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xfs: remove i_iolock and use i_rwsem in the VFS inode instead

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This patch drops the XFS-own i_iolock and uses the VFS i_rwsem which
recently replaced i_mutex instead.  This means we only have to take
one lock instead of two in many fast path operations, and we can
also shrink the xfs_inode structure.  Thanks to the xfs_ilock family
there is very little churn, the only thing of note is that we need
to switch to use the lock_two_directory helper for taking the i_rwsem
on two inodes in a few places to make sure our lock order matches
the one used in the VFS.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Jens Axboe <axboe@fb.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Christoph Hellwig
2016-11-30 14:33:25 +11:00
committed by Dave Chinner
parent f8319483f5
commit 6552321831
14 changed files with 86 additions and 159 deletions
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7
fs/xfs/xfs_inode.h
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@@ -56,7 +56,6 @@ typedef struct xfs_inode {
/* Transaction and locking information. */
struct xfs_inode_log_item *i_itemp; /* logging information */
mrlock_t i_lock; /* inode lock */
mrlock_t i_iolock; /* inode IO lock */
mrlock_t i_mmaplock; /* inode mmap IO lock */
atomic_t i_pincount; /* inode pin count */
spinlock_t i_flags_lock; /* inode i_flags lock */
@@ -333,7 +332,7 @@ static inline void xfs_ifunlock(struct xfs_inode *ip)
* IOLOCK values
*
* 0-3 subclass value
* 4-7 PARENT subclass values
* 4-7 unused
*
* MMAPLOCK values
*
@@ -348,10 +347,8 @@ static inline void xfs_ifunlock(struct xfs_inode *ip)
*
*/
#define XFS_IOLOCK_SHIFT 16
#define XFS_IOLOCK_PARENT_VAL 4
#define XFS_IOLOCK_MAX_SUBCLASS (XFS_IOLOCK_PARENT_VAL - 1)
#define XFS_IOLOCK_MAX_SUBCLASS 3
#define XFS_IOLOCK_DEP_MASK 0x000f0000
#define XFS_IOLOCK_PARENT (XFS_IOLOCK_PARENT_VAL << XFS_IOLOCK_SHIFT)
#define XFS_MMAPLOCK_SHIFT 20
#define XFS_MMAPLOCK_NUMORDER 0