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authorLinus Torvalds <torvalds@linux-foundation.org>2013-05-01 08:04:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-05-01 08:04:12 -0700
commit149b306089b88e186942a8d6647028ae6683aaf9 (patch)
tree1b7436034261947bae3efad41c55a91a8ef0f68d /Documentation/filesystems
parentb0ca4d0123608cfec73fc689c74295da89fc934e (diff)
parent0d606e2c9fccdd4e67febf1e2da500e1bfe9e045 (diff)
Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o: "Mostly performance and bug fixes, plus some cleanups. The one new feature this merge window is a new ioctl EXT4_IOC_SWAP_BOOT which allows installation of a hidden inode designed for boot loaders." * tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (50 commits) ext4: fix type-widening bug in inode table readahead code ext4: add check for inodes_count overflow in new resize ioctl ext4: fix Kconfig documentation for CONFIG_EXT4_DEBUG ext4: fix online resizing for ext3-compat file systems jbd2: trace when lock_buffer in do_get_write_access takes a long time ext4: mark metadata blocks using bh flags buffer: add BH_Prio and BH_Meta flags ext4: mark all metadata I/O with REQ_META ext4: fix readdir error in case inline_data+^dir_index. ext4: fix readdir error in the case of inline_data+dir_index jbd2: use kmem_cache_zalloc instead of kmem_cache_alloc/memset ext4: mext_insert_extents should update extent block checksum ext4: move quota initialization out of inode allocation transaction ext4: reserve xattr index for Rich ACL support jbd2: reduce journal_head size ext4: clear buffer_uninit flag when submitting IO ext4: use io_end for multiple bios ext4: make ext4_bio_write_page() use BH_Async_Write flags ext4: Use kstrtoul() instead of parse_strtoul() ext4: defragmentation code cleanup ...
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/ext4.txt21
1 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 34ea4f1fa6ea..f7cbf574a875 100644
--- 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.
+
..............................................................................
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