Patch "ext4: move check under lock scope to close a race." has been added to the 4.0-stable tree

Patch "ext4: move check under lock scope to close a race." has been added to the 4.0-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ext4: move check under lock scope to close a race.

to the 4.0-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ext4-move-check-under-lock-scope-to-close-a-race.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 280227a75b56ab5d35854f3a77ef74a7ad56a203 Mon Sep 17 00:00:00 2001
From: Davide Italiano <dccitaliano@gmail.com>
Date: Sat, 2 May 2015 23:21:15 -0400
Subject: ext4: move check under lock scope to close a race.

From: Davide Italiano <dccitaliano@gmail.com>

commit 280227a75b56ab5d35854f3a77ef74a7ad56a203 upstream.

fallocate() checks that the file is extent-based and returns
EOPNOTSUPP in case is not. Other tasks can convert from and to
indirect and extent so it's safe to check only after grabbing
the inode mutex.

Signed-off-by: Davide Italiano <dccitaliano@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/ext4/extents.c |   15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4934,13 +4934,6 @@ long ext4_fallocate(struct file *file, i
 	if (ret)
 		return ret;
 
-	/*
-	 * currently supporting (pre)allocate mode for extent-based
-	 * files _only_
-	 */
-	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
-		return -EOPNOTSUPP;
-
 	if (mode & FALLOC_FL_COLLAPSE_RANGE)
 		return ext4_collapse_range(inode, offset, len);
 
@@ -4962,6 +4955,14 @@ long ext4_fallocate(struct file *file, i
 
 	mutex_lock(&inode->i_mutex);
 
+	/*
+	 * We only support preallocation for extent-based files only
+	 */
+	if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
 	if (!(mode & FALLOC_FL_KEEP_SIZE) &&
 	     offset + len > i_size_read(inode)) {
 		new_size = offset + len;


Patches currently in stable-queue which might be from dccitaliano@gmail.com are

queue-4.0/ext4-move-check-under-lock-scope-to-close-a-race.patch