[PATCH AUTOSEL 4.4 1/5] gfs2: don't call quota_unhold if quotas are not locked

[PATCH AUTOSEL 4.4 1/5] gfs2: don't call quota_unhold if quotas are not locked

[Sasha Levin]

From: Bob Peterson <rpeterso@redhat.com>

[ Upstream commit c9cb9e381985bbbe8acd2695bbe6bd24bf06b81c ]

Before this patch, function gfs2_quota_unlock checked if quotas are
turned off, and if so, it branched to label out, which called
gfs2_quota_unhold. With the new system of gfs2_qa_get and put, we
no longer want to call gfs2_quota_unhold or we won't balance our
gets and puts.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/gfs2/quota.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index 3a31226531ea..4af00ed4960a 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -1080,7 +1080,7 @@ void gfs2_quota_unlock(struct gfs2_inode *ip)
 	int found;
 
 	if (!test_and_clear_bit(GIF_QD_LOCKED, &ip->i_flags))
-		goto out;
+		return;
 
 	for (x = 0; x < ip->i_res->rs_qa_qd_num; x++) {
 		struct gfs2_quota_data *qd;
@@ -1117,7 +1117,6 @@ void gfs2_quota_unlock(struct gfs2_inode *ip)
 			qd_unlock(qda[x]);
 	}
 
-out:
 	gfs2_quota_unhold(ip);
 }
 
-- 
2.25.1

[PATCH AUTOSEL 4.4 2/5] Revert "gfs2: Don't demote a glock until its revokes are written"

[Sasha Levin]

From: Bob Peterson <rpeterso@redhat.com>

[ Upstream commit b14c94908b1b884276a6608dea3d0b1b510338b7 ]

This reverts commit df5db5f9ee112e76b5202fbc331f990a0fc316d6.

This patch fixes a regression: patch df5db5f9ee112 allowed function
run_queue() to bypass its call to do_xmote() if revokes were queued for
the glock. That's wrong because its call to do_xmote() is what is
responsible for calling the go_sync() glops functions to sync both
the ail list and any revokes queued for it. By bypassing the call,
gfs2 could get into a stand-off where the glock could not be demoted
until its revokes are written back, but the revokes would not be
written back because do_xmote() was never called.

It "sort of" works, however, because there are other mechanisms like
the log flush daemon (logd) that can sync the ail items and revokes,
if it deems it necessary. The problem is: without file system pressure,
it might never deem it necessary.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/gfs2/glock.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index f80ffccb0316..1eb737c466dd 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -541,9 +541,6 @@ __acquires(&gl->gl_lockref.lock)
 			goto out_unlock;
 		if (nonblock)
 			goto out_sched;
-		smp_mb();
-		if (atomic_read(&gl->gl_revokes) != 0)
-			goto out_sched;
 		set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
 		GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
 		gl->gl_target = gl->gl_demote_state;
-- 
2.25.1

[PATCH AUTOSEL 4.4 3/5] cachefiles: Fix race between read_waiter and read_copier involving op->to_do

[Sasha Levin]

From: Lei Xue <carmark.dlut@gmail.com>

[ Upstream commit 7bb0c5338436dae953622470d52689265867f032 ]

There is a potential race in fscache operation enqueuing for reading and
copying multiple pages from cachefiles to netfs.  The problem can be seen
easily on a heavy loaded system (for example many processes reading files
continually on an NFS share covered by fscache triggered this problem within
a few minutes).

The race is due to cachefiles_read_waiter() adding the op to the monitor
to_do list and then then drop the object->work_lock spinlock before
completing fscache_enqueue_operation().  Once the lock is dropped,
cachefiles_read_copier() grabs the op, completes processing it, and
makes it through fscache_retrieval_complete() which sets the op->state to
the final state of FSCACHE_OP_ST_COMPLETE(4).  When cachefiles_read_waiter()
finally gets through the remainder of fscache_enqueue_operation()
it sees the invalid state, and hits the ASSERTCMP and the following
oops is seen:
[ 2259.612361] FS-Cache:
[ 2259.614785] FS-Cache: Assertion failed
[ 2259.618639] FS-Cache: 4 == 5 is false
[ 2259.622456] ------------[ cut here ]------------
[ 2259.627190] kernel BUG at fs/fscache/operation.c:70!
...
[ 2259.791675] RIP: 0010:[<ffffffffc061b4cf>]  [<ffffffffc061b4cf>] fscache_enqueue_operation+0xff/0x170 [fscache]
[ 2259.802059] RSP: 0000:ffffa0263d543be0  EFLAGS: 00010046
[ 2259.807521] RAX: 0000000000000019 RBX: ffffa01a4d390480 RCX: 0000000000000006
[ 2259.814847] RDX: 0000000000000000 RSI: 0000000000000046 RDI: ffffa0263d553890
[ 2259.822176] RBP: ffffa0263d543be8 R08: 0000000000000000 R09: ffffa0263c2d8708
[ 2259.829502] R10: 0000000000001e7f R11: 0000000000000000 R12: ffffa01a4d390480
[ 2259.844483] R13: ffff9fa9546c5920 R14: ffffa0263d543c80 R15: ffffa0293ff9bf10
[ 2259.859554] FS:  00007f4b6efbd700(0000) GS:ffffa0263d540000(0000) knlGS:0000000000000000
[ 2259.875571] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2259.889117] CR2: 00007f49e1624ff0 CR3: 0000012b38b38000 CR4: 00000000007607e0
[ 2259.904015] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 2259.918764] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 2259.933449] PKRU: 55555554
[ 2259.943654] Call Trace:
[ 2259.953592]  <IRQ>
[ 2259.955577]  [<ffffffffc03a7c12>] cachefiles_read_waiter+0x92/0xf0 [cachefiles]
[ 2259.978039]  [<ffffffffa34d3942>] __wake_up_common+0x82/0x120
[ 2259.991392]  [<ffffffffa34d3a63>] __wake_up_common_lock+0x83/0xc0
[ 2260.004930]  [<ffffffffa34d3510>] ? task_rq_unlock+0x20/0x20
[ 2260.017863]  [<ffffffffa34d3ab3>] __wake_up+0x13/0x20
[ 2260.030230]  [<ffffffffa34c72a0>] __wake_up_bit+0x50/0x70
[ 2260.042535]  [<ffffffffa35bdcdb>] unlock_page+0x2b/0x30
[ 2260.054495]  [<ffffffffa35bdd09>] page_endio+0x29/0x90
[ 2260.066184]  [<ffffffffa368fc81>] mpage_end_io+0x51/0x80

CPU1
cachefiles_read_waiter()
 20 static int cachefiles_read_waiter(wait_queue_entry_t *wait, unsigned mode,
 21                                   int sync, void *_key)
 22 {
...
 61         spin_lock(&object->work_lock);
 62         list_add_tail(&monitor->op_link, &op->to_do);
 63         spin_unlock(&object->work_lock);
<begin race window>
 64
 65         fscache_enqueue_retrieval(op);
182 static inline void fscache_enqueue_retrieval(struct fscache_retrieval *op)
183 {
184         fscache_enqueue_operation(&op->op);
185 }
 58 void fscache_enqueue_operation(struct fscache_operation *op)
 59 {
 60         struct fscache_cookie *cookie = op->object->cookie;
 61
 62         _enter("{OBJ%x OP%x,%u}",
 63                op->object->debug_id, op->debug_id, atomic_read(&op->usage));
 64
 65         ASSERT(list_empty(&op->pend_link));
 66         ASSERT(op->processor != NULL);
 67         ASSERT(fscache_object_is_available(op->object));
 68         ASSERTCMP(atomic_read(&op->usage), >, 0);
<end race window>

CPU2
cachefiles_read_copier()
168         while (!list_empty(&op->to_do)) {
...
202                 fscache_end_io(op, monitor->netfs_page, error);
203                 put_page(monitor->netfs_page);
204                 fscache_retrieval_complete(op, 1);

CPU1
 58 void fscache_enqueue_operation(struct fscache_operation *op)
 59 {
...
 69         ASSERTIFCMP(op->state != FSCACHE_OP_ST_IN_PROGRESS,
 70                     op->state, ==,  FSCACHE_OP_ST_CANCELLED);

Signed-off-by: Lei Xue <carmark.dlut@gmail.com>
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cachefiles/rdwr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c
index c05ab2ec0fef..5df898fd0a0a 100644
--- a/fs/cachefiles/rdwr.c
+++ b/fs/cachefiles/rdwr.c
@@ -64,9 +64,9 @@ static int cachefiles_read_waiter(wait_queue_t *wait, unsigned mode,
 	object = container_of(op->op.object, struct cachefiles_object, fscache);
 	spin_lock(&object->work_lock);
 	list_add_tail(&monitor->op_link, &op->to_do);
+	fscache_enqueue_retrieval(op);
 	spin_unlock(&object->work_lock);
 
-	fscache_enqueue_retrieval(op);
 	fscache_put_retrieval(op);
 	return 0;
 }
-- 
2.25.1

[PATCH AUTOSEL 4.4 4/5] usb: gadget: legacy: fix redundant initialization warnings

[Sasha Levin]

From: Masahiro Yamada <masahiroy@kernel.org>

[ Upstream commit d13cce757954fa663c69845611957396843ed87a ]

Fix the following cppcheck warnings:

drivers/usb/gadget/legacy/inode.c:1364:8: style: Redundant initialization for 'value'. The initialized value is overwritten$
 value = -EOPNOTSUPP;
       ^
drivers/usb/gadget/legacy/inode.c:1331:15: note: value is initialized
 int    value = -EOPNOTSUPP;
              ^
drivers/usb/gadget/legacy/inode.c:1364:8: note: value is overwritten
 value = -EOPNOTSUPP;
       ^
drivers/usb/gadget/legacy/inode.c:1817:8: style: Redundant initialization for 'value'. The initialized value is overwritten$
 value = -EINVAL;
       ^
drivers/usb/gadget/legacy/inode.c:1787:18: note: value is initialized
 ssize_t   value = len, length = len;
                 ^
drivers/usb/gadget/legacy/inode.c:1817:8: note: value is overwritten
 value = -EINVAL;
       ^
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/legacy/inode.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index 81f3c9cb333c..b95900168a6b 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -1360,7 +1360,6 @@ gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
 
 	req->buf = dev->rbuf;
 	req->context = NULL;
-	value = -EOPNOTSUPP;
 	switch (ctrl->bRequest) {
 
 	case USB_REQ_GET_DESCRIPTOR:
@@ -1806,7 +1805,7 @@ static ssize_t
 dev_config (struct file *fd, const char __user *buf, size_t len, loff_t *ptr)
 {
 	struct dev_data		*dev = fd->private_data;
-	ssize_t			value = len, length = len;
+	ssize_t			value, length = len;
 	unsigned		total;
 	u32			tag;
 	char			*kbuf;
-- 
2.25.1

[PATCH AUTOSEL 4.4 5/5] cifs: Fix null pointer check in cifs_read

[Sasha Levin]

From: Steve French <stfrench@microsoft.com>

[ Upstream commit 9bd21d4b1a767c3abebec203342f3820dcb84662 ]

Coverity scan noted a redundant null check

Coverity-id: 728517
Reported-by: Coverity <scan-admin@coverity.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Shyam Prasad N <nspmangalore@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 2ffdaedca7e9..b5a05092f862 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3230,7 +3230,7 @@ cifs_read(struct file *file, char *read_data, size_t read_size, loff_t *offset)
 			 * than it negotiated since it will refuse the read
 			 * then.
 			 */
-			if ((tcon->ses) && !(tcon->ses->capabilities &
+			if (!(tcon->ses->capabilities &
 				tcon->ses->server->vals->cap_large_files)) {
 				current_read_size = min_t(uint,
 					current_read_size, CIFSMaxBufSize);
-- 
2.25.1