[PATCH 2/3] btrfs: pass in DIO_SKIP_DIO_COUNT to do_blockdev_direct_IO()

From: Jens Axboe
Date: Wed Apr 15 2015 - 18:02:42 EST


btrfs_direct_IO() already holds the inode i_dio_count elevated, so
pass in that do_blockdev_direct_IO() does not need to. If we end
up dropping the inode dio count before calling this function, then
we drop the flag as well.

Cc: Chris Mason <clm@xxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxx>
---
fs/btrfs/inode.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6fe341a66ed8..3ecac37f10e0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8121,8 +8121,7 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
struct inode *inode = file->f_mapping->host;
u64 outstanding_extents = 0;
size_t count = 0;
- int flags = 0;
- bool wakeup = true;
+ int flags = DIO_SKIP_DIO_COUNT;
bool relock = false;
ssize_t ret;

@@ -8170,8 +8169,11 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
} else if (test_bit(BTRFS_INODE_READDIO_NEED_LOCK,
&BTRFS_I(inode)->runtime_flags)) {
inode_dio_dec(inode);
+ /*
+ * we know need i_dio_count inc/dec, the below overwrites
+ * the skip inc/dec flag.
+ */
flags = DIO_LOCKING | DIO_SKIP_HOLES;
- wakeup = false;
}

ret = __blockdev_direct_IO(rw, iocb, inode,
@@ -8187,7 +8189,7 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
count - (size_t)ret);
}
out:
- if (wakeup)
+ if (flags & DIO_SKIP_DIO_COUNT)
inode_dio_dec(inode);
if (relock)
mutex_lock(&inode->i_mutex);
--
1.9.1

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