11 years agoBtrfs: force a page fault if we have a shorty copy on a page boundary
Josef Bacik [Fri, 30 Sep 2011 19:23:54 +0000 (15:23 -0400)]
Btrfs: force a page fault if we have a shorty copy on a page boundary

A user reported a problem where ceph was getting into 100% cpu usage while doing
some writing.  It turns out it's because we were doing a short write on a not
uptodate page, which means we'd fall back at one page at a time and fault the
page in.  The problem is our position is on the page boundary, so our fault in
logic wasn't actually reading the page, so we'd just spin forever or until the
page got read in by somebody else.  This will force a readpage if we end up
doing a short copy.  Alexandre could reproduce this easily with ceph and reports
it fixes his problem.  I also wrote a reproducer that no longer hangs my box
with this patch.  Thanks,

Reported-and-tested-by: Alexandre Oliva <>
Signed-off-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: reserve sufficient space for ioctl clone
Sage Weil [Tue, 20 Sep 2011 18:48:51 +0000 (14:48 -0400)]
Btrfs: reserve sufficient space for ioctl clone

Fix a crash/BUG_ON in the clone ioctl due to insufficient reservation. We
need to reserve space for:

 - adjusting the old extent (possibly splitting it)
 - adding the new extent
 - updating the inode

Signed-off-by: Sage Weil <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: don't change inode flag of the dest clone file
Li Zefan [Sun, 18 Sep 2011 14:20:46 +0000 (10:20 -0400)]
Btrfs: don't change inode flag of the dest clone file

The dst file will have the same inode flags with dst file after
file clone, and I think it's unexpected.

For example, the dst file will suddenly become immutable after
getting some share of data with src file, if the src is immutable.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: don't make a file partly checksummed through file clone
Li Zefan [Sun, 18 Sep 2011 14:20:46 +0000 (10:20 -0400)]
Btrfs: don't make a file partly checksummed through file clone

To reproduce the bug:

  # mount /dev/sda7 /mnt
  # dd if=/dev/zero of=/mnt/src bs=4K count=1
  # umount /mnt

  # mount -o nodatasum /dev/sda7 /mnt
  # dd if=/dev/zero of=/mnt/dst bs=4K count=1
  # clone_range -s 4K -l 4K /mnt/src /mnt/dst

  # echo 3 > /proc/sys/vm/drop_caches
  # cat /mnt/dst
  # dmesg
  btrfs no csum found for inode 258 start 0
  btrfs csum failed ino 258 off 0 csum 2566472073 private 0

It's because part of the file is checksummed and the other part is not,
and then btrfs will complain checksum is not found when we read the file.

Disallow file clone if src and dst file have different checksum flag,
so we ensure a file is completely checksummed or unchecksummed.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix pages truncation in btrfs_ioctl_clone()
Li Zefan [Sun, 18 Sep 2011 14:20:46 +0000 (10:20 -0400)]
Btrfs: fix pages truncation in btrfs_ioctl_clone()

It's a bug in commit f81c9cdc567cd3160ff9e64868d9a1a7ee226480
(Btrfs: truncate pages from clone ioctl target range)

We should pass the dest range to the truncate function, but not the
src range.

Also move the function before locking extent state.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agobtrfs: fix d_off in the first dirent
Hidetoshi Seto [Sun, 18 Sep 2011 14:20:46 +0000 (10:20 -0400)]
btrfs: fix d_off in the first dirent

Since the d_off in the first dirent for "." (that originates from
the 4th argument "offset" of filldir() for the 2nd dirent for "..")
is wrongly assigned in btrfs_real_readdir(), telldir returns same
offset for different locations.

 | # mkfs.btrfs /dev/sdb1
 | # mount /dev/sdb1 fs0
 | # cd fs0
 | # touch file0 file1
 | # ../test
 | telldir: 0
 | readdir: d_off = 2, d_name = "."
 | telldir: 2
 | readdir: d_off = 2, d_name = ".."
 | telldir: 2
 | readdir: d_off = 3, d_name = "file0"
 | telldir: 3
 | readdir: d_off = 2147483647, d_name = "file1"
 | telldir: 2147483647

To fix this problem, pass filp->f_pos (which is loff_t) instead.

 | # ../test
 | telldir: 0
 | readdir: d_off = 1, d_name = "."
 | telldir: 1
 | readdir: d_off = 2, d_name = ".."
 | telldir: 2
 | readdir: d_off = 3, d_name = "file0"

At the moment the "offset" for "." is unused because there is no
preceding dirent, however it is better to pass filp->f_pos to follow
grammatical usage.

Signed-off-by: Hidetoshi Seto <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: add dummy extent if dst offset excceeds file end in
Li Zefan [Sun, 11 Sep 2011 14:52:25 +0000 (10:52 -0400)]
Btrfs: add dummy extent if dst offset excceeds file end in

You can see there's no file extent with range [0, 4096]. Check this by

 # btrfsck /dev/sda7
 root 5 inode 258 errors 100

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: calc file extent num_bytes correctly in file clone
Li Zefan [Sun, 11 Sep 2011 14:52:25 +0000 (10:52 -0400)]
Btrfs: calc file extent num_bytes correctly in file clone

num_bytes should be 4096 not 12288.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agobtrfs: xattr: fix attribute removal
David Sterba [Sun, 11 Sep 2011 14:52:25 +0000 (10:52 -0400)]
btrfs: xattr: fix attribute removal

An attribute is not removed by 'setfattr -x attr file' and remains
visible in attr list. This makes xfstests/062 pass again.

Signed-off-by: David Sterba <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix wrong nbytes information of the inode
Miao Xie [Sun, 11 Sep 2011 14:52:25 +0000 (10:52 -0400)]
Btrfs: fix wrong nbytes information of the inode

If we write some data into the data hole of the file(no preallocation for this
hole), Btrfs will allocate some disk space, and update nbytes of the inode, but
the other element--disk_i_size needn't be updated. At this condition, we must
update inode metadata though disk_i_size is not changed(btrfs_ordered_update_i_size()
return 1).

 # mkfs.btrfs /dev/sdb1
 # mount /dev/sdb1 /mnt
 # touch /mnt/a
 # truncate -s 856002 /mnt/a
 # dd if=/dev/zero of=/mnt/a bs=4K count=1 conv=nocreat,notrunc
 # umount /mnt
 # btrfsck /dev/sdb1
 root 5 inode 257 errors 400
 found 32768 bytes used err is 1

Signed-off-by: Miao Xie <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix the file extent gap when doing direct IO
Miao Xie [Sun, 11 Sep 2011 14:52:24 +0000 (10:52 -0400)]
Btrfs: fix the file extent gap when doing direct IO

When we write some data to the place that is beyond the end of the file
in direct I/O mode, a data hole will be created. And Btrfs should insert
a file extent item that point to this hole into the fs tree. But unfortunately
Btrfs forgets doing it.

The following is a simple way to reproduce it:
 # mkfs.btrfs /dev/sdc2
 # mount /dev/sdc2 /test4
 # touch /test4/a
 # dd if=/dev/zero of=/test4/a seek=8 count=1 bs=4K oflag=direct conv=nocreat,notrunc
 # umount /test4
 # btrfsck /dev/sdc2
 root 5 inode 257 errors 100

Reported-by: Tsutomu Itoh <>
Signed-off-by: Miao Xie <>
Tested-by: Tsutomu Itoh <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix unclosed transaction handle in btrfs_cont_expand
Miao Xie [Sun, 11 Sep 2011 14:52:24 +0000 (10:52 -0400)]
Btrfs: fix unclosed transaction handle in btrfs_cont_expand

The function - btrfs_cont_expand() forgot to close the transaction handle before
it jump out the while loop. Fix it.

Signed-off-by: Miao Xie <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix misuse of trans block rsv
Liu Bo [Sun, 11 Sep 2011 14:52:24 +0000 (10:52 -0400)]
Btrfs: fix misuse of trans block rsv

At the beginning of create_pending_snapshot, trans->block_rsv is set
to pending->block_rsv and is used for snapshot things, however, when
it is done, we do not recover it as will.

Signed-off-by: Liu Bo <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: reset to appropriate block rsv after orphan operations
Liu Bo [Sun, 11 Sep 2011 14:52:24 +0000 (10:52 -0400)]
Btrfs: reset to appropriate block rsv after orphan operations

While truncating free space cache, we forget to change trans->block_rsv
back to the original one, but leave it with the orphan_block_rsv, and
then with option inode_cache enable, it leads to countless warnings of
btrfs_alloc_free_block and btrfs_orphan_commit_root:

WARNING: at fs/btrfs/extent-tree.c:5711 btrfs_alloc_free_block+0x180/0x350 [btrfs]()
WARNING: at fs/btrfs/inode.c:2193 btrfs_orphan_commit_root+0xb0/0xc0 [btrfs]()

Signed-off-by: Liu Bo <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: skip locking if searching the commit root in csum lookup
Josef Bacik [Sun, 11 Sep 2011 14:52:24 +0000 (10:52 -0400)]
Btrfs: skip locking if searching the commit root in csum lookup

It's not enough to just search the commit root, since we could be cow'ing the
very block we need to search through, which would mean that its locked and we'll
still deadlock.  So use path->skip_locking as well.  Thanks,

Signed-off-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agobtrfs: fix warning in iput for bad-inode
Sergei Trofimovich [Sun, 11 Sep 2011 14:52:24 +0000 (10:52 -0400)]
btrfs: fix warning in iput for bad-inode

iput() shouldn't be called for inodes in I_NEW state.
We need to mark inode as constructed first.

WARNING: at fs/inode.c:1309 iput+0x20b/0x210()
Call Trace:
 [<ffffffff8103e7ba>] warn_slowpath_common+0x7a/0xb0
 [<ffffffff8103e805>] warn_slowpath_null+0x15/0x20
 [<ffffffff810eaf0b>] iput+0x20b/0x210
 [<ffffffff811b96fb>] btrfs_iget+0x1eb/0x4a0
 [<ffffffff811c3ad6>] btrfs_run_defrag_inodes+0x136/0x210
 [<ffffffff811ad55f>] cleaner_kthread+0x17f/0x1a0
 [<ffffffff81035b7d>] ? sub_preempt_count+0x9d/0xd0
 [<ffffffff811ad3e0>] ? transaction_kthread+0x280/0x280
 [<ffffffff8105af86>] kthread+0x96/0xa0
 [<ffffffff814336d4>] kernel_thread_helper+0x4/0x10
 [<ffffffff8105aef0>] ? kthread_worker_fn+0x190/0x190
 [<ffffffff814336d0>] ? gs_change+0xb/0xb

Signed-off-by: Sergei Trofimovich <>
CC: Konstantin Khlebnikov <>
Tested-by: David Sterba <>
CC: Josef Bacik <>
CC: Chris Mason <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix an oops when deleting snapshots
Liu Bo [Sun, 11 Sep 2011 14:52:24 +0000 (10:52 -0400)]
Btrfs: fix an oops when deleting snapshots

We can reproduce this oops via the following steps:

$ mkfs.btrfs /dev/sdb7
$ mount /dev/sdb7 /mnt/btrfs
$ for ((i=0; i<3; i++)); do btrfs sub snap /mnt/btrfs /mnt/btrfs/s_$i; done
$ rm -fr /mnt/btrfs/*
$ rm -fr /mnt/btrfs/*

then we'll get
------------[ cut here ]------------
kernel BUG at fs/btrfs/inode.c:2264!
Call Trace:
 [<ffffffffa05578c7>] btrfs_rmdir+0xf7/0x1b0 [btrfs]
 [<ffffffff81150b95>] vfs_rmdir+0xa5/0xf0
 [<ffffffff81153cc3>] do_rmdir+0x123/0x140
 [<ffffffff81145ac7>] ? fput+0x197/0x260
 [<ffffffff810aecff>] ? audit_syscall_entry+0x1bf/0x1f0
 [<ffffffff81153d0d>] sys_unlinkat+0x2d/0x40
 [<ffffffff8147896b>] system_call_fastpath+0x16/0x1b
RIP  [<ffffffffa054f7b9>] btrfs_orphan_add+0x179/0x1a0 [btrfs]

When it comes to btrfs_lookup_dentry, we may set a snapshot's inode->i_ino
while the snapshot's location.objectid remains unchanged.

However, btrfs_ino() does not take this into account, and returns a wrong ino,
and causes the oops.

Signed-off-by: Liu Bo <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: set i_size properly when fallocating and we already
Josef Bacik [Thu, 18 Aug 2011 14:36:39 +0000 (10:36 -0400)]
Btrfs: set i_size properly when fallocating and we already

xfstests exposed a problem with preallocate when it fallocates a range that
already has an extent.  We don't set the new i_size properly because we see that
we already have an extent.  This isn't right and we should update i_size if the
space already exists.  With this patch we now pass xfstests 075.  Thanks,

Signed-off-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: truncate pages from clone ioctl target range
Sage Weil [Wed, 10 Aug 2011 18:04:04 +0000 (18:04 +0000)]
Btrfs: truncate pages from clone ioctl target range

We need to truncate page cache pages for the clone ioctl target range or
else we'll confuse ourselves to no end.  If the old data was cached, we
used to still see it (until remount).  If the page was partially updated
we used to get a mix of old and new data.

Signed-off-by: Sage Weil <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix uninitialized sync_pending
Miao Xie [Fri, 5 Aug 2011 09:32:37 +0000 (09:32 +0000)]
Btrfs: fix uninitialized sync_pending

sync_pending is uninitialized before it be used, fix it.

Signed-off-by: Miao Xie <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix wrong free space information
Miao Xie [Fri, 5 Aug 2011 09:32:35 +0000 (09:32 +0000)]
Btrfs: fix wrong free space information

Btrfs subtracted the size of the allocated space twice when it allocated
the space from the bitmap in the cluster, it broke the free space information
and led to oops finally.

And this patch also fixes the bug that ctl->free_space was subtracted
without lock.

Reported-by: Liu Bo <>
Signed-off-by: Miao Xie <>
Signed-off-by: Chris Mason <>
11 years agobtrfs: memory leak in btrfs_add_inode_defrag()
Dan Carpenter [Fri, 5 Aug 2011 14:19:00 +0000 (14:19 +0000)]
btrfs: memory leak in btrfs_add_inode_defrag()

We don't use the defrag struct on this path.

Signed-off-by: Dan Carpenter <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: use plain page_address() in header fields setget functions
Li Zefan [Wed, 3 Aug 2011 08:11:41 +0000 (08:11 +0000)]
Btrfs: use plain page_address() in header fields setget functions

We've stopped using highmem for extent buffers.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: forced readonly when btrfs_drop_snapshot() fails
Tsutomu Itoh [Tue, 9 Aug 2011 07:11:13 +0000 (07:11 +0000)]
Btrfs: forced readonly when btrfs_drop_snapshot() fails

The filesystem turns readonly instead of returning the error to the
caller when detected error in btrfs_drop_snapshot().
and, because the caller doesn't check the error, the function type is
changed to 'void'.

Signed-off-by: Tsutomu Itoh <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: check if there is enough space for balancing smarter
liubo [Wed, 3 Aug 2011 10:15:25 +0000 (10:15 +0000)]
Btrfs: check if there is enough space for balancing smarter

When checking if there is enough space for balancing a block group,
since we do not take raid types into consideration, we do not account
corrent amounts of space that we needed.  This makes us do some extra
work before we get ENOSPC.

Signed-off-by: Liu Bo <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix a bug of balance on full multi-disk partitions
liubo [Tue, 2 Aug 2011 02:39:03 +0000 (02:39 +0000)]
Btrfs: fix a bug of balance on full multi-disk partitions

When balancing, we'll first try to shrink devices for some space,
but if it is working on a full multi-disk partition with raid protection,
we may encounter a bug, that is, while shrinking, total_bytes may be less
than bytes_used, and btrfs may allocate a dev extent that accesses out of
device's bounds.

Then we will not be able to write or read the data which stores at the end
of the device, and get the followings:

device fsid 0939f071-7ea3-46c8-95df-f176d773bfb6 devid 1 transid 10 /dev/sdb5
Btrfs detected SSD devices, enabling SSD mode
btrfs: relocating block group 476315648 flags 9
btrfs: found 4 extents
attempt to access beyond end of device
sdb5: rw=145, want=546176, limit=546147
attempt to access beyond end of device
sdb5: rw=145, want=546304, limit=546147
attempt to access beyond end of device
sdb5: rw=145, want=546432, limit=546147
attempt to access beyond end of device
sdb5: rw=145, want=546560, limit=546147
attempt to access beyond end of device

Signed-off-by: Liu Bo <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix an oops of log replay
liubo [Sat, 6 Aug 2011 08:35:23 +0000 (08:35 +0000)]
Btrfs: fix an oops of log replay

When btrfs recovers from a crash, it may hit the oops below:

------------[ cut here ]------------
kernel BUG at fs/btrfs/inode.c:4580!
RIP: 0010:[<ffffffffa03df251>]  [<ffffffffa03df251>] btrfs_add_link+0x161/0x1c0 [btrfs]
Call Trace:
 [<ffffffffa03e7b31>] ? btrfs_inode_ref_index+0x31/0x80 [btrfs]
 [<ffffffffa04054e9>] add_inode_ref+0x319/0x3f0 [btrfs]
 [<ffffffffa0407087>] replay_one_buffer+0x2c7/0x390 [btrfs]
 [<ffffffffa040444a>] walk_down_log_tree+0x32a/0x480 [btrfs]
 [<ffffffffa0404695>] walk_log_tree+0xf5/0x240 [btrfs]
 [<ffffffffa0406cc0>] btrfs_recover_log_trees+0x250/0x350 [btrfs]
 [<ffffffffa0406dc0>] ? btrfs_recover_log_trees+0x350/0x350 [btrfs]
 [<ffffffffa03d18b2>] open_ctree+0x1442/0x17d0 [btrfs]

This comes from that while replaying an inode ref item, we forget to
check those old conflicting DIR_ITEM and DIR_INDEX items in fs/file tree,
then we will come to conflict corners which lead to BUG_ON().

Signed-off-by: Liu Bo <>
Tested-by: Andy Lutomirski <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: detect wether a device supports discard
Josef Bacik [Thu, 4 Aug 2011 14:52:27 +0000 (14:52 +0000)]
Btrfs: detect wether a device supports discard

We have a problem where if a user specifies discard but doesn't actually support
it we will return EOPNOTSUPP from btrfs_discard_extent.  This is a problem
because this gets called (in a fashion) from the tree log recovery code, which
has a nice little BUG_ON(ret) after it, which causes us to fail the tree log
replay.  So instead detect wether our devices support discard when we're adding
them and then don't issue discards if we know that the device doesn't support
it.  And just for good measure set ret = 0 in btrfs_issue_discard just in case
we still get EOPNOTSUPP so we don't screw anybody up like this again.  Thanks,

Signed-off-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: force unplugs when switching from high to regular priority bios
Chris Mason [Thu, 4 Aug 2011 18:28:36 +0000 (14:28 -0400)]
Btrfs: force unplugs when switching from high to regular priority bios

Btrfs does bio submissions from a worker thread, and each device
has a list of high priority bios and regular priority bios.

Synchronous writes go to the high priority thread while async writes
go to regular list.  This commit brings back an explicit unplug
any time we switch from high to regular priority, which makes it
easier for the block layer to give us low latencies.

Signed-off-by: Chris Mason <>
11 years agoBtrfs: don't call writepages from within write_full_page
Josef Bacik [Mon, 1 Aug 2011 18:37:36 +0000 (14:37 -0400)]
Btrfs: don't call writepages from within write_full_page

When doing a writepage we call writepages to try and write out any other dirty
pages in the area.  This could cause problems where we commit a transaction and
then have somebody else dirtying metadata in the area as we could end up writing
out a lot more than we care about, which could cause latency on anybody who is
waiting for the transaction to completely finish committing.  Thanks,

Signed-off-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: Remove unused variable 'last_index' in file.c
Mitch Harder [Tue, 12 Jul 2011 19:43:45 +0000 (19:43 +0000)]
Btrfs: Remove unused variable 'last_index' in file.c

The variable 'last_index' is calculated in the __btrfs_buffered_write
function and passed as a parameter to the prepare_pages function,
but is not used anywhere in the prepare_pages function.

Remove instances of 'last_index' in these functions.

Signed-off-by: Mitch Harder <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: clean up for find_first_extent_bit()
Xiao Guangrong [Thu, 14 Jul 2011 03:19:45 +0000 (03:19 +0000)]
Btrfs: clean up for find_first_extent_bit()

find_first_extent_bit() and find_first_extent_bit_state() share
most of the code, and we can just make the former call the latter.

Signed-off-by: Xiao Guangrong <>
Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: clean up for wait_extent_bit()
Xiao Guangrong [Thu, 14 Jul 2011 03:19:27 +0000 (03:19 +0000)]
Btrfs: clean up for wait_extent_bit()

We can just use cond_resched_lock().

Signed-off-by: Xiao Guangrong <>
Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: clean up for insert_state()
Xiao Guangrong [Thu, 14 Jul 2011 03:19:08 +0000 (03:19 +0000)]
Btrfs: clean up for insert_state()

Don't duplicate set_state_bits().

Signed-off-by: Xiao Guangrong <>
Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: remove unused members from struct extent_state
Xiao Guangrong [Thu, 14 Jul 2011 03:18:52 +0000 (03:18 +0000)]
Btrfs: remove unused members from struct extent_state

These members are not used at all.

Signed-off-by: Xiao Guangrong <>
Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: clean up code for merging extent maps
Li Zefan [Thu, 14 Jul 2011 03:18:33 +0000 (03:18 +0000)]
Btrfs: clean up code for merging extent maps

unpin_extent_cache() and add_extent_mapping() shares the same code
that merges extent maps.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: clean up code for extent_map lookup
Li Zefan [Thu, 14 Jul 2011 03:18:15 +0000 (03:18 +0000)]
Btrfs: clean up code for extent_map lookup

lookup_extent_map() and search_extent_map() can share most of code.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: clean up search_extent_mapping()
Li Zefan [Thu, 14 Jul 2011 03:18:03 +0000 (03:18 +0000)]
Btrfs: clean up search_extent_mapping()

rb_node returned by __tree_search() can be a valid pointer or NULL,
but won't be some errno.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: remove redundant code for dir item lookup
Li Zefan [Thu, 14 Jul 2011 03:17:52 +0000 (03:17 +0000)]
Btrfs: remove redundant code for dir item lookup

When we search a dir item with a specific hash code, we can
just return NULL without further checking if btrfs_search_slot()
returns 1.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: make acl functions really no-op if acl is not enabled
Li Zefan [Thu, 14 Jul 2011 03:17:39 +0000 (03:17 +0000)]
Btrfs: make acl functions really no-op if acl is not enabled

So there's no overhead for something we don't use.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: remove remaining ref-cache code
Li Zefan [Thu, 14 Jul 2011 03:17:27 +0000 (03:17 +0000)]
Btrfs: remove remaining ref-cache code

Since commit f2a97a9dbd86eb1ef956bdf20e05c507b32beb96
("btrfs: remove all unused functions"), there's no extern functions
at all in ref-cache.c, so just remove the remaining dead code.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: remove a BUG_ON() in btrfs_commit_transaction()
Li Zefan [Thu, 14 Jul 2011 03:17:14 +0000 (03:17 +0000)]
Btrfs: remove a BUG_ON() in btrfs_commit_transaction()

wait_for_commit() always returns 0.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: use wait_event()
Li Zefan [Thu, 14 Jul 2011 03:17:00 +0000 (03:17 +0000)]
Btrfs: use wait_event()

Use wait_event() when possible to avoid code duplication.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: check the nodatasum flag when writing compressed files
Li Zefan [Thu, 14 Jul 2011 03:16:47 +0000 (03:16 +0000)]
Btrfs: check the nodatasum flag when writing compressed files

If mounting with nodatasum option, we won't csum file data for
general write or direct-io write, and this rule should also be
applied when writing compressed files.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: copy string correctly in INO_LOOKUP ioctl
Li Zefan [Thu, 14 Jul 2011 03:16:00 +0000 (03:16 +0000)]
Btrfs: copy string correctly in INO_LOOKUP ioctl

Memory areas [ptr, ptr+total_len] and [name, name+total_len]
may overlap, so it's wrong to use memcpy().

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: don't print the leaf if we had an error
Josef Bacik [Wed, 13 Jul 2011 15:03:50 +0000 (15:03 +0000)]
Btrfs: don't print the leaf if we had an error

In __btrfs_free_extent we will print the leaf if we fail to find the extent we
wanted, but the problem is if we get an error we won't have a leaf so often this
leads to a NULL pointer dereference and we lose the error that actually
occurred.  So only print the leaf if ret > 0, which means we didn't find the
item we were looking for but we didn't error either.  This way the error is

Signed-off-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agobtrfs: make btrfs_set_root_node void
Mark Fasheh [Thu, 14 Jul 2011 21:23:06 +0000 (21:23 +0000)]
btrfs: make btrfs_set_root_node void

This is fairly trivial - btrfs_set_root_node() - always returns zero so we
can just make it void.  All callers ignore the return code now anyway.  I
also made sure to check that none of the functions that
btrfs_set_root_node() calls returns an error that we might have needed to
catch and pass back.

Signed-off-by: Mark Fasheh <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix oops while writing data to SSD partitions
liubo [Wed, 27 Jul 2011 09:49:18 +0000 (09:49 +0000)]
Btrfs: fix oops while writing data to SSD partitions

Here I have a two SSD-partitions btrfs, and they are defaultly set to
"data=raid0, metadata=raid1", then I try to fill my btrfs partition
till "No space left on device", via "dd if=/dev/zero of=/mnt/btrfs/tmp".

I get an oops panic from kernel BUG at fs/btrfs/extent-tree.c:5199!, which
refers to find_free_extent's
BUG_ON(index != get_block_group_index(block_group));

In SSD mode, in order to find enough space to alloc, we may check the
block_group cache which has been checked sometime before, but the index is not
updated, where it hits the BUG_ON.

Signed-off-by: Liu Bo <>
Acked-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: Protect the readonly flag of block group
WuBo [Tue, 26 Jul 2011 03:30:11 +0000 (03:30 +0000)]
Btrfs: Protect the readonly flag of block group

The access for ro in btrfs_block_group_cache should be protected
because of the racy lock in relocation.

Signed-off-by: Wu Bo <>
Signed-off-by: Chris Mason <>
11 years agobtrfs: Make extent-io callbacks that never fail return void
Jeff Mahoney [Thu, 21 Jul 2011 16:56:09 +0000 (16:56 +0000)]
btrfs: Make extent-io callbacks that never fail return void

The set/clear bit and the extent split/merge hooks only ever return 0.

 Changing them to return void simplifies the error handling cases later.

 This patch changes the hook prototypes, the single implementation of each,
 and the functions that call them to return void instead.

 Since all four of these hooks execute under a spinlock, they're necessarily

Signed-off-by: Jeff Mahoney <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix readahead in file defrag
Li Zefan [Wed, 20 Jul 2011 03:46:35 +0000 (03:46 +0000)]
Btrfs: fix readahead in file defrag

We passed the wrong value to btrfs_force_ra(). Fix this by changing
the argument of btrfs_force_ra() from last_index to nr_page.

Signed-off-by: Li Zefan <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: return error to caller when btrfs_unlink() failes
Tsutomu Itoh [Tue, 19 Jul 2011 07:27:20 +0000 (07:27 +0000)]
Btrfs: return error to caller when btrfs_unlink() failes

When btrfs_unlink_inode() and btrfs_orphan_add() in btrfs_unlink()
are error, the error code is returned to the caller instead of

Signed-off-by: Tsutomu Itoh <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs:don't check the return value of __btrfs_add_inode_defrag
Wanlong Gao [Mon, 18 Jul 2011 12:19:35 +0000 (12:19 +0000)]
Btrfs:don't check the return value of __btrfs_add_inode_defrag

Don't need to check the return value of __btrfs_add_inode_defrag(),
since it will always return 0.

Signed-off-by: Wanlong Gao <>
Signed-off-by: Chris Mason <>
11 years agoMerge branch 'alloc_path' of git://
Chris Mason [Mon, 1 Aug 2011 18:27:34 +0000 (14:27 -0400)]
Merge branch 'alloc_path' of git://git./linux/kernel/git/mfasheh/btrfs-error-handling into for-linus

11 years agoMerge branch 'integration' into for-linus
Chris Mason [Wed, 27 Jul 2011 20:13:10 +0000 (16:13 -0400)]
Merge branch 'integration' into for-linus

11 years agoBtrfs: make sure reserve_metadata_bytes doesn't leak out strange errors
Chris Mason [Wed, 27 Jul 2011 19:57:44 +0000 (15:57 -0400)]
Btrfs: make sure reserve_metadata_bytes doesn't leak out strange errors

The btrfs transaction code will return any errors that come from
reserve_metadata_bytes.  We need to make sure we don't return funny
things like 1 or EAGAIN.

Signed-off-by: Chris Mason <>
11 years agoBtrfs: use the commit_root for reading free_space_inode crcs
Chris Mason [Tue, 26 Jul 2011 19:35:09 +0000 (15:35 -0400)]
Btrfs: use the commit_root for reading free_space_inode crcs

Now that we are using regular file crcs for the free space cache,
we can deadlock if we try to read the free_space_inode while we are
updating the crc tree.

This commit fixes things by using the commit_root to read the crcs.  This is
safe because we the free space cache file would already be loaded if
that block group had been changed in the current transaction.

Signed-off-by: Chris Mason <>
11 years agoBtrfs: reduce extent_state lock contention for metadata
Chris Mason [Mon, 25 Jul 2011 10:50:50 +0000 (06:50 -0400)]
Btrfs: reduce extent_state lock contention for metadata

For metadata buffers that don't straddle pages (all of them), btrfs
can safely use the page uptodate bits and extent_buffer uptodate bit
instead of needing to use the extent_state tree.

This greatly reduces contention on the state tree lock.

Signed-off-by: Chris Mason <>
11 years agoBtrfs: remove lockdep magic from btrfs_next_leaf
Chris Mason [Tue, 26 Jul 2011 20:01:59 +0000 (16:01 -0400)]
Btrfs: remove lockdep magic from btrfs_next_leaf

Before the reader/writer locks, btrfs_next_leaf needed to keep
the path blocking to avoid making lockdep upset.

Now that btrfs_next_leaf only takes read locks, this isn't required.

Signed-off-by: Chris Mason <>
11 years agoBtrfs: make a lockdep class for each root
Chris Mason [Tue, 26 Jul 2011 20:11:19 +0000 (16:11 -0400)]
Btrfs: make a lockdep class for each root

This patch was originally from Tejun Heo.  lockdep complains about the btrfs
locking because we sometimes take btree locks from two different trees at the
same time.  The current classes are based only on level in the btree, which
isn't enough information for lockdep to figure out if the lock is safe.

This patch makes a class for each type of tree, and lumps all the FS trees that
actually have files and directories into the same class.

Signed-off-by: Chris Mason <>
11 years agoBtrfs: switch the btrfs tree locks to reader/writer
Chris Mason [Sat, 16 Jul 2011 19:23:14 +0000 (15:23 -0400)]
Btrfs: switch the btrfs tree locks to reader/writer

The btrfs metadata btree is the source of significant
lock contention, especially in the root node.   This
commit changes our locking to use a reader/writer

The lock is built on top of rw spinlocks, and it
extends the lock tracking to remember if we have a
read lock or a write lock when we go to blocking.  Atomics
count the number of blocking readers or writers at any
given time.

It removes all of the adaptive spinning from the old code
and uses only the spinning/blocking hints inside of btrfs
to decide when it should continue spinning.

In read heavy workloads this is dramatically faster.  In write
heavy workloads we're still faster because of less contention
on the root node lock.

We suffer slightly in dbench because we schedule more often
during write locks, but all other benchmarks so far are improved.

Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix deadlock when throttling transactions
Josef Bacik [Sun, 24 Jul 2011 19:45:34 +0000 (15:45 -0400)]
Btrfs: fix deadlock when throttling transactions

Hit this nice little deadlock.  What happens is this

__btrfs_end_transaction with throttle set, --use_count so it equals 0
    <somebody else actually manages to start the commit>
    btrfs_end_transaction --use_count so now its -1 <== BAD
      we just return and wait on the transaction

This is bad because we just return after our use_count is -1 and don't let go
of our num_writer count on the transaction, so the guy committing the
transaction just sits there forever.  Fix this by inc'ing our use_count if we're
going to call commit_transaction so that if we call btrfs_end_transaction it's
valid.  Thanks,

Signed-off-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: stop using highmem for extent_buffers
Chris Mason [Tue, 19 Jul 2011 16:04:14 +0000 (12:04 -0400)]
Btrfs: stop using highmem for extent_buffers

The extent_buffers have a very complex interface where
we use HIGHMEM for metadata and try to cache a kmap mapping
to access the memory.

The next commit adds reader/writer locks, and concurrent use
of this kmap cache would make it even more complex.

This commit drops the ability to use HIGHMEM with extent buffers,
and rips out all of the related code.

Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix BUG_ON() caused by ENOSPC when relocating space
Miao Xie [Fri, 15 Jul 2011 10:34:36 +0000 (10:34 +0000)]
Btrfs: fix BUG_ON() caused by ENOSPC when relocating space

When we balanced the chunks across the devices, BUG_ON() in
__finish_chunk_alloc() was triggered.

------------[ cut here ]------------
kernel BUG at fs/btrfs/volumes.c:2568!
Call Trace:
 [<ffffffffa049525e>] btrfs_alloc_chunk+0x8e/0xa0 [btrfs]
 [<ffffffffa04546b0>] do_chunk_alloc+0x330/0x3a0 [btrfs]
 [<ffffffffa045c654>] btrfs_reserve_extent+0xb4/0x1f0 [btrfs]
 [<ffffffffa045c86b>] btrfs_alloc_free_block+0xdb/0x350 [btrfs]
 [<ffffffffa048a8d8>] ? read_extent_buffer+0xd8/0x1d0 [btrfs]
 [<ffffffffa04476fd>] __btrfs_cow_block+0x14d/0x5e0 [btrfs]
 [<ffffffffa044660d>] ? read_block_for_search+0x14d/0x4d0 [btrfs]
 [<ffffffffa0447c9b>] btrfs_cow_block+0x10b/0x240 [btrfs]
 [<ffffffffa044dd5e>] btrfs_search_slot+0x49e/0x7a0 [btrfs]
 [<ffffffffa044f07d>] btrfs_insert_empty_items+0x8d/0xf0 [btrfs]
 [<ffffffffa045e973>] insert_with_overflow+0x43/0x110 [btrfs]
 [<ffffffffa045eb0d>] btrfs_insert_dir_item+0xcd/0x1f0 [btrfs]
 [<ffffffffa0489bd0>] ? map_extent_buffer+0xb0/0xc0 [btrfs]
 [<ffffffff812276ad>] ? rb_insert_color+0x9d/0x160
 [<ffffffffa046cc40>] ? inode_tree_add+0xf0/0x150 [btrfs]
 [<ffffffffa0474801>] btrfs_add_link+0xc1/0x1c0 [btrfs]
 [<ffffffff811dacac>] ? security_inode_init_security+0x1c/0x30
 [<ffffffffa04a28aa>] ? btrfs_init_acl+0x4a/0x180 [btrfs]
 [<ffffffffa047492f>] btrfs_add_nondir+0x2f/0x70 [btrfs]
 [<ffffffffa046af16>] ? btrfs_init_inode_security+0x46/0x60 [btrfs]
 [<ffffffffa0474ac0>] btrfs_create+0x150/0x1d0 [btrfs]
 [<ffffffff81159c63>] ? generic_permission+0x23/0xb0
 [<ffffffff8115b415>] vfs_create+0xa5/0xc0
 [<ffffffff8115ce6e>] do_last+0x5fe/0x880
 [<ffffffff8115dc0d>] path_openat+0xcd/0x3d0
 [<ffffffff8115e029>] do_filp_open+0x49/0xa0
 [<ffffffff8116a965>] ? alloc_fd+0x95/0x160
 [<ffffffff8114f0c7>] do_sys_open+0x107/0x1e0
 [<ffffffff810bcc3f>] ? audit_syscall_entry+0x1bf/0x1f0
 [<ffffffff8114f1e0>] sys_open+0x20/0x30
 [<ffffffff81484ec2>] system_call_fastpath+0x16/0x1b
RIP  [<ffffffffa049444a>] __finish_chunk_alloc+0x20a/0x220 [btrfs]

The reason is:
Task1 Space balance task
    update device info
    in the chunk tree
      alloc system metadata block
relocate system metadata block group
  set system metadata block group
  readonly, This block group is the
  only one that can allocate space. So
  there is no free space that can be
  allocated now.
        find no space and don't try
        to alloc new chunk, and then
        return ENOSPC
  BUG_ON() in __finish_chunk_alloc()
  was triggered.

Fix this bug by allocating a new system metadata chunk before relocating the
old one if we find there is no free space which can be allocated after setting
the old block group to be read-only.

Reported-by: Tsutomu Itoh <>
Signed-off-by: Miao Xie <>
Tested-by: Tsutomu Itoh <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: tag pages for writeback in sync
Josef Bacik [Fri, 15 Jul 2011 21:26:38 +0000 (21:26 +0000)]
Btrfs: tag pages for writeback in sync

Everybody else does this, we need to do it too.  If we're syncing, we need to
tag the pages we're going to write for writeback so we don't end up writing the
same stuff over and over again if somebody is constantly redirtying our file.
This will keep us from having latencies with heavy sync workloads.  Thanks,

Signed-off-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: fix enospc problems with delalloc
Josef Bacik [Fri, 15 Jul 2011 15:16:44 +0000 (15:16 +0000)]
Btrfs: fix enospc problems with delalloc

So I had this brilliant idea to use atomic counters for outstanding and reserved
extents, but this turned out to be a bad idea.  Consider this where we have 1
outstanding extent and 1 reserved extent

Reserver Releaser
atomic_dec(outstanding) now 0
atomic_read(outstanding)+1 get 1
atomic_read(reserved) get 1
don't actually reserve anything because
they are the same
atomic_cmpxchg(reserved, 1, 0)
atomic_add(0, reserved)
free reserved space for 1 extent

Then the reserver now has no actual space reserved for it, and when it goes to
finish the ordered IO it won't have enough space to do it's allocation and you
get those lovely warnings.

Signed-off-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: don't flush delalloc arbitrarily
Josef Bacik [Fri, 15 Jul 2011 16:01:03 +0000 (16:01 +0000)]
Btrfs: don't flush delalloc arbitrarily

Kill the check to see if we have 512mb of reserved space in delalloc and
shrink_delalloc if we do.  This causes unexpected latencies and we have other
logic to see if we need to throttle.  Thanks,

Signed-off-by: Josef Bacik <>
Signed-off-by: Chris Mason <>
11 years agoBtrfs: use find_or_create_page instead of grab_cache_page
Josef Bacik [Mon, 11 Jul 2011 14:47:06 +0000 (10:47 -0400)]
Btrfs: use find_or_create_page instead of grab_cache_page

grab_cache_page will use mapping_gfp_mask(), which for all inodes is set to
GFP_HIGHUSER_MOVABLE.  So instead use find_or_create_page in all cases where we
need GFP_NOFS so we don't deadlock.  Thanks,

Signed-off-by: Josef Bacik <>
11 years agoBtrfs: use a worker thread to do caching
Josef Bacik [Thu, 30 Jun 2011 18:42:28 +0000 (14:42 -0400)]
Btrfs: use a worker thread to do caching

A user reported a deadlock when copying a bunch of files.  This is because they
were low on memory and kthreadd got hung up trying to migrate pages for an
allocation when starting the caching kthread.  The page was locked by the person
starting the caching kthread.  To fix this we just need to use the async thread
stuff so that the threads are already created and we don't have to worry about
deadlocks.  Thanks,

Reported-by: Roman Mamedov <>
Signed-off-by: Josef Bacik <>
11 years agobtrfs: don't BUG_ON allocation errors in btrfs_drop_snapshot
Mark Fasheh [Wed, 13 Jul 2011 17:59:59 +0000 (10:59 -0700)]
btrfs: don't BUG_ON allocation errors in btrfs_drop_snapshot

In addition to properly handling allocation failure from btrfs_alloc_path, I
also fixed up the kzalloc error handling code immediately below it.

Signed-off-by: Mark Fasheh <>
11 years agobtrfs: Don't BUG_ON alloc_path errors in find_next_chunk
Mark Fasheh [Tue, 12 Jul 2011 17:57:59 +0000 (10:57 -0700)]
btrfs: Don't BUG_ON alloc_path errors in find_next_chunk

I also removed the BUG_ON from error return of find_next_chunk in
init_first_rw_device(). It turns out that the only caller of
init_first_rw_device() also BUGS on any nonzero return so no actual behavior
change has occurred here.

do_chunk_alloc() also needed an update since it calls btrfs_alloc_chunk()
which can now return -ENOMEM. Instead of setting space_info->full on any
error from btrfs_alloc_chunk() I catch and return every error value _except_
-ENOSPC. Thanks goes to Tsutomu Itoh for pointing that issue out.

Signed-off-by: Mark Fasheh <>
11 years agoLinux 3.0 v3.0
Linus Torvalds [Fri, 22 Jul 2011 02:17:23 +0000 (19:17 -0700)]
Linux 3.0

11 years agoMerge branch 'for_linus' of git://
Linus Torvalds [Fri, 22 Jul 2011 00:20:57 +0000 (17:20 -0700)]
Merge branch 'for_linus' of git://git./linux/kernel/git/jwessel/linux-2.6-kgdb

* 'for_linus' of git://
  sparc,kgdbts: fix compile regression with kgdb test suite

11 years agosparc,kgdbts: fix compile regression with kgdb test suite
Jason Wessel [Tue, 19 Jul 2011 20:43:16 +0000 (15:43 -0500)]
sparc,kgdbts: fix compile regression with kgdb test suite

Commit 63ab25ebbc (kgdbts: unify/generalize gdb breakpoint adjustment)
introduced a compile regression on sparc.

kgdbts.c: In function 'check_and_rewind_pc':
kgdbts.c:307: error: implicit declaration of function 'instruction_pointer_set'

Simply add the correct macro definition for instruction pointer on the
Sparc architecture.

Signed-off-by: Jason Wessel <>
Acked-by: Mike Frysinger <>
Acked-by: David S. Miller <>
11 years agoMerge git://
Linus Torvalds [Thu, 21 Jul 2011 21:28:01 +0000 (14:28 -0700)]
Merge git://git./linux/kernel/git/sfrench/cifs-2.6

* git://
  CIFS: Fix wrong length in cifs_iovec_read

11 years agoMerge branch 'x86-urgent-for-linus' of git://
Linus Torvalds [Thu, 21 Jul 2011 19:25:39 +0000 (12:25 -0700)]
Merge branch 'x86-urgent-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'x86-urgent-for-linus' of git://
  x86: Make Dell Latitude E6420 use reboot=pci
  x86: Make Dell Latitude E5420 use reboot=pci

11 years agox86: Make Dell Latitude E6420 use reboot=pci
H. Peter Anvin [Thu, 21 Jul 2011 18:22:21 +0000 (11:22 -0700)]
x86: Make Dell Latitude E6420 use reboot=pci

Yet another variant of the Dell Latitude series which requires

From the E5420 bug report by Daniel J Blueman:

> The E6420 is affected also (same platform, different casing and
> features), which provides an external confirmation of the issue; I can
> submit a patch for that later or include it if you prefer:

Reported-by: Daniel J Blueman <>
Signed-off-by: H. Peter Anvin <>
Cc: <>
11 years agox86: Make Dell Latitude E5420 use reboot=pci
Daniel J Blueman [Fri, 13 May 2011 01:04:59 +0000 (09:04 +0800)]
x86: Make Dell Latitude E5420 use reboot=pci

Rebooting on the Dell E5420 often hangs with the keyboard or ACPI
methods, but is reliable via the PCI method.

[ hpa: this was deferred because we believed for a long time that the
  recent reshuffling of the boot priorities in commit
  660e34cebf0a11d54f2d5dd8838607452355f321 fixed this platform.
  Unfortunately that turned out to be incorrect. ]

Signed-off-by: Daniel J Blueman <>
Signed-off-by: H. Peter Anvin <>
Cc: <>
11 years agoMerge branch 'drm-intel-fixes' of git://
Linus Torvalds [Thu, 21 Jul 2011 18:07:18 +0000 (11:07 -0700)]
Merge branch 'drm-intel-fixes' of git://git./linux/kernel/git/keithp/linux-2.6

* 'drm-intel-fixes' of git://
  drm/i915: Fix unfenced alignment on pre-G33 hardware
  drm/i915: Add quirk to disable SSC on Lenovo U160 LVDS

11 years agovfs: drop conditional inode prefetch in __do_lookup_rcu
Linus Torvalds [Thu, 21 Jul 2011 18:01:42 +0000 (11:01 -0700)]
vfs: drop conditional inode prefetch in __do_lookup_rcu

It seems to hurt performance in real life.  Yes, the inode will be used
later, but the conditional doesn't seem to predict all that well
(negative dentries are not uncommon) and it looks like the cost of
prefetching is simply higher than depending on the cache doing the right

As usual.

Signed-off-by: Linus Torvalds <>
11 years agoFS-Cache: Fix __fscache_uncache_all_inode_pages()'s outer loop
Jan Beulich [Thu, 21 Jul 2011 14:02:43 +0000 (15:02 +0100)]
FS-Cache: Fix __fscache_uncache_all_inode_pages()'s outer loop

The compiler, at least for ix86 and m68k, validly warns that the

next <= (loff_t)-1

is always true (and it's always true also for x86-64 and probably all
other arches - as long as pgoff_t isn't wider than loff_t).  The
intention appears to be to avoid wrapping of "next", so rather than
eliminating the pointless comparison, fix the loop to indeed get exited
when "next" would otherwise wrap.

On m68k the following warning is observed:

  fs/fscache/page.c: In function '__fscache_uncache_all_inode_pages':
  fs/fscache/page.c:979: warning: comparison is always false due to limited range of data type

Reported-by: Geert Uytterhoeven <>
Reported-by: Jan Beulich <>
Signed-off-by: Jan Beulich <>
Signed-off-by: David Howells <>
Cc: Suresh Jayaraman <>
Cc: Geert Uytterhoeven <>
Signed-off-by: Linus Torvalds <>
11 years agoCIFS: Fix wrong length in cifs_iovec_read
Pavel Shilovsky [Wed, 20 Jul 2011 14:24:09 +0000 (18:24 +0400)]
CIFS: Fix wrong length in cifs_iovec_read

Signed-off-by: Pavel Shilovsky <>
Reviewed-by: Jeff Layton <>
Signed-off-by: Steve French <>
11 years agoMerge branch 'core-urgent-for-linus' of git://
Linus Torvalds [Wed, 20 Jul 2011 22:56:25 +0000 (15:56 -0700)]
Merge branch 'core-urgent-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'core-urgent-for-linus' of git://
  signal: align __lock_task_sighand() irq disabling and RCU
  softirq,rcu: Inform RCU of irq_exit() activity
  sched: Add irq_{enter,exit}() to scheduler_ipi()
  rcu: protect __rcu_read_unlock() against scheduler-using irq handlers
  rcu: Streamline code produced by __rcu_read_unlock()
  rcu: Fix RCU_BOOST race handling current->rcu_read_unlock_special
  rcu: decrease rcu_report_exp_rnp coupling with scheduler

11 years agoMerge branch 'sched-urgent-for-linus' of git://
Linus Torvalds [Wed, 20 Jul 2011 22:55:48 +0000 (15:55 -0700)]
Merge branch 'sched-urgent-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'sched-urgent-for-linus' of git://
  sched: Avoid creating superfluous NUMA domains on non-NUMA systems
  sched: Allow for overlapping sched_domain spans
  sched: Break out cpu_power from the sched_group structure

11 years agoMerge branch 'x86-urgent-for-linus' of git://
Linus Torvalds [Wed, 20 Jul 2011 22:33:59 +0000 (15:33 -0700)]
Merge branch 'x86-urgent-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'x86-urgent-for-linus' of git://
  x86. reboot: Make Dell Latitude E6320 use reboot=pci
  x86, doc only: Correct real-mode kernel header offset for init_size
  x86: Disable AMD_NUMA for 32bit for now

11 years agoMerge branch 'rcu/urgent' of git://
Ingo Molnar [Wed, 20 Jul 2011 18:59:26 +0000 (20:59 +0200)]
Merge branch 'rcu/urgent' of git://git./linux/kernel/git/paulmck/linux-2.6-rcu into core/urgent

11 years agosignal: align __lock_task_sighand() irq disabling and RCU
Paul E. McKenney [Tue, 19 Jul 2011 10:25:36 +0000 (03:25 -0700)]
signal: align __lock_task_sighand() irq disabling and RCU

The __lock_task_sighand() function calls rcu_read_lock() with interrupts
and preemption enabled, but later calls rcu_read_unlock() with interrupts
disabled.  It is therefore possible that this RCU read-side critical
section will be preempted and later RCU priority boosted, which means that
rcu_read_unlock() will call rt_mutex_unlock() in order to deboost itself, but
with interrupts disabled. This results in lockdep splats, so this commit
nests the RCU read-side critical section within the interrupt-disabled
region of code.  This prevents the RCU read-side critical section from
being preempted, and thus prevents the attempt to deboost with interrupts

It is quite possible that a better long-term fix is to make rt_mutex_unlock()
disable irqs when acquiring the rt_mutex structure's ->wait_lock.

Signed-off-by: Paul E. McKenney <>
Signed-off-by: Paul E. McKenney <>
11 years agosoftirq,rcu: Inform RCU of irq_exit() activity
Peter Zijlstra [Tue, 19 Jul 2011 22:32:00 +0000 (15:32 -0700)]
softirq,rcu: Inform RCU of irq_exit() activity

The rcu_read_unlock_special() function relies on in_irq() to exclude
scheduler activity from interrupt level.  This fails because exit_irq()
can invoke the scheduler after clearing the preempt_count() bits that
in_irq() uses to determine that it is at interrupt level.  This situation
can result in failures as follows:

 $task IRQ SoftIRQ


 /* do stuff */

 <preempt> |= UNLOCK_BLOCKED


/* do stuff, don't use RCU */

  /* do stuff */
          spin_lock_irq(&pi->lock) /* deadlock */


Ed can simply trigger this 'easy' because invoke_softirq() immediately
does a ttwu() of ksoftirqd/# instead of doing the in-place softirq stuff
first, but even without that the above happens.

Cure this by also excluding softirqs from the
rcu_read_unlock_special() handler and ensuring the force_irqthreads
ksoftirqd/# wakeup is done from full softirq context.

[ Alternatively, delaying the ->rcu_read_lock_nesting decrement
  until after the special handling would make the thing more robust
  in the face of interrupts as well.  And there is a separate patch
  for that. ]

Cc: Thomas Gleixner <>
Reported-and-tested-by: Ed Tomlinson <>
Signed-off-by: Peter Zijlstra <>
Signed-off-by: Paul E. McKenney <>
11 years agosched: Add irq_{enter,exit}() to scheduler_ipi()
Peter Zijlstra [Tue, 19 Jul 2011 22:07:25 +0000 (15:07 -0700)]
sched: Add irq_{enter,exit}() to scheduler_ipi()

Ensure scheduler_ipi() calls irq_{enter,exit} when it does some actual
work. Traditionally we never did any actual work from the resched IPI
and all magic happened in the return from interrupt path.

Now that we do do some work, we need to ensure irq_{enter,exit} are
called so that we don't confuse things.

This affects things like timekeeping, NO_HZ and RCU, basically
everything with a hook in irq_enter/exit.

Explicit examples of things going wrong are:

  sched_clock_cpu() -- has a callback when leaving NO_HZ state to take
                    a new reading from GTOD and TSC. Without this
                    callback, time is stuck in the past.

  RCU -- needs in_irq() to work in order to avoid some nasty deadlocks

Signed-off-by: Peter Zijlstra <>
Signed-off-by: Paul E. McKenney <>
11 years agorcu: protect __rcu_read_unlock() against scheduler-using irq handlers
Paul E. McKenney [Mon, 18 Jul 2011 04:14:35 +0000 (21:14 -0700)]
rcu: protect __rcu_read_unlock() against scheduler-using irq handlers

The addition of RCU read-side critical sections within runqueue and
priority-inheritance lock critical sections introduced some deadlock
cycles, for example, involving interrupts from __rcu_read_unlock()
where the interrupt handlers call wake_up().  This situation can cause
the instance of __rcu_read_unlock() invoked from interrupt to do some
of the processing that would otherwise have been carried out by the
task-level instance of __rcu_read_unlock().  When the interrupt-level
instance of __rcu_read_unlock() is called with a scheduler lock held
from interrupt-entry/exit situations where in_irq() returns false,
deadlock can result.

This commit resolves these deadlocks by using negative values of
the per-task ->rcu_read_lock_nesting counter to indicate that an
instance of __rcu_read_unlock() is in flight, which in turn prevents
instances from interrupt handlers from doing any special processing.
This patch is inspired by Steven Rostedt's earlier patch that similarly
made __rcu_read_unlock() guard against interrupt-mediated recursion
(see, but this commit refines
Steven's approach to avoid the need for preemption disabling on the
__rcu_read_unlock() fastpath and to also avoid the need for manipulating
a separate per-CPU variable.

This patch avoids need for preempt_disable() by instead using negative
values of the per-task ->rcu_read_lock_nesting counter.  Note that nested
rcu_read_lock()/rcu_read_unlock() pairs are still permitted, but they will
never see ->rcu_read_lock_nesting go to zero, and will therefore never
invoke rcu_read_unlock_special(), thus preventing them from seeing the
RCU_READ_UNLOCK_BLOCKED bit should it be set in ->rcu_read_unlock_special.
This patch also adds a check for ->rcu_read_unlock_special being negative
in rcu_check_callbacks(), thus preventing the RCU_READ_UNLOCK_NEED_QS
bit from being set should a scheduling-clock interrupt occur while
__rcu_read_unlock() is exiting from an outermost RCU read-side critical

Of course, __rcu_read_unlock() can be preempted during the time that
->rcu_read_lock_nesting is negative.  This could result in the setting
of the RCU_READ_UNLOCK_BLOCKED bit after __rcu_read_unlock() checks it,
and would also result it this task being queued on the corresponding
rcu_node structure's blkd_tasks list.  Therefore, some later RCU read-side
critical section would enter rcu_read_unlock_special() to clean up --
which could result in deadlock if that critical section happened to be in
the scheduler where the runqueue or priority-inheritance locks were held.

This situation is dealt with by making rcu_preempt_note_context_switch()
check for negative ->rcu_read_lock_nesting, thus refraining from
queuing the task (and from setting RCU_READ_UNLOCK_BLOCKED) if we are
already exiting from the outermost RCU read-side critical section (in
other words, we really are no longer actually in that RCU read-side
critical section).  In addition, rcu_preempt_note_context_switch()
invokes rcu_read_unlock_special() to carry out the cleanup in this case,
which clears out the ->rcu_read_unlock_special bits and dequeues the task
(if necessary), in turn avoiding needless delay of the current RCU grace
period and needless RCU priority boosting.

It is still illegal to call rcu_read_unlock() while holding a scheduler
lock if the prior RCU read-side critical section has ever had either
preemption or irqs enabled.  However, the common use case is legal,
namely where then entire RCU read-side critical section executes with
irqs disabled, for example, when the scheduler lock is held across the
entire lifetime of the RCU read-side critical section.

Signed-off-by: Paul E. McKenney <>
Signed-off-by: Paul E. McKenney <>
11 years agosched: Avoid creating superfluous NUMA domains on non-NUMA systems
Peter Zijlstra [Wed, 20 Jul 2011 16:42:57 +0000 (18:42 +0200)]
sched: Avoid creating superfluous NUMA domains on non-NUMA systems

When creating sched_domains, stop when we've covered the entire
target span instead of continuing to create domains, only to
later find they're redundant and throw them away again.

This avoids single node systems from touching funny NUMA
sched_domain creation code and reduces the risks of the new

Requested-by: Linus Torvalds <>
Signed-off-by: Peter Zijlstra <>
Cc: Anton Blanchard <>
Signed-off-by: Ingo Molnar <>
11 years agosched: Allow for overlapping sched_domain spans
Peter Zijlstra [Fri, 15 Jul 2011 08:35:52 +0000 (10:35 +0200)]
sched: Allow for overlapping sched_domain spans

Allow for sched_domain spans that overlap by giving such domains their
own sched_group list instead of sharing the sched_groups amongst

This is needed for machines with more than 16 nodes, because
sched_domain_node_span() will generate a node mask from the
16 nearest nodes without regard if these masks have any overlap.

Currently sched_domains have a sched_group that maps to their child
sched_domain span, and since there is no overlap we share the
sched_group between the sched_domains of the various CPUs. If however
there is overlap, we would need to link the sched_group list in
different ways for each cpu, and hence sharing isn't possible.

In order to solve this, allocate private sched_groups for each CPU's
sched_domain but have the sched_groups share a sched_group_power
structure such that we can uniquely track the power.

Reported-and-tested-by: Anton Blanchard <>
Signed-off-by: Peter Zijlstra <>
Cc: Linus Torvalds <>
Cc: Andrew Morton <>
Signed-off-by: Ingo Molnar <>
11 years agosched: Break out cpu_power from the sched_group structure
Peter Zijlstra [Thu, 14 Jul 2011 11:00:06 +0000 (13:00 +0200)]
sched: Break out cpu_power from the sched_group structure

In order to prepare for non-unique sched_groups per domain, we need to
carry the cpu_power elsewhere, so put a level of indirection in.

Reported-and-tested-by: Anton Blanchard <>
Signed-off-by: Peter Zijlstra <>
Cc: Linus Torvalds <>
Cc: Andrew Morton <>
Signed-off-by: Ingo Molnar <>
11 years agoMerge branch 'for-linus' of git://
Linus Torvalds [Wed, 20 Jul 2011 05:10:28 +0000 (22:10 -0700)]
Merge branch 'for-linus' of git://git./linux/kernel/git/sage/ceph-client

* 'for-linus' of git://
  ceph: fix file mode calculation

11 years agoMerge branch 'fixes' of git://
Linus Torvalds [Wed, 20 Jul 2011 05:10:05 +0000 (22:10 -0700)]
Merge branch 'fixes' of git://git./linux/kernel/git/arm/linux-arm-soc

* 'fixes' of git://
  davinci: DM365 EVM: fix video input mux bits
  ARM: davinci: Check for NULL return from irq_alloc_generic_chip
  arm: davinci: Fix low level gpio irq handlers' argument

11 years agovmscan: fix a livelock in kswapd
Shaohua Li [Tue, 19 Jul 2011 15:49:26 +0000 (08:49 -0700)]
vmscan: fix a livelock in kswapd

I'm running a workload which triggers a lot of swap in a machine with 4
nodes.  After I kill the workload, I found a kswapd livelock.  Sometimes
kswapd3 or kswapd2 are keeping running and I can't access filesystem,
but most memory is free.

This looks like a regression since commit 08951e545918c159 ("mm: vmscan:
correct check for kswapd sleeping in sleeping_prematurely").

Node 2 and 3 have only ZONE_NORMAL, but balance_pgdat() will return 0
for classzone_idx.  The reason is end_zone in balance_pgdat() is 0 by
default, if all zones have watermark ok, end_zone will keep 0.

Later sleeping_prematurely() always returns true.  Because this is an
order 3 wakeup, and if classzone_idx is 0, both balanced_pages and
present_pages in pgdat_balanced() are 0.  We add a special case here.
If a zone has no page, we think it's balanced.  This fixes the livelock.

Signed-off-by: Shaohua Li <>
Acked-by: Mel Gorman <>
Cc: Minchan Kim <>
Cc: <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>
11 years agofs/libfs.c: fix simple_attr_write() on 32bit machines
Akinobu Mita [Tue, 19 Jul 2011 15:49:25 +0000 (08:49 -0700)]
fs/libfs.c: fix simple_attr_write() on 32bit machines

Assume that /sys/kernel/debug/dummy64 is debugfs file created by

# cd /sys/kernel/debug
# echo 0x1234567812345678 > dummy64
# cat dummy64

# echo 0x80000000 > dummy64
# cat dummy64

A value larger than INT_MAX cannot be written to the debugfs file created
by debugfs_create_u64 or debugfs_create_x64 on 32bit machine.  Because
simple_attr_write() uses simple_strtol() for the conversion.

To fix this, use simple_strtoll() instead.

Signed-off-by: Akinobu Mita <>
Cc: Greg Kroah-Hartman <>
Signed-off-by: Andrew Morton <>
Signed-off-by: Linus Torvalds <>
11 years agoMerge branch 'for-linus' of git://
Linus Torvalds [Wed, 20 Jul 2011 04:50:21 +0000 (21:50 -0700)]
Merge branch 'for-linus' of git://git./linux/kernel/git/viro/vfs-2.6

* 'for-linus' of git://
  vfs: fix race in rcu lookup of pruned dentry
  Fix cifs_get_root()

[ Edited the last commit to get rid of a 'unused variable "seq"'
  warning due to Al editing the patch.  - Linus ]

11 years agovfs: fix race in rcu lookup of pruned dentry
Linus Torvalds [Mon, 18 Jul 2011 22:43:29 +0000 (15:43 -0700)]
vfs: fix race in rcu lookup of pruned dentry

Don't update *inode in __follow_mount_rcu() until we'd verified that
there is mountpoint there.  Kudos to Hugh Dickins for catching that
one in the first place and eventually figuring out the solution (and
catching a braino in the earlier version of patch).

Signed-off-by: Linus Torvalds <>
Signed-off-by: Al Viro <>
11 years agorcu: Streamline code produced by __rcu_read_unlock()
Paul E. McKenney [Sat, 21 May 2011 12:57:18 +0000 (05:57 -0700)]
rcu: Streamline code produced by __rcu_read_unlock()

Given some common flag combinations, particularly -Os, gcc will inline
rcu_read_unlock_special() despite its being in an unlikely() clause.
Use noinline to prohibit this misoptimization.

In addition, move the second barrier() in __rcu_read_unlock() so that
it is not on the common-case code path.  This will allow the compiler to
generate better code for the common-case path through __rcu_read_unlock().

Suggested-by: Linus Torvalds <>
Signed-off-by: Paul E. McKenney <>
Acked-by: Mathieu Desnoyers <>