linux-kernel - [PATCH 1/1 linux-next] ext4: fix journal data documentation regarding O

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Date:   Fri, 25 Nov 2016 20:53:59 +0100
From:   Fabian Frederick <fabf@...net.be>
To:     tytso@....edu
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        fabf@...net.be
Subject: [PATCH 1/1 linux-next] ext4: fix journal data documentation regarding O_DIRECT

O_DIRECT is declared disabled in data=journal mode but still served
as buffered-IO when one would expect such operations to be canceled.
This patch clarifies documentation and removes redundancy.

Thanks to Theodore Ts'o for explanations.

Signed-off-by: Fabian Frederick <fabf@...net.be>
---
 Documentation/filesystems/ext4.txt | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 6c0108e..12bb488 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -157,10 +157,7 @@ noload			if the filesystem was not unmounted cleanly,
                      	filesystem containing inconsistencies that can
                      	lead to any number of problems.
 
-data=journal		All data are committed into the journal prior to being
-			written into the main file system.  Enabling
-			this mode will disable delayed allocation and
-			O_DIRECT support.
+data=journal		See journal mode below.
 
 data=ordered	(*)	All data are forced directly out to the main file
 			system prior to its metadata being committed to the
@@ -415,7 +412,8 @@ In the event of a crash, the journal can be replayed, bringing both data and
 metadata into a consistent state.  This mode is the slowest except when data
 needs to be read from and written to disk at the same time where it
 outperforms all others modes.  Enabling this mode will disable delayed
-allocation and O_DIRECT support.
+allocation and O_DIRECT support; the later being silently served using
+buffered-IO.
 
 /proc entries
 =============
-- 
2.7.4