.SH NAME
ext2 \- the second extended file system
.br
-ext2 \- the third extended file system
+ext3 \- the third extended file system
.br
ext4 \- the fourth extended file system
.SH DESCRIPTION
This ext4 feature provides multiple mount protection (MMP). MMP helps to
protect the filesystem from being multiply mounted and is useful in
shared storage environments.
-@QUOTA_MAN_COMMENT@.TP
-@QUOTA_MAN_COMMENT@.B quota
-@QUOTA_MAN_COMMENT@.br
-@QUOTA_MAN_COMMENT@Create quota inodes (inode #3 for userquota and inode
-@QUOTA_MAN_COMMENT@#4 for group quota) and set them in the superblock.
-@QUOTA_MAN_COMMENT@With this feature, the quotas will be enabled
-@QUOTA_MAN_COMMENT@automatically when the filesystem is mounted.
-@QUOTA_MAN_COMMENT@.IP
-@QUOTA_MAN_COMMENT@Causes the quota files (i.e., user.quota and
-@QUOTA_MAN_COMMENT@group.quota which existed
-@QUOTA_MAN_COMMENT@in the older quota design) to be hidden inodes.
+.TP
+.B quota
+.br
+Create quota inodes (inode #3 for userquota and inode
+#4 for group quota) and set them in the superblock.
+With this feature, the quotas will be enabled
+automatically when the filesystem is mounted.
+.IP
+Causes the quota files (i.e., user.quota and
+group.quota which existed
+in the older quota design) to be hidden inodes.
+.TP
+.B project
+.br
+This ext4 feature provides project quota support. With this feature,
+the project ID of inode will be managed when the filesystem is mounted.
.TP
.B resize_inode
.br
.B i_version
Enable 64-bit inode version support. This option is off by default.
+.SH FILE ATTRIBUTES
+The ext2, ext3, and ext4 filesystems support setting the following file
+attributes on Linux systems using the
+.BR chattr (1)
+utility:
+.sp
+.BR a " - append only"
+.sp
+.BR A " - no atime updates"
+.sp
+.BR d " - no dump"
+.sp
+.BR D " - synchronous directory updates"
+.sp
+.BR i " - immutable"
+.sp
+.BR S " - synchronous updates"
+.sp
+.BR u " - undeletable"
+.sp
+In addition, the ext3 and ext4 filesystems support the following flag:
+.sp
+.BR j " - data journaling"
+.sp
+Finally, the ext4 filesystem also supports the following flag:
+.sp
+.BR e " - extents format"
+.sp
+For descriptions of these attribute flags, please refer to the
+.BR chattr (1)
+man page.
.SH SEE ALSO
.BR mke2fs (8),
.BR mke2fs.conf (5),
.BR dumpe2fs (8),
.BR tune2fs (8),
.BR debugfs (8),
-.BR mount (8)
+.BR mount (8),
+.BR chattr (1)