linux.git/fs/ext4/migrate.c, branch v2.6.32

ext4: Split uninitialized extents for direct I/O

2009-09-28T19:49:08+00:00

When writing into an unitialized extent via direct I/O, and the direct
I/O doesn't exactly cover the unitialized extent, split the extent
into uninitialized and initialized extents before submitting the I/O.
This avoids needing to deal with an ENOSPC error in the end_io
callback that gets used for direct I/O.

When the IO is complete, the written extent will be marked as initialized.

Singed-Off-By: Mingming Cao  
Signed-off-by: "Theodore Ts'o"

ext4: store EXT4_EXT_MIGRATE in i_state instead of i_flags

2009-09-17T12:32:22+00:00

EXT4_EXT_MIGRATE is only intended to be used for an in-memory flag,
and the hex value assigned to it collides with FS_DIRECTIO_FL (which
is also stored in i_flags).  There's no reason for the
EXT4_EXT_MIGRATE bit to be stored in i_flags, so we switch it to use
i_state instead.

Cc: "Aneesh Kumar K.V" 
Signed-off-by: "Theodore Ts'o"

ext4: Add missing unlock_new_inode() call in extent migration code

2009-08-26T02:36:05+00:00

We need to unlock the new inode before iput.  This patch fixes the
following warning when calling chattr +e to migrate a file to use
extents.  It also fixes problems in when e4defrag attempts to
defragment an inode.

[  470.400044] ------------[ cut here ]------------
[  470.400065] WARNING: at fs/inode.c:1210 generic_delete_inode+0x65/0x16a()
[  470.400072] Hardware name: N/A
.....
...
[  470.400353] Pid: 4451, comm: chattr Not tainted 2.6.31-rc7-red-debug #4
[  470.400359] Call Trace:
[  470.400372]  [] warn_slowpath_common+0x77/0x8f
[  470.400385]  [] warn_slowpath_null+0xf/0x11
[  470.400395]  [] generic_delete_inode+0x65/0x16a
[  470.400405]  [] generic_drop_inode+0x17/0x1bd
[  470.400413]  [] iput+0x61/0x65
[  470.400455]  [] ext4_ext_migrate+0x5eb/0x66a [ext4]
[  470.400492]  [] ext4_ioctl+0x340/0x756 [ext4]
[  470.400507]  [] vfs_ioctl+0x1d/0x82
[  470.400517]  [] do_vfs_ioctl+0x483/0x4c9
[  470.400527]  [] ? trace_hardirqs_on+0xd/0xf
[  470.400537]  [] sys_ioctl+0x51/0x74
[  470.400549]  [] system_call_fastpath+0x16/0x1b
[  470.400557] ---[ end trace ab85723542352dac ]---

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o"

ext4: teach the inode allocator to use a goal inode number

2009-06-13T15:45:35+00:00

Enhance the inode allocator to take a goal inode number as a
paremeter; if it is specified, it takes precedence over Orlov or
parent directory inode allocation algorithms.

The extents migration function uses the goal inode number so that the
extent trees allocated the migration function use the correct flex_bg.
In the future, the goal inode functionality will also be used to
allocate an adjacent inode for the extended attributes.

Also, for testing purposes the goal inode number can be specified via
/sys/fs/{dev}/inode_goal.  This can be useful for testing inode
allocation beyond 2^32 blocks on very large filesystems.

Signed-off-by: Andreas Dilger 
Signed-off-by: "Theodore Ts'o"

ext4: Use a hash of the topdir directory name for the Orlov parent group

2009-06-13T15:09:42+00:00

Instead of using a random number to determine the goal parent grop for
the Orlov top directories, use a hash of the directory name.  This
allows for repeatable results when trying to benchmark filesystem
layout algorithms.

Signed-off-by: "Theodore Ts'o"

ext4: Fix NULL dereference in ext4_ext_migrate()'s error handling

2009-02-16T01:02:19+00:00

This was found through a code checker (http://repo.or.cz/w/smatch.git/). 
It looks like you might be able to trigger the error by trying to migrate 
a readonly file system.

Signed-off-by: Dan Carpenter 
Signed-off-by: "Theodore Ts'o"

ext4: Remove "extents" mount option

2009-01-06T19:53:16+00:00

This mount option is largely superfluous, and in fact the way it was
implemented was buggy; if a filesystem which did not have the extents
feature flag was mounted -o extents, the filesystem would attempt to
create and use extents-based file even though the extents feature flag
was not eabled.  The simplest thing to do is to nuke the mount option
entirely.  It's not all that useful to force the non-creation of new
extent-based files if the filesystem can support it.

Signed-off-by: "Theodore Ts'o"

ext4: Allow ext4 to run without a journal

2009-01-07T05:06:22+00:00

A few weeks ago I posted a patch for discussion that allowed ext4 to run
without a journal.  Since that time I've integrated the excellent
comments from Andreas and fixed several serious bugs.  We're currently
running with this patch and generating some performance numbers against
both ext2 (with backported reservations code) and ext4 with and without
a journal.  It just so happens that running without a journal is
slightly faster for most everything.

We did
	iozone -T -t 4 s 2g -r 256k -T -I -i0 -i1 -i2

which creates 4 threads, each of which create and do reads and writes on
a 2G file, with a buffer size of 256K, using O_DIRECT for all file opens
to bypass the page cache.  Results:

                     ext2        ext4, default   ext4, no journal
  initial writes   13.0 MB/s        15.4 MB/s          15.7 MB/s
  rewrites         13.1 MB/s        15.6 MB/s          15.9 MB/s
  reads            15.2 MB/s        16.9 MB/s          17.2 MB/s
  re-reads         15.3 MB/s        16.9 MB/s          17.2 MB/s
  random readers    5.6 MB/s         5.6 MB/s           5.7 MB/s
  random writers    5.1 MB/s         5.3 MB/s           5.4 MB/s 

So it seems that, so far, this was a useful exercise.

Signed-off-by: Frank Mayhar 
Signed-off-by: "Theodore Ts'o"

ext4: elevate write count for migrate ioctl

2008-09-13T16:52:26+00:00

The migrate ioctl writes to the filsystem, so we need to elevate the
write count.

Signed-off-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o"

ext4: journal credits reservation fixes for extent file writepage

2008-08-20T02:16:05+00:00

This patch modified the writepage/write_begin credit calculation for
extent files, to use the credits caculation helper function.

The current calculation of how many index/leaf blocks should be
accounted is too conservetive, it always considered the worse case,
where the tree level is 5, and in the case of multiple chunk
allocations, it always assumed no blocks were dirtied in common across
the allocations. This path uses the accurate depth of the inode with
some extras to calculate the index blocks, and also less conservative in
the case of multiple allocation accounting.

Signed-off-by: Mingming Cao 
Reviewed-by: Aneesh Kumar K.V 
Signed-off-by: "Theodore Ts'o"