Merge tag 'soc-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm...

[linux-2.6-microblaze.git] / Documentation / filesystems / ext4.txt

diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 34ea4f1..f7cbf57 100644 (file)
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -494,6 +494,17 @@ Files in /sys/fs/ext4/<devname>
  session_write_kbytes         This file is read-only and shows the number of
                               kilobytes of data that have been written to this
                               filesystem since it was mounted.
+
+ reserved_clusters            This is RW file and contains number of reserved
+                              clusters in the file system which will be used
+                              in the specific situations to avoid costly
+                              zeroout, unexpected ENOSPC, or possible data
+                              loss. The default is 2% or 4096 clusters,
+                              whichever is smaller and this can be changed
+                              however it can never exceed number of clusters
+                              in the file system. If there is not enough space
+                              for the reserved space when mounting the file
+                              mount will _not_ fail.
 ..............................................................................
 
 Ioctls
@@ -587,6 +598,16 @@ Table of Ext4 specific ioctls
                              bitmaps and inode table, the userspace tool thus
                              just passes the new number of blocks.
 
+EXT4_IOC_SWAP_BOOT           Swap i_blocks and associated attributes
+                             (like i_blocks, i_size, i_flags, ...) from
+                             the specified inode with inode
+                             EXT4_BOOT_LOADER_INO (#5). This is typically
+                             used to store a boot loader in a secure part of
+                             the filesystem, where it can't be changed by a
+                             normal user by accident.
+                             The data blocks of the previous boot loader
+                             will be associated with the given inode.
+
 ..............................................................................
 
 References