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From: Theodore Ts'o <tytso@mit.edu>
To: Andreas Dilger <adilger@dilger.ca>
Cc: Ext4 Developers List <linux-ext4@vger.kernel.org>
Subject: [PATCH] ext4: renumber EXT4_EX_* flags to avoid flag aliasing problems flags
Date: Tue, 2 Sep 2014 21:44:16 -0400	[thread overview]
Message-ID: <20140903014416.GA2504@thunk.org> (raw)
In-Reply-To: <A71E6FF0-16EC-4747-89E4-F9574A89FF89@dilger.ca>

On Tue, Sep 02, 2014 at 01:01:54PM -0600, Andreas Dilger wrote:
> Why not move EXT4_EX_*CACHE flags to the end of the range (e.g. 0x8000
> and 0x4000) to minimize potential conflicts in the future?

Good idea, thanks!

					- Ted

commit ef78955523bffe055035f0b3a98aba31534bf27c
Author: Theodore Ts'o <tytso@mit.edu>
Date:   Tue Sep 2 21:41:59 2014 -0400

    ext4: renumber EXT4_EX_* flags to avoid flag aliasing problems
    
    Suggested-by: Andreas Dilger <adilger@dilger.ca>
    Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 4855800..f70c3fc 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -569,7 +569,6 @@ enum {
 #define EXT4_GET_BLOCKS_NO_PUT_HOLE		0x0200
 	/* Convert written extents to unwritten */
 #define EXT4_GET_BLOCKS_CONVERT_UNWRITTEN	0x0400
-/* DO NOT ASSIGN ADDITIONAL FLAG VALUES WITHOUT ADJUSTING THE FLAGS BELOW */
 
 /*
  * The bit position of these flags must not overlap with any of the
@@ -580,8 +579,8 @@ enum {
  * caching the extents when reading from the extent tree while a
  * truncate or punch hole operation is in progress.
  */
-#define EXT4_EX_NOCACHE				0x0800
-#define EXT4_EX_FORCE_CACHE			0x1000
+#define EXT4_EX_NOCACHE				0x40000000
+#define EXT4_EX_FORCE_CACHE			0x20000000
 
 /*
  * Flags used by ext4_free_blocks

      reply	other threads:[~2014-09-03  1:44 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-31 20:00 [PATCH] ext4: fix accidental flag aliasing in ext4_map_blocks flags Theodore Ts'o
2014-09-01 18:33 ` [PATCH] ext4: fix ZERO_RANGE bug hidden by flag aliasing Theodore Ts'o
2014-09-02 19:01 ` [PATCH] ext4: fix accidental flag aliasing in ext4_map_blocks flags Andreas Dilger
2014-09-03  1:44   ` Theodore Ts'o [this message]

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