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authorLinus Torvalds <torvalds@linux-foundation.org>2017-06-02 12:29:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-06-02 12:29:03 -0700
commite6e6d074369c839e84071c3b056adf20ead8da6e (patch)
treeef2cb726f59090d54d1c6c163587fb52abed5e53
parentb939c51445f0542e80a8f910014c418d04b5de6e (diff)
parent63db7c815bc0997c29e484d2409684fdd9fcd93b (diff)
downloadleg-kernel-e6e6d074369c839e84071c3b056adf20ead8da6e.tar.gz
Merge tag 'xfs-4.12-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull XFS fix from Darrick Wong: "I've one more bugfix for you for 4.12-rc4: Fix an unmount hang due to a race in io buffer accounting" * tag 'xfs-4.12-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: xfs: use ->b_state to fix buffer I/O accounting release race
-rw-r--r--fs/xfs/xfs_buf.c38
-rw-r--r--fs/xfs/xfs_buf.h5
2 files changed, 28 insertions, 15 deletions
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 62fa39276a24..07b77b73b024 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -97,12 +97,16 @@ static inline void
xfs_buf_ioacct_inc(
struct xfs_buf *bp)
{
- if (bp->b_flags & (XBF_NO_IOACCT|_XBF_IN_FLIGHT))
+ if (bp->b_flags & XBF_NO_IOACCT)
return;
ASSERT(bp->b_flags & XBF_ASYNC);
- bp->b_flags |= _XBF_IN_FLIGHT;
- percpu_counter_inc(&bp->b_target->bt_io_count);
+ spin_lock(&bp->b_lock);
+ if (!(bp->b_state & XFS_BSTATE_IN_FLIGHT)) {
+ bp->b_state |= XFS_BSTATE_IN_FLIGHT;
+ percpu_counter_inc(&bp->b_target->bt_io_count);
+ }
+ spin_unlock(&bp->b_lock);
}
/*
@@ -110,14 +114,24 @@ xfs_buf_ioacct_inc(
* freed and unaccount from the buftarg.
*/
static inline void
-xfs_buf_ioacct_dec(
+__xfs_buf_ioacct_dec(
struct xfs_buf *bp)
{
- if (!(bp->b_flags & _XBF_IN_FLIGHT))
- return;
+ ASSERT(spin_is_locked(&bp->b_lock));
- bp->b_flags &= ~_XBF_IN_FLIGHT;
- percpu_counter_dec(&bp->b_target->bt_io_count);
+ if (bp->b_state & XFS_BSTATE_IN_FLIGHT) {
+ bp->b_state &= ~XFS_BSTATE_IN_FLIGHT;
+ percpu_counter_dec(&bp->b_target->bt_io_count);
+ }
+}
+
+static inline void
+xfs_buf_ioacct_dec(
+ struct xfs_buf *bp)
+{
+ spin_lock(&bp->b_lock);
+ __xfs_buf_ioacct_dec(bp);
+ spin_unlock(&bp->b_lock);
}
/*
@@ -149,9 +163,9 @@ xfs_buf_stale(
* unaccounted (released to LRU) before that occurs. Drop in-flight
* status now to preserve accounting consistency.
*/
- xfs_buf_ioacct_dec(bp);
-
spin_lock(&bp->b_lock);
+ __xfs_buf_ioacct_dec(bp);
+
atomic_set(&bp->b_lru_ref, 0);
if (!(bp->b_state & XFS_BSTATE_DISPOSE) &&
(list_lru_del(&bp->b_target->bt_lru, &bp->b_lru)))
@@ -979,12 +993,12 @@ xfs_buf_rele(
* ensures the decrement occurs only once per-buf.
*/
if ((atomic_read(&bp->b_hold) == 1) && !list_empty(&bp->b_lru))
- xfs_buf_ioacct_dec(bp);
+ __xfs_buf_ioacct_dec(bp);
goto out_unlock;
}
/* the last reference has been dropped ... */
- xfs_buf_ioacct_dec(bp);
+ __xfs_buf_ioacct_dec(bp);
if (!(bp->b_flags & XBF_STALE) && atomic_read(&bp->b_lru_ref)) {
/*
* If the buffer is added to the LRU take a new reference to the
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 8d1d44f87ce9..1508121f29f2 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -63,7 +63,6 @@ typedef enum {
#define _XBF_KMEM (1 << 21)/* backed by heap memory */
#define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
#define _XBF_COMPOUND (1 << 23)/* compound buffer */
-#define _XBF_IN_FLIGHT (1 << 25) /* I/O in flight, for accounting purposes */
typedef unsigned int xfs_buf_flags_t;
@@ -84,14 +83,14 @@ typedef unsigned int xfs_buf_flags_t;
{ _XBF_PAGES, "PAGES" }, \
{ _XBF_KMEM, "KMEM" }, \
{ _XBF_DELWRI_Q, "DELWRI_Q" }, \
- { _XBF_COMPOUND, "COMPOUND" }, \
- { _XBF_IN_FLIGHT, "IN_FLIGHT" }
+ { _XBF_COMPOUND, "COMPOUND" }
/*
* Internal state flags.
*/
#define XFS_BSTATE_DISPOSE (1 << 0) /* buffer being discarded */
+#define XFS_BSTATE_IN_FLIGHT (1 << 1) /* I/O in flight */
/*
* The xfs_buftarg contains 2 notions of "sector size" -