When a block is freed, it can be immediately reused if it is from
the current transaction.  But, an extra check is required to make sure
the block had not been written yet.  If it were reused after being written,
the transid in the block header might match the transid of the
next time the block was allocated.

The parent node records the transaction ID of the block it is pointing to,
and this is used as part of validating the block on reads.  So, there
can only be one version of a block per transaction.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Checksums were only verified by btrfs_read_tree_block, which meant the
functions to probe the page cache for blocks were not validating checksums.
Normally this is fine because the buffers will only be in cache if they
have already been validated.

But, there is a window while the buffer is being read from disk where
it could be up to date in the cache but not yet verified.  This patch
makes sure all buffers go through checksum verification before they
are used.

This is safer, and it prevents modification of buffers before they go
through the csum code.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

There was an optimization to drop the fs_mutex when doing snapshot deletion
reads, but this can lead to false positives on checksumming errors.  Keep
the lock for now.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

In btrfs_name_hash, Local variable 'buf' is declared as

	__u32 buf[2];

but we then try to do this:

	buf[0] = 0x67452301;
	buf[1] = 0xefcdab89;
	buf[2] = 0x98badcfe;
	buf[3] = 0x10325476;

Oops. Fix buf to be the proper size.
Signed-off-by: NAlex Chiang <achiang@hp.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: Peter Teoh <htmldeveloper@gmail.com>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

This allows detection of blocks that have already been written in the
running transaction so they can be recowed instead of modified again.
It is step one in trusting the transid field of the block pointers.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

This also fixes one leak around the super block when failing to mount the
FS.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

This allows intelligent versions of unplug and congestion functions
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Remove the btrfs read_inode method, and use save_mount_options
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Here's a patch against the unstable tree that gets the code to build
against Linus's current tree (2.6.24-git12).  This is needed as the
kobject/kset api has changed there.

I tried to make the smallest changes needed, and it builds and loads
successfully, but I don't have a btrfs volume anywhere (yet) to try to
see if things still work properly :)
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

When we checkum file data during writepage, the checksumming is done one
page at a time, making it difficult to do bulk metadata modifications
to insert checksums for large ranges of the file at once.

This patch changes btrfs to checksum on a per-bio basis instead.  The
bios are checksummed before they are handed off to the block layer, so
each bio is contiguous and only has pages from the same inode.

Checksumming on a bio basis allows us to insert and modify the file
checksum items in large groups.  It also allows the checksumming to
be done more easily by async worker threads.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Yan Zheng noticed that we don't clear the extent state tree dirty and delalloc
bits when we clear the dirty bits on the page during file write.

This leads to csum errors later on.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Reduce CPU time searching for free blocks by optimizing find_first_extent_bit

Fix find_free_extent to make better use of the last_alloc hint.  Before it
was often finding blocks just before the hint.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Signed-off-by: NChris Mason <chris.mason@oracle.com>

Btrfs set/get macros lose type information needed to avoid
unaligned accesses on sparc64.
ere is a patch for the kernel bits which fixes most of the
unaligned accesses on sparc64.

btrfs_name_hash is modified to return the hash value instead
of getting a return location via a (potentially unaligned)
pointer.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

A few codes were not properly updated for changes of extent map.  This
may be the causes of "no csum found for inode" issue.
Signed-off-by: NChris Mason <chris.mason@oracle.com>

Now that delayed allocation accounting works, i_blocks accounting is changed
to only modify i_blocks when extents inserted or removed.

The fillattr call is changed to include the delayed allocation byte count
in the i_blocks result.
Signed-off-by: NChris Mason <chris.mason@oracle.com>