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Commit dcfcf205 authored by Dave Chinner's avatar Dave Chinner Committed by Dave Chinner
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xfs: provide a inode iolock lockdep class 



The XFS iolock needs to be re-initialised to a new lock class before
it enters reclaim to prevent lockdep false positives. Unfortunately,
this is not sufficient protection as inodes in the XFS_IRECLAIMABLE
state can be recycled and not re-initialised before being reused.

We need to re-initialise the lock state when transfering out of
XFS_IRECLAIMABLE state to XFS_INEW, but we need to keep the same
class as if the inode was just allocated. Hence we need a specific
lockdep class variable for the iolock so that both initialisations
use the same class.

While there, add a specific class for inodes in the reclaim state so
that it is easy to tell from lockdep reports what state the inode
was in that generated the report.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
parent 489a150f

fs/xfs/linux-2.6/xfs_super.c

+2 −0
Original line number Diff line number Diff line
@@ -1118,6 +1118,8 @@ xfs_fs_evict_inode( 
	 */

	ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));

	mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);

	lockdep_set_class_and_name(&ip->i_iolock.mr_lock,

			&xfs_iolock_reclaimable, "xfs_iolock_reclaimable");



	xfs_inactive(ip);

}

fs/xfs/xfs_iget.c

+19 −0
Original line number Diff line number Diff line
@@ -42,6 +42,17 @@ 
#include "xfs_trace.h"





/*

 * Define xfs inode iolock lockdep classes. We need to ensure that all active

 * inodes are considered the same for lockdep purposes, including inodes that

 * are recycled through the XFS_IRECLAIMABLE state. This is the the only way to

 * guarantee the locks are considered the same when there are multiple lock

 * initialisation siteѕ. Also, define a reclaimable inode class so it is

 * obvious in lockdep reports which class the report is against.

 */

static struct lock_class_key xfs_iolock_active;

struct lock_class_key xfs_iolock_reclaimable;



/*

 * Allocate and initialise an xfs_inode.

 */
@@ -71,6 +82,8 @@ xfs_inode_alloc( 
	ASSERT(completion_done(&ip->i_flush));



	mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);

	lockdep_set_class_and_name(&ip->i_iolock.mr_lock,

			&xfs_iolock_active, "xfs_iolock_active");



	/* initialise the xfs inode */

	ip->i_ino = ino;
@@ -218,6 +231,12 @@ xfs_iget_cache_hit( 
		ip->i_flags |= XFS_INEW;

		__xfs_inode_clear_reclaim_tag(mp, pag, ip);

		inode->i_state = I_NEW;



		ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock));

		mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino);

		lockdep_set_class_and_name(&ip->i_iolock.mr_lock,

				&xfs_iolock_active, "xfs_iolock_active");



		spin_unlock(&ip->i_flags_lock);

		write_unlock(&pag->pag_ici_lock);

	} else {

fs/xfs/xfs_inode.h

+2 −0
Original line number Diff line number Diff line
@@ -438,6 +438,8 @@ static inline void xfs_ifunlock(xfs_inode_t *ip) 
#define XFS_IOLOCK_DEP(flags)	(((flags) & XFS_IOLOCK_DEP_MASK) >> XFS_IOLOCK_SHIFT)

#define XFS_ILOCK_DEP(flags)	(((flags) & XFS_ILOCK_DEP_MASK) >> XFS_ILOCK_SHIFT)



extern struct lock_class_key xfs_iolock_reclaimable;



/*

 * Flags for xfs_itruncate_start().

 */