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Wed, 25 Nov 2020 07:19:14 -0500 X-MC-Unique: Isk531vVOqmxxVDKr-XQtg-1 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 1AB0FACBD; Wed, 25 Nov 2020 12:19:11 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id D76D91E130F; Wed, 25 Nov 2020 13:19:10 +0100 (CET) Date: Wed, 25 Nov 2020 13:19:10 +0100 From: Jan Kara To: Christoph Hellwig Message-ID: <20201125121910.GG16944@quack2.suse.cz> References: <20201124132751.3747337-1-hch@lst.de> <20201124132751.3747337-4-hch@lst.de> MIME-Version: 1.0 In-Reply-To: <20201124132751.3747337-4-hch@lst.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-loop: dm-devel@redhat.com Cc: Jens Axboe , Jan Kara , linux-fsdevel@vger.kernel.org, Mike Snitzer , Konrad Rzeszutek Wilk , Greg Kroah-Hartman , Jan Kara , Josef Bacik , Coly Li , linux-block@vger.kernel.org, Richard Weinberger , dm-devel@redhat.com, linux-mtd@lists.infradead.org, Johannes Thumshirn , Tejun Heo , xen-devel@lists.xenproject.org, linux-bcache@vger.kernel.org, linux-mm@kvack.org Subject: Re: [dm-devel] [PATCH 03/45] fs: remove get_super_thawed and get_super_exclusive_thawed X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Tue 24-11-20 14:27:09, Christoph Hellwig wrote: > Just open code the wait in the only caller of both functions. > > Signed-off-by: Christoph Hellwig Fine by me. You can add: Reviewed-by: Jan Kara Honza > --- > fs/internal.h | 2 ++ > fs/quota/quota.c | 31 +++++++++++++++++++++------- > fs/super.c | 51 ++-------------------------------------------- > include/linux/fs.h | 4 +--- > 4 files changed, 29 insertions(+), 59 deletions(-) > > diff --git a/fs/internal.h b/fs/internal.h > index a7cd0f64faa4ab..47be21dfeebef5 100644 > --- a/fs/internal.h > +++ b/fs/internal.h > @@ -114,7 +114,9 @@ extern struct file *alloc_empty_file_noaccount(int, const struct cred *); > */ > extern int reconfigure_super(struct fs_context *); > extern bool trylock_super(struct super_block *sb); > +struct super_block *__get_super(struct block_device *bdev, bool excl); > extern struct super_block *user_get_super(dev_t); > +void put_super(struct super_block *sb); > extern bool mount_capable(struct fs_context *); > > /* > diff --git a/fs/quota/quota.c b/fs/quota/quota.c > index 9af95c7a0bbe3c..f3d32b0d9008f2 100644 > --- a/fs/quota/quota.c > +++ b/fs/quota/quota.c > @@ -20,6 +20,7 @@ > #include > #include > #include "compat.h" > +#include "../internal.h" > > static int check_quotactl_permission(struct super_block *sb, int type, int cmd, > qid_t id) > @@ -868,6 +869,7 @@ static struct super_block *quotactl_block(const char __user *special, int cmd) > struct block_device *bdev; > struct super_block *sb; > struct filename *tmp = getname(special); > + bool excl = false, thawed = false; > > if (IS_ERR(tmp)) > return ERR_CAST(tmp); > @@ -875,17 +877,32 @@ static struct super_block *quotactl_block(const char __user *special, int cmd) > putname(tmp); > if (IS_ERR(bdev)) > return ERR_CAST(bdev); > - if (quotactl_cmd_onoff(cmd)) > - sb = get_super_exclusive_thawed(bdev); > - else if (quotactl_cmd_write(cmd)) > - sb = get_super_thawed(bdev); > - else > - sb = get_super(bdev); > + > + if (quotactl_cmd_onoff(cmd)) { > + excl = true; > + thawed = true; > + } else if (quotactl_cmd_write(cmd)) { > + thawed = true; > + } > + > +retry: > + sb = __get_super(bdev, excl); > + if (thawed && sb && sb->s_writers.frozen != SB_UNFROZEN) { > + if (excl) > + up_write(&sb->s_umount); > + else > + up_read(&sb->s_umount); > + wait_event(sb->s_writers.wait_unfrozen, > + sb->s_writers.frozen == SB_UNFROZEN); > + put_super(sb); > + goto retry; > + } > + > bdput(bdev); > if (!sb) > return ERR_PTR(-ENODEV); > - > return sb; > + > #else > return ERR_PTR(-ENODEV); > #endif > diff --git a/fs/super.c b/fs/super.c > index 98bb0629ee108e..343e5c1e538d2a 100644 > --- a/fs/super.c > +++ b/fs/super.c > @@ -307,7 +307,7 @@ static void __put_super(struct super_block *s) > * Drops a temporary reference, frees superblock if there's no > * references left. > */ > -static void put_super(struct super_block *sb) > +void put_super(struct super_block *sb) > { > spin_lock(&sb_lock); > __put_super(sb); > @@ -740,7 +740,7 @@ void iterate_supers_type(struct file_system_type *type, > > EXPORT_SYMBOL(iterate_supers_type); > > -static struct super_block *__get_super(struct block_device *bdev, bool excl) > +struct super_block *__get_super(struct block_device *bdev, bool excl) > { > struct super_block *sb; > > @@ -789,53 +789,6 @@ struct super_block *get_super(struct block_device *bdev) > } > EXPORT_SYMBOL(get_super); > > -static struct super_block *__get_super_thawed(struct block_device *bdev, > - bool excl) > -{ > - while (1) { > - struct super_block *s = __get_super(bdev, excl); > - if (!s || s->s_writers.frozen == SB_UNFROZEN) > - return s; > - if (!excl) > - up_read(&s->s_umount); > - else > - up_write(&s->s_umount); > - wait_event(s->s_writers.wait_unfrozen, > - s->s_writers.frozen == SB_UNFROZEN); > - put_super(s); > - } > -} > - > -/** > - * get_super_thawed - get thawed superblock of a device > - * @bdev: device to get the superblock for > - * > - * Scans the superblock list and finds the superblock of the file system > - * mounted on the device. The superblock is returned once it is thawed > - * (or immediately if it was not frozen). %NULL is returned if no match > - * is found. > - */ > -struct super_block *get_super_thawed(struct block_device *bdev) > -{ > - return __get_super_thawed(bdev, false); > -} > -EXPORT_SYMBOL(get_super_thawed); > - > -/** > - * get_super_exclusive_thawed - get thawed superblock of a device > - * @bdev: device to get the superblock for > - * > - * Scans the superblock list and finds the superblock of the file system > - * mounted on the device. The superblock is returned once it is thawed > - * (or immediately if it was not frozen) and s_umount semaphore is held > - * in exclusive mode. %NULL is returned if no match is found. > - */ > -struct super_block *get_super_exclusive_thawed(struct block_device *bdev) > -{ > - return __get_super_thawed(bdev, true); > -} > -EXPORT_SYMBOL(get_super_exclusive_thawed); > - > /** > * get_active_super - get an active reference to the superblock of a device > * @bdev: device to get the superblock for > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 8667d0cdc71e76..a61df0dd4f1989 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1409,7 +1409,7 @@ enum { > > struct sb_writers { > int frozen; /* Is sb frozen? */ > - wait_queue_head_t wait_unfrozen; /* for get_super_thawed() */ > + wait_queue_head_t wait_unfrozen; /* wait for thaw */ > struct percpu_rw_semaphore rw_sem[SB_FREEZE_LEVELS]; > }; > > @@ -3132,8 +3132,6 @@ extern struct file_system_type *get_filesystem(struct file_system_type *fs); > extern void put_filesystem(struct file_system_type *fs); > extern struct file_system_type *get_fs_type(const char *name); > extern struct super_block *get_super(struct block_device *); > -extern struct super_block *get_super_thawed(struct block_device *); > -extern struct super_block *get_super_exclusive_thawed(struct block_device *bdev); > extern struct super_block *get_active_super(struct block_device *bdev); > extern void drop_super(struct super_block *sb); > extern void drop_super_exclusive(struct super_block *sb); > -- > 2.29.2 > -- Jan Kara SUSE Labs, CR -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel