kernel.git/fs/btrfs/compression.c, branch linux-2.6.30.y

Btrfs: removed unused #include 's

2009-01-21T15:49:16Z

Removed unused #include 's in btrfs Signed-off-by: Huang Weiyi Signed-off-by: Chris Mason

Btrfs: Fix checkpatch.pl warnings

2009-01-06T02:25:51Z

There were many, most are fixed now. struct-funcs.c generates some warnings but these are bogus. Signed-off-by: Chris Mason

Btrfs: fix nodatasum handling in balancing code

2008-12-12T15:03:38Z

Checksums on data can be disabled by mount option, so it's possible some data extents don't have checksums or have invalid checksums. This causes trouble for data relocation. This patch contains following things to make data relocation work. 1) make nodatasum/nodatacow mount option only affects new files. Checksums and COW on data are only controlled by the inode flags. 2) check the existence of checksum in the nodatacow checker. If checksums exist, force COW the data extent. This ensure that checksum for a given block is either valid or does not exist. 3) update data relocation code to properly handle the case of checksum missing. Signed-off-by: Yan Zheng

Btrfs: move data checksumming into a dedicated tree

2008-12-08T21:58:54Z

Btrfs stores checksums for each data block. Until now, they have been stored in the subvolume trees, indexed by the inode that is referencing the data block. This means that when we read the inode, we've probably read in at least some checksums as well. But, this has a few problems: * The checksums are indexed by logical offset in the file. When compression is on, this means we have to do the expensive checksumming on the uncompressed data. It would be faster if we could checksum the compressed data instead. * If we implement encryption, we'll be checksumming the plain text and storing that on disk. This is significantly less secure. * For either compression or encryption, we have to get the plain text back before we can verify the checksum as correct. This makes the raid layer balancing and extent moving much more expensive. * It makes the front end caching code more complex, as we have touch the subvolume and inodes as we cache extents. * There is potentitally one copy of the checksum in each subvolume referencing an extent. The solution used here is to store the extent checksums in a dedicated tree. This allows us to index the checksums by phyiscal extent start and length. It means: * The checksum is against the data stored on disk, after any compression or encryption is done. * The checksum is stored in a central location, and can be verified without following back references, or reading inodes. This makes compression significantly faster by reducing the amount of data that needs to be checksummed. It will also allow much faster raid management code in general. The checksums are indexed by a key with a fixed objectid (a magic value in ctree.h) and offset set to the starting byte of the extent. This allows us to copy the checksum items into the fsync log tree directly (or any other tree), without having to invent a second format for them. Signed-off-by: Chris Mason

Btrfs: compat code fixes

2008-11-20T15:22:27Z

The btrfs git kernel trees is used to build a standalone tree for compiling against older kernels. This commit makes the standalone tree work with 2.6.27 Signed-off-by: Chris Mason

Btrfs: Fixes for 2.6.28-rc API changes

2008-11-20T02:17:22Z

* open/close_bdev_excl -> open/close_bdev_exclusive * blkdev_issue_discard takes a GFP mask now * Fix blkdev_issue_discard usage now that it is enabled Signed-off-by: Chris Mason

Btrfs: Fix compile warnings on 32 bit machines

2008-11-11T14:34:41Z

Simple casting here and there to fix things up. Signed-off-by: Chris Mason

Btrfs: Fix use after free during compressed reads

2008-11-10T16:44:58Z

Yan's fix to use the correct file offset during compressed reads used the extent_map struct pointer after it had been freed. This saves the fields we want for later use instead. Signed-off-by: Chris Mason

Btrfs: Fix csum error for compressed data

2008-11-10T12:34:43Z

The decompress code doesn't take the logical offset in extent pointer into account. If the logical offset isn't zero, data will be decompressed into wrong pages. The solution used here is to record the starting offset of the extent in the file separately from the logical start of the extent_map struct. This allows us to avoid problems inserting overlapping extents. Signed-off-by: Yan Zheng

Btrfs: make sure compressed bios don't complete too soon

2008-11-07T17:35:44Z

When writing a compressed extent, a number of bios are created that point to a single struct compressed_bio. At end_io time an atomic counter in the compressed_bio struct makes sure that all of the bios have finished before final end_io processing is done. But when multiple bios are needed to write a compressed extent, the counter was being incremented after the first bio was sent to submit_bio. It is possible the bio will complete before the counter is incremented, making the end_io handler free the compressed_bio struct before processing is finished. The fix is to increment the atomic counter before bio submission, both for compressed reads and writes. Signed-off-by: Chris Mason