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fs: simplify freeze_bdev/thaw_bdev

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Store the frozen superblock in struct block_device to avoid the awkward
interface that can return a sb only used a cookie, an ERR_PTR or NULL.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Chao Yu <yuchao0@huawei.com>		[f2fs]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2020-11-24 11:54:06 +01:00 committed by Jens Axboe
parent 60b498852b
commit 040f04bd2e
9 changed files with 35 additions and 61 deletions
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5
drivers/md/dm-core.h
View File

@ -96,11 +96,6 @@ struct mapped_device {
*/
struct workqueue_struct *wq;
/*
* freeze/thaw support require holding onto a super block
*/
struct super_block *frozen_sb;
/* forced geometry settings */
struct hd_geometry geometry;

20
drivers/md/dm.c
View File

@ -2392,27 +2392,19 @@ static int lock_fs(struct mapped_device *md)
{
int r;
WARN_ON(md->frozen_sb);
WARN_ON(test_bit(DMF_FROZEN, &md->flags));
md->frozen_sb = freeze_bdev(md->bdev);
if (IS_ERR(md->frozen_sb)) {
r = PTR_ERR(md->frozen_sb);
md->frozen_sb = NULL;
return r;
}
set_bit(DMF_FROZEN, &md->flags);
return 0;
r = freeze_bdev(md->bdev);
if (!r)
set_bit(DMF_FROZEN, &md->flags);
return r;
}
static void unlock_fs(struct mapped_device *md)
{
if (!test_bit(DMF_FROZEN, &md->flags))
return;
thaw_bdev(md->bdev, md->frozen_sb);
md->frozen_sb = NULL;
thaw_bdev(md->bdev);
clear_bit(DMF_FROZEN, &md->flags);
}

41
fs/block_dev.c
View File

@ -548,55 +548,47 @@ EXPORT_SYMBOL(fsync_bdev);
* count down in thaw_bdev(). When it becomes 0, thaw_bdev() will unfreeze
* actually.
*/
struct super_block *freeze_bdev(struct block_device *bdev)
int freeze_bdev(struct block_device *bdev)
{
struct super_block *sb;
int error = 0;
mutex_lock(&bdev->bd_fsfreeze_mutex);
if (++bdev->bd_fsfreeze_count > 1) {
/*
* We don't even need to grab a reference - the first call
* to freeze_bdev grab an active reference and only the last
* thaw_bdev drops it.
*/
sb = get_super(bdev);
if (sb)
drop_super(sb);
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return sb;
}
if (++bdev->bd_fsfreeze_count > 1)
goto done;
sb = get_active_super(bdev);
if (!sb)
goto out;
goto sync;
if (sb->s_op->freeze_super)
error = sb->s_op->freeze_super(sb);
else
error = freeze_super(sb);
if (error) {
deactivate_super(sb);
bdev->bd_fsfreeze_count--;
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return ERR_PTR(error);
}
deactivate_super(sb);
out:
if (error) {
bdev->bd_fsfreeze_count--;
goto done;
}
bdev->bd_fsfreeze_sb = sb;
sync:
sync_blockdev(bdev);
done:
mutex_unlock(&bdev->bd_fsfreeze_mutex);
return sb; /* thaw_bdev releases s->s_umount */
return error;
}
EXPORT_SYMBOL(freeze_bdev);
/**
* thaw_bdev -- unlock filesystem
* @bdev: blockdevice to unlock
* @sb: associated superblock
*
* Unlocks the filesystem and marks it writeable again after freeze_bdev().
*/
int thaw_bdev(struct block_device *bdev, struct super_block *sb)
int thaw_bdev(struct block_device *bdev)
{
struct super_block *sb;
int error = -EINVAL;
mutex_lock(&bdev->bd_fsfreeze_mutex);
@ -607,6 +599,7 @@ int thaw_bdev(struct block_device *bdev, struct super_block *sb)
if (--bdev->bd_fsfreeze_count > 0)
goto out;
sb = bdev->bd_fsfreeze_sb;
if (!sb)
goto out;

2
fs/buffer.c
View File

@ -523,7 +523,7 @@ repeat:
void emergency_thaw_bdev(struct super_block *sb)
{
while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb))
while (sb->s_bdev && !thaw_bdev(sb->s_bdev))
printk(KERN_WARNING "Emergency Thaw on %pg\n", sb->s_bdev);
}

2
fs/ext4/ioctl.c
View File

@ -624,7 +624,7 @@ static int ext4_shutdown(struct super_block *sb, unsigned long arg)
case EXT4_GOING_FLAGS_DEFAULT:
freeze_bdev(sb->s_bdev);
set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
thaw_bdev(sb->s_bdev, sb);
thaw_bdev(sb->s_bdev);
break;
case EXT4_GOING_FLAGS_LOGFLUSH:
set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);

14
fs/f2fs/file.c
View File

@ -2230,16 +2230,12 @@ static int f2fs_ioc_shutdown(struct file *filp, unsigned long arg)
switch (in) {
case F2FS_GOING_DOWN_FULLSYNC:
sb = freeze_bdev(sb->s_bdev);
if (IS_ERR(sb)) {
ret = PTR_ERR(sb);
ret = freeze_bdev(sb->s_bdev);
if (ret)
goto out;
}
if (sb) {
f2fs_stop_checkpoint(sbi, false);
set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
thaw_bdev(sb->s_bdev, sb);
}
f2fs_stop_checkpoint(sbi, false);
set_sbi_flag(sbi, SBI_IS_SHUTDOWN);
thaw_bdev(sb->s_bdev);
break;
case F2FS_GOING_DOWN_METASYNC:
/* do checkpoint only */

7
fs/xfs/xfs_fsops.c
View File

@ -433,13 +433,10 @@ xfs_fs_goingdown(
{
switch (inflags) {
case XFS_FSOP_GOING_FLAGS_DEFAULT: {
struct super_block *sb = freeze_bdev(mp->m_super->s_bdev);
if (sb && !IS_ERR(sb)) {
if (!freeze_bdev(mp->m_super->s_bdev)) {
xfs_force_shutdown(mp, SHUTDOWN_FORCE_UMOUNT);
thaw_bdev(sb->s_bdev, sb);
thaw_bdev(mp->m_super->s_bdev);
}
break;
}
case XFS_FSOP_GOING_FLAGS_LOGFLUSH:

1
include/linux/blk_types.h
View File

@ -46,6 +46,7 @@ struct block_device {
int bd_fsfreeze_count;
/* Mutex for freeze */
struct mutex bd_fsfreeze_mutex;
struct super_block *bd_fsfreeze_sb;
} __randomize_layout;
/*

4
include/linux/blkdev.h
View File

@ -2020,7 +2020,7 @@ static inline int sync_blockdev(struct block_device *bdev)
#endif
int fsync_bdev(struct block_device *bdev);
struct super_block *freeze_bdev(struct block_device *bdev);
int thaw_bdev(struct block_device *bdev, struct super_block *sb);
int freeze_bdev(struct block_device *bdev);
int thaw_bdev(struct block_device *bdev);
#endif /* _LINUX_BLKDEV_H */