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From: "J. Bruce Fields" <bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
To: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
Cc: Jeff Layton <jlayton-7I+n7zu2hftEKMMhf/gKZA@public.gmane.org>,
	linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	xfs-VZNHf3L845pBDgjK7y7TUQ@public.gmane.org
Subject: Re: [PATCH 03/20] fs: add FL_LAYOUT lease type
Date: Thu, 22 Jan 2015 15:14:42 -0500
Message-ID: <20150122201442.GJ898@fieldses.org> (raw)
In-Reply-To: <1421925006-24231-4-git-send-email-hch-jcswGhMUV9g@public.gmane.org>

On Thu, Jan 22, 2015 at 12:09:49PM +0100, Christoph Hellwig wrote:
> This (ab-)uses the file locking code to allow filesystems to recall
> outstanding pNFS layouts on a file.  This new lease type is similar but
> not quite the same as FL_DELEG.  A FL_LAYOUT lease can always be granted,
> an a per-filesystem lock (XFS iolock for the initial implementation)
> ensures not FL_LAYOUT leases granted when we would need to recall them.

So when there's a conflicting operation it's xfs's responsibility to
call break_layout and wait for the recall?

(And what roughly is the set of conflicting operations?)

--b.

> 
> Also included are changes that allow multiple outstanding read
> leases of different types on the same file as long as they have a
> differnt owner.  This wasn't a problem until now as nfsd never set
> FL_LEASE leases, and no one else used FL_DELEG leases, but given that
> nfsd will also issues FL_LAYOUT leases we will have to handle it now.
> 
> Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
> ---
>  fs/locks.c         | 14 ++++++++++----
>  include/linux/fs.h | 16 ++++++++++++++++
>  2 files changed, 26 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/locks.c b/fs/locks.c
> index 65350a23..6b9772d1 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -137,7 +137,7 @@
>  
>  #define IS_POSIX(fl)	(fl->fl_flags & FL_POSIX)
>  #define IS_FLOCK(fl)	(fl->fl_flags & FL_FLOCK)
> -#define IS_LEASE(fl)	(fl->fl_flags & (FL_LEASE|FL_DELEG))
> +#define IS_LEASE(fl)	(fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT))
>  #define IS_OFDLCK(fl)	(fl->fl_flags & FL_OFDLCK)
>  
>  static bool lease_breaking(struct file_lock *fl)
> @@ -1371,6 +1371,8 @@ static void time_out_leases(struct inode *inode, struct list_head *dispose)
>  
>  static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
>  {
> +	if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT))
> +		return false;
>  	if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE))
>  		return false;
>  	return locks_conflict(breaker, lease);
> @@ -1594,11 +1596,14 @@ int fcntl_getlease(struct file *filp)
>   * conflict with the lease we're trying to set.
>   */
>  static int
> -check_conflicting_open(const struct dentry *dentry, const long arg)
> +check_conflicting_open(const struct dentry *dentry, const long arg, int flags)
>  {
>  	int ret = 0;
>  	struct inode *inode = dentry->d_inode;
>  
> +	if (flags & FL_LAYOUT)
> +		return 0;
> +
>  	if ((arg == F_RDLCK) && (atomic_read(&inode->i_writecount) > 0))
>  		return -EAGAIN;
>  
> @@ -1647,7 +1652,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
>  
>  	spin_lock(&ctx->flc_lock);
>  	time_out_leases(inode, &dispose);
> -	error = check_conflicting_open(dentry, arg);
> +	error = check_conflicting_open(dentry, arg, lease->fl_flags);
>  	if (error)
>  		goto out;
>  
> @@ -1703,7 +1708,7 @@ generic_add_lease(struct file *filp, long arg, struct file_lock **flp, void **pr
>  	 * precedes these checks.
>  	 */
>  	smp_mb();
> -	error = check_conflicting_open(dentry, arg);
> +	error = check_conflicting_open(dentry, arg, lease->fl_flags);
>  	if (error) {
>  		locks_unlink_lock_ctx(lease, &ctx->flc_lease_cnt);
>  		goto out;
> @@ -1787,6 +1792,7 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp,
>  			WARN_ON_ONCE(1);
>  			return -ENOLCK;
>  		}
> +
>  		return generic_add_lease(filp, arg, flp, priv);
>  	default:
>  		return -EINVAL;
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index f87cb2f..d5658f4 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -875,6 +875,7 @@ static inline struct file *get_file(struct file *f)
>  #define FL_DOWNGRADE_PENDING	256 /* Lease is being downgraded */
>  #define FL_UNLOCK_PENDING	512 /* Lease is being broken */
>  #define FL_OFDLCK	1024	/* lock is "owned" by struct file */
> +#define FL_LAYOUT	2048	/* outstanding pNFS layout */
>  
>  /*
>   * Special return value from posix_lock_file() and vfs_lock_file() for
> @@ -2036,6 +2037,16 @@ static inline int break_deleg_wait(struct inode **delegated_inode)
>  	return ret;
>  }
>  
> +static inline int break_layout(struct inode *inode, bool wait)
> +{
> +	smp_mb();
> +	if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease))
> +		return __break_lease(inode,
> +				wait ? O_WRONLY : O_WRONLY | O_NONBLOCK,
> +				FL_LAYOUT);
> +	return 0;
> +}
> +
>  #else /* !CONFIG_FILE_LOCKING */
>  static inline int locks_mandatory_locked(struct file *file)
>  {
> @@ -2091,6 +2102,11 @@ static inline int break_deleg_wait(struct inode **delegated_inode)
>  	return 0;
>  }
>  
> +static inline int break_layout(struct inode *inode, bool wait)
> +{
> +	return 0;
> +}
> +
>  #endif /* CONFIG_FILE_LOCKING */
>  
>  /* fs/open.c */
> -- 
> 1.9.1
--
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  parent reply index

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-22 11:09 a simple and scalable pNFS block layout server V2 Christoph Hellwig
2015-01-22 11:09 ` [PATCH 04/20] nfsd: factor out a helper to decode nfstime4 values Christoph Hellwig
     [not found]   ` <1421925006-24231-5-git-send-email-hch-jcswGhMUV9g@public.gmane.org>
2015-01-22 20:15     ` J. Bruce Fields
2015-01-22 11:09 ` [PATCH 05/20] nfsd: move nfsd_fh_match to nfsfh.h Christoph Hellwig
2015-01-22 11:09 ` [PATCH 09/20] nfsd: make find_any_file available outside nfs4state.c Christoph Hellwig
2015-01-22 11:09 ` [PATCH 12/20] nfsd: update documentation for pNFS support Christoph Hellwig
2015-01-22 11:09 ` [PATCH 13/20] nfsd: add trace events Christoph Hellwig
2015-01-22 11:10 ` [PATCH 15/20] nfsd: pNFS block layout driver Christoph Hellwig
2015-01-22 11:10 ` [PATCH 18/20] xfs: factor out a xfs_update_prealloc_flags() helper Christoph Hellwig
     [not found]   ` <1421925006-24231-19-git-send-email-hch-jcswGhMUV9g@public.gmane.org>
2015-02-01 23:06     ` Dave Chinner
2015-01-22 16:04 ` a simple and scalable pNFS block layout server V2 Chuck Lever
2015-01-22 16:21   ` Christoph Hellwig
     [not found] ` <1421925006-24231-1-git-send-email-hch-jcswGhMUV9g@public.gmane.org>
2015-01-22 11:09   ` [PATCH 01/20] nfs: add LAYOUT_TYPE_MAX enum value Christoph Hellwig
2015-01-22 11:09   ` [PATCH 02/20] fs: track fl_owner for leases Christoph Hellwig
2015-01-22 11:09   ` [PATCH 03/20] fs: add FL_LAYOUT lease type Christoph Hellwig
2015-01-22 15:45     ` Jeff Layton
     [not found]     ` <1421925006-24231-4-git-send-email-hch-jcswGhMUV9g@public.gmane.org>
2015-01-22 20:14       ` J. Bruce Fields [this message]
     [not found]         ` <20150122201442.GJ898-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-01-22 20:18           ` Christoph Hellwig
2015-01-22 11:09   ` [PATCH 06/20] nfsd: add fh_fsid_match helper Christoph Hellwig
2015-01-22 11:09   ` [PATCH 07/20] nfsd: make lookup/alloc/unhash_stid available outside nfs4state.c Christoph Hellwig
2015-01-22 11:09   ` [PATCH 08/20] nfsd: make find/get/put file " Christoph Hellwig
2015-01-22 11:09   ` [PATCH 10/20] nfsd: implement pNFS operations Christoph Hellwig
     [not found]     ` <1421925006-24231-11-git-send-email-hch-jcswGhMUV9g@public.gmane.org>
2015-01-29 20:33       ` J. Bruce Fields
     [not found]         ` <20150129203346.GA11064-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-02-02 12:43           ` Christoph Hellwig
2015-02-02 14:28             ` J. Bruce Fields
     [not found]               ` <20150202142832.GC22301-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-02-02 14:56                 ` Christoph Hellwig
     [not found]                   ` <20150202145619.GA18387-jcswGhMUV9g@public.gmane.org>
2015-02-02 15:00                     ` J. Bruce Fields
     [not found]                       ` <20150202150032.GD22301-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-02-02 18:56                         ` Christoph Hellwig
     [not found]                           ` <20150202185638.GB23319-jcswGhMUV9g@public.gmane.org>
2015-02-03 16:08                             ` J. Bruce Fields
2015-01-22 11:09   ` [PATCH 11/20] nfsd: implement pNFS layout recalls Christoph Hellwig
2015-01-22 11:10   ` [PATCH 14/20] exportfs: add methods for block layout exports Christoph Hellwig
2015-01-22 11:10   ` [PATCH 16/20] xfs: pass a 64-bit count argument to xfs_iomap_write_unwritten Christoph Hellwig
2015-01-29 20:52     ` J. Bruce Fields
2015-02-02  7:30       ` Christoph Hellwig
2015-02-02 19:24         ` Dave Chinner
2015-02-02 19:43           ` Dave Chinner
2015-02-02 19:48             ` J. Bruce Fields
2015-02-03 18:35               ` Christoph Hellwig
     [not found]                 ` <20150203183533.GA16929-jcswGhMUV9g@public.gmane.org>
2015-02-11 22:35                   ` J. Bruce Fields
2015-02-11 22:54                     ` J. Bruce Fields
2015-02-04  7:57             ` Christoph Hellwig
     [not found]               ` <20150204075756.GA763-jcswGhMUV9g@public.gmane.org>
2015-02-04 20:02                 ` Dave Chinner
2015-01-22 11:10   ` [PATCH 17/20] xfs: update the superblock using a synchronous transaction in growfs Christoph Hellwig
2015-01-22 11:10   ` [PATCH 19/20] xfs: implement pNFS export operations Christoph Hellwig
     [not found]     ` <1421925006-24231-20-git-send-email-hch-jcswGhMUV9g@public.gmane.org>
2015-02-05  0:47       ` Dave Chinner
2015-02-05  7:08         ` Christoph Hellwig
     [not found]           ` <20150205070858.GA593-jcswGhMUV9g@public.gmane.org>
2015-02-05 13:57             ` Christoph Hellwig
     [not found]               ` <20150205135756.GA6386-jcswGhMUV9g@public.gmane.org>
2015-02-06 22:20                 ` Dave Chinner
2015-02-06 22:42                   ` J. Bruce Fields
2015-02-08 13:34                     ` Christoph Hellwig
     [not found]                       ` <20150208133435.GA27081-jcswGhMUV9g@public.gmane.org>
2015-02-08 14:09                         ` Jeff Layton
     [not found]                           ` <20150208090942.51e99687-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
2015-02-09 20:11                             ` J. Bruce Fields
     [not found]                               ` <20150209201154.GA27746-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-02-10  0:04                                 ` Dave Chinner
2015-02-13  1:11                                   ` J. Bruce Fields
2015-02-13  1:54                                     ` Dave Chinner
2015-02-13  2:38                                       ` Stephen Rothwell
2015-02-15 23:25                                         ` Dave Chinner
2015-01-22 11:10   ` [PATCH 20/20] xfs: recall pNFS layouts on conflicting access Christoph Hellwig
     [not found]     ` <1421925006-24231-21-git-send-email-hch-jcswGhMUV9g@public.gmane.org>
2015-02-05  0:51       ` Dave Chinner
2015-01-22 20:01   ` a simple and scalable pNFS block layout server V2 J. Bruce Fields
2015-01-22 20:06   ` J. Bruce Fields
2015-01-22 20:20     ` Christoph Hellwig
     [not found]     ` <20150122200618.GI898-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
2015-01-22 20:20       ` Jeff Layton

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