From 1e6f209515a08de29ec53b653eac73b50efd949c Mon Sep 17 00:00:00 2001
From: Anna Schumaker <Anna.Schumaker@Netapp.com>
Date: Tue, 25 Jul 2017 16:10:47 -0400
Subject: NFS: Use raw NFS access mask in nfs4_opendata_access()

Commit bd8b2441742b ("NFS: Store the raw NFS access mask in the inode's
access cache") changed how the access results are stored after an
access() call.  An NFS v4 OPEN might have access bits returned with the
opendata, so we should use the NFS4_ACCESS values when determining the
return value in nfs4_opendata_access().

Fixes: bd8b2441742b ("NFS: Store the raw NFS access mask in the inode's
access cache")
Reported-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Tested-by: Takashi Iwai <tiwai@suse.de>
---
 fs/nfs/nfs4proc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

(limited to 'fs/nfs')

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index e1a26c653e78..583c2b38c908 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2236,7 +2236,7 @@ static int nfs4_opendata_access(struct rpc_cred *cred,
 				int openflags)
 {
 	struct nfs_access_entry cache;
-	u32 mask;
+	u32 mask, flags;
 
 	/* access call failed or for some reason the server doesn't
 	 * support any access modes -- defer access call until later */
@@ -2250,16 +2250,20 @@ static int nfs4_opendata_access(struct rpc_cred *cred,
 	 */
 	if (openflags & __FMODE_EXEC) {
 		/* ONLY check for exec rights */
-		mask = MAY_EXEC;
+		if (S_ISDIR(state->inode->i_mode))
+			mask = NFS4_ACCESS_LOOKUP;
+		else
+			mask = NFS4_ACCESS_EXECUTE;
 	} else if ((fmode & FMODE_READ) && !opendata->file_created)
-		mask = MAY_READ;
+		mask = NFS4_ACCESS_READ;
 
 	cache.cred = cred;
 	cache.jiffies = jiffies;
 	nfs_access_set_mask(&cache, opendata->o_res.access_result);
 	nfs_access_add_cache(state->inode, &cache);
 
-	if ((mask & ~cache.mask & (MAY_READ | MAY_EXEC)) == 0)
+	flags = NFS4_ACCESS_READ | NFS4_ACCESS_EXECUTE | NFS4_ACCESS_LOOKUP;
+	if ((mask & ~cache.mask & flags) == 0)
 		return 0;
 
 	return -EACCES;
-- 
cgit v1.2.3


From 442ce0499c0535f8972b68fa1fda357357a5c953 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.com>
Date: Mon, 24 Jul 2017 13:18:50 +1000
Subject: NFS: invalidate file size when taking a lock.

Prior to commit ca0daa277aca ("NFS: Cache aggressively when file is open
for writing"), NFS would revalidate, or invalidate, the file size when
taking a lock.  Since that commit it only invalidates the file content.

If the file size is changed on the server while wait for the lock, the
client will have an incorrect understanding of the file size and could
corrupt data.  This particularly happens when writing beyond the
(supposed) end of file and can be easily be demonstrated with
posix_fallocate().

If an application opens an empty file, waits for a write lock, and then
calls posix_fallocate(), glibc will determine that the underlying
filesystem doesn't support fallocate (assuming version 4.1 or earlier)
and will write out a '0' byte at the end of each 4K page in the region
being fallocated that is after the end of the file.
NFS will (usually) detect that these writes are beyond EOF and will
expand them to cover the whole page, and then will merge the pages.
Consequently, NFS will write out large blocks of zeroes beyond where it
thought EOF was.  If EOF had moved, the pre-existing part of the file
will be over-written.  Locking should have protected against this,
but it doesn't.

This patch restores the use of nfs_zap_caches() which invalidated the
cached attributes.  When posix_fallocate() asks for the file size, the
request will go to the server and get a correct answer.

cc: stable@vger.kernel.org (v4.8+)
Fixes: ca0daa277aca ("NFS: Cache aggressively when file is open for writing")
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 fs/nfs/file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'fs/nfs')

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index 5713eb32a45e..d264363559db 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -750,7 +750,7 @@ do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
 	 */
 	nfs_sync_mapping(filp->f_mapping);
 	if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
-		nfs_zap_mapping(inode, filp->f_mapping);
+		nfs_zap_caches(inode);
 out:
 	return status;
 }
-- 
cgit v1.2.3


From 6ba80d4348bd8cce2a0a6bbc21e5e1e760de42a9 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.com>
Date: Mon, 24 Jul 2017 13:18:50 +1000
Subject: NFS: Optimize fallocate by refreshing mapping when needed.

posix_fallocate() will allocate space in an NFS file by considering
the last byte of every 4K block.  If it is before EOF, it will read
the byte and if it is zero, a zero is written out.  If it is after EOF,
the zero is unconditionally written.

For the blocks beyond EOF, if NFS believes its cache is valid, it will
expand these writes to write full pages, and then will merge the pages.
This results if (typically) 1MB writes.  If NFS believes its cache is
not valid (particularly if NFS_INO_INVALID_DATA or
NFS_INO_REVAL_PAGECACHE are set - see nfs_write_pageuptodate()), it will
send the individual 1-byte writes. This results in (typically) 256 times
as many RPC requests, and can be substantially slower.

Currently nfs_revalidate_mapping() is only used when reading a file or
mmapping a file, as these are times when the content needs to be
up-to-date.  Writes don't generally need the cache to be up-to-date, but
writes beyond EOF can benefit, particularly in the posix_fallocate()
case.

So this patch calls nfs_revalidate_mapping() when writing beyond EOF -
i.e. when there is a gap between the end of the file and the start of
the write.  If the cache is thought to be out of date (as happens after
taking a file lock), this will cause a GETATTR, and the two flags
mentioned above will be cleared.  With this, posix_fallocate() on a
newly locked file does not generate excessive tiny writes.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 fs/nfs/file.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'fs/nfs')

diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index d264363559db..af330c31f627 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -617,6 +617,8 @@ ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
 		if (result)
 			goto out;
 	}
+	if (iocb->ki_pos > i_size_read(inode))
+		nfs_revalidate_mapping(inode, file->f_mapping);
 
 	nfs_start_io_write(inode);
 	result = generic_write_checks(iocb, from);
-- 
cgit v1.2.3


From b7dbcc0e433f0f61acb89ed9861ec996be4f2b38 Mon Sep 17 00:00:00 2001
From: Benjamin Coddington <bcodding@redhat.com>
Date: Fri, 28 Jul 2017 12:33:54 -0400
Subject: NFSv4.1: Fix a race where CB_NOTIFY_LOCK fails to wake a waiter

nfs4_retry_setlk() sets the task's state to TASK_INTERRUPTIBLE within the
same region protected by the wait_queue's lock after checking for a
notification from CB_NOTIFY_LOCK callback.  However, after releasing that
lock, a wakeup for that task may race in before the call to
freezable_schedule_timeout_interruptible() and set TASK_WAKING, then
freezable_schedule_timeout_interruptible() will set the state back to
TASK_INTERRUPTIBLE before the task will sleep.  The result is that the task
will sleep for the entire duration of the timeout.

Since we've already set TASK_INTERRUPTIBLE in the locked section, just use
freezable_schedule_timout() instead.

Fixes: a1d617d8f134 ("nfs: allow blocking locks to be awoken by lock callbacks")
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
---
 fs/nfs/nfs4proc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'fs/nfs')

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 583c2b38c908..93c1d7352238 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6495,7 +6495,7 @@ nfs4_retry_setlk(struct nfs4_state *state, int cmd, struct file_lock *request)
 		set_current_state(TASK_INTERRUPTIBLE);
 		spin_unlock_irqrestore(&q->lock, flags);
 
-		freezable_schedule_timeout_interruptible(NFS4_LOCK_MAXTIMEOUT);
+		freezable_schedule_timeout(NFS4_LOCK_MAXTIMEOUT);
 	}
 
 	finish_wait(q, &wait);
-- 
cgit v1.2.3