Commit Graph

296 Commits

Author SHA1 Message Date
Linus Torvalds
5291a12f05 Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: fix error message formatting
  Btrfs: fix use after free in btrfs_start_workers fail path
  Btrfs: honor nodatacow/sum mount options for new files
  Btrfs: update backrefs while dropping snapshot
  Btrfs: account for space we may use in fallocate
  Btrfs: fix the file clone ioctl for preallocated extents
  Btrfs: don't log the inode in file_write while growing the file
2009-07-02 16:52:38 -07:00
Chris Mason
9427216476 Btrfs: honor nodatacow/sum mount options for new files
The btrfs attr patches unconditionally inherited the inode flags field
without honoring nodatacow and nodatasum.  This fix makes sure
we properly record the nodatacow/sum mount options in new inodes.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-02 13:41:17 -04:00
Josef Bacik
a970b0a16c Btrfs: account for space we may use in fallocate
Using Eric Sandeen's xfstest for fallocate, you can easily trigger a ENOSPC
panic on btrfs.  This is because we do not account for data we may use when
doing the fallocate.  This patch fixes the problem by properly reserving space,
and then just freeing it when we are done.  The reservation stuff was made with
delalloc in mind, so its a little crude for this case, but it keeps the box
from panicing.

Signed-off-by: Josef Bacik <jbacik@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-07-02 13:41:16 -04:00
Al Viro
72c04902d1 Get "no acls for this inode" right, fix shmem breakage
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-24 16:58:48 -04:00
Al Viro
5affd88a10 switch btrfs to inode->i_acl
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-24 08:17:05 -04:00
Christoph Hellwig
59d697b702 btrfs: remove ->write_super and stop maintaining ->s_dirt
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11 21:36:05 -04:00
Christoph Hellwig
6cbff00f46 Btrfs: implement FS_IOC_GETFLAGS/SETFLAGS/GETVERSION
Add support for the standard attributes set via chattr and read via
lsattr.  Currently we store the attributes in the flags value in
the btrfs inode, but I wonder whether we should split it into two so
that we don't have to keep converting between the two formats.

Remove the btrfs_clear_flag/btrfs_set_flag/btrfs_test_flag macros
as they were confusing the existing code and got in the way of the
new additions.

Also add the FS_IOC_GETVERSION ioctl for getting i_generation as it's
trivial.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 11:29:52 -04:00
Yan Zheng
5d4f98a28c Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)
This commit introduces a new kind of back reference for btrfs metadata.
Once a filesystem has been mounted with this commit, IT WILL NO LONGER
BE MOUNTABLE BY OLDER KERNELS.

When a tree block in subvolume tree is cow'd, the reference counts of all
extents it points to are increased by one.  At transaction commit time,
the old root of the subvolume is recorded in a "dead root" data structure,
and the btree it points to is later walked, dropping reference counts
and freeing any blocks where the reference count goes to 0.

The increments done during cow and decrements done after commit cancel out,
and the walk is a very expensive way to go about freeing the blocks that
are no longer referenced by the new btree root.  This commit reduces the
transaction overhead by avoiding the need for dead root records.

When a non-shared tree block is cow'd, we free the old block at once, and the
new block inherits old block's references. When a tree block with reference
count > 1 is cow'd, we increase the reference counts of all extents
the new block points to by one, and decrease the old block's reference count by
one.

This dead tree avoidance code removes the need to modify the reference
counts of lower level extents when a non-shared tree block is cow'd.
But we still need to update back ref for all pointers in the block.
This is because the location of the block is recorded in the back ref
item.

We can solve this by introducing a new type of back ref. The new
back ref provides information about pointer's key, level and in which
tree the pointer lives. This information allow us to find the pointer
by searching the tree. The shortcoming of the new back ref is that it
only works for pointers in tree blocks referenced by their owner trees.

This is mostly a problem for snapshots, where resolving one of these
fuzzy back references would be O(number_of_snapshots) and quite slow.
The solution used here is to use the fuzzy back references in the common
case where a given tree block is only referenced by one root,
and use the full back references when multiple roots have a reference
on a given block.

This commit adds per subvolume red-black tree to keep trace of cached
inodes. The red-black tree helps the balancing code to find cached
inodes whose inode numbers within a given range.

This commit improves the balancing code by introducing several data
structures to keep the state of balancing. The most important one
is the back ref cache. It caches how the upper level tree blocks are
referenced. This greatly reduce the overhead of checking back ref.

The improved balancing code scales significantly better with a large
number of snapshots.

This is a very large commit and was written in a number of
pieces.  But, they depend heavily on the disk format change and were
squashed together to make sure git bisect didn't end up in a
bad state wrt space balancing or the format change.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-06-10 11:29:46 -04:00
Chris Mason
cc7b0c9b70 Btrfs: remove some WARN_ONs in the IO failure path
These debugging WARN_ONs make too much console noise during regular
IO failures.  An IO failure will still generate a number of messages
as we verify checksums etc, but these two are not needed.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-05-14 14:00:33 -04:00
Chris Mason
2757495c90 Btrfs: init inode ordered_data_close flag properly
This flag is used to decide when we need to send a given file through
the ordered code to make sure it is fully written before a transaction
commits.  It was not being properly set to zero when the inode was
being setup.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-05-14 14:00:31 -04:00
Chris Mason
46a53cca82 Btrfs: look for acls during btrfs_read_locked_inode
This changes btrfs_read_locked_inode() to peek ahead in the btree for acl items.
If it is certain a given inode has no acls, it will set the in memory acl
fields to null to avoid acl lookups completely.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-27 13:18:35 -04:00
Chris Mason
7b1a14bbb0 Btrfs: fix acl caching
Linus noticed the btrfs code to cache acls wasn't properly caching
a NULL acl when the inode didn't have any acls.  This meant the common
case of no acls resulted in expensive btree searches every time the
kernel checked permissions (which is quite often).

This is a modified version of Linus' original patch:

Properly set initial acl fields to BTRFS_ACL_NOT_CACHED in the inode.
This forces an acl lookup when permission checks are done.

Fix btrfs_get_acl to avoid lookups and locking when the inode acls fields
are set to null.

Fix btrfs_get_acl to use the right return value from __btrfs_getxattr
when deciding to cache a NULL acl.  It was storing a NULL acl when
__btrfs_getxattr return -ENOENT, but __btrfs_getxattr was actually returning
-ENODATA for this case.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-27 13:18:26 -04:00
Chris Mason
45c06543af Btrfs: remove unused btrfs_bit_radix slab
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-27 08:37:48 -04:00
Chris Mason
193f284d49 Btrfs: ratelimit IO error printks
Btrfs has printks for various IO errors, including bad checksums and
mismatches between what we expect the block headers to contain and what
we actually find on the disk.

Longer term we need a real reporting mechanism for this, but for now
printk is going to have to do.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-27 07:41:47 -04:00
Chris Mason
e980b50cda Btrfs: fix fallocate deadlock on inode extent lock
The btrfs fallocate call takes an extent lock on the entire range
being fallocated, and then runs through insert_reserved_extent on each
extent as they are allocated.

The problem with this is that btrfs_drop_extents may decide to try
and take the same extent lock fallocate was already holding.  The solution
used here is to push down knowledge of the range that is already locked
going into btrfs_drop_extents.

It turns out that at least one other caller had the same bug.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-24 15:46:05 -04:00
Christoph Hellwig
9601e3f633 Btrfs: kill btrfs_cache_create
Just use kmem_cache_create directly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-24 15:46:04 -04:00
Chris Mason
546888da82 Btrfs: fix btrfs fallocate oops and deadlock
Btrfs fallocate was incorrectly starting a transaction with a lock held
on the extent_io tree for the file, which could deadlock.  Strictly
speaking it was using join_transaction which would be safe, but it is better
to move the transaction outside of the lock.

When preallocated extents are overwritten, btrfs_mark_buffer_dirty was
being called on an unlocked buffer.  This was triggering an assertion and
oops because the lock is supposed to be held.

The bug was calling btrfs_mark_buffer_dirty on a leaf after btrfs_del_item had
been run.  btrfs_del_item takes care of dirtying things, so the solution is a
to skip the btrfs_mark_buffer_dirty call in this case.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-21 12:45:12 -04:00
Linus Torvalds
b983471794 Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: BUG to BUG_ON changes
  Btrfs: remove dead code
  Btrfs: remove dead code
  Btrfs: fix typos in comments
  Btrfs: remove unused ftrace include
  Btrfs: fix __ucmpdi2 compile bug on 32 bit builds
  Btrfs: free inode struct when btrfs_new_inode fails
  Btrfs: fix race in worker_loop
  Btrfs: add flushoncommit mount option
  Btrfs: notreelog mount option
  Btrfs: introduce btrfs_show_options
  Btrfs: rework allocation clustering
  Btrfs: Optimize locking in btrfs_next_leaf()
  Btrfs: break up btrfs_search_slot into smaller pieces
  Btrfs: kill the pinned_mutex
  Btrfs: kill the block group alloc mutex
  Btrfs: clean up find_free_extent
  Btrfs: free space cache cleanups
  Btrfs: unplug in the async bio submission threads
  Btrfs: keep processing bios for a given bdev if our proc is batching
2009-04-03 15:14:44 -07:00
Shen Feng
09771430f3 Btrfs: free inode struct when btrfs_new_inode fails
btrfs_new_inode doesn't call iput to free the inode
when it fails.

Signed-off-by: Shen Feng <shen@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-04-02 16:46:06 -04:00
Linus Torvalds
c226fd659f Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: try to free metadata pages when we free btree blocks
  Btrfs: add extra flushing for renames and truncates
  Btrfs: make sure btrfs_update_delayed_ref doesn't increase ref_mod
  Btrfs: optimize fsyncs on old files
  Btrfs: tree logging unlink/rename fixes
  Btrfs: Make sure i_nlink doesn't hit zero too soon during log replay
  Btrfs: limit balancing work while flushing delayed refs
  Btrfs: readahead checksums during btrfs_finish_ordered_io
  Btrfs: leave btree locks spinning more often
  Btrfs: Only let very young transactions grow during commit
  Btrfs: Check for a blocking lock before taking the spin
  Btrfs: reduce stack in cow_file_range
  Btrfs: reduce stalls during transaction commit
  Btrfs: process the delayed reference queue in clusters
  Btrfs: try to cleanup delayed refs while freeing extents
  Btrfs: reduce stack usage in some crucial tree balancing functions
  Btrfs: do extent allocation and reference count updates in the background
  Btrfs: don't preallocate metadata blocks during btrfs_search_slot
2009-04-01 10:20:44 -07:00
Nick Piggin
56a76f8275 fs: fix page_mkwrite error cases in core code and btrfs
page_mkwrite is called with neither the page lock nor the ptl held.  This
means a page can be concurrently truncated or invalidated out from
underneath it.  Callers are supposed to prevent truncate races themselves,
however previously the only thing they can do in case they hit one is to
raise a SIGBUS.  A sigbus is wrong for the case that the page has been
invalidated or truncated within i_size (eg.  hole punched).  Callers may
also have to perform memory allocations in this path, where again, SIGBUS
would be wrong.

The previous patch ("mm: page_mkwrite change prototype to match fault")
made it possible to properly specify errors.  Convert the generic buffer.c
code and btrfs to return sane error values (in the case of page removed
from pagecache, VM_FAULT_NOPAGE will cause the fault handler to exit
without doing anything, and the fault will be retried properly).

This fixes core code, and converts btrfs as a template/example.  All other
filesystems defining their own page_mkwrite should be fixed in a similar
manner.

Acked-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:14 -07:00
Nick Piggin
c2ec175c39 mm: page_mkwrite change prototype to match fault
Change the page_mkwrite prototype to take a struct vm_fault, and return
VM_FAULT_xxx flags.  There should be no functional change.

This makes it possible to return much more detailed error information to
the VM (and also can provide more information eg.  virtual_address to the
driver, which might be important in some special cases).

This is required for a subsequent fix.  And will also make it easier to
merge page_mkwrite() with fault() in future.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:14 -07:00
Chris Mason
5a3f23d515 Btrfs: add extra flushing for renames and truncates
Renames and truncates are both common ways to replace old data with new
data.  The filesystem can make an effort to make sure the new data is
on disk before actually replacing the old data.

This is especially important for rename, which many application use as
though it were atomic for both the data and the metadata involved.  The
current btrfs code will happily replace a file that is fully on disk
with one that was just created and still has pending IO.

If we crash after transaction commit but before the IO is done, we'll end
up replacing a good file with a zero length file.  The solution used
here is to create a list of inodes that need special ordering and force
them to disk before the commit is done.  This is similar to the
ext3 style data=ordering, except it is only done on selected files.

Btrfs is able to get away with this because it does not wait on commits
very often, even for fsync (which use a sub-commit).

For renames, we order the file when it wasn't already
on disk and when it is replacing an existing file.  Larger files
are sent to filemap_flush right away (before the transaction handle is
opened).

For truncates, we order if the file goes from non-zero size down to
zero size.  This is a little different, because at the time of the
truncate the file has no dirty bytes to order.  But, we flag the inode
so that it is added to the ordered list on close (via release method).  We
also immediately add it to the ordered list of the current transaction
so that we can try to flush down any writes the application sneaks in
before commit.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-31 14:27:58 -04:00
Chris Mason
12fcfd22fe Btrfs: tree logging unlink/rename fixes
The tree logging code allows individual files or directories to be logged
without including operations on other files and directories in the FS.
It tries to commit the minimal set of changes to disk in order to
fsync the single file or directory that was sent to fsync or O_SYNC.

The tree logging code was allowing files and directories to be unlinked
if they were part of a rename operation where only one directory
in the rename was in the fsync log.  This patch adds a few new rules
to the tree logging.

1) on rename or unlink, if the inode being unlinked isn't in the fsync
log, we must force a full commit before doing an fsync of the directory
where the unlink was done.  The commit isn't done during the unlink,
but it is forced the next time we try to log the parent directory.

Solution: record transid of last unlink/rename per directory when the
directory wasn't already logged.  For renames this is only done when
renaming to a different directory.

mkdir foo/some_dir
normal commit
rename foo/some_dir foo2/some_dir
mkdir foo/some_dir
fsync foo/some_dir/some_file

The fsync above will unlink the original some_dir without recording
it in its new location (foo2).  After a crash, some_dir will be gone
unless the fsync of some_file forces a full commit

2) we must log any new names for any file or dir that is in the fsync
log.  This way we make sure not to lose files that are unlinked during
the same transaction.

2a) we must log any new names for any file or dir during rename
when the directory they are being removed from was logged.

2a is actually the more important variant.  Without the extra logging
a crash might unlink the old name without recreating the new one

3) after a crash, we must go through any directories with a link count
of zero and redo the rm -rf

mkdir f1/foo
normal commit
rm -rf f1/foo
fsync(f1)

The directory f1 was fully removed from the FS, but fsync was never
called on f1, only its parent dir.  After a crash the rm -rf must
be replayed.  This must be able to recurse down the entire
directory tree.  The inode link count fixup code takes care of the
ugly details.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-24 16:14:52 -04:00
Chris Mason
5d13a98f3b Btrfs: readahead checksums during btrfs_finish_ordered_io
This reads in blocks in the checksum btree before starting the
transaction in btrfs_finish_ordered_io.  It makes it much more likely
we'll be able to do operations inside the transaction without
needing any btree reads, which limits transaction latencies overall.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-24 16:14:51 -04:00
Chris Mason
b9473439d3 Btrfs: leave btree locks spinning more often
btrfs_mark_buffer dirty would set dirty bits in the extent_io tree
for the buffers it was dirtying.  This may require a kmalloc and it
was not atomic.  So, anyone who called btrfs_mark_buffer_dirty had to
set any btree locks they were holding to blocking first.

This commit changes dirty tracking for extent buffers to just use a flag
in the extent buffer.  Now that we have one and only one extent buffer
per page, this can be safely done without losing dirty bits along the way.

This also introduces a path->leave_spinning flag that callers of
btrfs_search_slot can use to indicate they will properly deal with a
path returned where all the locks are spinning instead of blocking.

Many of the btree search callers now expect spinning paths,
resulting in better btree concurrency overall.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-24 16:14:28 -04:00
Chris Mason
7f366cfecf Btrfs: reduce stack in cow_file_range
The fs/btrfs/inode.c code to run delayed allocation during writout
needed some stack usage optimization.  This is the first pass, it does
the check for compression earlier on, which allows us to do the common
(no compression) case higher up in the call chain.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-24 16:14:27 -04:00
Chris Mason
b7ec40d784 Btrfs: reduce stalls during transaction commit
To avoid deadlocks and reduce latencies during some critical operations, some
transaction writers are allowed to jump into the running transaction and make
it run a little longer, while others sit around and wait for the commit to
finish.

This is a bit unfair, especially when the callers that jump in do a bunch
of IO that makes all the others procs on the box wait.  This commit
reduces the stalls this produces by pre-reading file extent pointers
during btrfs_finish_ordered_io before the transaction is joined.

It also tunes the drop_snapshot code to politely wait for transactions
that have started writing out their delayed refs to finish.  This avoids
new delayed refs being flooded into the queue while we're trying to
close off the transaction.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-03-24 16:14:26 -04:00
Josef Bacik
6a63209fc0 Btrfs: add better -ENOSPC handling
This is a step in the direction of better -ENOSPC handling.  Instead of
checking the global bytes counter we check the space_info bytes counters to
make sure we have enough space.

If we don't we go ahead and try to allocate a new chunk, and then if that fails
we return -ENOSPC.  This patch adds two counters to btrfs_space_info,
bytes_delalloc and bytes_may_use.

bytes_delalloc account for extents we've actually setup for delalloc and will
be allocated at some point down the line. 

bytes_may_use is to keep track of how many bytes we may use for delalloc at
some point.  When we actually set the extent_bit for the delalloc bytes we
subtract the reserved bytes from the bytes_may_use counter.  This keeps us from
not actually being able to allocate space for any delalloc bytes.

Signed-off-by: Josef Bacik <jbacik@redhat.com>
2009-02-20 11:00:09 -05:00
Jeff Mahoney
e00f730865 Btrfs: remove btrfs_init_path
btrfs_init_path was initially used when the path objects were on the
stack.  Now all the work is done by btrfs_alloc_path and btrfs_init_path
isn't required.

This patch removes it, and just uses kmem_cache_zalloc to zero out the object.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-12 14:11:25 -05:00
Yan Zheng
b335b0034e Btrfs: Avoid using __GFP_HIGHMEM with slab allocator
btrfs_releasepage may call kmem_cache_alloc indirectly,
and provide same GFP flags it gets to kmem_cache_alloc.
So it's possible to use __GFP_HIGHMEM with the slab
allocator.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
2009-02-12 10:06:04 -05:00
Chris Mason
42f15d77df Btrfs: Make sure dir is non-null before doing S_ISGID checks
The S_ISGID check in btrfs_new_inode caused an oops during subvol creation
because sometimes the dir is null.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-06 11:35:57 -05:00
Chris Mason
06d9a8d7c2 Btrfs: Change btrfs_truncate_inode_items to stop when it hits the inode
btrfs_truncate_inode_items is setup to stop doing btree searches when
it has finished removing the items for the inode.  It used to detect the
end of the inode by looking for an objectid that didn't match the
one we were searching for.

But, this would result in an extra search through the btree, which
adds extra balancing and cow costs to the operation.

This commit adds a check to see if we found the inode item, which means
we can stop searching early.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 09:30:58 -05:00
Chris Mason
f03d9301f1 Btrfs: Don't try to compress pages past i_size
The compression code had some checks to make sure we were only
compressing bytes inside of i_size, but it wasn't catching every
case.  To make things worse, some incorrect math about the number
of bytes remaining would make it try to compress more pages than the
file really had.

The fix used here is to fall back to the non-compression code in this
case, which does all the proper cleanup of delalloc and other accounting.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 09:31:06 -05:00
Chris Ball
8c087b5183 Btrfs: Handle SGID bit when creating inodes
Before this patch, new files/dirs would ignore the SGID bit on their
parent directory and always be owned by the creating user's uid/gid.

Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 09:29:54 -05:00
Chris Mason
bd56b30205 Btrfs: Make btrfs_drop_snapshot work in larger and more efficient chunks
Every transaction in btrfs creates a new snapshot, and then schedules the
snapshot from the last transaction for deletion.  Snapshot deletion
works by walking down the btree and dropping the reference counts
on each btree block during the walk.

If if a given leaf or node has a reference count greater than one,
the reference count is decremented and the subtree pointed to by that
node is ignored.

If the reference count is one, walking continues down into that node
or leaf, and the references of everything it points to are decremented.

The old code would try to work in small pieces, walking down the tree
until it found the lowest leaf or node to free and then returning.  This
was very friendly to the rest of the FS because it didn't have a huge
impact on other operations.

But it wouldn't always keep up with the rate that new commits added new
snapshots for deletion, and it wasn't very optimal for the extent
allocation tree because it wasn't finding leaves that were close together
on disk and processing them at the same time.

This changes things to walk down to a level 1 node and then process it
in bulk.  All the leaf pointers are sorted and the leaves are dropped
in order based on their extent number.

The extent allocation tree and commit code are now fast enough for
this kind of bulk processing to work without slowing the rest of the FS
down.  Overall it does less IO and is better able to keep up with
snapshot deletions under high load.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 09:27:02 -05:00
Chris Mason
b4ce94de9b Btrfs: Change btree locking to use explicit blocking points
Most of the btrfs metadata operations can be protected by a spinlock,
but some operations still need to schedule.

So far, btrfs has been using a mutex along with a trylock loop,
most of the time it is able to avoid going for the full mutex, so
the trylock loop is a big performance gain.

This commit is step one for getting rid of the blocking locks entirely.
btrfs_tree_lock takes a spinlock, and the code explicitly switches
to a blocking lock when it starts an operation that can schedule.

We'll be able get rid of the blocking locks in smaller pieces over time.
Tracing allows us to find the most common cause of blocking, so we
can start with the hot spots first.

The basic idea is:

btrfs_tree_lock() returns with the spin lock held

btrfs_set_lock_blocking() sets the EXTENT_BUFFER_BLOCKING bit in
the extent buffer flags, and then drops the spin lock.  The buffer is
still considered locked by all of the btrfs code.

If btrfs_tree_lock gets the spinlock but finds the blocking bit set, it drops
the spin lock and waits on a wait queue for the blocking bit to go away.

Much of the code that needs to set the blocking bit finishes without actually
blocking a good percentage of the time.  So, an adaptive spin is still
used against the blocking bit to avoid very high context switch rates.

btrfs_clear_lock_blocking() clears the blocking bit and returns
with the spinlock held again.

btrfs_tree_unlock() can be called on either blocking or spinning locks,
it does the right thing based on the blocking bit.

ctree.c has a helper function to set/clear all the locked buffers in a
path as blocking.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-02-04 09:25:08 -05:00
Jim Owens
0279b4cd86 Btrfs: selinux support
Add call to LSM security initialization and save
resulting security xattr for new inodes.

Add xattr support to symlink inode ops.

Set inode->i_op for existing special files.

Signed-off-by: jim owens <jowens@hp.com>
2009-02-04 09:29:13 -05:00
Chris Mason
89f135d8b5 Btrfs: fix readdir on 32 bit machines
After btrfs_readdir has gone through all the directory items, it
sets the directory f_pos to the largest possible int.  This way
applications that mix readdir with creating new files don't
end up in an endless loop finding the new directory items as they go.

It was a workaround for a bug in git, but the assumption was that if git
could make this looping mistake than it would be a common problem.

The largest possible int chosen was INT_LIMIT(typeof(file->f_pos),
and it is possible for that to be a larger number than 32 bit glibc
expects to come out of readdir.

This patches switches that to INT_LIMIT(off_t), which should keep
applications happy on 32 and 64 bit machines.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-01-28 15:34:27 -05:00
Yehuda Sadeh
1506fcc818 Btrfs: fiemap support
Now that bmap support is gone, this is the only way to get extent
mappings for userland.  These are still not valid for IO, but they
can tell us if a file has holes or how much fragmentation there is.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
2009-01-21 14:39:14 -05:00
Chris Mason
35054394c4 Btrfs: stop providing a bmap operation to avoid swapfile corruptions
Swapfiles use bmap to build a list of extents belonging to the file,
and they assume these extents won't change over the life of the file.
They also use resulting list to do IO directly to the block device.

This causes problems for btrfs in a few ways:

btrfs returns logical block numbers through bmap, and these are not suitable
for IO.  They might translate to different devices, raid etc.

COW means that file block mappings are going to change frequently.

Using swapfiles on btrfs will lead to corruption, so we're avoiding the
problem for now by dropping bmap support entirely.  A later commit
will add fiemap support for people that really want to know how
a file is laid out.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-01-21 13:11:13 -05:00
Qinghuang Feng
c6e308713a Btrfs: simplify iteration codes
Merge list_for_each* and list_entry to list_for_each_entry*

Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-01-21 10:59:08 -05:00
Huang Weiyi
7eaebe7d50 Btrfs: removed unused #include <version.h>'s
Removed unused #include <version.h>'s in btrfs

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-01-21 10:49:16 -05:00
Chris Mason
9ab86c8e01 Btrfs: kmap_atomic(KM_USER0) is safe for btrfs_readpage_end_io_hook
None of the checksum verification code schedules, so we can use the faster
kmap_atomic

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-01-07 09:48:51 -05:00
Chris Mason
cc7172defc Btrfs: Don't use kmap_atomic(..., KM_IRQ0) during checksum verifies
Checksum verification happens in a helper thread, and there is no
need to mess with interrupts.  This switches to kmap() instead.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-01-06 13:26:40 -05:00
Yan Zheng
07d400a6df Btrfs: tree logging checksum fixes
This patch contains following things.

1) Limit the max size of btrfs_ordered_sum structure to PAGE_SIZE.  This
struct is kmalloced so we want to keep it reasonable.

2) Replace copy_extent_csums by btrfs_lookup_csums_range.  This was
duplicated code in tree-log.c

3) Remove replay_one_csum. csum items are replayed at the same time as
   replaying file extents. This guarantees we only replay useful csums.

4) nbytes accounting fix.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
2009-01-06 11:42:00 -05:00
Yan Zheng
180591bcfe Btrfs: Use btrfs_join_transaction to avoid deadlocks during snapshot creation
Snapshot creation happens at a specific time during transaction commit.  We
need to make sure the code called by snapshot creation doesn't wait
for the running transaction to commit.

This changes btrfs_delete_inode and finish_pending_snaps to use
btrfs_join_transaction instead of btrfs_start_transaction to avoid deadlocks.

It would be better if btrfs_delete_inode didn't use the join, but the
call path that triggers it is:

btrfs_commit_transaction->create_pending_snapshots->
create_pending_snapshot->btrfs_lookup_dentry->
fixup_tree_root_location->btrfs_read_fs_root->
btrfs_read_fs_root_no_name->btrfs_orphan_cleanup->iput

This will be fixed in a later patch by moving the orphan cleanup to the
cleaner thread.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-01-06 09:58:06 -05:00
Chris Mason
d397712bcc Btrfs: Fix checkpatch.pl warnings
There were many, most are fixed now.  struct-funcs.c generates some warnings
but these are bogus.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2009-01-05 21:25:51 -05:00
Chris Mason
cad321ad52 Btrfs: shift all end_io work to thread pools
bio_end_io for reads without checksumming on and btree writes were
happening without using async thread pools.  This means the extent_io.c
code had to use spin_lock_irq and friends on the rb tree locks for
extent state.

There were some irq safe vs unsafe lock inversions between the delallock
lock and the extent state locks.  This patch gets rid of them by moving
all end_io code into the thread pools.

To avoid contention and deadlocks between the data end_io processing and the
metadata end_io processing yet another thread pool is added to finish
off metadata writes.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-17 14:51:42 -05:00
Chris Mason
75eff68ea6 Btrfs: Don't use spin*lock_irq for the delalloc lock
The delalloc lock doesn't need to have irqs disabled, nobody that
changes the number of delalloc bytes in the FS is running with irqs off.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
2008-12-15 15:54:40 -05:00