linux-toradex.git/fs/btrfs/ioctl.c, branch v3.0.9

Btrfs: protect the pending_snapshots list with trans_lock

2011-06-15T17:24:46+00:00

Currently there is nothing protecting the pending_snapshots list on the
transaction.  We only hold the directory mutex that we are snapshotting and a
read lock on the subvol_sem, so we could race with somebody else creating a
snapshot in a different directory and end up with list corruption.  So protect
this list with the trans_lock.  Thanks,

Signed-off-by: Josef Bacik

Btrfs: avoid stack bloat in btrfs_ioctl_fs_info()

2011-06-10T22:57:10+00:00

The size of struct btrfs_ioctl_fs_info_args is as big as 1KB, so
don't declare the variable on stack.

Signed-off-by: Li Zefan 
Reviewed-by: Josef Bacik 
Signed-off-by: Chris Mason

btrfs: use btrfs_ino to access inode number

2011-06-04T12:03:46+00:00

commit 4cb5300bc ("Btrfs: add mount -o auto_defrag") accesses inode
number directly while it should use the helper with the new inode
number allocator.

Signed-off-by: David Sterba 
Signed-off-by: Chris Mason

Merge branch 'for-chris' of

2011-05-28T11:00:39+00:00

git://git.kernel.org/pub/scm/linux/kernel/git/josef/btrfs-work into for-linus

Conflicts:
	fs/btrfs/disk-io.c
	fs/btrfs/extent-tree.c
	fs/btrfs/free-space-cache.c
	fs/btrfs/inode.c
	fs/btrfs/transaction.c

Signed-off-by: Chris Mason

Btrfs: add mount -o auto_defrag

2011-05-26T21:52:15+00:00

This will detect small random writes into files and
queue the up for an auto defrag process.  It isn't well suited to
database workloads yet, but works for smaller files such as rpm, sqlite
or bdb databases.

Signed-off-by: Chris Mason

Merge branch 'cleanups_and_fixes' into inode_numbers

2011-05-23T18:37:47+00:00

Conflicts:
	fs/btrfs/tree-log.c
	fs/btrfs/volumes.c

Signed-off-by: Chris Mason

Btrfs: using rcu lock in the reader side of devices list

2011-05-23T17:24:43+00:00

fs_devices->devices is only updated on remove and add device paths, so we can
use rcu to protect it in the reader side

Signed-off-by: Xiao Guangrong 
Signed-off-by: Chris Mason

btrfs: Ensure the tree search ioctl returns the right number of records

2011-05-23T17:05:39+00:00

Btrfs's tree search ioctl has a field to indicate that no more than a
given number of records should be returned. The ioctl doesn't honour
this, as the tested value is not incremented until the end of the
copy_to_sk function. This patch removes an unnecessary local variable,
and updates the num_found counter as each key is found in the tree.

Signed-off-by: Hugo Mills 
Signed-off-by: Chris Mason

Btrfs: kill BTRFS_I(inode)->block_group

2011-05-23T17:03:12+00:00

Originally this was going to be used as a way to give hints to the allocator,
but frankly we can get much better hints elsewhere and it's not even used at all
for anything usefull.  In addition to be completely useless, when we initialize
an inode we try and find a freeish block group to set as the inodes block group,
and with a completely full 40gb fs this takes _forever_, so I imagine with say
1tb fs this is just unbearable.  So just axe the thing altoghether, we don't
need it and it saves us 8 bytes in the inode and saves us 500 microseconds per
inode lookup in my testcase.  Thanks,

Signed-off-by: Josef Bacik

Btrfs: kill trans_mutex

2011-05-23T17:00:57+00:00

We use trans_mutex for lots of things, here's a basic list

1) To serialize trans_handles joining the currently running transaction
2) To make sure that no new trans handles are started while we are committing
3) To protect the dead_roots list and the transaction lists

Really the serializing trans_handles joining is not too hard, and can really get
bogged down in acquiring a reference to the transaction.  So replace the
trans_mutex with a trans_lock spinlock and use it to do the following

1) Protect fs_info->running_transaction.  All trans handles have to do is check
this, and then take a reference of the transaction and keep on going.
2) Protect the fs_info->trans_list.  This doesn't get used too much, basically
it just holds the current transactions, which will usually just be the currently
committing transaction and the currently running transaction at most.
3) Protect the dead roots list.  This is only ever processed by splicing the
list so this is relatively simple.
4) Protect the fs_info->reloc_ctl stuff.  This is very lightweight and was using
the trans_mutex before, so this is a pretty straightforward change.
5) Protect fs_info->no_trans_join.  Because we don't hold the trans_lock over
the entirety of the commit we need to have a way to block new people from
creating a new transaction while we're doing our work.  So we set no_trans_join
and in join_transaction we test to see if that is set, and if it is we do a
wait_on_commit.
6) Make the transaction use count atomic so we don't need to take locks to
modify it when we're dropping references.
7) Add a commit_lock to the transaction to make sure multiple people trying to
commit the same transaction don't race and commit at the same time.
8) Make open_ioctl_trans an atomic so we don't have to take any locks for ioctl
trans.

I have tested this with xfstests, but obviously it is a pretty hairy change so
lots of testing is greatly appreciated.  Thanks,

Signed-off-by: Josef Bacik