- 23 Mar, 2020 40 commits
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David Sterba authored
All callers pass extent buffer start and length so the extent buffer itself should work fine. Reviewed-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by:
Anand Jain <anand.jain@oracle.com> Signed-off-by:
David Sterba <dsterba@suse.com>
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David Sterba authored
The helper btrfs_header_chunk_tree_uuid follows naming convention of other struct accessors but does something compeletly different. As the offsetof calculation is clear in the context of extent buffer operations we can remove it. Reviewed-by:
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David Sterba authored
The helper btrfs_header_fsid follows naming convention of other struct accessors but does something compeletly different. As the offsetof calculation is clear in the context of extent buffer operations we can remove it. Reviewed-by:
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David Sterba authored
There's a simple forwarded call based on the operation that would better fit the caller btrfs_map_block that's until now a trivial wrapper. Reviewed-by:
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David Sterba authored
The struct_size macro does the same calculation and is safe regarding overflows. Though we're not expecting them to happen, use the helper for clarity. Reviewed-by:
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Nikolay Borisov authored
This patch removes all haphazard code implementing nocow writers exclusion from pending snapshot creation and switches to using the drew lock to ensure this invariant still holds. 'Readers' are snapshot creators from create_snapshot and 'writers' are nocow writers from buffered write path or btrfs_setsize. This locking scheme allows for multiple snapshots to happen while any nocow writers are blocked, since writes to page cache in the nocow path will make snapshots inconsistent. So for performance reasons we'd like to have the ability to run multiple concurrent snapshots and also favors readers in this case. And in case there aren't pending snapshots (which will be the majority of the cases) we rely on the percpu's writers counter to avoid cacheline contention. The main gain from using the drew lock is it's now a lot easier to reason about the guarantees of the locking scheme and whether there is some silent breakage lurking. Signed-off-by:
Nikolay Borisov <nborisov@suse.com> Reviewed-by:
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Nikolay Borisov authored
A (D)ouble (R)eader (W)riter (E)xclustion lock is a locking primitive that allows to have multiple readers or multiple writers but not multiple readers and writers holding it concurrently. The code is factored out from the existing open-coded locking scheme used to exclude pending snapshots from nocow writers and vice-versa. Current implementation actually favors Readers (that is snapshot creaters) to writers (nocow writers of the filesystem). The API provides lock/unlock/trylock for reads and writes. Formal specification for TLA+ provided by Valentin Schneider is at https://lore.kernel.org/linux-btrfs/2dcaf81c-f0d3-409e-cb29-733d8b3b4cc9@arm.com/Signed-off-by:
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Johannes Thumshirn authored
The error cleanup gotos in __btrfs_write_out_cache() needlessly jump back making the code less readable then needed. Flatten them out so no back-jump is necessary and the read flow is uninterrupted. Reviewed-by:
Josef Bacik <josef@toxicpanda.com> Signed-off-by:
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Johannes Thumshirn authored
free-space-cache.c has it's own set of DEBUG ifdefs which need to be turned on instead of the global CONFIG_BTRFS_DEBUG to print debug messages about failed block-group writes. Switch this over to CONFIG_BTRFS_DEBUG so we always see these messages when running a debug kernel. Reviewed-by:
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Johannes Thumshirn authored
Make the uptodate argument of io_ctl_add_pages() boolean. Reviewed-by:
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Johannes Thumshirn authored
io_ctl_prepare_pages() gets a 'struct btrfs_io_ctl' as well as a 'struct inode', but btrfs_io_ctl::inode points to the same struct inode as this is assgined in io_ctl_init(). Use the inode form io_ctl to reduce the arguments of io_ctl_prepare_pages. Reviewed-by:
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Marcos Paulo de Souza authored
This ioctl will be responsible for deleting a subvolume using its id. This can be used when a system has a file system mounted from a subvolume, rather than the root file system, like below: / @subvol1/ @subvol2/ @subvol_default/ If only @subvol_default is mounted, we have no path to reach @subvol1 and @subvol2, thus no way to delete them. Current subvolume delete ioctl takes a file handle point as argument, and if @subvol_default is mounted, we can't reach @subvol1 and @subvol2 from the same mount point. This patch introduces a new ioctl BTRFS_IOC_SNAP_DESTROY_V2 that takes the extended structure with flags to allow to delete subvolume using subvolid. Now, we can use this new ioctl specifying the subvolume id and refer to the same mount point. It doesn't matter which subvolume was mounted, since we can reach to the desired one using the subvolume id, and then delete it. The full path to the subvolume id is resolved internally and access is verified as if the subvolume was accessed by path. The volume args v2 structure is extended to use the existing union for subvolume id specification, that's valid in case the BTRFS_SUBVOL_SPEC_BY_ID is set. Signed-off-by:
Marcos Paulo de Souza <mpdesouza@suse.com> Reviewed-by:
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Marcos Paulo de Souza authored
The functions will be used outside of export.c and super.c to allow resolving subvolume name from a given id, eg. for subvolume deletion by id ioctl. Signed-off-by:
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David Sterba authored
When the device remove v2 ioctl was added, the full support mask was added to sanity check the flags. However this would allow to let the subvolume related flags to be accepted. This is not supposed to happen. Use the correct support mask, which means that now any of BTRFS_SUBVOL_CREATE_ASYNC, BTRFS_SUBVOL_RDONLY or BTRFS_SUBVOL_QGROUP_INHERIT will be rejected as ENOTSUPP. Though this is a user-visible change, specifying subvolume flags for device deletion does not make sense and there are hopefully no applications doing that. Reviewed-by:
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David Sterba authored
Using the defined mask instead of flag enumeration in the ioctl handler is preferred. No functional changes. Reviewed-by:
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David Sterba authored
The ioctl data for devices or subvolumes can be passed via btrfs_ioctl_vol_args or btrfs_ioctl_vol_args_v2. The latter is more versatile and needs some caution as some of the flags make sense only for some ioctls. As we're going to extend the flags, define support masks for each ioctl class separately. Reviewed-by:
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Jules Irenge authored
Sparse reports a warning at release_extent_buffer() warning: context imbalance in release_extent_buffer() - unexpected unlock The root cause is the missing annotation at release_extent_buffer() Add the missing __releases(&eb->refs_lock) annotation Reviewed-by:
Jules Irenge <jbi.octave@gmail.com> Reviewed-by:
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Josef Bacik authored
In my EIO stress testing I noticed I was getting forced to rescan the uuid tree pretty often, which was weird. This is because my error injection stuff would sometimes inject an error after log replay but before we loaded the UUID tree. If log replay committed the transaction it wouldn't have updated the uuid tree generation, but the tree was valid and didn't change, so there's no reason to not update the generation here. Fix this by setting the BTRFS_FS_UPDATE_UUID_TREE_GEN bit immediately after reading all the fs roots if the uuid tree generation matches the fs generation. Then any transaction commits that happen during mount won't screw up our uuid tree state, forcing us to do needless uuid rescans. Fixes: 70f80175 ("Btrfs: check UUID tree during mount if required") CC: stable@vger.kernel.org # 4.19+ Signed-off-by:
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Josef Bacik authored
In doing my fsstress+EIO stress testing I started running into issues where umount would get stuck forever because the uuid checker was chewing through the thousands of subvolumes I had created. We shouldn't block umount on this, simply bail if we're unmounting the fs. We need to make sure we don't mark the UUID tree as ok, so we only set that bit if we made it through the whole rescan operation, but otherwise this is completely safe. Reviewed-by:
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Nikolay Borisov authored
It's used only during filesystem mount as such it can be made private to disk-io.c file. Also use the occasion to move btrfs_uuid_rescan_kthread as btrfs_check_uuid_tree is its sole caller. Reviewed-by:
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Nikolay Borisov authored
btrfs_uuid_tree_iterate is called from only once place and its 2nd argument is always btrfs_check_uuid_tree_entry. Simplify btrfs_uuid_tree_iterate's signature by removing its 2nd argument and directly calling btrfs_check_uuid_tree_entry. Also move the latter into uuid-tree.h. No functional changes. Reviewed-by:
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David Sterba authored
There are temporary variables tracking the index of P and Q stripes, but none of them is really used as such, merely for determining if the Q stripe is present. This leads to compiler warnings with -Wunused-but-set-variable and has been reported several times. fs/btrfs/raid56.c: In function ‘finish_rmw’: fs/btrfs/raid56.c:1199:6: warning: variable ‘p_stripe’ set but not used [-Wunused-but-set-variable] 1199 | int p_stripe = -1; | ^~~~~~~~ fs/btrfs/raid56.c: In function ‘finish_parity_scrub’: fs/btrfs/raid56.c:2356:6: warning: variable ‘p_stripe’ set but not used [-Wunused-but-set-variable] 2356 | int p_stripe = -1; | ^~~~~~~~ Replace the two variables with one that has a clear meaning and also get rid of the warnings. The logic that verifies that there are only 2 valid cases is unchanged. Reviewed-by: -
ethanwu authored
With the following patches: - btrfs: backref, only collect file extent items matching backref offset - btrfs: backref, not adding refs from shared block when resolving normal backref - btrfs: backref, only search backref entries from leaves of the same root we only collect the normal data refs we want, so the imprecise upper bound total_refs of that EXTENT_ITEM could now be changed to the count of the normal backref entry we want to search. Background and how the patches fit together: Btrfs has two types of data backref. For BTRFS_EXTENT_DATA_REF_KEY type of backref, we don't have the exact block number. Therefore, we need to call resolve_indirect_refs. It uses btrfs_search_slot to locate the leaf block. Then we need to walk through the leaves to search for the EXTENT_DATA items that have disk bytenr matching the extent item (add_all_parents). When resolving indirect refs, we could take entries that don't belong to the backref entry we are searching for right now. For that reason when searching backref entry, we always use total refs of that EXTENT_ITEM rather than individual count. For example: item 11 key (40831553536 EXTENT_ITEM 4194304) itemoff 15460 itemsize extent refs 24 gen 7302 flags DATA shared data backref parent 394985472 count 10 #1 extent data backref root 257 objectid 260 offset 1048576 count 3 #2 extent data backref root 256 objectid 260 offset 65536 count 6 #3 extent data backref root 257 objectid 260 offset 65536 count 5 #4 For example, when searching backref entry #4, we'll use total_refs 24, a very loose loop ending condition, instead of total_refs = 5. But using total_refs = 24 is not accurate. Sometimes, we'll never find all the refs from specific root. As a result, the loop keeps on going until we reach the end of that inode. The first 3 patches, handle 3 different types refs we might encounter. These refs do not belong to the normal backref we are searching, and hence need to be skipped. This patch changes the total_refs to correct number so that we could end loop as soon as we find all the refs we want. btrfs send uses backref to find possible clone sources, the following is a simple test to compare the results with and without this patch: $ btrfs subvolume create /sub1 $ for i in `seq 1 163840`; do dd if=/dev/zero of=/sub1/file bs=64K count=1 seek=$((i-1)) conv=notrunc oflag=direct done $ btrfs subvolume snapshot /sub1 /sub2 $ for i in `seq 1 163840`; do dd if=/dev/zero of=/sub1/file bs=4K count=1 seek=$(((i-1)*16+10)) conv=notrunc oflag=direct done $ btrfs subvolume snapshot -r /sub1 /snap1 $ time btrfs send /snap1 | btrfs receive /volume2 Without this patch: real 69m48.124s user 0m50.199s sys 70m15.600s With this patch: real 1m59.683s user 0m35.421s sys 2m42.684s Reviewed-by:ethanwu <ethanwu@synology.com> [ add patchset cover letter with background and numbers ] Signed-off-by:
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ethanwu authored
We could have some nodes/leaves in subvolume whose owner are not the that subvolume. In this way, when we resolve normal backrefs of that subvolume, we should avoid collecting those references from these blocks. Reviewed-by:
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ethanwu authored
All references from the block of SHARED_DATA_REF belong to that shared block backref. For example: item 11 key (40831553536 EXTENT_ITEM 4194304) itemoff 15460 itemsize 95 extent refs 24 gen 7302 flags DATA extent data backref root 257 objectid 260 offset 65536 count 5 extent data backref root 258 objectid 265 offset 0 count 9 shared data backref parent 394985472 count 10 Block 394985472 might be leaf from root 257, and the item obejctid and (file_pos - file_extent_item::offset) in that leaf just happens to be 260 and 65536 which is equal to the first extent data backref entry. Before this patch, when we resolve backref: root 257 objectid 260 offset 65536 we will add those refs in block 394985472 and wrongly treat those as the refs we want. Fix this by checking if the leaf we are processing is shared data backref, if so, just skip this leaf. Shared data refs added into preftrees.direct have all entry value = 0 (root_id = 0, key = NULL, level = 0) except parent entry. Other refs from indirect tree will have key value and root id != 0, and these values won't be changed when their parent is resolved and added to preftrees.direct. Therefore, we could reuse the preftrees.direct and search ref with all values = 0 except parent is set to avoid getting those resolved refs block. Reviewed-by: -
ethanwu authored
When resolving one backref of type EXTENT_DATA_REF, we collect all references that simply reference the EXTENT_ITEM even though their (file_pos - file_extent_item::offset) are not the same as the btrfs_extent_data_ref::offset we are searching for. This patch adds additional check so that we only collect references whose (file_pos - file_extent_item::offset) == btrfs_extent_data_ref::offset. Reviewed-by:
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Johannes Thumshirn authored
The integrity checking code for the super block mirrors is the last remaining user of buffer_heads, change it to using plain bios as well. Reviewed-by:
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Johannes Thumshirn authored
Now that the last caller of btrfsic_process_written_block() with buffer_heads is gone, remove the buffer_head processing path from it as well. Reviewed-by:
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Johannes Thumshirn authored
Now that the last use of btrfsic_submit_bh() is gone as the super block is now written using bios, remove the function as well. Reviewed-by:
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Johannes Thumshirn authored
Similar to the superblock read path, change the write path to using bios and pages instead of buffer_heads. This allows us to skip over the buffer_head code, for writing the superblock to disk. This is based on a patch originally authored by Nikolay Borisov. Co-developed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Johannes Thumshirn authored
Super-block reading in BTRFS is done using buffer_heads. Buffer_heads have some drawbacks, like not being able to propagate errors from the lower layers. Directly use the page cache for reading the super blocks from disk or invalidating an on-disk super block. We have to use the page cache so to avoid races between mkfs and udev. See also 6f60cbd3 ("btrfs: access superblock via pagecache in scan_one_device"). This patch unwraps the buffer head API and does not change the way the super block is actually read. Signed-off-by:
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Johannes Thumshirn authored
btrfs_scratch_superblocks() isn't used anywhere outside volumes.c so remove it from the header file and mark it as static. Also move it above it's callers so we don't need a forward declaration. Reviewed-by:
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Johannes Thumshirn authored
Block device mappings are never in highmem so kmap() / kunmap() calls for pages from block devices are unneeded. Use page_address() instead of kmap() to get to the virtual addreses. While we're at it, read_cache_page_gfp() doesn't return NULL on error, only an ERR_PTR, so use IS_ERR() to check for errors. Suggested-by:
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Nikolay Borisov authored
Preparatory patch for removal of buffer_head usage in btrfs. Signed-off-by:
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Filipe Manana authored
When attempting to set bits on a range of an exent io tree that already has those bits set we can end up splitting an extent state record, use the preallocated extent state record, insert it into the red black tree, do another search on the red black tree, merge the preallocated extent state record with the previous extent state record, remove that previous record from the red black tree and then free it. This is all unnecessary work that consumes time. This happens specifically at the following case at __set_extent_bit(): $ cat -n fs/btrfs/extent_io.c 957 static int __must_check 958 __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, (...) 1044 /* 1045 * | ---- desired range ---- | 1046 * | state | 1047 * or 1048 * | ------------- state -------------- | 1049 * (...) 1060 if (state->start < start) { 1061 if (state->state & exclusive_bits) { 1062 *failed_start = start; 1063 err = -EEXIST; 1064 goto out; 1065 } 1066 1067 prealloc = alloc_extent_state_atomic(prealloc); 1068 BUG_ON(!prealloc); 1069 err = split_state(tree, state, prealloc, start); 1070 if (err) 1071 extent_io_tree_panic(tree, err); 1072 1073 prealloc = NULL; So if our extent state represents a range from 0 to 1MiB for example, and we want to set bits in the range 128KiB to 256KiB for example, and that extent state record already has all those bits set, we end up splitting that record, so we end up with extent state records in the tree which represent the ranges from 0 to 128KiB and from 128KiB to 1MiB. This is temporary because a subsequent iteration in that function will end up merging the records. The splitting requires using the preallocated extent state record, so a future iteration that needs to do another split will need to allocate another extent state record in an atomic context, something not ideal that we try to avoid as much as possible. The splitting also requires an insertion in the red black tree, and a subsequent merge will require a deletion from the red black tree and freeing an extent state record. This change just skips the splitting of an extent state record when it already has all the bits the we need to set. Setting a bit that is already set for a range is very common in the inode's 'file_extent_tree' extent io tree for example, where we keep setting the EXTENT_DIRTY bit every time we replace an extent. This change also fixes a bug that happens after the recent patchset from Josef that avoids having implicit holes after a power failure when not using the NO_HOLES feature, more specifically the patch with the subject: "btrfs: introduce the inode->file_extent_tree" This patch introduced an extent io tree per inode to keep track of completed ordered extents and figure out at any time what is the safe value for the inode's disk_i_size. This assumes that for contiguous ranges in a file we always end up with a single extent state record in the io tree, but that is not the case, as there is a short time window where we can have two extent state records representing contiguous ranges. When this happens we end setting up an incorrect value for the inode's disk_i_size, resulting in data loss after a clean unmount of the filesystem. The following example explains how this can happen. Suppose we have an inode with an i_size and a disk_i_size of 1MiB, so in the inode's file_extent_tree we have a single extent state record that represents the range [0, 1MiB) with the EXTENT_DIRTY bit set. Then the following steps happen: 1) A buffered write against file range [512KiB, 768KiB) is made. At this point delalloc was not flushed yet; 2) Deduplication from some other inode into this inode's range [128KiB, 256KiB) is made. This causes btrfs_inode_set_file_extent_range() to be called, from btrfs_insert_clone_extent(), to mark the range [128KiB, 256KiB) with EXTENT_DIRTY in the inode's file_extent_tree; 3) When btrfs_inode_set_file_extent_range() calls set_extent_bits(), we end up at __set_extent_bit(). In the first iteration of that function's loop we end up in the following branch: $ cat -n fs/btrfs/extent_io.c 957 static int __must_check 958 __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, (...) 1044 /* 1045 * | ---- desired range ---- | 1046 * | state | 1047 * or 1048 * | ------------- state -------------- | 1049 * (...) 1060 if (state->start < start) { 1061 if (state->state & exclusive_bits) { 1062 *failed_start = start; 1063 err = -EEXIST; 1064 goto out; 1065 } 1066 1067 prealloc = alloc_extent_state_atomic(prealloc); 1068 BUG_ON(!prealloc); 1069 err = split_state(tree, state, prealloc, start); 1070 if (err) 1071 extent_io_tree_panic(tree, err); 1072 1073 prealloc = NULL; (...) 1089 goto search_again; This splits the state record into two, one for range [0, 128KiB) and another for the range [128KiB, 1MiB). Both already have the EXTENT_DIRTY bit set. Then we jump to the 'search_again' label, where we unlock the the spinlock protecting the extent io tree before jumping to the 'again' label to perform the next iteration; 4) In the meanwhile, delalloc is flushed, the ordered extent for the range [512KiB, 768KiB) is created and when it completes, at btrfs_finish_ordered_io(), it calls btrfs_inode_safe_disk_i_size_write() with a value of 0 for its 'new_size' argument; 5) Before the deduplication task currently at __set_extent_bit() moves to the next iteration, the task finishing the ordered extent calls find_first_extent_bit() through btrfs_inode_safe_disk_i_size_write() and gets 'start' set to 0 and 'end' set to 128KiB - because at this moment the io tree has two extent state records, one representing the range [0, 128KiB) and another representing the range [128KiB, 1MiB), both with EXTENT_DIRTY set. Then we set 'isize' to: isize = min(isize, end + 1) = min(1MiB, 128KiB - 1 + 1) = 128KiB Then we set the inode's disk_i_size to 128KiB (isize). After a clean unmount of the filesystem and mounting it again, we have the file with a size of 128KiB, and effectively lost all the data it had before in the range from 128KiB to 1MiB. This change fixes that issue too, as we never end up splitting extent state records when they already have all the bits we want set. Reviewed-by:Filipe Manana <fdmanana@suse.com> Signed-off-by:
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Josef Bacik authored
If we're allocating a logged extent we attempt to insert an extent record for the file extent directly. We increase space_info->bytes_reserved, because the extent entry addition will call btrfs_update_block_group(), which will convert the ->bytes_reserved to ->bytes_used. However if we fail at any point while inserting the extent entry we will bail and leave space on ->bytes_reserved, which will trigger a WARN_ON() on umount. Fix this by pinning the space if we fail to insert, which is what happens in every other failure case that involves adding the extent entry. CC: stable@vger.kernel.org # 5.4+ Reviewed-by:
Qu Wenruo <wqu@suse.com> Signed-off-by:
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Qu Wenruo authored
This function is only used in read_fs_root(), which is just a wrapper of btrfs_get_fs_root(). For all the mentioned essential roots except log root tree, btrfs_get_fs_root() has its own quick path to grab them from fs_info directly, thus no need for key.offset modification. For subvolume trees, btrfs_get_fs_root() with key.offset == -1 is completely fine. For log trees and log root tree, it's impossible to hit them, as for relocation all backrefs are fetched from commit root, which never records log tree blocks. Log tree blocks either get freed in regular transaction commit, or replayed at mount time. At runtime we should never hit an backref for log tree in extent tree. Reviewed-by:
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Nikolay Borisov authored
This commit flips the switch to start tracking/processing pinned extents on a per-transaction basis. It mostly replaces all references from btrfs_fs_info::(pinned_extents|freed_extents[]) to btrfs_transaction::pinned_extents. Two notable modifications that warrant explicit mention are changing clean_pinned_extents to get a reference to the previously running transaction. The other one is removal of call to btrfs_destroy_pinned_extent since transactions are going to be cleaned in btrfs_cleanup_one_transaction. Reviewed-by:
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Nikolay Borisov authored
Next patch is going to refactor how pinned extents are tracked which will necessitate changing this code. To ease that work and contain the changes factor the code now in preparation, this will also help review. Reviewed-by:
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Nikolay Borisov authored
In preparation to making pinned extents per-transaction ensure that log such extents are always excluded from caching. To achieve this in addition to marking them via btrfs_pin_extent_for_log_replay they also need to be marked with btrfs_add_excluded_extent to prevent log tree extent buffer being loaded by the free space caching thread. That's required since log tree blocks are not recorded in the extent tree, hence they always look free. Reviewed-by:
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