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Subject[PATCH 19/30] ocfs2: cluster aware flock()
Date
Hook up ocfs2_flock(), using the new flock lock type in dlmglue.c. A new
mount option, "localflocks" is added so that users can revert to old
functionality as need be.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
---
Documentation/filesystems/ocfs2.txt | 1 +
fs/ocfs2/Makefile | 1 +
fs/ocfs2/file.c | 60 ++++++++++++++++-
fs/ocfs2/locks.c | 125 +++++++++++++++++++++++++++++++++++
fs/ocfs2/locks.h | 31 +++++++++
fs/ocfs2/ocfs2.h | 1 +
fs/ocfs2/super.c | 19 +++++
7 files changed, 237 insertions(+), 1 deletions(-)
create mode 100644 fs/ocfs2/locks.c
create mode 100644 fs/ocfs2/locks.h

diff --git a/Documentation/filesystems/ocfs2.txt b/Documentation/filesystems/ocfs2.txt
index 071fad1..c318a8b 100644
--- a/Documentation/filesystems/ocfs2.txt
+++ b/Documentation/filesystems/ocfs2.txt
@@ -75,3 +75,4 @@ commit=nrsec (*) Ocfs2 can be told to sync all its data and metadata
localalloc=8(*) Allows custom localalloc size in MB. If the value is too
large, the fs will silently revert it to the default.
Localalloc is not enabled for local mounts.
+localflocks This disables cluster aware flock.
diff --git a/fs/ocfs2/Makefile b/fs/ocfs2/Makefile
index 3591890..4d4ce48 100644
--- a/fs/ocfs2/Makefile
+++ b/fs/ocfs2/Makefile
@@ -19,6 +19,7 @@ ocfs2-objs := \
ioctl.o \
journal.o \
localalloc.o \
+ locks.o \
mmap.o \
namei.o \
resize.o \
diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index 432e5f3..caefd57 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -51,6 +51,7 @@
#include "inode.h"
#include "ioctl.h"
#include "journal.h"
+#include "locks.h"
#include "mmap.h"
#include "suballoc.h"
#include "super.h"
@@ -63,6 +64,35 @@ static int ocfs2_sync_inode(struct inode *inode)
return sync_mapping_buffers(inode->i_mapping);
}

+static int ocfs2_init_file_private(struct inode *inode, struct file *file)
+{
+ struct ocfs2_file_private *fp;
+
+ fp = kzalloc(sizeof(struct ocfs2_file_private), GFP_KERNEL);
+ if (!fp)
+ return -ENOMEM;
+
+ fp->fp_file = file;
+ mutex_init(&fp->fp_mutex);
+ ocfs2_file_lock_res_init(&fp->fp_flock, fp);
+ file->private_data = fp;
+
+ return 0;
+}
+
+static void ocfs2_free_file_private(struct inode *inode, struct file *file)
+{
+ struct ocfs2_file_private *fp = file->private_data;
+ struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+ if (fp) {
+ ocfs2_simple_drop_lockres(osb, &fp->fp_flock);
+ ocfs2_lock_res_free(&fp->fp_flock);
+ kfree(fp);
+ file->private_data = NULL;
+ }
+}
+
static int ocfs2_file_open(struct inode *inode, struct file *file)
{
int status;
@@ -89,7 +119,18 @@ static int ocfs2_file_open(struct inode *inode, struct file *file)

oi->ip_open_count++;
spin_unlock(&oi->ip_lock);
- status = 0;
+
+ status = ocfs2_init_file_private(inode, file);
+ if (status) {
+ /*
+ * We want to set open count back if we're failing the
+ * open.
+ */
+ spin_lock(&oi->ip_lock);
+ oi->ip_open_count--;
+ spin_unlock(&oi->ip_lock);
+ }
+
leave:
mlog_exit(status);
return status;
@@ -108,11 +149,24 @@ static int ocfs2_file_release(struct inode *inode, struct file *file)
oi->ip_flags &= ~OCFS2_INODE_OPEN_DIRECT;
spin_unlock(&oi->ip_lock);

+ ocfs2_free_file_private(inode, file);
+
mlog_exit(0);

return 0;
}

+static int ocfs2_dir_open(struct inode *inode, struct file *file)
+{
+ return ocfs2_init_file_private(inode, file);
+}
+
+static int ocfs2_dir_release(struct inode *inode, struct file *file)
+{
+ ocfs2_free_file_private(inode, file);
+ return 0;
+}
+
static int ocfs2_sync_file(struct file *file,
struct dentry *dentry,
int datasync)
@@ -2191,6 +2245,7 @@ const struct file_operations ocfs2_fops = {
#ifdef CONFIG_COMPAT
.compat_ioctl = ocfs2_compat_ioctl,
#endif
+ .flock = ocfs2_flock,
.splice_read = ocfs2_file_splice_read,
.splice_write = ocfs2_file_splice_write,
};
@@ -2199,8 +2254,11 @@ const struct file_operations ocfs2_dops = {
.read = generic_read_dir,
.readdir = ocfs2_readdir,
.fsync = ocfs2_sync_file,
+ .release = ocfs2_dir_release,
+ .open = ocfs2_dir_open,
.ioctl = ocfs2_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = ocfs2_compat_ioctl,
#endif
+ .flock = ocfs2_flock,
};
diff --git a/fs/ocfs2/locks.c b/fs/ocfs2/locks.c
new file mode 100644
index 0000000..203f871
--- /dev/null
+++ b/fs/ocfs2/locks.c
@@ -0,0 +1,125 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * locks.c
+ *
+ * Userspace file locking support
+ *
+ * Copyright (C) 2007 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/fs.h>
+
+#define MLOG_MASK_PREFIX ML_INODE
+#include <cluster/masklog.h>
+
+#include "ocfs2.h"
+
+#include "dlmglue.h"
+#include "file.h"
+#include "locks.h"
+
+static int ocfs2_do_flock(struct file *file, struct inode *inode,
+ int cmd, struct file_lock *fl)
+{
+ int ret = 0, level = 0, trylock = 0;
+ struct ocfs2_file_private *fp = file->private_data;
+ struct ocfs2_lock_res *lockres = &fp->fp_flock;
+
+ if (fl->fl_type == F_WRLCK)
+ level = 1;
+ if (!IS_SETLKW(cmd))
+ trylock = 1;
+
+ mutex_lock(&fp->fp_mutex);
+
+ if (lockres->l_flags & OCFS2_LOCK_ATTACHED &&
+ lockres->l_level > LKM_NLMODE) {
+ int old_level = 0;
+
+ if (lockres->l_level == LKM_EXMODE)
+ old_level = 1;
+
+ if (level == old_level)
+ goto out;
+
+ /*
+ * Converting an existing lock is not guaranteed to be
+ * atomic, so we can get away with simply unlocking
+ * here and allowing the lock code to try at the new
+ * level.
+ */
+
+ flock_lock_file_wait(file,
+ &(struct file_lock){.fl_type = F_UNLCK});
+
+ ocfs2_file_unlock(file);
+ }
+
+ ret = ocfs2_file_lock(file, level, trylock);
+ if (ret) {
+ if (ret == -EAGAIN && trylock)
+ ret = -EWOULDBLOCK;
+ else
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = flock_lock_file_wait(file, fl);
+
+out:
+ mutex_unlock(&fp->fp_mutex);
+
+ return ret;
+}
+
+static int ocfs2_do_funlock(struct file *file, int cmd, struct file_lock *fl)
+{
+ int ret;
+ struct ocfs2_file_private *fp = file->private_data;
+
+ mutex_lock(&fp->fp_mutex);
+ ocfs2_file_unlock(file);
+ ret = flock_lock_file_wait(file, fl);
+ mutex_unlock(&fp->fp_mutex);
+
+ return ret;
+}
+
+/*
+ * Overall flow of ocfs2_flock() was influenced by gfs2_flock().
+ */
+int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl)
+{
+ struct inode *inode = file->f_mapping->host;
+ struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+ if (!(fl->fl_flags & FL_FLOCK))
+ return -ENOLCK;
+ if (__mandatory_lock(inode))
+ return -ENOLCK;
+
+ if ((osb->s_mount_opt & OCFS2_MOUNT_LOCALFLOCKS) ||
+ ocfs2_mount_local(osb))
+ return flock_lock_file_wait(file, fl);
+
+ if (fl->fl_type == F_UNLCK)
+ return ocfs2_do_funlock(file, cmd, fl);
+ else
+ return ocfs2_do_flock(file, inode, cmd, fl);
+}
diff --git a/fs/ocfs2/locks.h b/fs/ocfs2/locks.h
new file mode 100644
index 0000000..9743ef2
--- /dev/null
+++ b/fs/ocfs2/locks.h
@@ -0,0 +1,31 @@
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * locks.h
+ *
+ * Function prototypes for Userspace file locking support
+ *
+ * Copyright (C) 2002, 2004 Oracle. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef OCFS2_LOCKS_H
+#define OCFS2_LOCKS_H
+
+int ocfs2_flock(struct file *file, int cmd, struct file_lock *fl);
+
+#endif /* OCFS2_LOCKS_H */
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 63c131e..22e334d 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -171,6 +171,7 @@ enum ocfs2_mount_options
OCFS2_MOUNT_NOINTR = 1 << 2, /* Don't catch signals */
OCFS2_MOUNT_ERRORS_PANIC = 1 << 3, /* Panic on errors */
OCFS2_MOUNT_DATA_WRITEBACK = 1 << 4, /* No data ordering */
+ OCFS2_MOUNT_LOCALFLOCKS = 1 << 5, /* No cluster aware user file locks */
};

#define OCFS2_OSB_SOFT_RO 0x0001
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 1104f14..4a091f5 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -153,6 +153,7 @@ enum {
Opt_slot,
Opt_commit,
Opt_localalloc,
+ Opt_localflocks,
Opt_err,
};

@@ -170,6 +171,7 @@ static match_table_t tokens = {
{Opt_slot, "preferred_slot=%u"},
{Opt_commit, "commit=%u"},
{Opt_localalloc, "localalloc=%d"},
+ {Opt_localflocks, "localflocks"},
{Opt_err, NULL}
};

@@ -848,6 +850,20 @@ static int ocfs2_parse_options(struct super_block *sb,
if (option >= 0 && (option <= ocfs2_local_alloc_size(sb) * 8))
mopt->localalloc_opt = option;
break;
+ case Opt_localflocks:
+ /*
+ * Changing this during remount could race
+ * flock() requests, or "unbalance" existing
+ * ones (e.g., a lock is taken in one mode but
+ * dropped in the other). If users care enough
+ * to flip locking modes during remount, we
+ * could add a "local" flag to individual
+ * flock structures for proper tracking of
+ * state.
+ */
+ if (!is_remount)
+ mopt->mount_opt |= OCFS2_MOUNT_LOCALFLOCKS;
+ break;
default:
mlog(ML_ERROR,
"Unrecognized mount option \"%s\" "
@@ -903,6 +919,9 @@ static int ocfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
if (osb->local_alloc_size != OCFS2_DEFAULT_LOCAL_ALLOC_SIZE)
seq_printf(s, ",localalloc=%d", osb->local_alloc_size);

+ if (opts & OCFS2_MOUNT_LOCALFLOCKS)
+ seq_printf(s, ",localflocks,");
+
return 0;
}

--
1.5.3.6


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