- 05 Dec, 2022 40 commits
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Filipe Manana authored
Currently send does not do the best decisions when it comes to decide between multiple clone sources, which results in clone operations for partial extent ranges, which has the following disadvantages: 1) We get less shared extents at the destination; 2) We have to read more data during the send operation and emit more write commands. Besides not being optimal behaviour, it also breaks user expectations and is often reported by users, with a recent example in the Link tag at the bottom of this change log. Part of the reason for this non-optimal behaviour is that the backref walking code does not provide information about the length of the file extent items that were found for each backref, so send is blind about which backref is the best to chose as a cloning source. The other existing reasons are just silliness, namely always prefering the inode with the lowest number when multiple are found for the same root and when we can clone from multiple roots, always prefer the send root over any of the other clone roots. This does not make any sense since any inode or root is fine and as good as any other inode/root. Fix this by making backref walking pass information about the number of bytes referenced by each file extent item and then have send's backref callback pick the inode with the highest number of bytes for each root. Finally select the root from which we can clone more bytes from. Example reproducer: $ cat test.sh #!/bin/bash DEV=/dev/sdi MNT=/mnt/sdi mkfs.btrfs -f $DEV mount $DEV $MNT xfs_io -f -c "pwrite -S 0xab -b 2M 0 2M" $MNT/foo cp --reflink=always $MNT/foo $MNT/bar cp --reflink=always $MNT/foo $MNT/baz sync # Overwrite the second half of file foo. xfs_io -c "pwrite -S 0xcd -b 1M 1M 1M" $MNT/foo sync echo echo "*** fiemap in the original filesystem ***" echo xfs_io -c "fiemap -v" $MNT/foo xfs_io -c "fiemap -v" $MNT/bar xfs_io -c "fiemap -v" $MNT/baz echo btrfs filesystem du $MNT btrfs subvolume snapshot -r $MNT $MNT/snap btrfs send -f /tmp/send_stream $MNT/snap umount $MNT mkfs.btrfs -f $DEV &> /dev/null mount $DEV $MNT btrfs receive -f /tmp/send_stream $MNT echo echo "*** fiemap in the new filesystem ***" echo xfs_io -r -c "fiemap -v" $MNT/snap/foo xfs_io -r -c "fiemap -v" $MNT/snap/bar xfs_io -r -c "fiemap -v" $MNT/snap/baz echo btrfs filesystem du $MNT rm -f /tmp/send_stream rm -f /tmp/snap.fssum umount $MNT Before this change: $ ./test.sh (...) *** fiemap in the original filesystem *** /mnt/sdi/foo: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..2047]: 26624..28671 2048 0x2000 1: [2048..4095]: 30720..32767 2048 0x1 /mnt/sdi/bar: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..4095]: 26624..30719 4096 0x2001 /mnt/sdi/baz: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..4095]: 26624..30719 4096 0x2001 Total Exclusive Set shared Filename 2.00MiB 1.00MiB - /mnt/sdi/foo 2.00MiB 0.00B - /mnt/sdi/bar 2.00MiB 0.00B - /mnt/sdi/baz 6.00MiB 1.00MiB 2.00MiB /mnt/sdi Create a readonly snapshot of '/mnt/sdi' in '/mnt/sdi/snap' At subvol /mnt/sdi/snap At subvol snap *** fiemap in the new filesystem *** /mnt/sdi/snap/foo: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..4095]: 26624..30719 4096 0x2001 /mnt/sdi/snap/bar: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..2047]: 26624..28671 2048 0x2000 1: [2048..4095]: 30720..32767 2048 0x1 /mnt/sdi/snap/baz: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..2047]: 26624..28671 2048 0x2000 1: [2048..4095]: 32768..34815 2048 0x1 Total Exclusive Set shared Filename 2.00MiB 0.00B - /mnt/sdi/snap/foo 2.00MiB 1.00MiB - /mnt/sdi/snap/bar 2.00MiB 1.00MiB - /mnt/sdi/snap/baz 6.00MiB 2.00MiB - /mnt/sdi/snap 6.00MiB 2.00MiB 2.00MiB /mnt/sdi We end up with two 1M extents that are not shared for files bar and baz. After this change: $ ./test.sh (...) *** fiemap in the original filesystem *** /mnt/sdi/foo: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..2047]: 26624..28671 2048 0x2000 1: [2048..4095]: 30720..32767 2048 0x1 /mnt/sdi/bar: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..4095]: 26624..30719 4096 0x2001 /mnt/sdi/baz: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..4095]: 26624..30719 4096 0x2001 Total Exclusive Set shared Filename 2.00MiB 1.00MiB - /mnt/sdi/foo 2.00MiB 0.00B - /mnt/sdi/bar 2.00MiB 0.00B - /mnt/sdi/baz 6.00MiB 1.00MiB 2.00MiB /mnt/sdi Create a readonly snapshot of '/mnt/sdi' in '/mnt/sdi/snap' At subvol /mnt/sdi/snap At subvol snap *** fiemap in the new filesystem *** /mnt/sdi/snap/foo: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..4095]: 26624..30719 4096 0x2001 /mnt/sdi/snap/bar: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..2047]: 26624..28671 2048 0x2000 1: [2048..4095]: 30720..32767 2048 0x2001 /mnt/sdi/snap/baz: EXT: FILE-OFFSET BLOCK-RANGE TOTAL FLAGS 0: [0..2047]: 26624..28671 2048 0x2000 1: [2048..4095]: 30720..32767 2048 0x2001 Total Exclusive Set shared Filename 2.00MiB 0.00B - /mnt/sdi/snap/foo 2.00MiB 0.00B - /mnt/sdi/snap/bar 2.00MiB 0.00B - /mnt/sdi/snap/baz 6.00MiB 0.00B - /mnt/sdi/snap 6.00MiB 0.00B 3.00MiB /mnt/sdi Now there's a much better sharing, files bar and baz share 1M of the extent of file foo and the second extent of files bar and baz is shared between themselves. This will later be turned into a test case for fstests. Link: https://lore.kernel.org/linux-btrfs/20221008005704.795b44b0@crass-HP-ZBook-15-G2/Signed-off-by:Filipe Manana <fdmanana@suse.com> Signed-off-by:
David Sterba <dsterba@suse.com>
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Filipe Manana authored
At find_extent_clone(), unless we are given an inline extent, a file extent item that represents hole or an extent that starts beyond the i_size, we always do backref walking to look for clone sources, unless if we have more than SEND_MAX_EXTENT_REFS (64) known references on the extent. However if we know we only have one reference in the extent item and only one clone source (the send root), then it's pointless to do the backref walking to search for clone sources, as we can't clone from any other root. So skip the backref walking in that case. The following test was run on a non-debug kernel (Debian's default kernel config): $ cat test.sh #!/bin/bash DEV=/dev/sdi MNT=/mnt/sdi mkfs.btrfs -f $DEV mount $DEV $MNT # Create an extent tree that's not too small and none of the # extents is shared. for ((i = 1; i <= 50000; i++)); do xfs_io -f -c "pwrite 0 4K" $MNT/file_$i > /dev/null echo -ne "\r$i files created..." done echo btrfs subvolume snapshot -r $MNT $MNT/snap start=$(date +%s%N) btrfs send $MNT/snap > /dev/null end=$(date +%s%N) dur=$(( (end - start) / 1000000 )) echo -e "\nsend took $dur milliseconds" umount $MNT Before this change: send took 5389 milliseconds After this change: send took 4519 milliseconds (-16.1%) Signed-off-by: -
Filipe Manana authored
At find_extent_clone() we are initializing to zero the 'found_itself' and 'found' fields of the backref context before we use it but we have already initialized the structure to zeroes when we declared it on stack, so it's pointless to initialize those fields and they are unnecessarily increasing the object text size with two "mov" instructions (x86_64). Similarly make the 'extent_len' initialization more clear by using an if- -then-else instead of a double assignment to it in case the extent's end crosses the i_size boundary. Before this change: $ size fs/btrfs/send.o text data bss dec hex filename 68694 4252 16 72962 11d02 fs/btrfs/send.o After this change: $ size fs/btrfs/send.o text data bss dec hex filename 68678 4252 16 72946 11cf2 fs/btrfs/send.o Signed-off-by: -
Filipe Manana authored
We have this unclear comment at find_extent_clone() about extents starting at a file offset greater than or equals to the i_size of the inode. It's not really informative and it's misleading, since it mentions the author found such extents with snapshots and large files. Such extents are a result of fallocate with FALLOC_FL_KEEP_SIZE and there is no relation to snapshots or large files (all write paths update the i_size before inserting a new file extent item). So update the comment to be precise about it and why we don't bother looking for clone sources in that case. Signed-off-by:
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Filipe Manana authored
When looking for an extent clone, at find_extent_clone(), we start by allocating a path and then check for cases where we can't have clones and exit immediately in those cases. It's a waste of time to allocate the path before those cases, so reorder the logic so that we check for those cases before allocating the path. Signed-off-by:
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Qu Wenruo authored
Since we have switched all raid56 workload to submit-and-wait method, there is no use for btrfs_fs_info::endio_raid56_workers workqueue and btrfs_raid_bio::end_io_work. Remove them to save some memory. Signed-off-by:
Qu Wenruo <wqu@suse.com> Signed-off-by:
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Qu Wenruo authored
This switch involves the following changes: - Make finish_parity_scrub() only to submit the write bios It will no longer call rbio_orig_end_io(), and now it will return error. - Add a new helper, recover_scrub_rbio(), to handle recovery It's just doing extra scrub related checks, and then call recover_sectors(). - Rename raid56_parity_scrub_stripe() to scrub_rbio() - Rename scrub_parity_work() to scrub_rbio_work_locked() To follow the existing naming scheme. - Delete unused functions Including: * finish_rmw() * raid_write_end_io() * raid56_bio_end_io() * __raid_recover_end_io() Signed-off-by:
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Qu Wenruo authored
Just like what we did for write/recovery, also extract the read bio assembly code into a helper for scrub. The difference between the three are: - rmw_assemble_read_bios() only submit reads for missing sectors Thus it will skip cached sectors, but will also read sectors which is not covered by any full stripe. (For cache usage) - recover_assemble_read_bios() reads every sector which has not failed - scrub_assemble_read_bios() has extra check for vertical stripes It's mostly the same as rmw_assemble_read_bios(), but will skip sectors which is not covered by a vertical stripe. Signed-off-by:
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Qu Wenruo authored
This includes the following changes: - Implement new raid_unplug() functions Now we don't need a workqueue to run the plug, as all our work is just queue rmw_rbio_work() call, which can be executed without sleep. - Implement a rmw_rbio_work_locked() helper This is for unlock_stripe(), which is already holding the full stripe lock. - Remove all the old functions This should already shows how complex the old functions are, as we ended up removing the following functions: * rmw_work() * validate_rbio_for_rmw() * raid56_rmw_end_io_work() * raid56_rmw_stripe() * full_stripe_write() * partial_stripe_write() * __raid56_parity_write() * run_plug() * unplug_work() * btrfs_raid_unplug() * rmw_work() * __raid56_parity_recover() * raid_recover_end_io_work() - Unexport rmw_rbio() Signed-off-by:
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Qu Wenruo authored
The new entrance will be called rmw_rbio(), it will have a streamlined workflow by using submit-and-wait method. Thus there will be no weird jumps between tons of functions, thus way more reader friendly, and will make later expansion easier, as it's now a straight workflow, the timing is way more clear. Unfortunately we can not yet migrate the RMW path to use this new entrance as we still need extra work to address the plug and unlock_stripe() function. Signed-off-by:
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Qu Wenruo authored
The helper will be later used to refactor the rmw write path. Signed-off-by:
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Qu Wenruo authored
The helper will later be used to refactor the whole RMW path. Signed-off-by:
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Qu Wenruo authored
Currently btrfs uses end_io functions to jump between different stages of recovery. For example, we go the following different functions: - raid56_bio_end_io() This handles the read for all the sectors (except the missing device). - __raid_recover_end_io() This does the real work, it's called inside the delayed work function raid_recover_end_io_work(). This one recovery path involves at least 3 different functions, which is a big burden for readers. This patch will change the behavior by: - Introduce a unified recovery entrance, recover_rbio() - Use submit-and-wait method So the workflow is not interrupted by the endio function jump. This doesn't bring performance change, but reduce the burden for reviewers. - Run the main function in the rmw_workers workqueue Now raid56_parity_recover() only needs to setup the work, and queue the work using start_async_work(). Now readers only need to do one function jump (start_async_work()) to find out the main entrance of recovery path. Furthermore, recover_rbio() function can easily be reused by other paths. The old recovery path is still utilized by degraded write path. It will be cleaned up when we have migrated the write path. Signed-off-by:
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Qu Wenruo authored
This includes extra changes: - The allocation for unmap_array[] and pointers[] Now we allocate them in one go, and free them together. - Remove @err Use errno_to_blk_status(ret) instead. Signed-off-by:
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Qu Wenruo authored
This new helper will be also utilized in the incoming refactor of recovery path. Signed-off-by:
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Qu Wenruo authored
Currently finish_rmw() will update the P/Q stripes before submitting the writes. It's done behind a for(;;) loop, it's a little congested indent-wise, so extract the code into a helper called generate_pq_vertical(). Signed-off-by:
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Qu Wenruo authored
This refactor includes the following behavior change first: - Don't error out if only P/Q is corrupted The old code will directly error out if only P/Q is corrupted. Although it is an logical error if we go into rebuild path with only P/Q corrupted, there is no need to error out. Just skip the rebuild and return the already good data. Then comes the following refactor which shouldn't cause behavior changes: - Introduce a helper to do vertical stripe recovery This not only reduce one indent level, but also paves the road for later data checksum verification in RMW cycles. - Sort rbio->faila/b before recovery So we don't need to do the same swap every vertical stripe - Replace a BUG_ON() with ASSERT() Or checkpatch won't let me pass. - Mark recovered sectors uptodate after the recover loop - Do the cleanup for pointers unconditionally We only need to initialize @pointers and @unmap_array to NULL, so we can safely free them unconditionally. - Mark the repaired sector uptodate in recover_vertical() Signed-off-by:
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David Sterba authored
The two structures appear on the same call paths, btrfs_bio_ctrl is embedded in extent_page_data and we pass bio_ctrl to some functions. After merging there are fewer indirections and we have only one control structure. The packing remains same. The btrfs_bio_ctrl was selected as the target structure as the operation is closer to bio processing. Structure layout: struct btrfs_bio_ctrl { struct bio * bio; /* 0 8 */ int mirror_num; /* 8 4 */ enum btrfs_compression_type compress_type; /* 12 4 */ u32 len_to_stripe_boundary; /* 16 4 */ u32 len_to_oe_boundary; /* 20 4 */ btrfs_bio_end_io_t end_io_func; /* 24 8 */ bool extent_locked; /* 32 1 */ bool sync_io; /* 33 1 */ /* size: 40, cachelines: 1, members: 8 */ /* padding: 6 */ /* last cacheline: 40 bytes */ }; Signed-off-by: -
David Sterba authored
The semantics of the two members is a boolean, so change the type accordingly. We have space in extent_page_data due to alignment there's no change in size. Signed-off-by: -
David Sterba authored
The div_factor* helpers calculate fraction or percentage fraction. The name is a bit confusing, we use it only for percentage calculations and there are two helpers. There's a helper mult_frac that's for general fractions, that tries to be accurate but we multiply and divide by small numbers so we can use the div_u64 helper. Rename the div_factor* helpers and use 1..100 percentage range, also drop the case checking for percentage == 100, it's never hit. The conversions: * div_factor calculates tenths and the numbers need to be adjusted * div_factor_fine is direct replacement Signed-off-by: -
Filipe Manana authored
If when doing a direct IO write we need to fallback to buffered IO, we this comment at btrfs_direct_write() that says we can't directly fallback to buffered IO if we have a NOWAIT iocb, because we have no support for NOWAIT buffered writes. That is not true anymore, as support for NOWAIT buffered writes was added recently in commit 926078b2 ("btrfs: enable nowait async buffered writes"). However we still can't fallback to a buffered write in case we have a NOWAIT iocb, because we'll need to flush delalloc and wait for it to complete after doing the buffered write, and that can block for several reasons, the main reason being waiting for IO to complete. So update the comment to mention all that. Signed-off-by:
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David Sterba authored
The header files should use the /* */ comment style, introduced in commit f3a84ccd ("btrfs: move the tree mod log code into its own file"). Signed-off-by:
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Qu Wenruo authored
Currently we have inline extent read code behind two levels of indentation, factor them them out into a new function, read_inline_extent(), to make it a little easier to read. Since we're here, also remove @extent_offset and @pg_offset arguments from uncompress_inline() function, as it's not possible to have inline extents at non-inline file offset. Signed-off-by:
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Qu Wenruo authored
The argument @new_inline changes the following members of extent_map: - em->compress_type - EXTENT_FLAG_COMPRESSED of em->flags However neither members makes a difference for inline extents: - Inline extent read never use above em members As inside btrfs_get_extent() we directly use the file extent item to do the read. - Inline extents are never to be split Thus code really needs em->compress_type or that flag will never be executed on inlined extents. (btrfs_drop_extent_cache() would be one example) - Fiemap no longer relies on extent maps Recent fiemap optimization makes fiemap to search subvolume tree directly, without using any extent map at all. Thus those members make no difference for inline extents any more. Furthermore such exception without much explanation is really a source of confusion. Thus this patch will completely remove the argument, and always set the involved members, unifying the behavior. Signed-off-by:
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Qu Wenruo authored
Currently for inline extents read inside btrfs_get_extent(), we will reset several extent map members: - em->start Reset to extent_start, which is completely unnecessary. The extent_start and em->start should have already be zero, ensured by tree-checker already. - em->len Reset the round_up(copy_size, fs_info->sectorsize), which is again unnecessary. - em->orig_block_len Reset to em->len (sectorsize), while it is originally unset from btrfs_extent_item_to_extent_map(). This makes no difference, as all extent map handling paths will ignore the orig_block_len if they found it's an inlined extent. Such inline extent orig_block_len ignoring examples can be found in btrfs_drop_extent_cache(). - em->orig_start Reset to em->start (0), while it is originally set to EXTENT_MAP_HOLE. This makes no difference either, as all extent map handling paths will ignore the em->orig_start if they found it's an inline extent. Thus all these em members resetting are unnecessary. Replace them with ASSERT()s checking the only two members (block_start and length) that make sense. Signed-off-by:
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Qu Wenruo authored
Currently we calculate inline extent read in a way that inline extent can start at non-zero offset. This is consistent with the inode selftests, which puts an inline extent at file offset 5. Meanwhile the inline extent creation code will only create inline extent at file offset 0. Furthermore with the introduction of tree-checker on file extents, we are actively rejecting inline extent which starts at non-zero file offset. And so far we haven't yet seen any report of rejected inline extents at non-zero file offset. This all means, the extra calculation to support inline extents at non-zero file offset is mostly paper weight, and damaging the readability of the code. Thus this patch will: - Add extra ASSERT()s to make sure involved file offset are all 0 - Remove @extent_offset calculation - Simplify the involved code As several variables are now single-use, no need to declare them as a variable anymore. Signed-off-by:
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Qu Wenruo authored
In our inode-tests.c, we create an inline offset at file offset 5, which is no longer possible since the introduction of tree-checker. Thus I don't think we should spend time maintaining some corner cases which are already ruled out by tree-checker. So this patch will: - Change the inline extent to start at file offset 0 Also change its length to 6 to cover the original length - Add an extra ASSERT() for btrfs_add_extent_mapping() This is to make sure tree-checker is working correctly. - Update the inode selftest Signed-off-by:
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Josef Bacik authored
Move these out of ctree.h into orphan.h to cut down on code in ctree.h. Signed-off-by:
Josef Bacik <josef@toxicpanda.com> Reviewed-by:
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Josef Bacik authored
This will make syncing fs.h to user space a little easier if we can pull the super block specific helpers out of fs.h and put them in super.h. Reviewed-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by:
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Josef Bacik authored
Move these out of ctree.h into super.h to cut down on code in ctree.h. Reviewed-by:
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Josef Bacik authored
We already have a few of these in fs.h, move the remaining checks out of ctree.h into fs.h. Reviewed-by:
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Josef Bacik authored
Move these out of ctree.h into verity.h to cut down on code in ctree.h. Reviewed-by:
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Josef Bacik authored
We already have a dev-replace.h, simply move these prototypes and helpers into dev-replace.h where they belong. Reviewed-by:
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Josef Bacik authored
Move these out of ctree.h into scrub.h to cut down on code in ctree.h. Reviewed-by:
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Josef Bacik authored
Move these out of ctree.h into relocation.h to cut down on code in ctree.h Reviewed-by:
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Josef Bacik authored
Move these out of ctree.h into acl.h to cut down on code in ctree.h. Reviewed-by:
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Josef Bacik authored
These belong in extent-tree.h, they were missed because they were not grouped with the other extent-tree.c prototypes. Reviewed-by:
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Josef Bacik authored
The code for these functions are in messages.c, move the defines and prototypes to messages.h. Reviewed-by:
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Josef Bacik authored
Move these out of ctree.h into file.h to cut down on code in ctree.h. Reviewed-by:
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Josef Bacik authored
Move these out of ctree.h into ioctl.h to cut down on code in ctree.h. Reviewed-by:
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