On Wed, 18 Jul 2012, Eric Sandeen wrote:

Date: Wed, 18 Jul 2012 14:54:04 -0500
From: Eric Sandeen <redacted>
To: Lukas Czerner <redacted>
Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, tytso@mit.edu,
    achender@linux.vnet.ibm.com, Hugh Dickins [off-list ref]
Subject: Re: [PATCH 03/12 v2] shmem: pass LLONG_MAX to shmem_truncate_range

On 7/13/12 8:19 AM, Lukas Czerner wrote:

quoted

Currently we're passing -1 to shmem_truncate_range which can then call
truncate_inode_pages_range() which is actually really confusing since the
argument is signed so we do not get "huge" number as one would expect,
but rather just -1. To make things clearer and easier for
truncate_inode_pages_range() just pass LLONG_MAX since it is actually what
was intended anyway.

It also makes thing easier for allowing truncate_inode_pages_range() to
handle non page aligned regions. Moreover letting the lend argument to
be negative might actually hide some bugs.

Signed-off-by: Lukas Czerner <redacted>
Cc: Hugh Dickins <hughd@google.com>
---
 mm/shmem.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 4ce02e0..3199733 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c

@@ -2961,7 +2961,8 @@ void shmem_unlock_mapping(struct address_space *mapping)
 
 void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
 {
-	truncate_inode_pages_range(inode->i_mapping, lstart, lend);
+	truncate_inode_pages_range(inode->i_mapping, lstart,
+				   lend == -1 ? LLONG_MAX : last);

Where'd "last" come from?  That won't build; should be "lend" right?

(code only goes this way if !CONFIG_SHMEM so you might have missed it)

Ah, I definitely missed it. Thanks Eric. But from the discussion
with the Hugh, we're going to do this a bit differently anyway.

-Lukas

-Eric

quoted

 }
 EXPORT_SYMBOL_GPL(shmem_truncate_range);