From: Goldwyn Rodrigues Date: Fri, 14 Jun 2013 21:05:10 -0500 Subject: [Ocfs2-devel] [PATCH] unlink performance: wait for open lock in case of dirs Message-ID: <20130615020510.GA4487@shrek.cartoons> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com This patch is to improve the unlink performance. Here is the scenario: On node A, create multiple directories say d1-d8, and each have 3 files under it f1, f2 and f3. On node B, delete all directories using rm -Rf d* The FS first unlinks f1, f2 and f3. However, when it performs ocfs2_evict_inode() -> ocfs2_delete_inode() -> ocfs2_query_inode_wipe() -> ocfs2_try_open_lock() on d1, it fails with -EAGAIN. The open lock fails because on the remote node a PR->EX convert takes longer than a simple EX grant. This starts a checkpoint because OCFS2_INODE_DELETED flag is not set on the directory inode. Now, a checkpoint interferes with the journaling of the inodes deleted in the following unlinks, in our case, directories d2-d8 and the files contained in it. With this patch, We wait on a directory EX lock only if we already have an open_lock in PR mode. This way we will avoid the ABBA locking. By waiting for the open_lock on the directory, I am getting a unlink performance improvement of a rm -Rf of 50-60% in the usual case. Also, folded ocfs2_open_lock and ocfs2_try_open_lock into one. Let me know if you would like to see the test case. Signed-off-by: Goldwyn Rodrigues Index: linux-3.0-SLE11-SP3/fs/ocfs2/dlmglue.c =================================================================== --- linux-3.0-SLE11-SP3.orig/fs/ocfs2/dlmglue.c 2013-06-14 06:47:29.322506695 -0500 +++ linux-3.0-SLE11-SP3/fs/ocfs2/dlmglue.c 2013-06-14 09:19:48.651924037 -0500 @@ -1681,9 +1681,9 @@ void ocfs2_rw_unlock(struct inode *inode /* * ocfs2_open_lock always get PR mode lock. */ -int ocfs2_open_lock(struct inode *inode) +int ocfs2_open_lock(struct inode *inode, int write, int wait) { - int status = 0; + int status = 0, level, flags; struct ocfs2_lock_res *lockres; struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); @@ -1696,43 +1696,25 @@ int ocfs2_open_lock(struct inode *inode) goto out; lockres = &OCFS2_I(inode)->ip_open_lockres; - - status = ocfs2_cluster_lock(OCFS2_SB(inode->i_sb), lockres, - DLM_LOCK_PR, 0, 0); - if (status < 0) - mlog_errno(status); - -out: - return status; -} - -int ocfs2_try_open_lock(struct inode *inode, int write) -{ - int status = 0, level; - struct ocfs2_lock_res *lockres; - struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); - - BUG_ON(!inode); - - mlog(0, "inode %llu try to take %s open lock\n", - (unsigned long long)OCFS2_I(inode)->ip_blkno, - write ? "EXMODE" : "PRMODE"); - - if (ocfs2_mount_local(osb)) - goto out; - - lockres = &OCFS2_I(inode)->ip_open_lockres; - level = write ? DLM_LOCK_EX : DLM_LOCK_PR; + if (wait) { + flags = 0; + /* If we don't already have the lock in PR mode, + * don't wait. + * + * This should avoid ABBA locking. + */ + if ((lockres->l_level != DLM_LOCK_PR) && write) + flags = DLM_LKF_NOQUEUE; + + } else + flags = DLM_LKF_NOQUEUE; - /* - * The file system may already holding a PRMODE/EXMODE open lock. - * Since we pass DLM_LKF_NOQUEUE, the request won't block waiting on - * other nodes and the -EAGAIN will indicate to the caller that - * this inode is still in use. - */ status = ocfs2_cluster_lock(OCFS2_SB(inode->i_sb), lockres, - level, DLM_LKF_NOQUEUE, 0); + level, flags, 0); + + if ((status < 0) && (flags && (status != -EAGAIN))) + mlog_errno(status); out: return status; Index: linux-3.0-SLE11-SP3/fs/ocfs2/inode.c =================================================================== --- linux-3.0-SLE11-SP3.orig/fs/ocfs2/inode.c 2013-06-13 22:54:32.527606012 -0500 +++ linux-3.0-SLE11-SP3/fs/ocfs2/inode.c 2013-06-14 07:33:53.960196648 -0500 @@ -455,7 +455,7 @@ static int ocfs2_read_locked_inode(struc 0, inode); if (can_lock) { - status = ocfs2_open_lock(inode); + status = ocfs2_open_lock(inode, 0, 1); if (status) { make_bad_inode(inode); mlog_errno(status); @@ -470,7 +470,7 @@ static int ocfs2_read_locked_inode(struc } if (args->fi_flags & OCFS2_FI_FLAG_ORPHAN_RECOVERY) { - status = ocfs2_try_open_lock(inode, 0); + status = ocfs2_open_lock(inode, 0, 0); if (status) { make_bad_inode(inode); return status; @@ -923,7 +923,8 @@ static int ocfs2_query_inode_wipe(struct * Though we call this with the meta data lock held, the * trylock keeps us from ABBA deadlock. */ - status = ocfs2_try_open_lock(inode, 1); + status = ocfs2_open_lock(inode, 1, S_ISDIR(inode->i_mode)); + if (status == -EAGAIN) { status = 0; reason = 3; Index: linux-3.0-SLE11-SP3/fs/ocfs2/dlmglue.h =================================================================== --- linux-3.0-SLE11-SP3.orig/fs/ocfs2/dlmglue.h 2013-06-10 09:45:20.787386504 -0500 +++ linux-3.0-SLE11-SP3/fs/ocfs2/dlmglue.h 2013-06-14 07:38:49.861576515 -0500 @@ -110,8 +110,7 @@ int ocfs2_create_new_inode_locks(struct int ocfs2_drop_inode_locks(struct inode *inode); int ocfs2_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); +int ocfs2_open_lock(struct inode *inode, int write, int wait); void ocfs2_open_unlock(struct inode *inode); int ocfs2_inode_lock_atime(struct inode *inode, struct vfsmount *vfsmnt, Index: linux-3.0-SLE11-SP3/fs/ocfs2/namei.c =================================================================== --- linux-3.0-SLE11-SP3.orig/fs/ocfs2/namei.c 2013-06-13 22:54:32.527606012 -0500 +++ linux-3.0-SLE11-SP3/fs/ocfs2/namei.c 2013-06-14 07:40:06.623785914 -0500 @@ -2302,7 +2302,7 @@ int ocfs2_create_inode_in_orphan(struct } /* get open lock so that only nodes can't remove it from orphan dir. */ - status = ocfs2_open_lock(inode); + status = ocfs2_open_lock(inode, 0, 1); if (status < 0) mlog_errno(status);