ocfs2: add ocfs2_try_rw_lock() and ocfs2_try_inode_lock()

Patch series "ocfs2: add nowait aio support", v4.

VFS layer has introduced the non-blocking aio flag IOCB_NOWAIT, which
tells the kernel to bail out if an AIO request will block for reasons
such as file allocations, or writeback triggering, or would block while
allocating requests while performing direct I/O.

Subsequently, pwritev2/preadv2 also can leverage this part of kernel
code.  So far, ext4/xfs/btrfs have supported this feature.  Add the
related code for the ocfs2 file system.

This patch (of 3):

Add ocfs2_try_rw_lock and ocfs2_try_inode_lock functions, which will be
used in non-blocking IO scenarios.

[ghe@suse.com: v2]
Link: http://lkml.kernel.org/r/1511944612-9629-2-git-send-email-ghe@suse.com
Link: http://lkml.kernel.org/r/1511775987-841-2-git-send-email-ghe@suse.com
Signed-off-by: Gang He <ghe@suse.com>
Reviewed-by: Jun Piao <piaojun@huawei.com>
Acked-by: alex chen <alex.chen@huawei.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index f5643e3ff31723849e033d60b63c3986fa67fe5d..13fa809f48855c197f9515868bb62cea7d5f5cdd 100644 (file)
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -1764,6 +1764,27 @@ int ocfs2_rw_lock(struct inode *inode, int write)
        return status;
 }
 
+int ocfs2_try_rw_lock(struct inode *inode, int write)
+{
+       int status, level;
+       struct ocfs2_lock_res *lockres;
+       struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+       mlog(0, "inode %llu try to take %s RW lock\n",
+            (unsigned long long)OCFS2_I(inode)->ip_blkno,
+            write ? "EXMODE" : "PRMODE");
+
+       if (ocfs2_mount_local(osb))
+               return 0;
+
+       lockres = &OCFS2_I(inode)->ip_rw_lockres;
+
+       level = write ? DLM_LOCK_EX : DLM_LOCK_PR;
+
+       status = ocfs2_cluster_lock(osb, lockres, level, DLM_LKF_NOQUEUE, 0);
+       return status;
+}
+
 void ocfs2_rw_unlock(struct inode *inode, int write)
 {
        int level = write ? DLM_LOCK_EX : DLM_LOCK_PR;

diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h
index 2253688b0107d65da50f92e5c50c07e84fc25389..34139a3d71189c1d533f2da919a5755f1e6637bc 100644 (file)
--- a/fs/ocfs2/dlmglue.h
+++ b/fs/ocfs2/dlmglue.h
@@ -139,6 +139,7 @@ void ocfs2_lock_res_free(struct ocfs2_lock_res *res);
 int ocfs2_create_new_inode_locks(struct inode *inode);
 int ocfs2_drop_inode_locks(struct inode *inode);
 int ocfs2_rw_lock(struct inode *inode, int write);
+int ocfs2_try_rw_lock(struct inode *inode, int write);
 void ocfs2_rw_unlock(struct inode *inode, int write);
 int ocfs2_open_lock(struct inode *inode);
 int ocfs2_try_open_lock(struct inode *inode, int write);
@@ -163,6 +164,9 @@ int ocfs2_inode_lock_with_page(struct inode *inode,
 /* 99% of the time we don't want to supply any additional flags --
  * those are for very specific cases only. */
 #define ocfs2_inode_lock(i, b, e) ocfs2_inode_lock_full_nested(i, b, e, 0, OI_LS_NORMAL)
+#define ocfs2_try_inode_lock(i, b, e)\
+               ocfs2_inode_lock_full_nested(i, b, e, OCFS2_META_LOCK_NOQUEUE,\
+               OI_LS_NORMAL)
 void ocfs2_inode_unlock(struct inode *inode,
                       int ex);
 int ocfs2_super_lock(struct ocfs2_super *osb,