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2020-05-08xfs: refactor log recovery item sorting into a generic dispatch structureDarrick J. Wong1-0/+3
Create a generic dispatch structure to delegate recovery of different log item types into various code modules. This will enable us to move code specific to a particular log item type out of xfs_log_recover.c and into the log item source. The first operation we virtualize is the log item sorting. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-04xfs: stop CONFIG_XFS_DEBUG from changing compiler flagsArnd Bergmann1-2/+0
I ran into a linker warning in XFS that originates from a mismatch between libelf, binutils and objtool when certain files in the kernel are built with "gcc -g": x86_64-linux-ld: fs/xfs/xfs_trace.o: unable to initialize decompress status for section .debug_info After some discussion, nobody could identify why xfs sets this flag here. CONFIG_XFS_DEBUG used to enable lots of unrelated settings, but now its main purpose is to enable extra consistency checks and assertions that are unrelated to the debug info. Remove the Makefile logic to set the flag here. If anyone relies on the debug info, this can simply be enabled again with the global CONFIG_DEBUG_INFO option. Dave Chinner writes: I'm pretty sure it was needed for the original kgdb integration back in the early 2000s. That was when SGI used to patch their XFS dev tree with kgdb and debug symbols were needed by the custom kgdb modules that were ported across from the Irix kernel debugger. ISTR that the early kcrash kernel dump analysis tools (again, originated from the Irix "icrash" kernel dump tools) had custom XFS debug scripts that needed also the debug info to work correctly... Which is a long way of saying "we don't need it anymore" instead of "nobody knows why it was set"... :) Suggested-by: Christoph Hellwig <hch@infradead.org> Link: https://lore.kernel.org/lkml/20200409074130.GD21033@infradead.org/ Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Allison Collins <allison.henderson@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-03-18xfs: introduce fake roots for ag-rooted btreesDarrick J. Wong1-0/+1
Create an in-core fake root for AG-rooted btree types so that callers can generate a whole new btree using the upcoming btree bulk load function without making the new tree accessible from the rest of the filesystem. It is up to the individual btree type to provide a function to create a staged cursor (presumably with the appropriate callouts to update the fakeroot) and then commit the staged root back into the filesystem. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2019-11-11xfs: remove the now unused dir ops infrastructureChristoph Hellwig1-1/+0
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-07-15xfs: move xfs_trans_inode.c to libxfs/Eric Sandeen1-2/+2
Userspace now has an identical xfs_trans_inode.c which it has already moved to libxfs/ so do the same move for kernelspace. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-07-03xfs: multithreaded iwalk implementationDarrick J. Wong1-0/+1
Create a parallel iwalk implementation and switch quotacheck to use it. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2019-07-02xfs: create simplified inode walk functionDarrick J. Wong1-0/+1
Create a new iterator function to simplify walking inodes in an XFS filesystem. This new iterator will replace the existing open-coded walking that goes on in various places. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2019-06-29xfs: merge xfs_trans_bmap.c into xfs_bmap_item.cChristoph Hellwig1-1/+0
Keep all bmap item related code together. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-29xfs: merge xfs_trans_rmap.c into xfs_rmap_item.cChristoph Hellwig1-2/+1
Keep all rmap item related code together in one file. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-29xfs: merge xfs_trans_refcount.c into xfs_refcount_item.cChristoph Hellwig1-1/+0
Keep all the refcount item related code together in one file. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-29xfs: merge xfs_trans_extfree.c into xfs_extfree_item.cChristoph Hellwig1-1/+0
Keep all the extree item related code together in one file. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-06-29xfs: use bios directly to read and write the log recovery buffersChristoph Hellwig1-0/+1
The xfs_buf structure is basically used as a glorified container for a memory allocation in the log recovery code. Replace it with a call to kmem_alloc_large and a simple abstraction to read into or write from it synchronously using chained bios. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-05-18treewide: prefix header search paths with $(srctree)/Masahiro Yamada1-2/+2
Currently, the Kbuild core manipulates header search paths in a crazy way [1]. To fix this mess, I want all Makefiles to add explicit $(srctree)/ to the search paths in the srctree. Some Makefiles are already written in that way, but not all. The goal of this work is to make the notation consistent, and finally get rid of the gross hacks. Having whitespaces after -I does not matter since commit 48f6e3cf5bc6 ("kbuild: do not drop -I without parameter"). [1]: https://patchwork.kernel.org/patch/9632347/ Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-04-30xfs: add online scrub for superblock countersDarrick J. Wong1-0/+1
Teach online scrub how to check the filesystem summary counters. We use the incore delalloc block counter along with the incore AG headers to compute expected values for fdblocks, icount, and ifree, and then check that the percpu counter is within a certain threshold of the expected value. This is done to avoid having to freeze or otherwise lock the filesystem, which means that we're only checking that the counters are fairly close, not that they're exactly correct. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2019-04-16xfs: scrub/repair should update filesystem metadata healthDarrick J. Wong1-0/+1
Now that we have the ability to track sick metadata in-core, make scrub and repair update those health assessments after doing work. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2019-04-15xfs: track metadata health statusDarrick J. Wong1-0/+1
Add the necessary in-core metadata fields to keep track of which parts of the filesystem have been observed and which parts were observed to be unhealthy, and print a warning at unmount time if we have unfixed problems. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2018-07-30xfs: move the repair extent list into its own fileDarrick J. Wong1-0/+1
Move the xrep_extent_list code into a separate file. Logically, this data structure is really just a clumsy bitmap, and in the next patch we'll make this more obvious. No functional changes. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2018-06-08xfs: move various type verifiers to common fileDave Chinner1-0/+1
New verification functions like xfs_verify_fsbno() and xfs_verify_agino() are spread across multiple files and different header files. They really don't fit cleanly into the places they've been put, and have wider scope than the current header includes. Move the type verifiers to a new file in libxfs (xfs-types.c) and the prototypes to xfs_types.h where they will be visible to all the code that uses the types. Signed-Off-By: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-06-07xfs: convert to SPDX license tagsDave Chinner1-13/+1
Remove the verbose license text from XFS files and replace them with SPDX tags. This does not change the license of any of the code, merely refers to the common, up-to-date license files in LICENSES/ This change was mostly scripted. fs/xfs/Makefile and fs/xfs/libxfs/xfs_fs.h were modified by hand, the rest were detected and modified by the following command: for f in `git grep -l "GNU General" fs/xfs/` ; do echo $f cat $f | awk -f hdr.awk > $f.new mv -f $f.new $f done And the hdr.awk script that did the modification (including detecting the difference between GPL-2.0 and GPL-2.0+ licenses) is as follows: $ cat hdr.awk BEGIN { hdr = 1.0 tag = "GPL-2.0" str = "" } /^ \* This program is free software/ { hdr = 2.0; next } /any later version./ { tag = "GPL-2.0+" next } /^ \*\// { if (hdr > 0.0) { print "// SPDX-License-Identifier: " tag print str print $0 str="" hdr = 0.0 next } print $0 next } /^ \* / { if (hdr > 1.0) next if (hdr > 0.0) { if (str != "") str = str "\n" str = str $0 next } print $0 next } /^ \*/ { if (hdr > 0.0) next print $0 next } // { if (hdr > 0.0) { if (str != "") str = str "\n" str = str $0 next } print $0 } END { } $ Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-05-30xfs: repair superblocksDarrick J. Wong1-0/+1
If one of the backup superblocks is found to differ seriously from superblock 0, write out a fresh copy from the in-core sb. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2018-05-16xfs: move growfs core to libxfsDave Chinner1-0/+1
So it can be shared with userspace (e.g. mkfs) easily. Signed-Off-By: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-05-16xfs: implement the metadata repair ioctl flagDarrick J. Wong1-0/+7
Plumb in the pieces necessary to make the "scrub" subfunction of the scrub ioctl actually work. This means that we make the IFLAG_REPAIR flag to the scrub ioctl actually do something, and we add an errortag knob so that xfstests can force the kernel to rebuild a metadata structure even if there's nothing wrong with it. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-11-06xfs: use a b+tree for the in-core extent listChristoph Hellwig1-0/+1
Replace the current linear list and the indirection array for the in-core extent list with a b+tree to avoid the need for larger memory allocations for the indirection array when lots of extents are present. The current extent list implementations leads to heavy pressure on the memory allocator when modifying files with a high extent count, and can lead to high latencies because of that. The replacement is a b+tree with a few quirks. The leaf nodes directly store the extent record in two u64 values. The encoding is a little bit different from the existing in-core extent records so that the start offset and length which are required for lookups can be retreived with simple mask operations. The inner nodes store a 64-bit key containing the start offset in the first half of the node, and the pointers to the next lower level in the second half. In either case we walk the node from the beginninig to the end and do a linear search, as that is more efficient for the low number of cache lines touched during a search (2 for the inner nodes, 4 for the leaf nodes) than a binary search. We store termination markers (zero length for the leaf nodes, an otherwise impossible high bit for the inner nodes) to terminate the key list / records instead of storing a count to use the available cache lines as efficiently as possible. One quirk of the algorithm is that while we normally split a node half and half like usual btree implementations we just spill over entries added at the very end of the list to a new node on its own. This means we get a 100% fill grade for the common cases of bulk insertion when reading an inode into memory, and when only sequentially appending to a file. The downside is a slightly higher chance of splits on the first random insertions. Both insert and removal manually recurse into the lower levels, but the bulk deletion of the whole tree is still implemented as a recursive function call, although one limited by the overall depth and with very little stack usage in every iteration. For the first few extents we dynamically grow the list from a single extent to the next powers of two until we have a first full leaf block and that building the actual tree. The code started out based on the generic lib/btree.c code from Joern Engel based on earlier work from Peter Zijlstra, but has since been rewritten beyond recognition. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-10-27xfs: scrub quota informationDarrick J. Wong1-0/+1
Perform some quick sanity testing of the disk quota information. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub realtime bitmap/summaryDarrick J. Wong1-0/+2
Perform simple tests of the realtime bitmap and summary. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub directory parent pointersDarrick J. Wong1-0/+1
Scrub parent pointers, sort of. For directories, we can ride the '..' entry up to the parent to confirm that there's at most one dentry that points back to this directory. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub symbolic linksDarrick J. Wong1-0/+1
Create the infrastructure to scrub symbolic link data. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub extended attributesDarrick J. Wong1-0/+1
Scrub the hash tree, keys, and values in an extended attribute structure. Refactor the attribute code to use the transaction if the caller supplied one to avoid buffer deadocks. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub directory metadataDarrick J. Wong1-0/+1
Scrub the hash tree and all the entries in a directory. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub directory/attribute btreesDarrick J. Wong1-0/+1
Provide a way to check the shape and scrub the hashes and records in a directory or extended attribute btree. These are helper functions for the directory & attribute scrubbers in subsequent patches. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [fengguang: remove unneeded variable to store return value] Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub inode block mappingsDarrick J. Wong1-0/+1
Scrub an individual inode's block mappings to make sure they make sense. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub inodesDarrick J. Wong1-0/+1
Scrub the fields within an inode. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub refcount btreesDarrick J. Wong1-0/+1
Plumb in the pieces necessary to check the refcount btree. If rmap is available, check the reference count by performing an interval query against the rmapbt. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub rmap btreesDarrick J. Wong1-0/+1
Check the reverse mapping records to make sure that the contents make sense. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub inode btreesDarrick J. Wong1-0/+1
Check the records of the inode btrees to make sure that the values make sense given the inode records themselves. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub free space btreesDarrick J. Wong1-0/+1
Check the extent records free space btrees to ensure that the values look sane. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: scrub the secondary superblocksDarrick J. Wong1-0/+1
Ensure that the geometry presented in the backup superblocks matches the primary superblock so that repair can recover the filesystem if that primary gets corrupted. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: create helpers to scrub a metadata btreeDarrick J. Wong1-0/+1
Create helper functions and tracepoints to deal with errors while scrubbing a metadata btree. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: probe the scrub ioctlDarrick J. Wong1-0/+1
Create a probe scrubber with id 0. This will be used by xfs_scrub to probe the kernel's abilities to scrub (and repair) the metadata. We do this by validating the ioctl inputs from userspace, preparing the filesystem for a scrub (or a repair) operation, and immediately returning to userspace. Userspace can use the returned errno and structure state to decide (in broad terms) if scrub/repair are supported by the running kernel. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-10-27xfs: create an ioctl to scrub AG metadataDarrick J. Wong1-0/+11
Create an ioctl that can be used to scrub internal filesystem metadata. The new ioctl takes the metadata type, an (optional) AG number, an (optional) inode number and generation, and a flags argument. This will be used by the upcoming XFS online scrub tool. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-06-05xfs: use the common helper uuid_is_null()Amir Goldstein1-2/+1
Use the common helper uuid_is_null() and remove the xfs specific helper uuid_is_nil(). The common helper does not check for the NULL pointer value as xfs helper did, but xfs code never calls the helper with a pointer that can be NULL. Conform comments and warning strings to use the term 'null uuid' instead of 'nil uuid', because this is the terminology used by lib/uuid.c and its users. It is also the terminology used in userspace by libuuid and xfsprogs. Signed-off-by: Amir Goldstein <amir73il@gmail.com> [hch: remove now unused uuid.[ch]] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2017-04-04xfs: implement the GETFSMAP ioctlDarrick J. Wong1-0/+1
Introduce a new ioctl that uses the reverse mapping btree to return information about the physical layout of the filesystem. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com>
2016-10-05xfs: introduce the CoW forkDarrick J. Wong1-0/+1
Introduce a new in-core fork for storing copy-on-write delalloc reservations and allocated extents that are in the process of being written out. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-10-04xfs: log bmap intent itemsDarrick J. Wong1-0/+1
Provide a mechanism for higher levels to create BUI/BUD items, submit them to the log, and a stub function to deal with recovered BUI items. These parts will be connected to the rmapbt in a later patch. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-10-04xfs: create bmbt update intent log itemsDarrick J. Wong1-0/+1
Create bmbt update intent/done log items to record redo information in the log. Because we roll transactions multiple times for reflink operations, we also have to track the status of the metadata updates that will be recorded in the post-roll transactions in case we crash before committing the final transaction. This mechanism enables log recovery to finish what was already started. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-10-03xfs: log refcount intent itemsDarrick J. Wong1-0/+1
Provide a mechanism for higher levels to create CUI/CUD items, submit them to the log, and a stub function to deal with recovered CUI items. These parts will be connected to the refcountbt in a later patch. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-10-03xfs: create refcount update intent log itemsDarrick J. Wong1-0/+1
Create refcount update intent/done log items to record redo information in the log. Because we need to roll transactions between updating the bmbt mapping and updating the reverse mapping, we also have to track the status of the metadata updates that will be recorded in the post-roll transactions, just in case we crash before committing the final transaction. This mechanism enables log recovery to finish what was already started. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-10-03xfs: add refcount btree operationsDarrick J. Wong1-0/+1
Implement the generic btree operations required to manipulate refcount btree blocks. The implementation is similar to the bmapbt, though it will only allocate and free blocks from the AG. Since the refcount root and level fields are separate from the existing roots and levels array, they need a separate logging flag. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> [hch: fix logging of AGF refcount btree fields] Signed-off-by: Christoph Hellwig <hch@lst.de>
2016-10-03xfs: define the on-disk refcount btree formatDarrick J. Wong1-0/+1
Start constructing the refcount btree implementation by establishing the on-disk format and everything needed to read, write, and manipulate the refcount btree blocks. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de>
2016-09-19xfs: set up per-AG free space reservationsDarrick J. Wong1-0/+1
One unfortunate quirk of the reference count and reverse mapping btrees -- they can expand in size when blocks are written to *other* allocation groups if, say, one large extent becomes a lot of tiny extents. Since we don't want to start throwing errors in the middle of CoWing, we need to reserve some blocks to handle future expansion. The transaction block reservation counters aren't sufficient here because we have to have a reserve of blocks in every AG, not just somewhere in the filesystem. Therefore, create two per-AG block reservation pools. One feeds the AGFL so that rmapbt expansion always succeeds, and the other feeds all other metadata so that refcountbt expansion never fails. Use the count of how many reserved blocks we need to have on hand to create a virtual reservation in the AG. Through selective clamping of the maximum length of allocation requests and of the length of the longest free extent, we can make it look like there's less free space in the AG unless the reservation owner is asking for blocks. In other words, play some accounting tricks in-core to make sure that we always have blocks available. On the plus side, there's nothing to clean up if we crash, which is contrast to the strategy that the rough draft used (actually removing extents from the freespace btrees). Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>