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path: root/fs/btrfs/disk-io.c
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* Btrfs: remove some WARN_ONs in the IO failure pathChris Mason2009-05-14
| | | | | | | | 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>
* Btrfs: Fix a bunch of printk() warnings.Joel Becker2009-04-27
| | | | | | | | Just happened to notice a bunch of %llu vs u64 warnings. Here's a patch to cast them all. Signed-off-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: ratelimit IO error printksChris Mason2009-04-27
| | | | | | | | | | | 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>
* Btrfs: remove #if 0 codeChris Mason2009-04-27
| | | | | | Btrfs had some old code sitting around under #if 0, this drops it. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: try to keep a healthy ratio of metadata vs data block groupsJosef Bacik2009-04-24
| | | | | | | | | | | | | | | This patch makes the chunk allocator keep a good ratio of metadata vs data block groups. By default for every 8 data block groups, we'll allocate 1 metadata chunk, or about 12% of the disk will be allocated for metadata. This can be changed by specifying the metadata_ratio mount option. This is simply the number of data block groups that have to be allocated to force a metadata chunk allocation. By making sure we allocate metadata chunks more often, we are less likely to get into situations where the whole disk has been allocated as data block groups. Signed-off-by: Josef Bacik <jbacik@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: add a priority queue to the async thread helpersChris Mason2009-04-20
| | | | | | | | | | | | | | | | | | | | | | | | | | Btrfs is using WRITE_SYNC_PLUG to send down synchronous IOs with a higher priority. But, the checksumming helper threads prevent it from being fully effective. There are two problems. First, a big queue of pending checksumming will delay the synchronous IO behind other lower priority writes. Second, the checksumming uses an ordered async work queue. The ordering makes sure that IOs are sent to the block layer in the same order they are sent to the checksumming threads. Usually this gives us less seeky IO. But, when we start mixing IO priorities, the lower priority IO can delay the higher priority IO. This patch solves both problems by adding a high priority list to the async helper threads, and a new btrfs_set_work_high_prio(), which is used to make put a new async work item onto the higher priority list. The ordering is still done on high priority IO, but all of the high priority bios are ordered separately from the low priority bios. This ordering is purely an IO optimization, it is not involved in data or metadata integrity. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: use WRITE_SYNC for synchronous writesChris Mason2009-04-20
| | | | | | | | | | | | | | | | | Part of reducing fsync/O_SYNC/O_DIRECT latencies is using WRITE_SYNC for writes we plan on waiting on in the near future. This patch mirrors recent changes in other filesystems and the generic code to use WRITE_SYNC when WB_SYNC_ALL is passed and to use WRITE_SYNC for other latency critical writes. Btrfs uses async worker threads for checksumming before the write is done, and then again to actually submit the bios. The bio submission code just runs a per-device list of bios that need to be sent down the pipe. This list is split into low priority and high priority lists so the WRITE_SYNC IO happens first. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstableLinus Torvalds2009-04-03
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 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
| * Btrfs: remove dead codeDan Carpenter2009-04-02
| | | | | | | | | | | | | | | | Remove an unneeded return statement and conditional Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
| * Btrfs: rework allocation clusteringChris Mason2009-04-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Because btrfs is copy-on-write, we end up picking new locations for blocks very often. This makes it fairly difficult to maintain perfect read patterns over time, but we can at least do some optimizations for writes. This is done today by remembering the last place we allocated and trying to find a free space hole big enough to hold more than just one allocation. The end result is that we tend to write sequentially to the drive. This happens all the time for metadata and it happens for data when mounted -o ssd. But, the way we record it is fairly racey and it tends to fragment the free space over time because we are trying to allocate fairly large areas at once. This commit gets rid of the races by adding a free space cluster object with dedicated locking to make sure that only one process at a time is out replacing the cluster. The free space fragmentation is somewhat solved by allowing a cluster to be comprised of smaller free space extents. This part definitely adds some CPU time to the cluster allocations, but it allows the allocator to consume the small holes left behind by cow. Signed-off-by: Chris Mason <chris.mason@oracle.com>
| * Btrfs: kill the pinned_mutexJosef Bacik2009-04-03
| | | | | | | | | | | | | | | | | | | | | | This patch removes the pinned_mutex. The extent io map has an internal tree lock that protects the tree itself, and since we only copy the extent io map when we are committing the transaction we don't need it there. We also don't need it when caching the block group since searching through the tree is also protected by the internal map spin lock. Signed-off-by: Josef Bacik <jbacik@redhat.com>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstableLinus Torvalds2009-04-01
|\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 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
| * Btrfs: add extra flushing for renames and truncatesChris Mason2009-03-31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * Btrfs: leave btree locks spinning more oftenChris Mason2009-03-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * Btrfs: process the delayed reference queue in clustersChris Mason2009-03-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The delayed reference queue maintains pending operations that need to be done to the extent allocation tree. These are processed by finding records in the tree that are not currently being processed one at a time. This is slow because it uses lots of time searching through the rbtree and because it creates lock contention on the extent allocation tree when lots of different procs are running delayed refs at the same time. This commit changes things to grab a cluster of refs for processing, using a cursor into the rbtree as the starting point of the next search. This way we walk smoothly through the rbtree. Signed-off-by: Chris Mason <chris.mason@oracle.com>
| * Btrfs: do extent allocation and reference count updates in the backgroundChris Mason2009-03-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The extent allocation tree maintains a reference count and full back reference information for every extent allocated in the filesystem. For subvolume and snapshot trees, every time a block goes through COW, the new copy of the block adds a reference on every block it points to. If a btree node points to 150 leaves, then the COW code needs to go and add backrefs on 150 different extents, which might be spread all over the extent allocation tree. These updates currently happen during btrfs_cow_block, and most COWs happen during btrfs_search_slot. btrfs_search_slot has locks held on both the parent and the node we are COWing, and so we really want to avoid IO during the COW if we can. This commit adds an rbtree of pending reference count updates and extent allocations. The tree is ordered by byte number of the extent and byte number of the parent for the back reference. The tree allows us to: 1) Modify back references in something close to disk order, reducing seeks 2) Significantly reduce the number of modifications made as block pointers are balanced around 3) Do all of the extent insertion and back reference modifications outside of the performance critical btrfs_search_slot code. #3 has the added benefit of greatly reducing the btrfs stack footprint. The extent allocation tree modifications are done without the deep (and somewhat recursive) call chains used in the past. These delayed back reference updates must be done before the transaction commits, and so the rbtree is tied to the transaction. Throttling is implemented to help keep the queue of backrefs at a reasonable size. Since there was a similar mechanism in place for the extent tree extents, that is removed and replaced by the delayed reference tree. Yan Zheng <yan.zheng@oracle.com> helped review and fixup this code. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* | btrfs: get rid of current_is_pdflush() in btrfs_btree_balance_dirtyJens Axboe2009-03-26
|/ | | | | | | Chris says it's safe to kill. Acked-by: Chris Mason <chris.mason@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Btrfs: fix spinlock assertions on UP systemsChris Mason2009-03-09
| | | | | | | | | | | btrfs_tree_locked was being used to make sure a given extent_buffer was properly locked in a few places. But, it wasn't correct for UP compiled kernels. This switches it to using assert_spin_locked instead, and renames it to btrfs_assert_tree_locked to better reflect how it was really being used. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: make a lockdep class for the extent buffer locksChris Mason2009-02-12
| | | | | | | | | | | | | | | | | | | | Btrfs is currently using spin_lock_nested with a nested value based on the tree depth of the block. But, this doesn't quite work because the max tree depth is bigger than what spin_lock_nested can deal with, and because locks are sometimes taken before the level field is filled in. The solution here is to use lockdep_set_class_and_name instead, and to set the class before unlocking the pages when the block is read from the disk and just after init of a freshly allocated tree block. btrfs_clear_path_blocking is also changed to take the locks in the proper order, and it also makes sure all the locks currently held are properly set to blocking before it tries to retake the spinlocks. Otherwise, lockdep gets upset about bad lock orderin. The lockdep magic cam from Peter Zijlstra <peterz@infradead.org> Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: Change btree locking to use explicit blocking pointsChris Mason2009-02-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* Btrfs: hash_lock is no longer neededChris Mason2009-02-04
| | | | | | | | | | | | | | | Before metadata is written to disk, it is updated to reflect that writeout has begun. Once this update is done, the block must be cow'd before it can be modified again. This update was originally synchronized by using a per-fs spinlock. Today the buffers for the metadata blocks are locked before writeout begins, and everyone that tests the flag has the buffer locked as well. So, the per-fs spinlock (called hash_lock for no good reason) is no longer required. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: async threads should try harder to find workChris Mason2009-02-04
| | | | | | | | | | | | Tracing shows the delay between when an async thread goes to sleep and when more work is added is often very short. This commit adds a little bit of delay and extra checking to the code right before we schedule out. It allows more work to be added to the worker without requiring notifications from other procs. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: fix tree logs parallel syncYan Zheng2009-01-21
| | | | | | | | | | | | | | | | | | | | | | | | | | To improve performance, btrfs_sync_log merges tree log sync requests. But it wrongly merges sync requests for different tree logs. If multiple tree logs are synced at the same time, only one of them actually gets synced. This patch has following changes to fix the bug: Move most tree log related fields in btrfs_fs_info to btrfs_root. This allows merging sync requests separately for each tree log. Don't insert root item into the log root tree immediately after log tree is allocated. Root item for log tree is inserted when log tree get synced for the first time. This allows syncing the log root tree without first syncing all log trees. At tree-log sync, btrfs_sync_log first sync the log tree; then updates corresponding root item in the log root tree; sync the log root tree; then update the super block. Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
* Btrfs: open_ctree() error handling can oops on fs_infoQinghuang Feng2009-01-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | a bug in open_ctree: struct btrfs_root *open_ctree(..) { .... if (!extent_root || !tree_root || !fs_info || !chunk_root || !dev_root || !csum_root) { err = -ENOMEM; goto fail; //When code flow goes to "fail", fs_info may be NULL or uninitialized. } .... fail: btrfs_close_devices(fs_info->fs_devices);// ! btrfs_mapping_tree_free(&fs_info->mapping_tree);// ! kfree(extent_root); kfree(tree_root); bdi_destroy(&fs_info->bdi);// ! ... ) Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: simplify iteration codesQinghuang Feng2009-01-21
| | | | | | | | 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>
* Btrfs: check return value for kthread_run() correctlyQinghuang Feng2009-01-21
| | | | | | | | kthread_run() returns the kthread or ERR_PTR(-ENOMEM), not NULL. Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: removed unused #include <version.h>'sHuang Weiyi2009-01-21
| | | | | | | | 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>
* Btrfs: Fix checkpatch.pl warningsChris Mason2009-01-05
| | | | | | | 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>
* Btrfs: avoid potential super block corruptionYan Zheng2009-01-05
| | | | | | | | | | | | | The data in fs_info->super_for_commit are zeros before the first transaction commit. If tree log sync and system crash both occur before the first transaction commit, super block will get corrupted. This fixes it by properly filling in the super_for_commit field at open time. Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
* Btrfs: Fix compile warning around num_online_cpus() in a min statementChris Mason2008-12-19
| | | | Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: shift all end_io work to thread poolsChris Mason2008-12-17
| | | | | | | | | | | | | | | | | | 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>
* Btrfs: shared seed deviceYan Zheng2008-12-12
| | | | | | | | | | This patch makes seed device possible to be shared by multiple mounted file systems. The sharing is achieved by cloning seed device's btrfs_fs_devices structure. Thanks you, Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
* Btrfs: Add checking of csum tree in balancing codeYan Zheng2008-12-10
| | | | | | | | This updates the space balancing code for the new checksum format. Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
* Btrfs: superblock duplicationYan Zheng2008-12-08
| | | | | | | | | | | This patch implements superblock duplication. Superblocks are stored at offset 16K, 64M and 256G on every devices. Spaces used by superblocks are preserved by the allocator, which uses a reverse mapping function to find the logical addresses that correspond to superblocks. Thank you, Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
* Btrfs: move data checksumming into a dedicated treeChris Mason2008-12-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Btrfs stores checksums for each data block. Until now, they have been stored in the subvolume trees, indexed by the inode that is referencing the data block. This means that when we read the inode, we've probably read in at least some checksums as well. But, this has a few problems: * The checksums are indexed by logical offset in the file. When compression is on, this means we have to do the expensive checksumming on the uncompressed data. It would be faster if we could checksum the compressed data instead. * If we implement encryption, we'll be checksumming the plain text and storing that on disk. This is significantly less secure. * For either compression or encryption, we have to get the plain text back before we can verify the checksum as correct. This makes the raid layer balancing and extent moving much more expensive. * It makes the front end caching code more complex, as we have touch the subvolume and inodes as we cache extents. * There is potentitally one copy of the checksum in each subvolume referencing an extent. The solution used here is to store the extent checksums in a dedicated tree. This allows us to index the checksums by phyiscal extent start and length. It means: * The checksum is against the data stored on disk, after any compression or encryption is done. * The checksum is stored in a central location, and can be verified without following back references, or reading inodes. This makes compression significantly faster by reducing the amount of data that needs to be checksummed. It will also allow much faster raid management code in general. The checksums are indexed by a key with a fixed objectid (a magic value in ctree.h) and offset set to the starting byte of the extent. This allows us to copy the checksum items into the fsync log tree directly (or any other tree), without having to invent a second format for them. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: add support for multiple csum algorithmsJosef Bacik2008-12-02
| | | | | | | | | This patch gives us the space we will need in order to have different csum algorithims at some point in the future. We save the csum algorithim type in the superblock, and use those instead of define's. Signed-off-by: Josef Bacik <jbacik@redhat.com>
* Btrfs: fix panic on error during mountJosef Bacik2008-12-02
| | | | | | | | | | | This needs to be applied on top of my previous patches, but is needed for more than just my new stuff. We're going to the wrong label when we have an error, we try to stop the workers, but they are started below all of this code. This fixes it so we go to the right error label and not panic when we fail one of these cases. Signed-off-by: Josef Bacik <jbacik@redhat.com>
* Btrfs: add support for compat flags to btrfsJosef Bacik2008-12-02
| | | | | | | | | | | | | | | | This adds the necessary disk format for handling compatibility flags in the future to handle disk format changes. We have a compat_flags, compat_ro_flags and incompat_flags set for the super block. Compat flags will be to hold the features that are compatible with older versions of btrfs, compat_ro flags have features that are compatible with older versions of btrfs if the fs is mounted read only, and incompat_flags has features that are incompatible with older versions of btrfs. This also axes the compat_flags field for the inode and just makes the flags field a 64bit field, and changes the root item flags field to 64bit. Signed-off-by: Josef Bacik <jbacik@redhat.com>
* Btrfs: fix shadowed variable declarationsChristoph Hellwig2008-12-02
| | | | | Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: make things static and include the right headersChristoph Hellwig2008-12-02
| | | | | | | | Shut up various sparse warnings about symbols that should be either static or have their declarations in scope. Signed-off-by: Christoph Hellwig <hch@lst.de>
* Btrfs: Drop dirty roots created by log replay immediately whenYan Zheng2008-11-20
| | | | | | | | | | The log replay produces dirty roots. These dirty roots should be dropped immediately if the fs is mounted as ro. Otherwise they can be added to the dirty root list again when remounting the fs as rw. Thank you, Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
* Btrfs: compat code fixesChris Mason2008-11-20
| | | | | | | | The btrfs git kernel trees is used to build a standalone tree for compiling against older kernels. This commit makes the standalone tree work with 2.6.27 Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: Do fsync log replay when mount -o ro, except when on readonly mediaChris Mason2008-11-19
| | | | | | | | | | | | | | fsync log replay can change the filesystem, so it cannot be delayed until mount -o rw,remount, and it can't be forgotten entirely. So, this patch changes btrfs to do with reiserfs, ext3 and xfs do, which is to do the log replay even when mounted readonly. On a readonly device if log replay is required, the mount is aborted. Getting all of this right had required fixing up some of the error handling in open_ctree. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: Avoid writeback stallsChris Mason2008-11-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | While building large bios in writepages, btrfs may end up waiting for other page writeback to finish if WB_SYNC_ALL is used. While it is waiting, the bio it is building has a number of pages with the writeback bit set and they aren't getting to the disk any time soon. This lowers the latencies of writeback in general by sending down the bio being built before waiting for other pages. The bio submission code tries to limit the total number of async bios in flight by waiting when we're over a certain number of async bios. But, the waits are happening while writepages is building bios, and this can easily lead to stalls and other problems for people calling wait_on_page_writeback. The current fix is to let the congestion tests take care of waiting. sync() and others make sure to drain the current async requests to make sure that everything that was pending when the sync was started really get to disk. The code would drain pending requests both before and after submitting a new request. But, if one of the requests is waiting for page writeback to finish, the draining waits might block that page writeback. This changes the draining code to only wait after submitting the bio being processed. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: unplug all devices in the unplug call backChris Mason2008-11-18
| | | | | | | | | | | | For larger multi-device filesystems, there was logic to limit the number of devices unplugged to just the page that was sent to our sync_page function. But, the code wasn't always unplugging the right device. Since this was just an optimization, disable it for now. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: prevent loops in the directory tree when creating snapshotsChris Mason2008-11-17
| | | | | | | | | | | | | | | For a directory tree: /mnt/subvolA/subvolB btrfsctl -s /mnt/subvolA/subvolB /mnt Will create a directory loop with subvolA under subvolB. This commit uses the forward refs for each subvol and snapshot to error out before creating the loop. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: Give each subvol and snapshot their own anonymous devidChris Mason2008-11-17
| | | | | | | | | | | | | | Each subvolume has its own private inode number space, and so we need to fill in different device numbers for each subvolume to avoid confusing applications. This commit puts a struct super_block into struct btrfs_root so it can call set_anon_super() and get a different device number generated for each root. btrfs_rename is changed to prevent renames across subvols. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: Allow subvolumes and snapshots anywhere in the directory treeChris Mason2008-11-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Before, all snapshots and subvolumes lived in a single flat directory. This was awkward and confusing because the single flat directory was only writable with the ioctls. This commit changes the ioctls to create subvols and snapshots at any point in the directory tree. This requires making separate ioctls for snapshot and subvol creation instead of a combining them into one. The subvol ioctl does: btrfsctl -S subvol_name parent_dir After the ioctl is done subvol_name lives inside parent_dir. The snapshot ioctl does: btrfsctl -s path_for_snapshot root_to_snapshot path_for_snapshot can be an absolute or relative path. btrfsctl breaks it up into directory and basename components. root_to_snapshot can be any file or directory in the FS. The snapshot is taken of the entire root where that file lives. Signed-off-by: Chris Mason <chris.mason@oracle.com>
* Btrfs: Seed device supportYan Zheng2008-11-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Seed device is a special btrfs with SEEDING super flag set and can only be mounted in read-only mode. Seed devices allow people to create new btrfs on top of it. The new FS contains the same contents as the seed device, but it can be mounted in read-write mode. This patch does the following: 1) split code in btrfs_alloc_chunk into two parts. The first part does makes the newly allocated chunk usable, but does not do any operation that modifies the chunk tree. The second part does the the chunk tree modifications. This division is for the bootstrap step of adding storage to the seed device. 2) Update device management code to handle seed device. The basic idea is: For an FS grown from seed devices, its seed devices are put into a list. Seed devices are opened on demand at mounting time. If any seed device is missing or has been changed, btrfs kernel module will refuse to mount the FS. 3) make btrfs_find_block_group not return NULL when all block groups are read-only. Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
* Btrfs: mount ro and remount supportYan Zheng2008-11-12
| | | | | | | | | | | This patch adds mount ro and remount support. The main changes in patch are: adding btrfs_remount and related helper function; splitting the transaction related code out of close_ctree into btrfs_commit_super; updating allocator to properly handle read only block group. Signed-off-by: Yan Zheng <zheng.yan@oracle.com>