Currently if we have corrupted items things will blow up in spectacular ways.
So as we read in blocks and they are leaves, check the entire leaf to make sure
all of the items are correct and point to valid parts in the leaf for the item
data the are responsible for. If the item is corrupt we will kick back EIO and
not read any of the copies since they are likely to not be correct either. This
will catch generic corruptions, it will be up to the individual callers of
btrfs_search_slot to make sure their items are right. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
If we cannot truncate an inode for some reason we will never delete the orphan
item associated with that inode, which means that we will loop forever in
btrfs_orphan_cleanup. Instead of doing this just return error so we fail to
mount. It sucks, but hey it's better than hanging. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
We track delayed allocation per inodes via 2 counters, one is
outstanding_extents and reserved_extents. Outstanding_extents is already an
atomic_t, but reserved_extents is not and is protected by a spinlock. So
convert this to an atomic_t and instead of using a spinlock, use atomic_cmpxchg
when releasing delalloc bytes. This makes our inode 72 bytes smaller, and
reduces locking overhead (albiet it was minimal to begin with). Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: break out of shrink_delalloc earlier
btrfs: fix not enough reserved space
btrfs: fix dip leak
Btrfs: make sure not to return overlapping extents to fiemap
Btrfs: deal with short returns from copy_from_user
Btrfs: fix regressions in copy_from_user handling
Josef had changed shrink_delalloc to exit after three shrink
attempts, which wasn't quite enough because new writers could
race in and steal free space.
But it also fixed deadlocks and stalls as we tried to recover
delalloc reservations. The code was tweaked to loop 1024
times, and would reset the counter any time a small amount
of progress was made. This was too drastic, and with a
lot of writers we can end up stuck in shrink_delalloc forever.
The shrink_delalloc loop is fairly complex because the caller is looping
too, and the caller will go ahead and force a transaction commit to make
sure we reclaim space.
This reworks things to exit shrink_delalloc when we've forced some
writeback and the delalloc reservations have gone down. This means
the writeback has not just started but has also finished at
least some of the metadata changes required to reclaim delalloc
space.
If we've got this wrong, we're returning ENOSPC too early, which
is a big improvement over the current behavior of hanging the machine.
Test 224 in xfstests hammers on this nicely, and with 1000 writers
trying to fill a 1GB drive we get our first ENOSPC at 93% full. The
other writers are able to continue until we get 100%.
This is a worst case test for btrfs because the 1000 writers are doing
small IO, and the small FS size means we don't have a lot of room
for metadata chunks.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: fix fiemap bugs with delalloc
Btrfs: set FMODE_EXCL in btrfs_device->mode
Btrfs: make btrfs_rm_device() fail gracefully
Btrfs: Avoid accessing unmapped kernel address
Btrfs: Fix BTRFS_IOC_SUBVOL_SETFLAGS ioctl
Btrfs: allow balance to explicitly allocate chunks as it relocates
Btrfs: put ENOSPC debugging under a mount option
Btrfs device shrinking and balancing ends up reallocating all the blocks
in order to allow COW to move them to new destinations. It is somewhat
awkward in terms of ENOSPC because most of the enospc code is built
around the idea that some operation on a reference counted tree triggers
allocations in the non-reference counted trees.
This commit changes the balancing code to deal with enospc by trying to
allocate a new chunk. If that allocation succeeds, we go ahead and
retry whatever failed due to enospc.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
ENOSPC in btrfs is getting to the point where the extra debugging isn't
required. I've put it under mount -o enospc_debug just in case someone
is having difficult problems.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
I add the check on the return value of alloc_extent_map() to several places.
In addition, alloc_extent_map() returns only the address or NULL.
Therefore, check by IS_ERR() is unnecessary. So, I remove IS_ERR() checking.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (33 commits)
Btrfs: Fix page count calculation
btrfs: Drop __exit attribute on btrfs_exit_compress
btrfs: cleanup error handling in btrfs_unlink_inode()
Btrfs: exclude super blocks when we read in block groups
Btrfs: make sure search_bitmap finds something in remove_from_bitmap
btrfs: fix return value check of btrfs_start_transaction()
btrfs: checking NULL or not in some functions
Btrfs: avoid uninit variable warnings in ordered-data.c
Btrfs: catch errors from btrfs_sync_log
Btrfs: make shrink_delalloc a little friendlier
Btrfs: handle no memory properly in prepare_pages
Btrfs: do error checking in btrfs_del_csums
Btrfs: use the global block reserve if we cannot reserve space
Btrfs: do not release more reserved bytes to the global_block_rsv than we need
Btrfs: fix check_path_shared so it returns the right value
btrfs: check return value of btrfs_start_ioctl_transaction() properly
btrfs: fix return value check of btrfs_join_transaction()
fs/btrfs/inode.c: Add missing IS_ERR test
btrfs: fix missing break in switch phrase
btrfs: fix several uncheck memory allocations
...
This has been resulting in a BUT_ON(ret) after btrfs_reserve_extent in
btrfs_cow_file_range. The reason is we don't actually calculate the bytes_super
for a block group until we go to cache it, which means that the space_info can
hand out reservations for space that it doesn't actually have, and we can run
out of data space. This is also a problem if you are using space caching since
we don't ever calculate bytes_super for the block groups. So instead everytime
we read a block group call exclude_super_stripes, which calculates the
bytes_super for the block group so it can be left out of the space_info. Then
whenever caching completes we just call free_excluded_extents so that the super
excluded extents are freed up. Also if we are unmounting and we hit any block
groups that haven't been cached we still need to call free_excluded_extents to
make sure things are cleaned up properly. Thanks,
Reported-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The error check of btrfs_start_transaction() is added, and the mistake
of the error check on several places is corrected.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Because NULL is returned when the memory allocation fails,
it is checked whether it is NULL.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Xfstests 224 will just sit there and spin for ever until eventually we give up
flushing delalloc and exit. On my box this took several hours. I could not
interrupt this process either, even though we use INTERRUPTIBLE. So do 2 things
1) Keep us from looping over and over again without reclaiming anything
2) If we get interrupted exit the loop
I tested this and the test now exits in a reasonable amount of time, and can be
interrupted with ctrl+c. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
We call use_block_rsv right before we make an allocation in order to make sure
we have enough space. Now normally people have called btrfs_start_transaction()
with the appropriate amount of space that we need, so we just use some of that
pre-reserved space and move along happily. The problem is where people use
btrfs_join_transaction(), which doesn't actually reserve any space. So we try
and reserve space here, but we cannot flush delalloc, so this forces us to
return -ENOSPC when in reality we have plenty of space. The most common symptom
is seeing a bunch of "couldn't dirty inode" messages in syslog. With
xfstests 224 we end up falling back to start_transaction and then doing all the
flush delalloc stuff which causes to hang for a very long time.
So instead steal from the global reserve, which is what this is meant for
anyway. With this patch and the other 2 I have sent xfstests 224 now passes
successfully. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When we do btrfs_block_rsv_release, if global_block_rsv is not full we will
release all the extra bytes to global_block_rsv, even if it's only a little
short of the amount of space that we need to reserve. This causes us to starve
ourselves of reservable space during the transaction which will force us to
shrink delalloc bytes and commit the transaction more often than we should. So
instead just add the amount of bytes we need to add to the global reserve so
reserved == size, and then add the rest back into the space_info for general
use. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The error check of btrfs_join_transaction()/btrfs_join_transaction_nolock()
is added, and the mistake of the error check in several places is
corrected.
For more stable Btrfs, I think that we should reduce BUG_ON().
But, I think that long time is necessary for this.
So, I propose this patch as a short-term solution.
With this patch:
- To more stable Btrfs, the part that should be corrected is clarified.
- The panic isn't done by the NULL pointer reference etc. (even if
BUG_ON() is increased temporarily)
- The error code is returned in the place where the error can be easily
returned.
As a long-term plan:
- BUG_ON() is reduced by using the forced-readonly framework, etc.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (25 commits)
Btrfs: forced readonly mounts on errors
btrfs: Require CAP_SYS_ADMIN for filesystem rebalance
Btrfs: don't warn if we get ENOSPC in btrfs_block_rsv_check
btrfs: Fix memory leak in btrfs_read_fs_root_no_radix()
btrfs: check NULL or not
btrfs: Don't pass NULL ptr to func that may deref it.
btrfs: mount failure return value fix
btrfs: Mem leak in btrfs_get_acl()
btrfs: fix wrong free space information of btrfs
btrfs: make the chunk allocator utilize the devices better
btrfs: restructure find_free_dev_extent()
btrfs: fix wrong calculation of stripe size
btrfs: try to reclaim some space when chunk allocation fails
btrfs: fix wrong data space statistics
fs/btrfs: Fix build of ctree
Btrfs: fix off by one while setting block groups readonly
Btrfs: Add BTRFS_IOC_SUBVOL_GETFLAGS/SETFLAGS ioctls
Btrfs: Add readonly snapshots support
Btrfs: Refactor btrfs_ioctl_snap_create()
btrfs: Extract duplicate decompress code
...
This patch comes from "Forced readonly mounts on errors" ideas.
As we know, this is the first step in being more fault tolerant of disk
corruptions instead of just using BUG() statements.
The major content:
- add a framework for generating errors that should result in filesystems
going readonly.
- keep FS state in disk super block.
- make sure that all of resource will be freed and released at umount time.
- make sure that fter FS is forced readonly on error, there will be no more
disk change before FS is corrected. For this, we should stop write operation.
After this patch is applied, the conversion from BUG() to such a framework can
happen incrementally.
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
If we run low on space we could get a bunch of warnings out of
btrfs_block_rsv_check, but this is mostly just called via the transaction code
to see if we need to end the transaction, it expects to see failures, so let's
not WARN and freak everybody out for no reason. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When we store data by raid profile in btrfs with two or more different size
disks, df command shows there is some free space in the filesystem, but the
user can not write any data in fact, df command shows the wrong free space
information of btrfs.
# mkfs.btrfs -d raid1 /dev/sda9 /dev/sda10
# btrfs-show
Label: none uuid: a95cd49e-6e33-45b8-8741-a36153ce4b64
Total devices 2 FS bytes used 28.00KB
devid 1 size 5.01GB used 2.03GB path /dev/sda9
devid 2 size 10.00GB used 2.01GB path /dev/sda10
# btrfs device scan /dev/sda9 /dev/sda10
# mount /dev/sda9 /mnt
# dd if=/dev/zero of=tmpfile0 bs=4K count=9999999999
(fill the filesystem)
# sync
# df -TH
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda9 btrfs 17G 8.6G 5.4G 62% /mnt
# btrfs-show
Label: none uuid: a95cd49e-6e33-45b8-8741-a36153ce4b64
Total devices 2 FS bytes used 3.99GB
devid 1 size 5.01GB used 5.01GB path /dev/sda9
devid 2 size 10.00GB used 4.99GB path /dev/sda10
It is because btrfs cannot allocate chunks when one of the pairing disks has
no space, the free space on the other disks can not be used for ever, and should
be subtracted from the total space, but btrfs doesn't subtract this space from
the total. It is strange to the user.
This patch fixes it by calcing the free space that can be used to allocate
chunks.
Implementation:
1. get all the devices free space, and align them by stripe length.
2. sort the devices by the free space.
3. check the free space of the devices,
3.1. if it is not zero, and then check the number of the devices that has
more free space than this device,
if the number of the devices is beyond the min stripe number, the free
space can be used, and add into total free space.
if the number of the devices is below the min stripe number, we can not
use the free space, the check ends.
3.2. if the free space is zero, check the next devices, goto 3.1
This implementation is just likely fake chunk allocation.
After appling this patch, df can show correct space information:
# df -TH
Filesystem Type Size Used Avail Use% Mounted on
/dev/sda9 btrfs 17G 8.6G 0 100% /mnt
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
- make it return the start position and length of the max free space when it can
not find a suitable free space.
- make it more readability
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
We cannot write data into files when when there is tiny space in the filesystem.
Reproduce steps:
# mkfs.btrfs /dev/sda1
# mount /dev/sda1 /mnt
# dd if=/dev/zero of=/mnt/tmpfile0 bs=4K count=1
# dd if=/dev/zero of=/mnt/tmpfile1 bs=4K count=99999999999999
(fill the filesystem)
# umount /mnt
# mount /dev/sda1 /mnt
# rm -f /mnt/tmpfile0
# dd if=/dev/zero of=/mnt/tmpfile0 bs=4K count=1
(failed with nospec)
But if we do the last step again, we can write data successfully. The reason of
the problem is that btrfs didn't try to commit the current transaction and
reclaim some space when chunk allocation failed.
This patch fixes it by committing the current transaction to reclaim some
space when chunk allocation fails.
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When we read in block groups, we'll set non-redundant groups
readonly if we find a raid1, DUP or raid10 group. But the
ro code has an off by one bug in the math around testing to
make sure out accounting doesn't go wrong.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: prevent RAID level downgrades when space is low
Btrfs: account for missing devices in RAID allocation profiles
Btrfs: EIO when we fail to read tree roots
Btrfs: fix compiler warnings
Btrfs: Make async snapshot ioctl more generic
Btrfs: pwrite blocked when writing from the mmaped buffer of the same page
Btrfs: Fix a crash when mounting a subvolume
Btrfs: fix sync subvol/snapshot creation
Btrfs: Fix page leak in compressed writeback path
Btrfs: do not BUG if we fail to remove the orphan item for dead snapshots
Btrfs: fixup return code for btrfs_del_orphan_item
Btrfs: do not do fast caching if we are allocating blocks for tree_root
Btrfs: deal with space cache errors better
Btrfs: fix use after free in O_DIRECT
The extent allocator has code that allows us to fill
allocations from any available block group, even if it doesn't
match the raid level we've requested.
This was put in because adding a new drive to a filesystem
made with the default mkfs options actually upgrades the metadata from
single spindle dup to full RAID1.
But, the code also allows us to allocate from a raid0 chunk when we
really want a raid1 or raid10 chunk. This can cause big trouble because
mkfs creates a small (4MB) raid0 chunk for data and metadata which then
goes unused for raid1/raid10 installs.
The allocator will happily wander in and allocate from that chunk when
things get tight, which is not correct.
The fix here is to make sure that we provide duplication when the
caller has asked for it. It does all the dups to be any raid level,
which preserves the dup->raid1 upgrade abilities.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
When we mount in RAID degraded mode without adding a new device to
replace the failed one, we can end up using the wrong RAID flags for
allocations.
This results in strange combinations of block groups (raid1 in a raid10
filesystem) and corruptions when we try to allocate blocks from single
spindle chunks on drives that are actually missing.
The first device has two small 4MB chunks in it that mkfs creates and
these are usually unused in a raid1 or raid10 setup. But, in -o degraded,
the allocator will fall back to these because the mask of desired raid groups
isn't correct.
The fix here is to count the missing devices as we build up the list
of devices in the system. This count is used when picking the
raid level to make sure we continue using the same levels that were
in place before we lost a drive.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Not being able to delete an orphan item isn't a horrible thing. The worst that
happens is the next time around we try and do the orphan cleanup and we can't
find the referenced object and just delete the item and move on.
Signed-off-by: Josef Bacik <josef@redhat.com>
Since the fast caching uses normal tree locking, we can possibly deadlock if we
get to the caching via a btrfs_search_slot() on the tree_root. So just check to
see if the root we are on is the tree root, and just don't do the fast caching.
Reported-by: Sage Weil <sage@newdream.net>
Signed-off-by: Josef Bacik <josef@redhat.com>
Currently if the space cache inode generation number doesn't match the
generation number in the space cache header we will just fail to load the space
cache, but we won't mark the space cache as an error, so we'll keep getting that
error each time somebody tries to cache that block group until we actually clear
the thing. Fix this by marking the space cache as having an error so we only
get the message once. This patch also makes it so that we don't try and setup
space cache for a block group that isn't cached, since we won't be able to write
it out anyway. None of these problems are actual problems, they are just
annoying and sub-optimal. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (24 commits)
Btrfs: don't use migrate page without CONFIG_MIGRATION
Btrfs: deal with DIO bios that span more than one ordered extent
Btrfs: setup blank root and fs_info for mount time
Btrfs: fix fiemap
Btrfs - fix race between btrfs_get_sb() and umount
Btrfs: update inode ctime when using links
Btrfs: make sure new inode size is ok in fallocate
Btrfs: fix typo in fallocate to make it honor actual size
Btrfs: avoid NULL pointer deref in try_release_extent_buffer
Btrfs: make btrfs_add_nondir take parent inode as an argument
Btrfs: hold i_mutex when calling btrfs_log_dentry_safe
Btrfs: use dget_parent where we can UPDATED
Btrfs: fix more ESTALE problems with NFS
Btrfs: handle NFS lookups properly
btrfs: make 1-bit signed fileds unsigned
btrfs: Show device attr correctly for symlinks
btrfs: Set file size correctly in file clone
btrfs: Check if dest_offset is block-size aligned before cloning file
Btrfs: handle the space_cache option properly
btrfs: Fix early enospc because 'unused' calculated with wrong sign.
...
'unused' calculated with wrong sign in reserve_metadata_bytes().
This might have lead to unwanted over-reservations.
Signed-off-by: Arne Jansen <sensille@gmx.net>
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (39 commits)
Btrfs: deal with errors from updating the tree log
Btrfs: allow subvol deletion by unprivileged user with -o user_subvol_rm_allowed
Btrfs: make SNAP_DESTROY async
Btrfs: add SNAP_CREATE_ASYNC ioctl
Btrfs: add START_SYNC, WAIT_SYNC ioctls
Btrfs: async transaction commit
Btrfs: fix deadlock in btrfs_commit_transaction
Btrfs: fix lockdep warning on clone ioctl
Btrfs: fix clone ioctl where range is adjacent to extent
Btrfs: fix delalloc checks in clone ioctl
Btrfs: drop unused variable in block_alloc_rsv
Btrfs: cleanup warnings from gcc 4.6 (nonbugs)
Btrfs: Fix variables set but not read (bugs found by gcc 4.6)
Btrfs: Use ERR_CAST helpers
Btrfs: use memdup_user helpers
Btrfs: fix raid code for removing missing drives
Btrfs: Switch the extent buffer rbtree into a radix tree
Btrfs: restructure try_release_extent_buffer()
Btrfs: use the flusher threads for delalloc throttling
Btrfs: tune the chunk allocation to 5% of the FS as metadata
...
Fix up trivial conflicts in fs/btrfs/super.c and fs/fs-writeback.c, and
remove use of INIT_RCU_HEAD in fs/btrfs/extent_io.c (that init macro was
useless and removed in commit 5e8067adfd: "rcu head remove init")
These are all the cases where a variable is set, but not read which are
not bugs as far as I can see, but simply leftovers.
Still needs more review.
Found by gcc 4.6's new warnings
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
We have a fairly complex set of loops around walking our list of
delalloc inodes when we find metadata delalloc space running low.
It doesn't work very well, can use large amounts of CPU and doesn't
do very efficient writeback.
This switches us to kick the bdi flusher threads instead. All dirty
data in btrfs is accounted as delalloc data, so this is very similar
in terms of what it writes, but we're able to just kick off the IO
and wait for progress.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
An earlier commit tried to keep us from allocating too many
empty metadata chunks. It was somewhat too restrictive and could
lead to ENOSPC errors on empty filesystems.
This increases the limits to about 5% of the FS size, allowing more
metadata chunks to be preallocated.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
If you mount -o space_cache, the option will be persistent across mounts, but to
make sure the user knows that they did this, emit a message telling them if they
didn't mount with -o space_cache but the feature is still used.
Signed-off-by: Josef Bacik <josef@redhat.com>
If something goes wrong with the free space cache we need a way to make sure
it's not loaded on mount and that it's cleared for everybody. When you pass the
clear_cache option it will make it so all block groups are setup to be cleared,
which keeps them from being loaded and then they will be truncated when the
transaction is committed. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
There are just a few things that need to be fixed in the kernel to support mixed
data+metadata block groups. Mostly we just need to make sure that if we are
using mixed block groups that we continue to allocate mixed block groups as we
need them. Also we need to make sure __find_space_info will find our space info
if we search for DATA or METADATA only. Tested this with xfstests and it works
nicely. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
With the free space disk caching we can mark the block group as started with the
caching, but we don't have a caching ctl. This can race with anybody else who
tries to get the caching ctl before we cache (this is very hard to do btw). So
instead check to see if cache->caching_ctl is set, and if not return NULL.
Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
This patch actually loads the free space cache if it exists. The only thing
that really changes here is that we need to cache the block group if we're going
to remove an extent from it. Previously we did not do this since the caching
kthread would pick it up. With the on disk cache we don't have this luxury so
we need to make sure we read the on disk cache in first, and then remove the
extent, that way when the extent is unpinned the free space is added to the
block group. This has been tested with all sorts of things.
Signed-off-by: Josef Bacik <josef@redhat.com>
This is a simple bit, just dump the free space cache out to our preallocated
inode when we're writing out dirty block groups. There are a bunch of changes
in inode.c in order to account for special cases. Mostly when we're doing the
writeout we're holding trans_mutex, so we need to use the nolock transacation
functions. Also we can't do asynchronous completions since the async thread
could be blocked on already completed IO waiting for the transaction lock. This
has been tested with xfstests and btrfs filesystem balance, as well as my ENOSPC
tests. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
In order to save free space cache, we need an inode to hold the data, and we
need a special item to point at the right inode for the right block group. So
first, create a special item that will point to the right inode, and the number
of extent entries we will have and the number of bitmaps we will have. We
truncate and pre-allocate space everytime to make sure it's uptodate.
This feature will be turned on as soon as you mount with -o space_cache, however
it is safe to boot into old kernels, they will just generate the cache the old
fashion way. When you boot back into a newer kernel we will notice that we
modified and not the cache and automatically discard the cache.
Signed-off-by: Josef Bacik <josef@redhat.com>
Because btrfs_dirty_inode does a btrfs_join_transaction, it doesn't actually
reserve space. It does this so we can try and dirty the inode quickly without
having to deal with the ENOSPC problems. But if it does get back ENOSPC it
handles it properly. The problem is use_block_rsv does a WARN_ON whenever this
case happens, even tho btrfs_dirty_inode takes it into account and actually
expects to get -ENOSPC if things are particularly tight. So instead just remove
the warning. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
btrfs_commit_transaction will free our trans, but because we pass trans to
shrink_delalloc we could possibly have a use after free situation. So instead
if we commit the transaction, set trans to null and set committed to true so we
don't keep trying to commit a transaction. This fixes a panic I could reproduce
at will. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
With multi-threaded writes we were getting ENOSPC early because somebody would
come in, start flushing delalloc because they couldn't make their reservation,
and in the meantime other threads would come in and use the space that was
getting freed up, so when the original thread went to check to see if they had
space they didn't and they'd return ENOSPC. So instead if we have some free
space but not enough for our reservation, take the reservation and then start
doing the flushing. The only time we don't take reservations is when we've
already overcommitted our space, that way we don't have people who come late to
the party way overcommitting ourselves. This also moves all of the retrying and
flushing code into reserve_metdata_bytes so it's all uniform. This keeps my
fs_mark test from returning -ENOSPC as soon as it starts and actually lets me
fill up the disk. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Because the ENOSPC code over reserves super aggressively we end up allocating
chunks way more often than we should. For example with my fs_mark tests on a
2gb fs I can end up reserved 1gb just for metadata, when only 34mb of that is
being used. So instead check to see if the amount of space actually used is
less than 30% of the total space, and if so don't allocate a chunk, but only if
we have at least 256mb of free space to make sure we don't put too much pressure
on free space.
Signed-off-by: Josef Bacik <josef@redhat.com>
