[PATCH 07/14] xfs: Refactor xfs_isilocked()

Jan Kara
2021-06-07T14:52:47Z

From: Pavel Reichl <preichl@redhat.com>

Refactor xfs_isilocked() to use newly introduced __xfs_rwsem_islocked().
__xfs_rwsem_islocked() is a helper function which encapsulates checking
state of rw_semaphores hold by inode.

Signed-off-by: Pavel Reichl <preichl@redhat.com>
Suggested-by: Dave Chinner <dchinner@redhat.com>
Suggested-by: Eric Sandeen <sandeen@redhat.com>
Suggested-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/xfs/xfs_inode.c | 39 +++++++++++++++++++++++++++++++--------
fs/xfs/xfs_inode.h | 21 ++++++++++++++-------
2 files changed, 45 insertions(+), 15 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 0369eb22c1bb..6247977870bd 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -342,9 +342,34 @@ xfs_ilock_demote(
}

#if defined(DEBUG) || defined(XFS_WARN)
-int
+static inline bool
+__xfs_rwsem_islocked(
+ struct rw_semaphore *rwsem,
+ int lock_flags,
+ int shift)
+{
+ lock_flags >>= shift;
+
+ if (!debug_locks)
+ return rwsem_is_locked(rwsem);
+ /*
+ * If the shared flag is not set, pass 0 to explicitly check for
+ * exclusive access to the lock. If the shared flag is set, we typically
+ * want to make sure the lock is at least held in shared mode
+ * (i.e., shared | excl) but we don't necessarily care that it might
+ * actually be held exclusive. Therefore, pass -1 to check whether the
+ * lock is held in any mode rather than one of the explicit shared mode
+ * values (1 or 2)."
+ */
+ if (lock_flags & (1 << XFS_SHARED_LOCK_SHIFT)) {
+ return lockdep_is_held_type(rwsem, -1);
+ }
+ return lockdep_is_held_type(rwsem, 0);
+}
+
+bool
xfs_isilocked(
- xfs_inode_t *ip,
+ struct xfs_inode *ip,
uint lock_flags)
{
if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
@@ -359,15 +384,13 @@ xfs_isilocked(
return rwsem_is_locked(&ip->i_mmaplock.mr_lock);
}

- if (lock_flags & (XFS_IOLOCK_EXCL|XFS_IOLOCK_SHARED)) {
- if (!(lock_flags & XFS_IOLOCK_SHARED))
- return !debug_locks ||
- lockdep_is_held_type(&VFS_I(ip)->i_rwsem, 0);
- return rwsem_is_locked(&VFS_I(ip)->i_rwsem);
+ if (lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) {
+ return __xfs_rwsem_islocked(&VFS_I(ip)->i_rwsem, lock_flags,
+ XFS_IOLOCK_FLAG_SHIFT);
}

ASSERT(0);
- return 0;
+ return false;
}
#endif

diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index ca826cfba91c..1c0e15c480bc 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -262,12 +262,19 @@ static inline bool xfs_inode_has_bigtime(struct xfs_inode *ip)
* Bit ranges: 1<<1 - 1<<16-1 -- iolock/ilock modes (bitfield)
* 1<<16 - 1<<32-1 -- lockdep annotation (integers)
*/
-#define XFS_IOLOCK_EXCL (1<<0)
-#define XFS_IOLOCK_SHARED (1<<1)
-#define XFS_ILOCK_EXCL (1<<2)
-#define XFS_ILOCK_SHARED (1<<3)
-#define XFS_MMAPLOCK_EXCL (1<<4)
-#define XFS_MMAPLOCK_SHARED (1<<5)
+
+#define XFS_IOLOCK_FLAG_SHIFT 0
+#define XFS_ILOCK_FLAG_SHIFT 2
+#define XFS_MMAPLOCK_FLAG_SHIFT 4
+
+#define XFS_SHARED_LOCK_SHIFT 1
+
+#define XFS_IOLOCK_EXCL (1 << XFS_IOLOCK_FLAG_SHIFT)
+#define XFS_IOLOCK_SHARED (XFS_IOLOCK_EXCL << XFS_SHARED_LOCK_SHIFT)
+#define XFS_ILOCK_EXCL (1 << XFS_ILOCK_FLAG_SHIFT)
+#define XFS_ILOCK_SHARED (XFS_ILOCK_EXCL << XFS_SHARED_LOCK_SHIFT)
+#define XFS_MMAPLOCK_EXCL (1 << XFS_MMAPLOCK_FLAG_SHIFT)
+#define XFS_MMAPLOCK_SHARED (XFS_MMAPLOCK_EXCL << XFS_SHARED_LOCK_SHIFT)

#define XFS_LOCK_MASK (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED \
| XFS_ILOCK_EXCL | XFS_ILOCK_SHARED \
@@ -410,7 +417,7 @@ void xfs_ilock(xfs_inode_t *, uint);
int xfs_ilock_nowait(xfs_inode_t *, uint);
void xfs_iunlock(xfs_inode_t *, uint);
void xfs_ilock_demote(xfs_inode_t *, uint);
-int xfs_isilocked(xfs_inode_t *, uint);
+bool xfs_isilocked(struct xfs_inode *, uint);
uint xfs_ilock_data_map_shared(struct xfs_inode *);
uint xfs_ilock_attr_map_shared(struct xfs_inode *);

--
2.26.2