linux.git/fs/btrfs, branch v3.11

btrfs: don't loop on large offsets in readdir

2013-08-09T23:34:56+00:00

When btrfs readdir() hits the last entry it sets the readdir offset to a
huge value to stop buggy apps from breaking when the same name is
returned by readdir() with concurrent rename()s.

But unconditionally setting the offset to INT_MAX causes readdir() to
loop returning any entries with offsets past INT_MAX.  It only takes a
few hours of constant file creation and removal to create entries past
INT_MAX.

So let's set the huge offset to LLONG_MAX if the last entry has already
overflowed 32bit loff_t.   Without large offsets behaviour is identical.
With large offsets 64bit apps will work and 32bit apps will be no more
broken than they currently are if they see large offsets.

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

Btrfs: check to see if root_list is empty before adding it to dead roots

2013-08-09T23:30:23+00:00

A user reported a panic when running with autodefrag and deleting snapshots.
This is because we could end up trying to add the root to the dead roots list
twice.  To fix this check to see if we are empty before adding ourselves to the
dead roots list.  Thanks,

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

Btrfs: release both paths before logging dir/changed extents

2013-08-09T23:30:16+00:00

The ceph guys tripped over this bug where we were still holding onto the
original path that we used to copy the inode with when logging.  This is based
on Chris's fix which was reported to fix the problem.  We need to drop the paths
in two cases anyway so just move the drop up so that we don't have duplicate
code.  Thanks,

Cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrfs: allow splitting of hole em's when dropping extent cache

2013-08-09T23:30:09+00:00

I noticed while running multi-threaded fsync tests that sometimes fsck would
complain about an improper gap.  This happens because we fail to add a hole
extent to the file, which was happening when we'd split a hole EM because
btrfs_drop_extent_cache was just discarding the whole em instead of splitting
it.  So this patch fixes this by allowing us to split a hole em properly, which
means that added holes actually get logged properly and we no longer see this
fsck error.  Thankfully we're tolerant of these sort of problems so a user would
not see any adverse effects of this bug, other than fsck complaining.  Thanks,

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

Btrfs: make sure the backref walker catches all refs to our extent

2013-08-09T23:30:03+00:00

Because we don't mess with the offset into the extent for compressed we will
properly find both extents for this case

[extent a][extent b][rest of extent a]

but because we already added a ref for the front half we won't add the inode
information for the second half.  This causes us to leak that memory and not
print out the other offset when we do logical-resolve.  So fix this by calling
ulist_add_merge and then add our eie to the existing entry if there is one.
With this patch we get both offsets out of logical-resolve.  With this and the
other 2 patches I've sent we now pass btrfs/276 on my vm with compress-force=lzo
set.  Thanks,

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

Btrfs: fix backref walking when we hit a compressed extent

2013-08-09T23:29:56+00:00

If you do btrfs inspect-internal logical-resolve on a compressed extent that has
been partly overwritten it won't find anything.  This is because we try and
match the extent offset we've searched for based on the extent offset in the
data extent entry.  However this doesn't work for compressed extents because the
offsets are for the uncompressed size, not the compressed size.  So instead only
do this check if we are not compressed, that way we can get an actual entry for
the physical offset rather than nothing for compressed.  Thanks,

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

Btrfs: do not offset physical if we're compressed

2013-08-09T23:29:50+00:00

xfstest btrfs/276 was freaking out on slower boxes partly because fiemap was
offsetting the physical based on the extent offset.  This is perfectly fine with
uncompressed extents, however the extent offset is into the uncompressed area,
not the compressed.  So we can return a physical value that isn't at all within
the area we have allocated on disk.  Fix this by returning the start of the
extent if it is compressed no matter what the offset.  Thanks,

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

Btrfs: fix extent buffer leak after backref walking

2013-08-09T23:29:42+00:00

commit 47fb091fb787420cd195e66f162737401cce023f(Btrfs: fix unlock after free on rewinded tree blocks)
takes an extra increment on the reference of allocated dummy extent buffer, so now we
cannot free this dummy one, and end up with extent buffer leak.

Signed-off-by: Liu Bo 
Reviewed-by: Jan Schmidt 
Signed-off-by: Josef Bacik 
Signed-off-by: Chris Mason

Btrfs: fix a bug of snapshot-aware defrag to make it work on partial extents

2013-08-09T23:29:17+00:00

For partial extents, snapshot-aware defrag does not work as expected,
since
a) we use the wrong logical offset to search for parents, which should be
   disk_bytenr + extent_offset, not just disk_bytenr,
b) 'offset' returned by the backref walking just refers to key.offset, not
   the 'offset' stored in btrfs_extent_data_ref which is
   (key.offset - extent_offset).

The reproducer:
$ mkfs.btrfs sda
$ mount sda /mnt
$ btrfs sub create /mnt/sub
$ for i in `seq 5 -1 1`; do dd if=/dev/zero of=/mnt/sub/foo bs=5k count=1 seek=$i conv=notrunc oflag=sync; done
$ btrfs sub snap /mnt/sub /mnt/snap1
$ btrfs sub snap /mnt/sub /mnt/snap2
$ sync; btrfs filesystem defrag /mnt/sub/foo;
$ umount /mnt
$ btrfs-debug-tree sda (Here we can check whether the defrag operation is snapshot-awared.

This addresses the above two problems.

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

btrfs: fix file truncation if FALLOC_FL_KEEP_SIZE is specified

2013-08-09T23:28:56+00:00

Create a small file and fallocate it to a big size with
FALLOC_FL_KEEP_SIZE option, then truncate it back to the
small size again, the disk free space is not changed back
in this case. i.e,

total 4
-rw-r--r-- 1 root root 512 Jun 28 11:35 test

Filesystem      Size  Used Avail Use% Mounted on
....
/dev/sdb1       8.0G   56K  7.2G   1% /mnt

-rw-r--r-- 1 root root 512 Jun 28 11:35 /mnt/test

Filesystem      Size  Used Avail Use% Mounted on
....
/dev/sdb1       8.0G  5.1G  2.2G  70% /mnt

Filesystem      Size  Used Avail Use% Mounted on
....
/dev/sdb1       8.0G  5.1G  2.2G  70% /mnt

With this fix, the truncated up space is back as:
Filesystem      Size  Used Avail Use% Mounted on
....
/dev/sdb1       8.0G   56K  7.2G   1% /mnt

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