From 7c2d238ac6c435c07780a54719760da2beb46a43 Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <darrick.wong@oracle.com>
Date: Fri, 26 Jan 2018 15:27:33 -0800
Subject: [PATCH] xfs: allow xfs_lock_two_inodes to take different EXCL/SHARED
modes
Git-commit: 7c2d238ac6c435c07780a54719760da2beb46a43
Patch-mainline: v4.16-rc1
References: bsc#1132370, bsc#1132219
Refactor xfs_lock_two_inodes to take separate locking modes for each
inode. Specifically, this enables us to take a SHARED lock on one inode
and an EXCL lock on the other. The lock class (MMAPLOCK/ILOCK) must be
the same for each inode.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Anthony Iliopoulos <ailiopoulos@suse.com>
---
fs/xfs/xfs_bmap_util.c | 4 ++--
fs/xfs/xfs_inode.c | 49 ++++++++++++++++++++++++++++++++-----------------
fs/xfs/xfs_inode.h | 3 ++-
fs/xfs/xfs_reflink.c | 5 +++--
4 files changed, 39 insertions(+), 22 deletions(-)
diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 6d37ab43195f..c83f549dc17b 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1872,7 +1872,7 @@ xfs_swap_extents(
*/
lock_two_nondirectories(VFS_I(ip), VFS_I(tip));
lock_flags = XFS_MMAPLOCK_EXCL;
- xfs_lock_two_inodes(ip, tip, XFS_MMAPLOCK_EXCL);
+ xfs_lock_two_inodes(ip, XFS_MMAPLOCK_EXCL, tip, XFS_MMAPLOCK_EXCL);
/* Verify that both files have the same format */
if ((VFS_I(ip)->i_mode & S_IFMT) != (VFS_I(tip)->i_mode & S_IFMT)) {
@@ -1919,7 +1919,7 @@ xfs_swap_extents(
* Lock and join the inodes to the tansaction so that transaction commit
* or cancel will unlock the inodes from this point onwards.
*/
- xfs_lock_two_inodes(ip, tip, XFS_ILOCK_EXCL);
+ xfs_lock_two_inodes(ip, XFS_ILOCK_EXCL, tip, XFS_ILOCK_EXCL);
lock_flags |= XFS_ILOCK_EXCL;
xfs_trans_ijoin(tp, ip, 0);
xfs_trans_ijoin(tp, tip, 0);
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 5366fb619db6..e7f6d5291a7a 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -546,23 +546,36 @@ xfs_lock_inodes(
/*
* xfs_lock_two_inodes() can only be used to lock one type of lock at a time -
- * the iolock, the mmaplock or the ilock, but not more than one at a time. If we
- * lock more than one at a time, lockdep will report false positives saying we
- * have violated locking orders.
+ * the mmaplock or the ilock, but not more than one type at a time. If we lock
+ * more than one at a time, lockdep will report false positives saying we have
+ * violated locking orders. The iolock must be double-locked separately since
+ * we use i_rwsem for that. We now support taking one lock EXCL and the other
+ * SHARED.
*/
void
xfs_lock_two_inodes(
- xfs_inode_t *ip0,
- xfs_inode_t *ip1,
- uint lock_mode)
+ struct xfs_inode *ip0,
+ uint ip0_mode,
+ struct xfs_inode *ip1,
+ uint ip1_mode)
{
- xfs_inode_t *temp;
+ struct xfs_inode *temp;
+ uint mode_temp;
int attempts = 0;
xfs_log_item_t *lp;
- ASSERT(!(lock_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)));
- if (lock_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL))
- ASSERT(!(lock_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
+ ASSERT(hweight32(ip0_mode) == 1);
+ ASSERT(hweight32(ip1_mode) == 1);
+ ASSERT(!(ip0_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)));
+ ASSERT(!(ip1_mode & (XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL)));
+ ASSERT(!(ip0_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||
+ !(ip0_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
+ ASSERT(!(ip1_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||
+ !(ip1_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
+ ASSERT(!(ip1_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||
+ !(ip0_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
+ ASSERT(!(ip0_mode & (XFS_MMAPLOCK_SHARED|XFS_MMAPLOCK_EXCL)) ||
+ !(ip1_mode & (XFS_ILOCK_SHARED|XFS_ILOCK_EXCL)));
ASSERT(ip0->i_ino != ip1->i_ino);
@@ -570,10 +583,13 @@ xfs_lock_two_inodes(
temp = ip0;
ip0 = ip1;
ip1 = temp;
+ mode_temp = ip0_mode;
+ ip0_mode = ip1_mode;
+ ip1_mode = mode_temp;
}
again:
- xfs_ilock(ip0, xfs_lock_inumorder(lock_mode, 0));
+ xfs_ilock(ip0, xfs_lock_inumorder(ip0_mode, 0));
/*
* If the first lock we have locked is in the AIL, we must TRY to get
@@ -582,18 +598,17 @@ xfs_lock_two_inodes(
*/
lp = (xfs_log_item_t *)ip0->i_itemp;
if (lp && (lp->li_flags & XFS_LI_IN_AIL)) {
- if (!xfs_ilock_nowait(ip1, xfs_lock_inumorder(lock_mode, 1))) {
- xfs_iunlock(ip0, lock_mode);
+ if (!xfs_ilock_nowait(ip1, xfs_lock_inumorder(ip1_mode, 1))) {
+ xfs_iunlock(ip0, ip0_mode);
if ((++attempts % 5) == 0)
delay(1); /* Don't just spin the CPU */
goto again;
}
} else {
- xfs_ilock(ip1, xfs_lock_inumorder(lock_mode, 1));
+ xfs_ilock(ip1, xfs_lock_inumorder(ip1_mode, 1));
}
}
-
void
__xfs_iflock(
struct xfs_inode *ip)
@@ -1421,7 +1436,7 @@ xfs_link(
if (error)
goto std_return;
- xfs_lock_two_inodes(sip, tdp, XFS_ILOCK_EXCL);
+ xfs_lock_two_inodes(sip, XFS_ILOCK_EXCL, tdp, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, sip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, tdp, XFS_ILOCK_EXCL);
@@ -2585,7 +2600,7 @@ xfs_remove(
goto std_return;
}
- xfs_lock_two_inodes(dp, ip, XFS_ILOCK_EXCL);
+ xfs_lock_two_inodes(dp, XFS_ILOCK_EXCL, ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 386b0bb3c92a..3e8dc990d41c 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -423,7 +423,8 @@ void xfs_iunpin_wait(xfs_inode_t *);
#define xfs_ipincount(ip) ((unsigned int) atomic_read(&ip->i_pincount))
int xfs_iflush(struct xfs_inode *, struct xfs_buf **);
-void xfs_lock_two_inodes(xfs_inode_t *, xfs_inode_t *, uint);
+void xfs_lock_two_inodes(struct xfs_inode *ip0, uint ip0_mode,
+ struct xfs_inode *ip1, uint ip1_mode);
xfs_extlen_t xfs_get_extsz_hint(struct xfs_inode *ip);
xfs_extlen_t xfs_get_cowextsz_hint(struct xfs_inode *ip);
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index bac464f0bc59..bcc58c24287c 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -944,7 +944,7 @@ xfs_reflink_set_inode_flag(
if (src->i_ino == dest->i_ino)
xfs_ilock(src, XFS_ILOCK_EXCL);
else
- xfs_lock_two_inodes(src, dest, XFS_ILOCK_EXCL);
+ xfs_lock_two_inodes(src, XFS_ILOCK_EXCL, dest, XFS_ILOCK_EXCL);
if (!xfs_is_reflink_inode(src)) {
trace_xfs_reflink_set_inode_flag(src);
@@ -1324,7 +1324,8 @@ xfs_reflink_remap_range(
if (same_inode)
xfs_ilock(src, XFS_MMAPLOCK_EXCL);
else
- xfs_lock_two_inodes(src, dest, XFS_MMAPLOCK_EXCL);
+ xfs_lock_two_inodes(src, XFS_MMAPLOCK_EXCL, dest,
+ XFS_MMAPLOCK_EXCL);
/* Check file eligibility and prepare for block sharing. */
ret = -EINVAL;
--
2.16.4