From: Eric Sandeen <sandeen@redhat.com>
Subject: [PATCH 2/2] e2fsprogs: revise and extend chattr(1) and chattr usage()
Date: Thu, 19 Jun 2014 18:24:25 -0500
Message-ID: <53A37129.2040409@redhat.com>
References: <53A36F0E.6090105@redhat.com>
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To: ext4 development <linux-ext4@vger.kernel.org>
In-Reply-To: <53A36F0E.6090105@redhat.com>
Sender: linux-ext4-owner@vger.kernel.org

The chattr(1) manpage and chattr usage() output were missing some flags.

Add those, and make some other minor cosmetic fixes.

(I've left out the 'B' (EXT2_COMPRBLK_FL) flag, because
it's not actually used anywhere, and I can't figure out
how it differs from 'c' (EXT2_COMPR_FL))

Also, because the matrix of filesystems & flags is quite large,
refer to filesystem-specific manpages for detailed discussion
of flags supported by those filesystems, rather than trying to
cover it all in this manpage.  I'll send those manpage
updates to the appropriate lists a bit later.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/misc/chattr.1.in b/misc/chattr.1.in
index ce426e8..6f64e09 100644
--- a/misc/chattr.1.in
+++ b/misc/chattr.1.in
@@ -47,8 +47,17 @@ but not modified by chattr:
 compression error (E),
 huge file (h),
 indexed directory (I),
+inline data (N),
 compression raw access (X),
 and compressed dirty file (Z).
+.PP
+Not all flags are supported or utilized by all filesystems; refer to
+filesystem-specific man pages such as
+.BR btrfs (5), 
+.BR ext4 (5),
+and
+.BR xfs (5)
+for more filesystem-specific details.
 .SH OPTIONS
 .TP
 .B \-R
@@ -67,7 +76,7 @@ A file with the `a' attribute set can only be open in append mode for writing.
 Only the superuser or a process possessing the CAP_LINUX_IMMUTABLE
 capability can set or clear this attribute.
 .PP
-When a file with the 'A' attribute set is accessed, its atime record is
+When a file with the `A' attribute set is accessed, its atime record is
 not modified.  This avoids a certain amount of disk I/O for laptop
 systems.
 .PP
@@ -77,12 +86,12 @@ this file compresses data before storing them on the disk.  Note: please
 make sure to read the bugs and limitations section at the end of this
 document.
 .PP
-A file with the 'C' attribute set will not be subject to copy-on-write
+A file with the `C' attribute set will not be subject to copy-on-write
 updates.  This flag is only supported on file systems which perform
-copy-on-write.  (Note: For btrfs, the 'C' flag should be
+copy-on-write.  (Note: For btrfs, the `C' flag should be
 set on new or empty files.  If it is set on a file which already has
 data blocks, it is undefined when the blocks assigned to the file will
-be fully stable.  If the 'C' flag is set on a directory, it will have no
+be fully stable.  If the `C' flag is set on a directory, it will have no
 effect on the directory, but new files created in that directory will
 the No_COW attribute.)
 .PP
@@ -94,18 +103,18 @@ When a directory with the `D' attribute set is modified,
 the changes are written synchronously on the disk; this is equivalent to
 the `dirsync' mount option applied to a subset of the files.
 .PP
-The 'e' attribute indicates that the file is using extents for mapping
+The `e' attribute indicates that the file is using extents for mapping
 the blocks on disk.  It may not be removed using
 .BR chattr (1).
 .PP
-The 'E' attribute is used by the experimental compression patches to
+The `E' attribute is used by the experimental compression patches to
 indicate that a compressed file has a compression error.  It may not be
 set or reset using
 .BR chattr (1),
 although it can be displayed by
 .BR lsattr (1).
 .PP
-The 'h' attribute indicates the file is storing its blocks in units of the
+The `h' attribute indicates the file is storing its blocks in units of the
 filesystem blocksize instead of in units of sectors, and means that the file
 is (or at one time was) larger than 2TB.  It may not be set or reset using
 .BR chattr (1),
@@ -117,7 +126,7 @@ renamed, no link can be created to this file and no data can be written
 to the file.  Only the superuser or a process possessing the
 CAP_LINUX_IMMUTABLE capability can set or clear this attribute.
 .PP
-The 'I' attribute is used by the htree code to indicate that a directory
+The `I' attribute is used by the htree code to indicate that a directory
 is being indexed using hashed trees.  It may not be set or reset using
 .BR chattr (1),
 although it can be displayed by
@@ -131,6 +140,12 @@ is already journalled and this attribute has no effect.  Only
 the superuser or a process possessing the CAP_SYS_RESOURCE
 capability can set or clear this attribute.
 .PP
+A file with the `N' attribute set indicates that the file has data 
+stored inline, within the inode itself. It may not be set or reset using
+.BR chattr (1),
+although it can be displayed by
+.BR lsattr (1).
+.PP
 When a file with the `s' attribute set is deleted, its blocks are zeroed
 and written back to the disk.  Note: please make sure to read the bugs
 and limitations section at the end of this document.
@@ -139,19 +154,19 @@ When a file with the `S' attribute set is modified,
 the changes are written synchronously on the disk; this is equivalent to
 the `sync' mount option applied to a subset of the files.
 .PP
-A file with the 't' attribute will not have a partial block fragment at
+A file with the `t' attribute will not have a partial block fragment at
 the end of the file merged with other files (for those filesystems which
 support tail-merging).  This is necessary for applications such as LILO
 which read the filesystem directly, and which don't understand tail-merged
 files.  Note: As of this writing, the ext2 or ext3 filesystems do not
 (yet, except in very experimental patches) support tail-merging.
 .PP
-A directory with the 'T' attribute will be deemed to be the top of
+A directory with the `T' attribute will be deemed to be the top of
 directory hierarchies for the purposes of the Orlov block allocator.
 This is a hint to the block allocator used by ext3 and ext4 that the
 subdirectories under this directory are not related, and thus should be
 spread apart for allocation purposes.   For example it is a very good
-idea to set the 'T' attribute on the /home directory, so that /home/john
+idea to set the `T' attribute on the /home directory, so that /home/john
 and /home/mary are placed into separate block groups.  For directories
 where this attribute is not set, the Orlov block allocator will try to
 group subdirectories closer together where possible.
@@ -161,14 +176,14 @@ 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
-The 'X' attribute is used by the experimental compression patches to
-indicate that a raw contents of a compressed file can be accessed
+The `X' attribute is used by the experimental compression patches to
+indicate that the raw contents of a compressed file can be accessed
 directly.  It currently may not be set or reset using
 .BR chattr (1),
 although it can be displayed by
 .BR lsattr (1).
 .PP
-The 'Z' attribute is used by the experimental compression patches to
+The `Z' attribute is used by the experimental compression patches to
 indicate a compressed file is dirty.  It may not be set or reset using
 .BR chattr (1),
 although it can be displayed by
@@ -179,7 +194,7 @@ although it can be displayed by
 was written by Remy Card <Remy.Card@linux.org>.  It is currently being
 maintained by Theodore Ts'o <tytso@alum.mit.edu>.
 .SH BUGS AND LIMITATIONS
-The `c', 's',  and `u' attributes are not honored
+The `c', `s',  and `u' attributes are not honored
 by the ext2, ext3, and ext4 filesystems as implemented in the current
 mainline Linux kernels.
 .PP
@@ -191,4 +206,7 @@ The `D' option is only useful on Linux kernel 2.5.19 and later.
 is part of the e2fsprogs package and is available from
 http://e2fsprogs.sourceforge.net.
 .SH SEE ALSO
-.BR lsattr (1)
+.BR lsattr (1),
+.BR btrfs (5),
+.BR ext4 (5),
+.BR xfs (5).
diff --git a/misc/chattr.c b/misc/chattr.c
index d5a6a61..f130108 100644
--- a/misc/chattr.c
+++ b/misc/chattr.c
@@ -83,7 +83,7 @@ static unsigned long sf;
 static void usage(void)
 {
 	fprintf(stderr,
-		_("Usage: %s [-RVf] [-+=aAcCdDeijsSu] [-v version] files...\n"),
+		_("Usage: %s [-RVf] [-+=aAcCdDeijsStTu] [-v version] files...\n"),
 		program_name);
 	exit(1);
 }