 @@ EXPORT_SYMBOL(find_get_page);
  * page cache page, it is returned locked and with an increased
  * refcount.
  *
- * If the slot holds a shadow entry of a previously evicted page, it
- * is returned.
+ * If the slot holds a shadow entry of a previously evicted page, or a
+ * swap entry from shmem/tmpfs, it is returned.
  *
  * Otherwise, %NULL is returned.
  *
@@ -1099,8 +1099,8 @@ EXPORT_SYMBOL(find_or_create_page);
  * with ascending indexes.  There may be holes in the indices due to
  * not-present pages.
  *
- * Any shadow entries of evicted pages are included in the returned
- * array.
+ * Any shadow entries of evicted pages, or swap entries from
+ * shmem/tmpfs, are included in the returned array.
  *
  * find_get_entries() returns the number of pages and shadow entries
  * which were found.
@@ -1128,9 +1128,9 @@ repeat:
 			if (radix_tree_deref_retry(page))
 				goto restart;
 			/*
-			 * Otherwise, we must be storing a swap entry
-			 * here as an exceptional entry: so return it
-			 * without attempting to raise page count.
+			 * A shadow entry of a recently evicted page,
+			 * or a swap entry from shmem/tmpfs.  Return
+			 * it without attempting to raise page count.
 			 */
 			goto export;
 		}
@@ -1198,9 +1198,9 @@ repeat:
 				goto restart;
 			}
 			/*
-			 * Otherwise, shmem/tmpfs must be storing a swap entry
-			 * here as an exceptional entry: so skip over it -
-			 * we only reach this from invalidate_mapping_pages().
+			 * A shadow entry of a recently evicted page,
+			 * or a swap entry from shmem/tmpfs.  Skip
+			 * over it.
 			 */
 			continue;
 		}
@@ -1265,9 +1265,9 @@ repeat:
 				goto restart;
 			}
 			/*
-			 * Otherwise, shmem/tmpfs must be storing a swap entry
-			 * here as an exceptional entry: so stop looking for
-			 * contiguous pages.
+			 * A shadow entry of a recently evicted page,
+			 * or a swap entry from shmem/tmpfs.  Stop
+			 * looking for contiguous pages.
 			 */
 			break;
 		}
@@ -1341,10 +1341,17 @@ repeat:
 				goto restart;
 			}
 			/*
-			 * This function is never used on a shmem/tmpfs
-			 * mapping, so a swap entry won't be found here.
+			 * A shadow entry of a recently evicted page.
+			 *
+			 * Those entries should never be tagged, but
+			 * this tree walk is lockless and the tags are
+			 * looked up in bulk, one radix tree node at a
+			 * time, so there is a sizable window for page
+			 * reclaim to evict a page we saw tagged.
+			 *
+			 * Skip over it.
 			 */
-			BUG();
+			continue;
 		}
 
 		if (!page_cache_get_speculative(page))
@@ -2581,7 +2588,6 @@ EXPORT_SYMBOL(generic_perform_write);
  * @iocb:	IO state structure (file, offset, etc.)
  * @iov:	vector with data to write
  * @nr_segs:	number of segments in the vector
- * @ppos:	position where to write
  *
  * This function does all the work needed for actually writing data to a
  * file. It does all basic checks, removes SUID from the file, updates