Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (33 commits)
  ext4: Regularize mount options
  ext4: fix locking typo in mballoc which could cause soft lockup hangs
  ext4: fix typo which causes a memory leak on error path
  jbd2: Update locking coments
  ext4: Rename pa_linear to pa_type
  ext4: add checks of block references for non-extent inodes
  ext4: Check for an valid i_mode when reading the inode from disk
  ext4: Use WRITE_SYNC for commits which are caused by fsync()
  ext4: Add auto_da_alloc mount option
  ext4: Use struct flex_groups to calculate get_orlov_stats()
  ext4: Use atomic_t's in struct flex_groups
  ext4: remove /proc tuning knobs
  ext4: Add sysfs support
  ext4: Track lifetime disk writes
  ext4: Fix discard of inode prealloc space with delayed allocation.
  ext4: Automatically allocate delay allocated blocks on rename
  ext4: Automatically allocate delay allocated blocks on close
  ext4: add EXT4_IOC_ALLOC_DA_BLKS ioctl
  ext4: Simplify delalloc code by removing mpage_da_writepages()
  ext4: Save stack space by removing fake buffer heads
  ...

1 files changed, 27 insertions, 3 deletions

diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index cec829bc7291..97882df04865 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -85,7 +85,7 @@ Note: More extensive information for getting started with ext4 can be
 * extent format more robust in face of on-disk corruption due to magics,
 * internal redundancy in tree
 * improved file allocation (multi-block alloc)
-* fix 32000 subdirectory limit
+* lift 32000 subdirectory limit imposed by i_links_count[1]
 * nsec timestamps for mtime, atime, ctime, create time
 * inode version field on disk (NFSv4, Lustre)
 * reduced e2fsck time via uninit_bg feature
@@ -100,6 +100,9 @@ Note: More extensive information for getting started with ext4 can be
 * efficent new ordered mode in JBD2 and ext4(avoid using buffer head to force
   the ordering)
 
+[1] Filesystems with a block size of 1k may see a limit imposed by the
+directory hash tree having a maximum depth of two.
+
 2.2 Candidate features for future inclusion
 
 * Online defrag (patches available but not well tested)
@@ -180,8 +183,8 @@ commit=nrsec	(*)	Ext4 can be told to sync all its data and metadata
                         performance.
 
 barrier=<0|1(*)>        This enables/disables the use of write barriers in
-                        the jbd code.  barrier=0 disables, barrier=1 enables.
-                        This also requires an IO stack which can support
+barrier(*)              the jbd code.  barrier=0 disables, barrier=1 enables.
+nobarrier               This also requires an IO stack which can support
                         barriers, and if jbd gets an error on a barrier
                         write, it will disable again with a warning.
                         Write barriers enforce proper on-disk ordering
@@ -189,6 +192,9 @@ barrier=<0|1(*)>	This enables/disables the use of write barriers in
                         safe to use, at some performance penalty.  If
                         your disks are battery-backed in one way or another,
                         disabling barriers may safely improve performance.
+                        The mount options "barrier" and "nobarrier" can
+                        also be used to enable or disable barriers, for
+                        consistency with other ext4 mount options.
 
 inode_readahead=n       This tuning parameter controls the maximum
                         number of inode table blocks that ext4's inode
@@ -310,6 +316,24 @@ journal_ioprio=prio	The I/O priority (from 0 to 7, where 0 is the
                         a slightly higher priority than the default I/O
                         priority.
 
+auto_da_alloc(*)        Many broken applications don't use fsync() when 
+noauto_da_alloc         replacing existing files via patterns such as
+                        fd = open("foo.new")/write(fd,..)/close(fd)/
+                        rename("foo.new", "foo"), or worse yet,
+                        fd = open("foo", O_TRUNC)/write(fd,..)/close(fd).
+                        If auto_da_alloc is enabled, ext4 will detect
+                        the replace-via-rename and replace-via-truncate
+                        patterns and force that any delayed allocation
+                        blocks are allocated such that at the next
+                        journal commit, in the default data=ordered
+                        mode, the data blocks of the new file are forced
+                        to disk before the rename() operation is
+                        commited.  This provides roughly the same level
+                        of guarantees as ext3, and avoids the
+                        "zero-length" problem that can happen when a
+                        system crashes before the delayed allocation
+                        blocks are forced to disk.
+
 Data Mode
 =========
 There are 3 different data modes: