linux-ext4 - [PATCH 1/6] chattr.1: document the verity attribute

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Message-Id: <20191118014852.390686-2-ebiggers@kernel.org>
Date:   Sun, 17 Nov 2019 17:48:47 -0800
From:   Eric Biggers <ebiggers@...nel.org>
To:     linux-ext4@...r.kernel.org
Subject: [PATCH 1/6] chattr.1: document the verity attribute

From: Eric Biggers <ebiggers@...gle.com>

Document the verity file attribute ('V').

Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 misc/chattr.1.in | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/misc/chattr.1.in b/misc/chattr.1.in
index 1c9e8964..2122a13e 100644
--- a/misc/chattr.1.in
+++ b/misc/chattr.1.in
@@ -52,7 +52,8 @@ The following attributes are read-only, and may be listed by
 but not modified by chattr:
 encrypted (E),
 indexed directory (I),
-and inline data (N).
+inline data (N),
+and verity (V).
 .PP
 Not all flags are supported or utilized by all filesystems; refer to
 filesystem-specific man pages such as
@@ -189,6 +190,15 @@ saved.  This allows the user to ask for its undeletion.  Note: please
 make sure to read the bugs and limitations section at the end of this
 document.
 .PP
+A file with the 'V' attribute set has fs-verity enabled.  It cannot be
+written to, and the filesystem will automatically verify all data read
+from it against a cryptographic hash that covers the entire file's
+contents, e.g. via a Merkle tree.  This makes it possible to efficiently
+authenticate the file.  This attribute may not be set or reset using
+.BR chattr (1),
+although it can be displayed by
+.BR lsattr (1).
+.PP
 .SH AUTHOR
 .B chattr
 was written by Remy Card <Remy.Card@...ux.org>.  It is currently being
-- 
2.24.0