linux-toradex.git/fs/btrfs/relocation.c, branch v3.12

Btrfs: fix oops caused by the space balance and dead roots

2013-10-11T01:31:02+00:00

When doing space balance and subvolume destroy at the same time, we met
the following oops:

kernel BUG at fs/btrfs/relocation.c:2247!
RIP: 0010: [] prepare_to_merge+0x154/0x1f0 [btrfs]
Call Trace:
 [] relocate_block_group+0x466/0x4e6 [btrfs]
 [] btrfs_relocate_block_group+0x143/0x275 [btrfs]
 [] btrfs_relocate_chunk.isra.27+0x5c/0x5a2 [btrfs]
 [] ? btrfs_item_key_to_cpu+0x15/0x31 [btrfs]
 [] ? btrfs_get_token_64+0x7e/0xcd [btrfs]
 [] ? btrfs_tree_read_unlock_blocking+0xb2/0xb7 [btrfs]
 [] btrfs_balance+0x9c7/0xb6f [btrfs]
 [] btrfs_ioctl_balance+0x234/0x2ac [btrfs]
 [] btrfs_ioctl+0xd87/0x1ef9 [btrfs]
 [] ? path_openat+0x234/0x4db
 [] ? __do_page_fault+0x31d/0x391
 [] ? vma_link+0x74/0x94
 [] vfs_ioctl+0x1d/0x39
 [] do_vfs_ioctl+0x32d/0x3e2
 [] SyS_ioctl+0x57/0x83
 [] ? do_page_fault+0xe/0x10
 [] system_call_fastpath+0x16/0x1b

It is because we returned the error number if the reference of the root was 0
when doing space relocation. It was not right here, because though the root
was dead(refs == 0), but the space it held still need be relocated, or we
could not remove the block group. So in this case, we should return the root
no matter it is dead or not.

Signed-off-by: Miao Xie 
Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrfs: kill delay_iput arg to the wait_ordered functions

2013-09-21T15:05:27+00:00

This is a left over of how we used to wait for ordered extents, which was to
grab the inode and then run filemap flush on it.  However if we have an ordered
extent then we already are holding a ref on the inode, and we just use
btrfs_start_ordered_extent anyway, so there is no reason to have an extra ref on
the inode to start work on the ordered extent.  Thanks,

Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrfs: fixup error handling in btrfs_reloc_cow

2013-09-21T14:58:54+00:00

If we failed to actually allocate the correct size of the extent to relocate we
will end up in an infinite loop because we won't return an error, we'll just
move on to the next extent.  So fix this up by returning an error, and then fix
all the callers to return an error up the stack rather than BUG_ON()'ing.
Thanks,

Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrf: cleanup: don't check for root_refs == 0 twice

2013-09-01T12:16:29+00:00

btrfs_read_fs_root_no_name() already checks if btrfs_root_refs()
is zero and returns ENOENT in this case. There is no need to do
it again in three more places.

Signed-off-by: Stefan Behrens 
Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrfs: Remove superfluous casts from u64 to unsigned long long

2013-09-01T12:16:08+00:00

u64 is "unsigned long long" on all architectures now, so there's no need to
cast it when formatting it using the "ll" length modifier.

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrfs: change how we queue blocks for backref checking

2013-09-01T12:04:41+00:00

Previously we only added blocks to the list to have their backrefs checked if
the level of the block is right above the one we are searching for.  This is
because we want to make sure we don't add the entire path up to the root to the
lists to make sure we process things one at a time.  This assumes that if any
blocks in the path to the root are going to be not checked (shared in other
words) then they will be in the level right above the current block on up.  This
isn't quite right though since we can have blocks higher up the list that are
shared because they are attached to a reloc root.  But we won't add this block
to be checked and then later on we will BUG_ON(!upper->checked).  So instead
keep track of wether or not we've queued a block to be checked in this current
search, and if we haven't go ahead and queue it to be checked.  This patch fixed
the panic I was seeing where we BUG_ON(!upper->checked).  Thanks,

Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrfs: check to see if we have an inline item properly

2013-09-01T12:04:40+00:00

If our item isn't big enough to have an actual inline item when we have skinny
metadata enabled just return 1 in find_inline_backref so we can move on to the
next item.  This probably wasn't causing a problem since we check the values of
ptr and end properly, but just in case this will keep us from doing extra work.
Thanks,

Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrfs: cleanup reloc roots properly on error

2013-09-01T12:04:24+00:00

I was hitting the BUG_ON() at the end of merge_reloc_roots() because we were
aborting the transaction at some point previously and then getting an error when
we tried to drop the reloc root.  I fixed btrfs_drop_snapshot to re-add us to
the dead roots list if we failed, but this isn't the right thing to do for reloc
roots since it uses root->root_list for it's own stuff in order to know what
needs to be cleaned up.  So fix btrfs_drop_snapshot to only do the re-add if we
aren't dropping for reloc, and handle errors from merge_reloc_root() by dropping
the reloc root we are processing since it won't be on the list of roots to
cleanup.  With this patch my reproducer no longer panics.  Thanks,

Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrfs: add missing error checks to add_data_references

2013-09-01T11:57:35+00:00

The function relocation.c:add_data_references() was not checking
if all calls to __add_tree_block() and find_data_references() were
succeeding or not.

Signed-off-by: Filipe David Borba Manana 
Reviewed-by: David Sterba 
Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrfs: remove btrfs_sector_sum structure

2013-07-02T15:50:47+00:00

Using the structure btrfs_sector_sum to keep the checksum value is
unnecessary, because the extents that btrfs_sector_sum points to are
continuous, we can find out the expected checksums by btrfs_ordered_sum's
bytenr and the offset, so we can remove btrfs_sector_sum's bytenr. After
removing bytenr, there is only one member in the structure, so it makes
no sense to keep the structure, just remove it, and use a u32 array to
store the checksum value.

By this change, we don't use the while loop to get the checksums one by
one. Now, we can get several checksum value at one time, it improved the
performance by ~74% on my SSD (31MB/s -> 54MB/s).

test command:
 # dd if=/dev/zero of=/mnt/btrfs/file0 bs=1M count=1024 oflag=sync

Signed-off-by: Miao Xie 
Signed-off-by: Josef Bacik