From patchwork Wed Sep 9 10:26:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Thumshirn X-Patchwork-Id: 11765309 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E571859D for ; Wed, 9 Sep 2020 10:27:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CAFC121D90 for ; Wed, 9 Sep 2020 10:27:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b="KwXsGz1D" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726060AbgIIK1D (ORCPT ); Wed, 9 Sep 2020 06:27:03 -0400 Received: from esa1.hgst.iphmx.com ([68.232.141.245]:43807 "EHLO esa1.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726399AbgIIK0e (ORCPT ); Wed, 9 Sep 2020 06:26:34 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1599647194; x=1631183194; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=WII/fNe9AqpyUS4G2Rrf4+UgqqJabIxQGisG0W1rEJ0=; b=KwXsGz1Dgsd+Zix+3qgDwrWH1jPfK1Vk8cq+p0/ASR7bxJB5ivnV+TJp 9VZaN7ObA6wEDZ2wdr8jtNmaM0QYMJMIOXLttfIvAnQBniu+AxsV2xv8c vKZmoDWCypjGs4k9qbWlQcpHd2pqSFfKHtMQvKT+dVtsjmqMAoWBy3tui bi6p7Cs5Xm3ikGE7LQl3uhrf+g5DXFYV3VTgpUlnrX/1RT/nDV5LnQptu 72CHd8L0qH/s5jWmjUbVIBfqMscsNyhJ9sMdiEGparWMs1V396sjX/Cnx QATzP6Yccu68ND6EsF9T025IdqPRUF7VFwGyDmAF57DSqcNquw+OavAge w==; IronPort-SDR: pC8apetMp/Vzn6gPTGJ7q7hH2Hon1SPHqakr8kec1Hny4Rwe9C3a3/TArEmu/k2KBbfXZt2nyD MFMBfBHbHBabOe4tBsu7wEyRLTUzDszJz9iJkG8aAOMWmr/wGBFWv7Xuz9/ImhctoOyr3Lywve G83IXznHuI0U6jO164T5Wwq2MOlLkRmaBHkVB2+rPyt5qLdI5P/ovnvWzFSG71eAVZ4Ab3iI1M fAx8Owqml023CVNzlblCt5P+xuOjdoYmC7V65GbDbARjBdGgPj+epGfp51z20doyxrnrw9dCv9 B6s= X-IronPort-AV: E=Sophos;i="5.76,409,1592841600"; d="scan'208";a="256500002" Received: from uls-op-cesaip01.wdc.com (HELO uls-op-cesaep01.wdc.com) ([199.255.45.14]) by ob1.hgst.iphmx.com with ESMTP; 09 Sep 2020 18:26:32 +0800 IronPort-SDR: /zRgzl5/K8OivQgTKu/wfqmKiHxVJDLNscQ+Uw9esH9pXO8jlUkSeBGYyeaNDtY6fIQ0YMoZOR kaDNXOhjjYHQ== Received: from uls-op-cesaip02.wdc.com ([10.248.3.37]) by uls-op-cesaep01.wdc.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Sep 2020 03:13:50 -0700 IronPort-SDR: iAfwNAX0M4VpdNDHpfmR6U84DIQ4pAwPt9nGQUV4pGkmz5fYkE3dwCOWyLcmFKI+Ry4c//LTbg ws4mefrQ4Olg== WDCIronportException: Internal Received: from unknown (HELO redsun60.ssa.fujisawa.hgst.com) ([10.149.66.36]) by uls-op-cesaip02.wdc.com with ESMTP; 09 Sep 2020 03:26:31 -0700 From: Johannes Thumshirn To: Damien Le Moal Cc: linux-fsdevel@vger.kernel.org, Johannes Thumshirn Subject: [PATCH v2 1/3] zonefs: introduce helper for zone management Date: Wed, 9 Sep 2020 19:26:12 +0900 Message-Id: <20200909102614.40585-2-johannes.thumshirn@wdc.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200909102614.40585-1-johannes.thumshirn@wdc.com> References: <20200909102614.40585-1-johannes.thumshirn@wdc.com> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Introduce a helper function for sending zone management commands to the block device. As zone management commands can change a zone write pointer position reflected in the size of the zone file, this function expects the truncate mutex to be held. Signed-off-by: Johannes Thumshirn Reviewed-by: Damien Le Moal --- Changes to v1: - centralize failure logging --- fs/zonefs/super.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c index 8ec7c8f109d7..dc828bd1210b 100644 --- a/fs/zonefs/super.c +++ b/fs/zonefs/super.c @@ -24,6 +24,26 @@ #include "zonefs.h" +static inline int zonefs_zone_mgmt(struct inode *inode, + enum req_opf op) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + int ret; + + lockdep_assert_held(&zi->i_truncate_mutex); + + ret = blkdev_zone_mgmt(inode->i_sb->s_bdev, op, zi->i_zsector, + zi->i_zone_size >> SECTOR_SHIFT, GFP_NOFS); + if (ret) { + zonefs_err(inode->i_sb, + "Zone management operation %s at %llu failed %d", + blk_op_str(op), zi->i_zsector, ret); + return ret; + } + + return 0; +} + static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, unsigned int flags, struct iomap *iomap, struct iomap *srcmap) @@ -397,14 +417,9 @@ static int zonefs_file_truncate(struct inode *inode, loff_t isize) if (isize == old_isize) goto unlock; - ret = blkdev_zone_mgmt(inode->i_sb->s_bdev, op, zi->i_zsector, - zi->i_zone_size >> SECTOR_SHIFT, GFP_NOFS); - if (ret) { - zonefs_err(inode->i_sb, - "Zone management operation at %llu failed %d", - zi->i_zsector, ret); + ret = zonefs_zone_mgmt(inode, op); + if (ret) goto unlock; - } zonefs_update_stats(inode, isize); truncate_setsize(inode, isize); From patchwork Wed Sep 9 10:26:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Thumshirn X-Patchwork-Id: 11765307 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7379F618 for ; Wed, 9 Sep 2020 10:27:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FA1021D82 for ; Wed, 9 Sep 2020 10:27:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b="VXTOL0fZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727936AbgIIK0u (ORCPT ); Wed, 9 Sep 2020 06:26:50 -0400 Received: from esa1.hgst.iphmx.com ([68.232.141.245]:43807 "EHLO esa1.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727087AbgIIK0g (ORCPT ); Wed, 9 Sep 2020 06:26:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1599647196; x=1631183196; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=PoCbDfGLhC1Dyvt5Hwgd+v4IVLF6CWmSmfx4FNMePCo=; b=VXTOL0fZdqsBeL5+9/567JCTDYrZ9HI6owUR06+drT2WHmF/f+rMB0tO 3I2xXSoDNTUW/Y3ja6d/BJx06rw6amz7FJ57bF/owBjkVbMvxM7k71ycg CLxFqz7r531zykTN01knRlq0wTBp2ghdZ5PXJ1CIfW45eIzb7HmRVKS2w IYhJeBepDv+XDPg+3aC/MP2IwxeEOAOFTqjYV0EEgNy24PpUony4pnvMr VKXj2DKCS9hqlcTl+jR14dj2Xyu5O6xQ96Kxh64XiINtTy3FLbk9PGvEU 2fIk20UYve2eOFke0TZxSB3ILXjW4iHAFkhKzmVtkf9Vt/R5nkJaZPssQ g==; IronPort-SDR: zsWt8F6+WUwJrvneRNs3uxTePwZ/hSHQBTq0z6GuOZBSnspzVoW8lwg7To8N060tZziJroCYaS d7j4G9Dcytihrdsa8OfMfnNn3Lm1UtoM8Lo6oTcCYCK/lGDqSea89wGLKR18J9/IQ88Qld/Vfh UrnDS5wedi1e8sNMhPsLXG80SHMh3nz5AX6m7DZ0iqobEt4U+FSGstfFIie9z2g0+YEqRPqmXC z4ZDuF9LY0FhVDJ0tC6uAv+0J+pPP5qgUsujOAKnkFFRcnBYkV1MzCy8sIoaVbVUu7T4+q0VSV a8U= X-IronPort-AV: E=Sophos;i="5.76,409,1592841600"; d="scan'208";a="256500005" Received: from uls-op-cesaip01.wdc.com (HELO uls-op-cesaep01.wdc.com) ([199.255.45.14]) by ob1.hgst.iphmx.com with ESMTP; 09 Sep 2020 18:26:33 +0800 IronPort-SDR: 7j/A0uc0f2clo7Befwx3stXy+qnqIUFV5GQz5BqmMDksvd90eT/GtdDSB4sv33P7MDFV4pchgl SFhnp8zpREGg== Received: from uls-op-cesaip02.wdc.com ([10.248.3.37]) by uls-op-cesaep01.wdc.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Sep 2020 03:13:51 -0700 IronPort-SDR: KwjgaXMh3M3kRsvaHBdSxgypb0rRAJZKyZiMt05FpMvHyyDiPacYQAwkT1mM2DhqLksuK/GfLW SS5xf1Lu15VA== WDCIronportException: Internal Received: from unknown (HELO redsun60.ssa.fujisawa.hgst.com) ([10.149.66.36]) by uls-op-cesaip02.wdc.com with ESMTP; 09 Sep 2020 03:26:32 -0700 From: Johannes Thumshirn To: Damien Le Moal Cc: linux-fsdevel@vger.kernel.org, Johannes Thumshirn Subject: [PATCH v2 2/3] zonefs: open/close zone on file open/close Date: Wed, 9 Sep 2020 19:26:13 +0900 Message-Id: <20200909102614.40585-3-johannes.thumshirn@wdc.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200909102614.40585-1-johannes.thumshirn@wdc.com> References: <20200909102614.40585-1-johannes.thumshirn@wdc.com> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org NVMe Zoned Namespace introduced the concept of active zones, which are zones in the implicit open, explicit open or closed condition. Drives may have a limit on the number of zones that can be simultaneously active. This potential limitation translate into a risk for applications to see write IO errors due to this limit if the zone of a file being written to is not already active when a write request is issued. To avoid these potential errors, the zone of a file can explicitly be made active using an open zone command when the file is open for the first time. If the zone open command succeeds, the application is then guaranteed that write requests can be processed. This indirect management of active zones relies on the maximum number of open zones of a drive, which is always lower or equal to the maximum number of active zones. On the first open of a sequential zone file, send a REQ_OP_ZONE_OPEN command to the block device. Conversely, on the last release of a zone file and send a REQ_OP_ZONE_CLOSE to the device if the zone is not full or empty. As truncating a zone file to 0 or max can deactivate a zone as well, we need to serialize against truncates and also be careful not to close a zone as the file may still be open for writing, e.g. the user called ftruncate(). If the zone file is not open and a process does a truncate(), then no close operation is needed. Signed-off-by: Johannes Thumshirn --- fs/zonefs/super.c | 160 +++++++++++++++++++++++++++++++++++++++++++-- fs/zonefs/zonefs.h | 10 +++ 2 files changed, 166 insertions(+), 4 deletions(-) diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c index dc828bd1210b..07717df2fac9 100644 --- a/fs/zonefs/super.c +++ b/fs/zonefs/super.c @@ -44,6 +44,80 @@ static inline int zonefs_zone_mgmt(struct inode *inode, return 0; } +static int zonefs_open_zone(struct inode *inode) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb); + int ret = 0; + + mutex_lock(&zi->i_truncate_mutex); + + zi->i_wr_refcnt++; + if (zi->i_wr_refcnt == 1) { + + if (atomic_inc_return(&sbi->s_open_zones) > sbi->s_max_open_zones) { + atomic_dec(&sbi->s_open_zones); + ret = -EBUSY; + goto unlock; + } + + if (i_size_read(inode) < zi->i_max_size) { + ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN); + if (ret) { + zi->i_wr_refcnt--; + atomic_dec(&sbi->s_open_zones); + goto unlock; + } + zi->i_flags |= ZONEFS_ZONE_OPEN; + } + } + +unlock: + mutex_unlock(&zi->i_truncate_mutex); + + return ret; +} + +static int zonefs_close_zone(struct inode *inode) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + int ret = 0; + + mutex_lock(&zi->i_truncate_mutex); + + zi->i_wr_refcnt--; + if (!zi->i_wr_refcnt) { + struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb); + + if (zi->i_flags & ZONEFS_ZONE_OPEN) { + ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_CLOSE); + if (ret) + goto unlock; + zi->i_flags &= ~ZONEFS_ZONE_OPEN; + } + + atomic_dec(&sbi->s_open_zones); + } + +unlock: + mutex_unlock(&zi->i_truncate_mutex); + + return ret; +} + +static inline void zonefs_i_size_write(struct inode *inode, loff_t isize) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + + i_size_write(inode, isize); + /* + * A full zone is no longer open/active and does not need + * explicit closing. + */ + if (isize >= zi->i_max_size) + zi->i_flags &= ~ZONEFS_ZONE_OPEN; +} + static int zonefs_iomap_begin(struct inode *inode, loff_t offset, loff_t length, unsigned int flags, struct iomap *iomap, struct iomap *srcmap) @@ -335,7 +409,7 @@ static int zonefs_io_error_cb(struct blk_zone *zone, unsigned int idx, * invalid data. */ zonefs_update_stats(inode, data_size); - i_size_write(inode, data_size); + zonefs_i_size_write(inode, data_size); zi->i_wpoffset = data_size; return 0; @@ -421,6 +495,25 @@ static int zonefs_file_truncate(struct inode *inode, loff_t isize) if (ret) goto unlock; + /* + * If the mount option ZONEFS_MNTOPT_EXPLICIT_OPEN is set, + * take care of open zones. + */ + if (zi->i_flags & ZONEFS_ZONE_OPEN) { + /* + * Truncating a zone to EMPTY or FULL is the equivalent of + * closing the zone. For a truncation to 0, we need to + * re-open the zone to ensure new writes can be processed. + * For a truncation to the maximum file size, the zone is + * closed and writes cannot be accepted anymore, so clear + * the open flag. + */ + if (!isize) + ret = zonefs_zone_mgmt(inode, REQ_OP_ZONE_OPEN); + else + zi->i_flags &= ~ZONEFS_ZONE_OPEN; + } + zonefs_update_stats(inode, isize); truncate_setsize(inode, isize); zi->i_wpoffset = isize; @@ -599,7 +692,7 @@ static int zonefs_file_write_dio_end_io(struct kiocb *iocb, ssize_t size, mutex_lock(&zi->i_truncate_mutex); if (i_size_read(inode) < iocb->ki_pos + size) { zonefs_update_stats(inode, iocb->ki_pos + size); - i_size_write(inode, iocb->ki_pos + size); + zonefs_i_size_write(inode, iocb->ki_pos + size); } mutex_unlock(&zi->i_truncate_mutex); } @@ -880,8 +973,55 @@ static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) return ret; } +static inline bool zonefs_file_use_exp_open(struct inode *inode, struct file *file) +{ + struct zonefs_inode_info *zi = ZONEFS_I(inode); + struct zonefs_sb_info *sbi = ZONEFS_SB(inode->i_sb); + + if (!(sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN)) + return false; + + if (zi->i_ztype != ZONEFS_ZTYPE_SEQ) + return false; + + if (!(file->f_mode & FMODE_WRITE)) + return false; + + return true; +} + +static int zonefs_file_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = generic_file_open(inode, file); + if (ret) + return ret; + + if (zonefs_file_use_exp_open(inode, file)) + return zonefs_open_zone(inode); + + return 0; +} + +static int zonefs_file_release(struct inode *inode, struct file *file) +{ + /* + * If we explicitly open a zone we must close it again as well, but the + * zone management operation can fail (either due to an IO error or as + * the zone has gone offline or read-only). Make sure we don't fail the + * close(2) for user-space. + */ + if (zonefs_file_use_exp_open(inode, file)) + if (zonefs_close_zone(inode)) + zonefs_io_error(inode, false); + + return 0; +} + static const struct file_operations zonefs_file_operations = { - .open = generic_file_open, + .open = zonefs_file_open, + .release = zonefs_file_release, .fsync = zonefs_file_fsync, .mmap = zonefs_file_mmap, .llseek = zonefs_file_llseek, @@ -905,6 +1045,7 @@ static struct inode *zonefs_alloc_inode(struct super_block *sb) inode_init_once(&zi->i_vnode); mutex_init(&zi->i_truncate_mutex); init_rwsem(&zi->i_mmap_sem); + zi->i_wr_refcnt = 0; return &zi->i_vnode; } @@ -955,7 +1096,7 @@ static int zonefs_statfs(struct dentry *dentry, struct kstatfs *buf) enum { Opt_errors_ro, Opt_errors_zro, Opt_errors_zol, Opt_errors_repair, - Opt_err, + Opt_explicit_open, Opt_err, }; static const match_table_t tokens = { @@ -963,6 +1104,7 @@ static const match_table_t tokens = { { Opt_errors_zro, "errors=zone-ro"}, { Opt_errors_zol, "errors=zone-offline"}, { Opt_errors_repair, "errors=repair"}, + { Opt_explicit_open, "explicit-open" }, { Opt_err, NULL} }; @@ -999,6 +1141,9 @@ static int zonefs_parse_options(struct super_block *sb, char *options) sbi->s_mount_opts &= ~ZONEFS_MNTOPT_ERRORS_MASK; sbi->s_mount_opts |= ZONEFS_MNTOPT_ERRORS_REPAIR; break; + case Opt_explicit_open: + sbi->s_mount_opts |= ZONEFS_MNTOPT_EXPLICIT_OPEN; + break; default: return -EINVAL; } @@ -1418,6 +1563,13 @@ static int zonefs_fill_super(struct super_block *sb, void *data, int silent) sbi->s_gid = GLOBAL_ROOT_GID; sbi->s_perm = 0640; sbi->s_mount_opts = ZONEFS_MNTOPT_ERRORS_RO; + sbi->s_max_open_zones = bdev_max_open_zones(sb->s_bdev); + atomic_set(&sbi->s_open_zones, 0); + if (!sbi->s_max_open_zones && + sbi->s_mount_opts & ZONEFS_MNTOPT_EXPLICIT_OPEN) { + zonefs_info(sb, "No open zones limit. Ignoring explicit_open mount option\n"); + sbi->s_mount_opts &= ~ZONEFS_MNTOPT_EXPLICIT_OPEN; + } ret = zonefs_read_super(sb); if (ret) diff --git a/fs/zonefs/zonefs.h b/fs/zonefs/zonefs.h index 55b39970acb2..51141907097c 100644 --- a/fs/zonefs/zonefs.h +++ b/fs/zonefs/zonefs.h @@ -38,6 +38,8 @@ static inline enum zonefs_ztype zonefs_zone_type(struct blk_zone *zone) return ZONEFS_ZTYPE_SEQ; } +#define ZONEFS_ZONE_OPEN (1 << 0) + /* * In-memory inode data. */ @@ -74,6 +76,10 @@ struct zonefs_inode_info { */ struct mutex i_truncate_mutex; struct rw_semaphore i_mmap_sem; + + /* guarded by i_truncate_mutex */ + unsigned int i_wr_refcnt; + unsigned int i_flags; }; static inline struct zonefs_inode_info *ZONEFS_I(struct inode *inode) @@ -154,6 +160,7 @@ enum zonefs_features { #define ZONEFS_MNTOPT_ERRORS_MASK \ (ZONEFS_MNTOPT_ERRORS_RO | ZONEFS_MNTOPT_ERRORS_ZRO | \ ZONEFS_MNTOPT_ERRORS_ZOL | ZONEFS_MNTOPT_ERRORS_REPAIR) +#define ZONEFS_MNTOPT_EXPLICIT_OPEN (1 << 4) /* Explicit open/close of zones on open/close */ /* * In-memory Super block information. @@ -175,6 +182,9 @@ struct zonefs_sb_info { loff_t s_blocks; loff_t s_used_blocks; + + unsigned int s_max_open_zones; + atomic_t s_open_zones; }; static inline struct zonefs_sb_info *ZONEFS_SB(struct super_block *sb) From patchwork Wed Sep 9 10:26:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Thumshirn X-Patchwork-Id: 11765305 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E2B3D618 for ; Wed, 9 Sep 2020 10:26:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C57E121D82 for ; Wed, 9 Sep 2020 10:26:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b="H1EpbGtw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727900AbgIIK0q (ORCPT ); Wed, 9 Sep 2020 06:26:46 -0400 Received: from esa1.hgst.iphmx.com ([68.232.141.245]:43811 "EHLO esa1.hgst.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725877AbgIIK0g (ORCPT ); Wed, 9 Sep 2020 06:26:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1599647196; x=1631183196; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Mw92ho8PPfqLP3dj3WwR/jhErPBWuGbZ4I7LMFxaQ/4=; b=H1EpbGtwAxltre6MqtuTjyMo4bNaInounkZlzi0a3sqLk5SjyBktztEt tMC2xRZ2jY2C3TyUThe5JQKo2aBo9fRvo6WVhcFnoohR2VnD6C1F3sQgY TcDepDwGCILRNcMLlQXxE78yXdrBglbn8ZlKciSuN1cgl2CJ0vFgtxcFh r+U/XgocdMyukoxnMbxsxk7ldODb5AgGms42K87TyphQ6Lg7ToVfZi/rh I1/+FXGg/CUzCPsEB5oMAOC1dmszvdncNX+1Pv7fOlPDyXSugkD1STPhH kmDzsCzfIHhmMeczOiqjz5IUANDSEo7bQ+cMzXBM+QiOKV+TElMNM5LJY w==; IronPort-SDR: VpYXexOUQxLqWuUKC2thFtYk8gJwoEUC2qqI4bCaHepufOGll4+y9s56fvcHP9Vwuz5/R6Uk70 lhPCjCDTQvwvlo9nYwmERw32NCXABCUtOwKDhk8faYYQLJGE+Ozv4RT9oDFZO43XPRvX6f8prg 0gA1JYKUdauBpmJs4F1uWqgbsKZOswNyHWYIJVyicNAv5muAm+8sIMlPecM4KoyWWq2uA3Ez9T 6mTdmVnHY7LtVssSqfEhwnvpnOMCWaJlmWnZmyGl4rQsncsKdcItjCGH9qPp1U+/czKzaFKs44 Gfo= X-IronPort-AV: E=Sophos;i="5.76,409,1592841600"; d="scan'208";a="256500009" Received: from uls-op-cesaip01.wdc.com (HELO uls-op-cesaep01.wdc.com) ([199.255.45.14]) by ob1.hgst.iphmx.com with ESMTP; 09 Sep 2020 18:26:34 +0800 IronPort-SDR: XADWj5MnBUxFOuBpzmcbks74P7x0vHm0wrwMHPOwxew39PPZmFUS3vZNZp4M9Qt/YjNiMVRhRJ eDi+fJuaTeaw== Received: from uls-op-cesaip02.wdc.com ([10.248.3.37]) by uls-op-cesaep01.wdc.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Sep 2020 03:13:52 -0700 IronPort-SDR: XQ6lMlLohu3wAWFFDiLIYrbbPghflCgBvhj0YTkKKCmtUlyx541YqmsS78Rp0iVO7CnpE1+Am4 agsahIA23Ddw== WDCIronportException: Internal Received: from unknown (HELO redsun60.ssa.fujisawa.hgst.com) ([10.149.66.36]) by uls-op-cesaip02.wdc.com with ESMTP; 09 Sep 2020 03:26:33 -0700 From: Johannes Thumshirn To: Damien Le Moal Cc: linux-fsdevel@vger.kernel.org, Johannes Thumshirn Subject: [PATCH v2 3/3] zonefs: document the explicit-open mount option Date: Wed, 9 Sep 2020 19:26:14 +0900 Message-Id: <20200909102614.40585-4-johannes.thumshirn@wdc.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200909102614.40585-1-johannes.thumshirn@wdc.com> References: <20200909102614.40585-1-johannes.thumshirn@wdc.com> MIME-Version: 1.0 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Document the newly introduced explicit-open mount option. Signed-off-by: Johannes Thumshirn Reviewed-by: Damien Le Moal --- Changes to v1: - Address Randy's comments --- Documentation/filesystems/zonefs.rst | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/Documentation/filesystems/zonefs.rst b/Documentation/filesystems/zonefs.rst index 6c18bc8ce332..6b213fe9a33e 100644 --- a/Documentation/filesystems/zonefs.rst +++ b/Documentation/filesystems/zonefs.rst @@ -326,6 +326,21 @@ discover the amount of data that has been written to the zone. In the case of a read-only zone discovered at run-time, as indicated in the previous section. The size of the zone file is left unchanged from its last updated value. +A zoned block device (e.g. an NVMe Zoned Namespace device) may have limits on +the number of zones that can be active, that is, zones that are in the +implicit open, explicit open or closed conditions. This potential limitation +translates into a risk for applications to see write IO errors due to this +limit being exceeded if the zone of a file is not already active when a write +request is issued by the user. + +To avoid these potential errors, the "explicit-open" mount option forces zones +to be made active using an open zone command when a file is opened for writing +for the first time. If the zone open command succeeds, the application is then +guaranteed that write requests can be processed. Conversely, the +"explicit-open" mount option will result in a zone close command being issued +to the device on the last close() of a zone file if the zone is not full nor +empty. + Zonefs User Space Tools =======================