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From: Jens Axboe <axboe@kernel.dk>
To: io-uring@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 03/10] fs: add namei support for doing a non-blocking path lookup
Date: Fri, 13 Dec 2019 11:36:25 -0700
Message-ID: <20191213183632.19441-4-axboe@kernel.dk> (raw)
In-Reply-To: <20191213183632.19441-1-axboe@kernel.dk>

If the fast lookup fails, then return -EAGAIN to have the caller retry
the path lookup. This is in preparation for supporting non-blocking
open.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 fs/namei.c            | 2 ++
 include/linux/namei.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/fs/namei.c b/fs/namei.c
index 2dda552bcf7a..50899721f699 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1801,6 +1801,8 @@ static int walk_component(struct nameidata *nd, int flags)
 	if (unlikely(err <= 0)) {
 		if (err < 0)
 			return err;
+		if (nd->flags & LOOKUP_NONBLOCK)
+			return -EAGAIN;
 		path.dentry = lookup_slow(&nd->last, nd->path.dentry,
 					  nd->flags);
 		if (IS_ERR(path.dentry))
diff --git a/include/linux/namei.h b/include/linux/namei.h
index 397a08ade6a2..a50ad21e3457 100644
--- a/include/linux/namei.h
+++ b/include/linux/namei.h
@@ -38,6 +38,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND};
 #define LOOKUP_JUMPED		0x1000
 #define LOOKUP_ROOT		0x2000
 #define LOOKUP_ROOT_GRABBED	0x0008
+#define LOOKUP_NONBLOCK		0x10000	/* don't block for lookup */
 
 extern int path_pts(struct path *path);
 
-- 
2.24.1


  parent reply index

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-13 18:36 [PATCHSET 0/10] io_uring items for 5.6 Jens Axboe
2019-12-13 18:36 ` [PATCH 01/10] io_uring: add support for fallocate() Jens Axboe
2019-12-13 18:36 ` [PATCH 02/10] io_uring: remove 'sqe' parameter to the OP helpers that take it Jens Axboe
2019-12-13 18:36 ` Jens Axboe [this message]
2019-12-27  0:42   ` [PATCH 03/10] fs: add namei support for doing a non-blocking path lookup Al Viro
2019-12-27  5:05     ` Jens Axboe
2019-12-27  5:25       ` Jens Axboe
2019-12-27 15:45         ` Jens Axboe
2019-12-28 19:03           ` Jens Axboe
2019-12-13 18:36 ` [PATCH 04/10] fs: make build_open_flags() available internally Jens Axboe
2019-12-13 18:36 ` [PATCH 05/10] io_uring: add support for IORING_OP_OPENAT Jens Axboe
2019-12-13 18:36 ` [PATCH 06/10] fs: move filp_close() outside of __close_fd_get_file() Jens Axboe
2019-12-16 19:27   ` Jann Horn
2019-12-16 19:39     ` Jens Axboe
2019-12-13 18:36 ` [PATCH 07/10] io-wq: add support for uncancellable work Jens Axboe
2019-12-13 18:36 ` [PATCH 08/10] io_uring: add support for IORING_OP_CLOSE Jens Axboe
2019-12-13 18:36 ` [PATCH 09/10] io_uring: use u64_to_user_ptr() consistently Jens Axboe
2019-12-13 18:36 ` [PATCH 10/10] io_uring: avoid ring quiesce for fixed file set unregister and update Jens Axboe

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