[Ocfs2-devel] [PATCH 2/2] ocfs2: cluster aware flock()
Joel Becker
Joel.Becker at oracle.com
Mon Dec 24 13:58:06 PST 2007
On Thu, Dec 20, 2007 at 04:55:48PM -0800, Mark Fasheh wrote:
> 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 at oracle.com>
Signed-off-by: Joel Becker <joel.becker at 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 ed55238..81007e8 100644
> --- a/Documentation/filesystems/ocfs2.txt
> +++ b/Documentation/filesystems/ocfs2.txt
> @@ -62,3 +62,4 @@ data=writeback Data ordering is not preserved, data may be written
> preferred_slot=0(*) During mount, try to use this filesystem slot first. If
> it is in use by another node, the first empty one found
> will be chosen. Invalid values will be ignored.
> +localflocks This disables cluster aware flock.
> diff --git a/fs/ocfs2/Makefile b/fs/ocfs2/Makefile
> index 9fb8132..c268c91 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 \
> slot_map.o \
> diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
> index b75b2e1..67a7cfc 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)
> @@ -2216,6 +2270,7 @@ 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,
> };
> @@ -2224,8 +2279,11 @@ 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 9c34b83..f653995 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 5ee7754..edb1241 100644
> --- a/fs/ocfs2/super.c
> +++ b/fs/ocfs2/super.c
> @@ -150,6 +150,7 @@ enum {
> Opt_data_writeback,
> Opt_atime_quantum,
> Opt_slot,
> + Opt_localflocks,
> Opt_err,
> };
>
> @@ -165,6 +166,7 @@ static match_table_t tokens = {
> {Opt_data_writeback, "data=writeback"},
> {Opt_atime_quantum, "atime_quantum=%u"},
> {Opt_slot, "preferred_slot=%u"},
> + {Opt_localflocks, "localflocks"},
> {Opt_err, NULL}
> };
>
> @@ -816,6 +818,20 @@ static int ocfs2_parse_options(struct super_block *sb,
> if (option)
> mopt->slot = (s16)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\" "
> @@ -864,6 +880,9 @@ static int ocfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
> if (osb->s_atime_quantum != OCFS2_DEFAULT_ATIME_QUANTUM)
> seq_printf(s, ",atime_quantum=%u", osb->s_atime_quantum);
>
> + if (opts & OCFS2_MOUNT_LOCALFLOCKS)
> + seq_printf(s, ",localflocks,");
> +
> return 0;
> }
>
> --
> 1.5.3.6
>
>
> _______________________________________________
> Ocfs2-devel mailing list
> Ocfs2-devel at oss.oracle.com
> http://oss.oracle.com/mailman/listinfo/ocfs2-devel
--
Life's Little Instruction Book #198
"Feed a stranger's expired parking meter."
Joel Becker
Principal Software Developer
Oracle
E-mail: joel.becker at oracle.com
Phone: (650) 506-8127
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