From: Takashi Sato Subject: [PATCH 3/3] Add timeout feature Date: Tue, 22 Jul 2008 18:36:30 +0900 Message-ID: <20080722183630t-sato__45666.5062265985$1216719543$gmane$org@mail.jp.nec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: "linux-kernel@vger.kernel.org" To: "dm-devel@redhat.com" , "linux-fsdevel@vger.kernel.org" , Andrew Morton , "viro@ZenIV.linux.org.uk" Received: from TYO201.gate.nec.co.jp ([202.32.8.193]:46211 "EHLO tyo201.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753154AbYGVJhN (ORCPT ); Tue, 22 Jul 2008 05:37:13 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: The timeout feature is added to freeze ioctl. And new ioctl to reset the timeout period is added. o Freeze the filesystem int ioctl(int fd, int FIFREEZE, long *timeout_sec) fd: The file descriptor of the mountpoint FIFREEZE: request code for the freeze timeout_sec: the timeout period in seconds If it's 0 or 1, the timeout isn't set. This special case of "1" is implemented to keep the compatibility with XFS applications. Return value: 0 if the operation succeeds. Otherwise, -1 o Reset the timeout period int ioctl(int fd, int FIFREEZE_RESET_TIMEOUT, long *timeout_sec) fd:file descriptor of mountpoint FIFREEZE_RESET_TIMEOUT: request code for reset of timeout period timeout_sec: new timeout period in seconds Return value: 0 if the operation succeeds. Otherwise, -1 Error number: If the filesystem has already been unfrozen, errno is set to EINVAL. Signed-off-by: Takashi Sato Signed-off-by: Masayuki Hamaguchi --- drivers/md/dm.c | 2 - fs/block_dev.c | 2 + fs/buffer.c | 16 +++++++-- fs/ioctl.c | 77 ++++++++++++++++++++++++++++++++++++++++++-- fs/super.c | 57 ++++++++++++++++++++++++++++++++ fs/xfs/xfs_fsops.c | 2 - include/linux/buffer_head.h | 3 + include/linux/fs.h | 10 +++++ 8 files changed, 160 insertions(+), 9 deletions(-) diff -uprN -X linux-2.6.26.org/Documentation/dontdiff linux-2.6.26-xfs/drivers/md/dm.c linux-2.6.26-timeout/drivers/md/d m.c --- linux-2.6.26-xfs/drivers/md/dm.c 2008-07-17 11:33:03.000000000 +0900 +++ linux-2.6.26-timeout/drivers/md/dm.c 2008-07-17 11:36:00.000000000 +0900 @@ -1407,7 +1407,7 @@ static int lock_fs(struct mapped_device WARN_ON(md->frozen_sb); - md->frozen_sb = freeze_bdev(md->suspended_bdev); + md->frozen_sb = freeze_bdev(md->suspended_bdev, 0); if (IS_ERR(md->frozen_sb)) { r = PTR_ERR(md->frozen_sb); md->frozen_sb = NULL; diff -uprN -X linux-2.6.26.org/Documentation/dontdiff linux-2.6.26-xfs/fs/block_dev.c linux-2.6.26-timeout/fs/block_dev. c --- linux-2.6.26-xfs/fs/block_dev.c 2008-07-18 15:53:51.000000000 +0900 +++ linux-2.6.26-timeout/fs/block_dev.c 2008-07-18 17:12:22.000000000 +0900 @@ -287,6 +287,8 @@ static void init_once(struct kmem_cache inode_init_once(&ei->vfs_inode); /* Initialize semaphore for freeze. */ sema_init(&bdev->bd_freeze_sem, 1); + /* Setup freeze timeout function. */ + INIT_DELAYED_WORK(&bdev->bd_freeze_timeout, freeze_timeout); } static inline void __bd_forget(struct inode *inode) diff -uprN -X linux-2.6.26.org/Documentation/dontdiff linux-2.6.26-xfs/fs/buffer.c linux-2.6.26-timeout/fs/buffer.c --- linux-2.6.26-xfs/fs/buffer.c 2008-07-18 15:53:51.000000000 +0900 +++ linux-2.6.26-timeout/fs/buffer.c 2008-07-18 17:17:50.000000000 +0900 @@ -190,14 +190,18 @@ int fsync_bdev(struct block_device *bdev /** * freeze_bdev -- lock a filesystem and force it into a consistent state - * @bdev: blockdevice to lock + * @bdev: blockdevice to lock + * @timeout_msec: timeout period * * This takes the block device bd_mount_sem to make sure no new mounts * happen on bdev until thaw_bdev() is called. * If a superblock is found on this device, we take the s_umount semaphore * on it to make sure nobody unmounts until the snapshot creation is done. + * If timeout_msec is bigger than 0, this registers the delayed work for + * timeout of the freeze feature. */ -struct super_block *freeze_bdev(struct block_device *bdev) +struct super_block *freeze_bdev(struct block_device *bdev, + unsigned int timeout_msec) { struct super_block *sb; @@ -228,8 +232,11 @@ struct super_block *freeze_bdev(struct b } sync_blockdev(bdev); - up(&bdev->bd_freeze_sem); + /* Setup unfreeze timer. */ + if (timeout_msec > 0) + add_freeze_timeout(bdev, timeout_msec); + up(&bdev->bd_freeze_sem); return sb; /* thaw_bdev releases s->s_umount and bd_mount_sem */ } EXPORT_SYMBOL(freeze_bdev); @@ -255,6 +262,9 @@ int thaw_bdev(struct block_device *bdev, return 0; } + /* Delete unfreeze timer. */ + del_freeze_timeout(bdev); + if (sb) { BUG_ON(sb->s_bdev != bdev); diff -uprN -X linux-2.6.26.org/Documentation/dontdiff linux-2.6.26-xfs/fs/ioctl.c linux-2.6.26-timeout/fs/ioctl.c --- linux-2.6.26-xfs/fs/ioctl.c 2008-07-18 21:57:20.000000000 +0900 +++ linux-2.6.26-timeout/fs/ioctl.c 2008-07-22 11:50:42.000000000 +0900 @@ -145,12 +145,16 @@ static int ioctl_fioasync(unsigned int f * ioctl_freeze - Freeze the filesystem. * * @filp: target file + * @argp: timeout value(sec) * * Call freeze_bdev() to freeze the filesystem. */ -static int ioctl_freeze(struct file *filp) +static int ioctl_freeze(struct file *filp, int __user *argp) { + int timeout_sec; + unsigned int timeout_msec; struct super_block *sb = filp->f_path.dentry->d_inode->i_sb; + int error; if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -163,8 +167,25 @@ static int ioctl_freeze(struct file *fil if (sb->s_bdev == NULL) return -EINVAL; + /* arg(sec) to tick value. */ + error = get_user(timeout_sec, argp); + if (error != 0) + return error; + + if (timeout_sec < 0 || timeout_sec > UINT_MAX/1000) + return -EINVAL; + + /* + * If 1 is specified as the timeout period it is changed into 0 + * to retain compatibility with XFS's xfs_freeze. + */ + if (timeout_sec == 1) + timeout_sec = 0; + + timeout_msec = timeout_sec * 1000; + /* Freeze */ - sb = freeze_bdev(sb->s_bdev); + sb = freeze_bdev(sb->s_bdev, timeout_msec); if (IS_ERR(sb)) return PTR_ERR(sb); return 0; @@ -193,6 +214,52 @@ static int ioctl_thaw(struct file *filp) } /* + * ioctl_freeze_reset_timeout - Reset timeout for freeze. + * + * @filp: target file + * @argp: timeout value(sec) + * + * Reset timeout for freeze. + */ +static int +ioctl_freeze_reset_timeout(struct file *filp, int __user *argp) +{ + int timeout_sec; + unsigned int timeout_msec; + struct super_block *sb = filp->f_path.dentry->d_inode->i_sb; + struct block_device *bdev = sb->s_bdev; + int error; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + /* If a regular file or a directory isn't specified, return EINVAL. */ + if (bdev == NULL) + return -EINVAL; + + /* arg(sec) to tick value */ + error = get_user(timeout_sec, argp); + if (error) + return error; + + if (timeout_sec <= 0 || timeout_sec > UINT_MAX/1000) + return -EINVAL; + + timeout_msec = timeout_sec * 1000; + + down(&bdev->bd_freeze_sem); + if (!bdev->bd_freeze_count) { + up(&bdev->bd_freeze_sem); + return -EINVAL; + } + /* setup unfreeze timer */ + add_freeze_timeout(bdev, timeout_msec); + up(&bdev->bd_freeze_sem); + + return 0; +} + +/* * When you add any new common ioctls to the switches above and below * please update compat_sys_ioctl() too. * @@ -235,13 +302,17 @@ int do_vfs_ioctl(struct file *filp, unsi break; case FIFREEZE: - error = ioctl_freeze(filp); + error = ioctl_freeze(filp, argp); break; case FITHAW: error = ioctl_thaw(filp); break; + case FIFREEZE_RESET_TIMEOUT: + error = ioctl_freeze_reset_timeout(filp, argp); + break; + default: if (S_ISREG(filp->f_path.dentry->d_inode->i_mode)) error = file_ioctl(filp, cmd, arg); diff -uprN -X linux-2.6.26.org/Documentation/dontdiff linux-2.6.26-xfs/fs/super.c linux-2.6.26-timeout/fs/super.c --- linux-2.6.26-xfs/fs/super.c 2008-07-17 11:33:13.000000000 +0900 +++ linux-2.6.26-timeout/fs/super.c 2008-07-17 11:36:00.000000000 +0900 @@ -980,3 +980,60 @@ struct vfsmount *kern_mount_data(struct } EXPORT_SYMBOL_GPL(kern_mount_data); + +/* + * freeze_timeout - Thaw the filesystem. + * + * @work: work queue (delayed_work.work) + * + * Called by the delayed work when elapsing the timeout period. + * Thaw the filesystem. + */ +void freeze_timeout(struct work_struct *work) +{ + struct block_device *bd = container_of(work, + struct block_device, bd_freeze_timeout.work); + struct super_block *sb = get_super(bd); + + thaw_bdev(bd, sb); + + if (sb) + drop_super(sb); +} +EXPORT_SYMBOL_GPL(freeze_timeout); + +/* + * add_freeze_timeout - Add timeout for freeze. + * + * @bdev: block device struct + * @timeout_msec: timeout period + * + * Add the delayed work for freeze timeout to the delayed work queue. + */ +void add_freeze_timeout(struct block_device *bdev, unsigned int timeout_msec) +{ + s64 timeout_jiffies = msecs_to_jiffies(timeout_msec); + + /* Set delayed work queue */ + cancel_delayed_work_sync(&bdev->bd_freeze_timeout); + schedule_delayed_work(&bdev->bd_freeze_timeout, timeout_jiffies); +} + +/* + * del_freeze_timeout - Delete timeout for freeze. + * + * @bdev: block device struct + * + * Delete the delayed work for freeze timeout from the delayed work queue. + */ +void del_freeze_timeout(struct block_device *bdev) +{ + /* + * It's possible that the delayed work task (freeze_timeout()) calls + * del_freeze_timeout(). If the delayed work task calls + * cancel_delayed_work_sync((), the deadlock will occur. + * So we need this check (delayed_work_pending()). + */ + if (delayed_work_pending(&bdev->bd_freeze_timeout)) + cancel_delayed_work_sync(&bdev->bd_freeze_timeout); +} diff -uprN -X linux-2.6.26.org/Documentation/dontdiff linux-2.6.26-xfs/fs/xfs/xfs_fsops.c linux-2.6.26-timeout/fs/xfs/xf s_fsops.c --- linux-2.6.26-xfs/fs/xfs/xfs_fsops.c 2008-07-17 11:33:13.000000000 +0900 +++ linux-2.6.26-timeout/fs/xfs/xfs_fsops.c 2008-07-17 11:36:00.000000000 +0900 @@ -619,7 +619,7 @@ xfs_fs_goingdown( { switch (inflags) { case XFS_FSOP_GOING_FLAGS_DEFAULT: { - struct super_block *sb = freeze_bdev(mp->m_super->s_bdev); + struct super_block *sb = freeze_bdev(mp->m_super->s_bdev, 0); if (sb && !IS_ERR(sb)) { xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT); diff -uprN -X linux-2.6.26.org/Documentation/dontdiff linux-2.6.26-xfs/include/linux/buffer_head.h linux-2.6.26-timeout/ include/linux/buffer_head.h --- linux-2.6.26-xfs/include/linux/buffer_head.h 2008-07-17 11:33:14.000000000 +0900 +++ linux-2.6.26-timeout/include/linux/buffer_head.h 2008-07-17 11:36:00.000000000 +0900 @@ -170,7 +170,8 @@ int sync_blockdev(struct block_device *b void __wait_on_buffer(struct buffer_head *); wait_queue_head_t *bh_waitq_head(struct buffer_head *bh); int fsync_bdev(struct block_device *); -struct super_block *freeze_bdev(struct block_device *); +struct super_block *freeze_bdev(struct block_device *, + unsigned int timeout_msec); int thaw_bdev(struct block_device *, struct super_block *); int fsync_super(struct super_block *); int fsync_no_super(struct block_device *); diff -uprN -X linux-2.6.26.org/Documentation/dontdiff linux-2.6.26-xfs/include/linux/fs.h linux-2.6.26-timeout/include/l inux/fs.h --- linux-2.6.26-xfs/include/linux/fs.h 2008-07-18 15:53:51.000000000 +0900 +++ linux-2.6.26-timeout/include/linux/fs.h 2008-07-18 21:51:41.000000000 +0900 @@ -8,6 +8,7 @@ #include #include +#include /* * It's silly to have NR_OPEN bigger than NR_FILE, but you can change @@ -226,6 +227,7 @@ extern int dir_notify_enable; #define FIGETBSZ _IO(0x00,2) /* get the block size used for bmap */ #define FIFREEZE _IOWR('X', 119, int) /* Freeze */ #define FITHAW _IOWR('X', 120, int) /* Thaw */ +#define FIFREEZE_RESET_TIMEOUT _IO(0x00, 3) /* Reset freeze timeout */ #define FS_IOC_GETFLAGS _IOR('f', 1, long) #define FS_IOC_SETFLAGS _IOW('f', 2, long) @@ -550,10 +552,13 @@ struct block_device { * care to not mess up bd_private for that case. */ unsigned long bd_private; + /* The counter of freeze processes */ int bd_freeze_count; /* Semaphore for freeze */ struct semaphore bd_freeze_sem; + /* Delayed work for freeze */ + struct delayed_work bd_freeze_timeout; }; /* @@ -2140,5 +2145,10 @@ int proc_nr_files(struct ctl_table *tabl int get_filesystem_list(char * buf); +extern void add_freeze_timeout(struct block_device *bdev, + unsigned int timeout_msec); +extern void del_freeze_timeout(struct block_device *bdev); +extern void freeze_timeout(struct work_struct *work); + #endif /* __KERNEL__ */ #endif /* _LINUX_FS_H */