File syncs and directory syncs are optimized by copying their
items into a special (copy-on-write) log tree. There is one log tree per
subvolume and the btrfs super block points to a tree of log tree roots.
After a crash, items are copied out of the log tree and back into the
subvolume. See tree-log.c for all the details.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
btrfs actually stores the whole xattr name, including the prefix ondisk,
so using the generic resolver that strips off the prefix is not very
helpful. Instead do the real ondisk xattrs manually and only use the
generic resolver for synthetic xattrs like ACLs.
(Sorry Josef for guiding you towards the wrong direction here intially)
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The ->list handler is really not useful at all, because we always call
btrfs_xattr_generic_list anyway. After this is done
find_btrfs_xattr_handler becomes unused, and it becomes obvious that the
temporary name buffer allocation isn't needed but we can directly copy
into the supplied buffer.
Tested with various getfattr -d calls on varying xattr lists.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This patch makes btrfs so it will compile properly when acls are disabled. I
tested this and it worked with CONFIG_FS_POSIX_ACL off and on.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The current code waits for the count of async bio submits to get below
a given threshold if it is too high right after adding the latest bio
to the work queue. This isn't optimal because the caller may have
sequential adjacent bios pending they are waiting to send down the pipe.
This changeset requires the caller to wait on the async bio count,
and changes the async checksumming submits to wait for async bios any
time they self throttle.
The end result is much higher sequential throughput.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Date: Tue, 19 Aug 2008 22:20:17 +0100
btrfs_lookup_fs_root() only finds subvol roots which have already been
seen and put into the cache. For btrfs_get_dentry() we actually have to
go to the medium -- so use btrfs_read_fs_root_no_name() instead.
In btrfs_get_parent(), notice when we've hit the root of the
subvolume and return the real root instead.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Date: Tue, 19 Aug 2008 19:21:57 +0100
Using a 64-bit hash as the readdir cookie is just asking for trouble.
And gets it, when we try to export the file system by NFS.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Date: Tue, 19 Aug 2008 16:49:35 +0100
This disappeared when I removed the special case for '.' in btrfs_lookup()
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Date: Mon, 18 Aug 2008 13:10:20 +0100
This means that subvolumes get a different fsid, and NFS exporting them
works properly.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Date: Sun, 17 Aug 2008 15:14:48 +0100
We never get asked by the VFS to lookup either of them, and we can
handle the readdir() case a lot more simply, too.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Date: Mon, 21 Jul 2008 02:01:56 +0530
Here's an implementation of NFS support for btrfs. It relies on the
fixes which are going in to 2.6.28 for the NFS readdir/lookup deadlock.
This uses the btrfs_iget helper introduced previously.
[dwmw2: Tidy up a little, switch to d_obtain_alias() w/compat routine,
change fh_type, store parent's root object ID where needed,
fix some get_parent() and fs_to_dentry() bugs]
Signed-off-by: Balaji Rao <balajirrao@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Date: Mon, 21 Jul 2008 02:01:04 +0530
This patch introduces a btrfs_iget helper to be used in NFS support.
Signed-off-by: Balaji Rao <balajirrao@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Before, the btrfs bdi congestion function was used to test for too many
async bios. This keeps that check to throttle pdflush, but also
adds a check while queuing bios.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This optimization had been removed because I thought it was triggering
csum errors. The real cause of the errors was elsewhere, and so
this optimization is back.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
add_extent_mapping was allowing the insertion of overlapping extents.
This never used to happen because it only inserted the extents from disk
and those were never overlapping.
But, with the data=ordered code, the disk and memory representations of the
file are not the same. add_extent_mapping needs to ensure a new extent
does not overlap before it inserts.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
These ended up freeing objects while they were still using them. Under
guidance from Chris, just rip out the 'clever' bits and do things the
simple way.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Before this change, btrfs would use a bdi congestion function to make
sure there weren't too many pending async checksum work items.
This change makes the process creating async work items wait instead,
leading to fewer congestion returns from the bdi. This improves
pdflush background_writeout scanning.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
After writing out all the remaining btree blocks in the transaction,
the commit code would use filemap_fdatawait to make sure it was all
on disk. This means it would wait for blocks written by other procs
as well.
The new code walks the list of blocks for this transaction again
and waits only for those required by this transaction.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The writeback_index field is used by write_cache_pages to pick up where
writeback on a given inode left off. But, it is never set to a sane
value, so writeback can often start at a random offset in the file.
Kernels 2.6.28 and higher will have this fixed, but for everyone else,
we also fill in the value in btrfs.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Newer RHEL5 kernels define both ClearPageFSMisc and
ClearPageChecked, so test for both before redefining.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---
Signed-off-by: Chris Mason <chris.mason@oracle.com>
rename and link don't always have a lock on the source inode, and
our use of a per-inode index variable was racy. This changes things to
store the index in a local variable instead.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The multi-bio code is responsible for duplicating blocks in raid1 and
single spindle duplication. It has counters to make sure all of
the locations for a given extent are properly written before io completion
is returned to the higher layers.
But, it didn't always complete the same bio it was given, sometimes a
clone was completed instead. This lead to problems with the async
work queues because they saved a pointer to the bio in a struct off
bi_private.
The fix is to remember the original bio and only complete that one.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Far from the perfect fix, but these structs are small. TODO for the
next release. The block group cache structs are referenced in many
different places, and it isn't safe to just free them while resizing.
A real fix will be a larger change to the allocator so that it doesn't
have to carry about the block group cache structs to find good places
to search for free blocks.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Commit 597:466b27332893 (btrfs_start_transaction: wait for commits in
progress) breaks the transaction start/stop ioctls by making
btrfs_start_transaction conditionally wait for the next transaction to
start. If an application artificially is holding a transaction open,
things deadlock.
This workaround maintains a count of open ioctl-initiated transactions in
fs_info, and avoids wait_current_trans() if any are currently open (in
start_transaction() and btrfs_throttle()). The start transaction ioctl
uses a new btrfs_start_ioctl_transaction() that _does_ call
wait_current_trans(), effectively pushing the join/wait decision to the
outer ioctl-initiated transaction.
This more or less neuters btrfs_throttle() when ioctl-initiated
transactions are in use, but that seems like a pretty fundamental
consequence of wrapping lots of write()'s in a transaction. Btrfs has no
way to tell if the application considers a given operation as part of it's
transaction.
Obviously, if the transaction start/stop ioctls aren't being used, there
is no effect on current behavior.
Signed-off-by: Sage Weil <sage@newdream.net>
---
ctree.h | 1 +
ioctl.c | 12 +++++++++++-
transaction.c | 18 +++++++++++++-----
transaction.h | 2 ++
4 files changed, 27 insertions(+), 6 deletions(-)
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Intel doesn't yet ship hardware to the public with this enabled, but when they
do, they will be ready. Original code from:
Austin Zhang <austin_zhang@linux.intel.com>
It is currently disabled, but edit crc32c.h to turn it on.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Make walk_down_tree wake up throttled tasks more often
* Make walk_down_tree call cond_resched during long loops
* As the size of the ref cache grows, wait longer in throttle
* Get rid of the reada code in walk_down_tree, the leaves don't get
read anymore, thanks to the ref cache.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
A btree block cow has two parts, the first is to allocate a destination
block and the second is to copy the old bock over.
The first part needs locks in the extent allocation tree, and may need to
do IO. This changeset splits that into a separate function that can be
called without any tree locks held.
btrfs_search_slot is changed to drop its path and start over if it has
to COW a contended block. This often means that many writers will
pre-alloc a new destination for a the same contended block, but they
cache their prealloc for later use on lower levels in the tree.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
