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2010-04-12Merge branch 'master' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable * 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: Btrfs: make sure the chunk allocator doesn't create zero length chunks Btrfs: fix data enospc check overflow
2010-04-06Btrfs: make sure the chunk allocator doesn't create zero length chunksChris Mason
A recent commit allowed for smaller chunks to be created, but didn't make sure they were always bigger than a stripe. After some divides, this led to zero length stripes. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-04-05Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstableLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: Btrfs: add check for changed leaves in setup_leaf_for_split Btrfs: create snapshot references in same commit as snapshot Btrfs: fix small race with delalloc flushing waitqueue's Btrfs: use add_to_page_cache_lru, use __page_cache_alloc Btrfs: fix chunk allocate size calculation Btrfs: kill max_extent mount option Btrfs: fail to mount if we have problems reading the block groups Btrfs: check btrfs_get_extent return for IS_ERR() Btrfs: handle kmalloc() failure in inode lookup ioctl Btrfs: dereferencing freed memory Btrfs: Simplify num_stripes's calculation logical for __btrfs_alloc_chunk() Btrfs: Add error handle for btrfs_search_slot() in btrfs_read_chunk_tree() Btrfs: Remove unnecessary finish_wait() in wait_current_trans() Btrfs: add NULL check for do_walk_down() Btrfs: remove duplicate include in ioctl.c Fix trivial conflict in fs/btrfs/compression.c due to slab.h include cleanups.
2010-04-05Btrfs: fix data enospc check overflowJosef Bacik
Because we account for reserved space we get from the allocator before we actually account for allocating delalloc space, we can have a small window where the amount of "used" space in a space_info is more than the total amount of space in the space_info. This will cause a overflow in our check, so it will seem like we have _tons_ of free space, and we'll allow reservations to occur that will end up larger than the amount of space we have. I've seen users report ENOSPC panic's in cow_file_range a few times recently, so I tried to reproduce this problem and found I could reproduce it if I ran one of my tests in a loop for like 20 minutes. With this patch my test ran all night without issues. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-04-05Btrfs: add check for changed leaves in setup_leaf_for_splitChris Mason
setup_leaf_for_split needs to drop the path and search again, and has checks to see if the item we want to split changed size. But, it misses the case where the leaf changed and now has enough room for the item we want to insert. This adds an extra check to make sure the leaf really needs splitting before we call btrfs_split_leaf(), which keeps us from trying to split a leaf with a single item. btrfs_split_leaf() will blindly split the single item leaf, leaving us with one good leaf and one empty leaf and then a crash. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-04-05Btrfs: create snapshot references in same commit as snapshotSage Weil
This creates the reference to a new snapshot in the same commit as the snapshot itself. This avoids the need for a second commit in order for a snapshot to be persistent, and also avoids the problem of "leaking" a new snapshot tree root if the host crashes before the second commit takes place. It is not at all clear to me why it wasn't always done this way. If there is still a reason for the two-stage {create,finish}_pending_snapshots() approach I'm missing something! :) I've been running this for a couple weeks under pretty heavy usage (a few snapshots per minute) without obvious problems. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-04-05Btrfs: fix small race with delalloc flushing waitqueue'sJosef Bacik
Everytime we start a new flushing thread, we init the waitqueue if there isn't a flushing thread running. The problem with this is we check space_info->flushing, which we clear right before doing a wake_up on the flushing waitqueue, which causes problems if we init the waitqueue in the middle of clearing the flushing flagh and calling wake_up. This is hard to hit, but the code is wrong anyway, so init the flushing/allocating waitqueue when creating the space info and let it be. I haven't seen the panic since I've been using this patch. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-04-05Btrfs: use add_to_page_cache_lru, use __page_cache_allocNick Piggin
Pagecache pages should be allocated with __page_cache_alloc, so they obey pagecache memory policies. add_to_page_cache_lru is exported, so it should be used. Benefits over using a private pagevec: neater code, 128 bytes fewer stack used, percpu lru ordering is preserved, and finally don't need to flush pagevec before returning so batching may be shared with other LRU insertions. Signed-off-by: Nick Piggin <npiggin@suse.de>: Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: fix chunk allocate size calculationJosef Bacik
If the amount of free space left in a device is less than what we think should be the minimum size, just ignore the minimum size and use the amount we have. I ran into this running tests on a 600mb volume, the chunk allocator wouldn't let me allocate the last 52mb of the disk for data because we want to have at least 64mb chunks for data. This patch fixes that problem. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: kill max_extent mount optionJosef Bacik
As Yan pointed out, theres not much reason for all this complicated math to account for file extents being split up into max_extent chunks, since they are likely to all end up in the same leaf anyway. Since there isn't much reason to use max_extent, just remove the option altogether so we have one less thing we need to test. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: fail to mount if we have problems reading the block groupsJosef Bacik
We don't actually check the return value of btrfs_read_block_groups, so we can possibly succeed to mount, but then fail to say read the superblock xattr for selinux which will cause the vfs code to deactivate the super. This is a problem because in find_free_extent we just assume that we will find the right space_info for the allocation we want. But if we failed to read the block groups, we won't have setup any space_info's, and we'll hit a NULL pointer deref in find_free_extent. This patch fixes that problem by checking the return value of btrfs_read_block_groups, and failing out properly. I've also added a check in find_free_extent so if for some reason we don't find an appropriate space_info, we just return -ENOSPC. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: check btrfs_get_extent return for IS_ERR()Dan Carpenter
btrfs_get_extent() never returns NULL, only a valid pointer or ERR_PTR() Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: handle kmalloc() failure in inode lookup ioctlDan Carpenter
Return -ENOMEM if kmalloc() fails. Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: dereferencing freed memoryDan Carpenter
The original code dereferenced range on the next line. Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: Simplify num_stripes's calculation logical for __btrfs_alloc_chunk()Zhao Lei
We can use this simple method to make source more readable. Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: Add error handle for btrfs_search_slot() in btrfs_read_chunk_tree()Zhao Lei
We need to check return value of btrfs_search_slot() in btrfs_read_chunk_tree() and do corresponding error handing. Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: Remove unnecessary finish_wait() in wait_current_trans()Zhao Lei
We only need to call finish_wait() after wait loop. By the way, this patch makes code of waiting loop similar to example in wait.h(no functional change) Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: add NULL check for do_walk_down()Miao Xie
btrfs_find_create_tree_block() may return NULL, so we must check the returned value, or we will access a NULL pointer. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30Btrfs: remove duplicate include in ioctl.cAndrea Gelmini
fs/btrfs/ioctl.c: ctree.h is included more than once. Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstableLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (30 commits) Btrfs: fix the inode ref searches done by btrfs_search_path_in_tree Btrfs: allow treeid==0 in the inode lookup ioctl Btrfs: return keys for large items to the search ioctl Btrfs: fix key checks and advance in the search ioctl Btrfs: buffer results in the space_info ioctl Btrfs: use __u64 types in ioctl.h Btrfs: fix search_ioctl key advance Btrfs: fix gfp flags masking in the compression code Btrfs: don't look at bio flags after submit_bio btrfs: using btrfs_stack_device_id() get devid btrfs: use memparse Btrfs: add a "df" ioctl for btrfs Btrfs: cache the extent state everywhere we possibly can V2 Btrfs: cache ordered extent when completing io Btrfs: cache extent state in find_delalloc_range Btrfs: change the ordered tree to use a spinlock instead of a mutex Btrfs: finish read pages in the order they are submitted btrfs: fix btrfs_mkdir goto for no free objectids Btrfs: flush data on snapshot creation Btrfs: make df be a little bit more understandable ...
2010-03-18Btrfs: fix the inode ref searches done by btrfs_search_path_in_treeChris Mason
This is used by the inode lookup ioctl to follow all the backrefs up to the subvol root. But the search being done would sometimes land one past the last item in the leaf instead of finding the backref. This changes the search to look for the highest possible backref and hop back one item. It also fixes a leaked path on failure to find the root. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-18Btrfs: allow treeid==0 in the inode lookup ioctlChris Mason
When a root id of 0 is sent to the inode lookup ioctl, it will use the root of the file we're ioctling and pass the root id back to userland along with the results. This allows userland to do searches based on that root later on. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-18Btrfs: return keys for large items to the search ioctlChris Mason
The search ioctl was skipping large items entirely (ones that are too big for the results buffer). This changes things to at least copy the item header so that we can send information about the item back to userland. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-18Btrfs: fix key checks and advance in the search ioctlChris Mason
The search ioctl was working well for finding tree roots, but using it for generic searches requires a few changes to how the keys are advanced. This treats the search control min fields for objectid, type and offset more like a key, where we drop the offset to zero once we bump the type, etc. The downside of this is that we are changing the min_type and min_offset fields during the search, and so the ioctl caller needs extra checks to make sure the keys in the result are the ones it wanted. This also changes key_in_sk to use btrfs_comp_cpu_keys, just to make things more readable. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-16Btrfs: buffer results in the space_info ioctlChris Mason
The space_info ioctl was using copy_to_user inside rcu_read_lock. This commit changes things to copy into a buffer first and then dump the result down to userland. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-16Btrfs: use __u64 types in ioctl.hSage Weil
Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-16Btrfs: fix search_ioctl key advanceSage Weil
key->type is u8, not u64. fs/btrfs/ioctl.c: In function 'copy_to_sk': fs/btrfs/ioctl.c:1024: warning: comparison is always true due to limited range of data type Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: fix gfp flags masking in the compression codeNick Piggin
GFP_FS must be masked out, NOFS can't be or'd in. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: don't look at bio flags after submit_bioChris Mason
After callling submit_bio, the bio can be freed at any time. The btrfs submission thread helper was checking the bio flags too late, which might not give the correct answer. When CONFIG_DEBUG_PAGE_ALLOC is turned on, it can lead to oopsen. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15btrfs: using btrfs_stack_device_id() get devidXiao Guangrong
We can use btrfs_stack_device_id() to get dev_item->devid Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15btrfs: use memparseAkinobu Mita
Use memparse() instead of its own private implementation. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: linux-btrfs@vger.kernel.org Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: add a "df" ioctl for btrfsJosef Bacik
df is a very loaded question in btrfs. This gives us a way to get the per-space usage information so we can tell exactly what is in use where. This will help us figure out ENOSPC problems, and help users better understand where their disk space is going. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: cache the extent state everywhere we possibly can V2Josef Bacik
This patch just goes through and fixes everybody that does lock_extent() blah unlock_extent() to use lock_extent_bits() blah unlock_extent_cached() and pass around a extent_state so we only have to do the searches once per function. This gives me about a 3 mb/s boots on my random write test. I have not converted some things, like the relocation and ioctl's, since they aren't heavily used and the relocation stuff is in the middle of being re-written. I also changed the clear_extent_bit() to only unset the cached state if we are clearing EXTENT_LOCKED and related stuff, so we can do things like this lock_extent_bits() clear delalloc bits unlock_extent_cached() without losing our cached state. I tested this thoroughly and turned on LEAK_DEBUG to make sure we weren't leaking extent states, everything worked out fine. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: cache ordered extent when completing ioJosef Bacik
When finishing io we run btrfs_dec_test_ordered_pending, and then immediately run btrfs_lookup_ordered_extent, but btrfs_dec_test_ordered_pending does that already, so we're searching twice when we don't have to. This patch lets us pass a btrfs_ordered_extent in to btrfs_dec_test_ordered_pending so if we do complete io on that ordered extent we can just use the one we found then instead of having to do another btrfs_lookup_ordered_extent. This made my fio job with the other patch go from 24 mb/s to 29 mb/s. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: cache extent state in find_delalloc_rangeJosef Bacik
This patch makes us cache the extent state we find in find_delalloc_range since we'll have to lock the extent later on in the function. This will keep us from re-searching for the rang when we try to lock the extent. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: change the ordered tree to use a spinlock instead of a mutexJosef Bacik
The ordered tree used to need a mutex, but currently all we use it for is to protect the rb_tree, and a spin_lock is just fine for that. Using a spin_lock instead makes dbench run a little faster, 58 mb/s instead of 51 mb/s, and have less latency, 3445.138 ms instead of 3820.633 ms. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: finish read pages in the order they are submittedChris Mason
The endio is done at reverse order of bio vectors. That means for a sequential read, the page first submitted will finish last in a bio. Considering we will do checksum (making cache hot) for every page, this does introduce delay (and chance to squeeze cache used soon) for pages submitted at the begining. I don't observe obvious performance difference with below patch at my simple test, but seems more natural to finish read in the order they are submitted. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15btrfs: fix btrfs_mkdir goto for no free objectidsMiao Xie
btrfs_mkdir() must jump to the place of ending transaction after btrfs_find_free_objectid() failed. Or this transaction can't end. Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: flush data on snapshot creationSage Weil
Flush any delalloc extents when we create a snapshot, so that recently written file data is always included in the snapshot. A later commit will add the ability to snapshot without the flush, but most people expect flushing. Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: make df be a little bit more understandableJosef Bacik
The way we report df usage is way confusing for everybody, including some other utilities (bacula for one). So this patch makes df a little bit more understandable. First we make used actually count the total amount of used space in all space info's. This will give us a real view of how much disk space is in use. Second, for blocks available, only count data space. This makes things like bacula work because it says 0 when you can no longer write anymore data to the disk. I think this is a nice compromise, since you will end up with something like the following [root@alpha ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup-lv_root 148G 30G 111G 21% / /dev/sda1 194M 116M 68M 64% /boot tmpfs 985M 12K 985M 1% /dev/shm /dev/mapper/VolGroup-LogVol02 145G 140G 0 100% /mnt/btrfs-test Compare this with btrfsctl -i output [root@alpha btrfs-progs-unstable]# ./btrfsctl -i /mnt/btrfs-test/ Metadata, DUP: total=4.62GB, used=2.46GB System, DUP: total=8.00MB, used=24.00KB Data: total=134.80GB, used=134.80GB Metadata: total=8.00MB, used=0.00 System: total=4.00MB, used=0.00 operation complete This way we show that there is no more data space to be used, but we have another 5GB of space left for metadata. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15btrfs: Update existing btrfs_device for renaming deviceTARUISI Hiroaki
When we scan devices in a multi-device filesystem, we memorize the original name. If the device gets a new name, later scans don't update the in-kernel structures related to it, and we're not able to mount the filesystem. This patch updates device name during scaning. Signed-off-by: TARUISI Hiroaki <taruishi.hiroak@jp.fujitsu.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: add new defrag-range ioctl.Chris Mason
The btrfs defrag ioctl was limited to doing the entire file. This commit adds a new interface that can defrag a specific range inside the file. It can also force compression on the file, allowing you to selectively compress individual files after they were created, even when mount -o compress isn't turned on. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: be more selective in the defrag ioctlChris Mason
The btrfs defrag ioctl had some bugs around delalloc accounting, and it wasn't properly skipping pages that were not in the mapping. It wasn't properly clearing the page checked flag, which could make the writeback code ignore the page forever while pinning it as dirty. This commit fixes those problems and makes defrag a little smarter. It skips holes and it doesn't waste time defragging large extents. If a tiny extent comes before a very large extent, it will defrag both of them to make sure the tiny extent ends up next to something big. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: run the backing dev more often in the submit_bio helperChris Mason
The submit_bio helper thread can decide to loop back around to service more bios. This commit forces it to unplug first, which helps reduce the latency seen by submitters. Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: make subvolid=0 mount the original default rootJosef Bacik
Since theres not a good way to make sure the user sees the original default root tree id, and not to mention it's 5 so is way different than any other volume, just make subvol=0 mount the original default root. This makes it a bit easier for users to handle in the long run. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: add ioctl and incompat flag to set the default mount subvolJosef Bacik
This patch needs to go along with my previous patch. This lets us set the default dir item's location to whatever root we want to use as our default mounting subvol. With this we don't have to use mount -o subvol=<tree id> anymore to mount a different subvol, we can just set the new one and it will just magically work. I've done some moderate testing with this, mostly just switching the default mount around, mounting subvols and the default mount at the same time and such, everything seems to work. Thanks, Older kernels would generally be able to still mount the filesystem with the default subvolume set, but it would result in a different volume being mounted, which could be an even more unpleasant suprise for users. So if you set your default subvolume, you can't go back to older kernels. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: change how we mount subvolumesJosef Bacik
This work is in preperation for being able to set a different root as the default mounting root. There is currently a problem with how we mount subvolumes. We cannot currently mount a subvolume of a subvolume, you can only mount subvolumes/snapshots of the default subvolume. So say you take a snapshot of the default subvolume and call it snap1, and then take a snapshot of snap1 and call it snap2, so now you have / /snap1 /snap1/snap2 as your available volumes. Currently you can only mount / and /snap1, you cannot mount /snap1/snap2. To fix this problem instead of passing subvolid=<name> you must pass in subvolid=<treeid>, where <treeid> is the tree id that gets spit out via the subvolume listing you get from the subvolume listing patches (btrfs filesystem list). This allows us to mount /, /snap1 and /snap1/snap2 as the root volume. In addition to the above, we also now read the default dir item in the tree root to get the root key that it points to. For now this just points at what has always been the default subvolme, but later on I plan to change it to point at whatever root you want to be the new default root, so you can just set the default mount and not have to mount with -o subvolid=<treeid>. I tested this out with the above scenario and it worked perfectly. Thanks, mount -o subvol operates inside the selected subvolid. For example: mount -o subvol=snap1,subvolid=256 /dev/xxx /mnt /mnt will have the snap1 directory for the subvolume with id 256. mount -o subvol=snap /dev/xxx /mnt /mnt will be the snap directory of whatever the default subvolume is. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: make set/get functions for the super compat_ro flags use compat_roJosef Bacik
Our set/get functions for compat_ro_flags actually look at compat_flags. This will mess any attempt to use compat flags up. The fix is obvious. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
2010-03-15Btrfs: add search and inode lookup ioctlsChris Mason
The search ioctl is a generic tool for doing btree searches from userland applications. The first user of the search ioctl is a subvolume listing feature, but we'll also use it to find new files in a subvolume. The search ioctl allows you to specify min and max keys to search for, along with min and max transid. It returns the items along with a header that includes the item key. Signed-off-by: Chris Mason <chris.mason@oracle.com>