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e8513c012d
Add ref_tracker infrastructure for struct btrfs_delayed_node.
It is a response to the largest btrfs related crash in our fleet. We're
seeing soft lockups in btrfs_kill_all_delayed_nodes() that seem to be a
result of delayed_nodes not being released properly.
A ref_tracker object is allocated on reference count increases and freed
on reference count decreases. The ref_tracker object stores a stack
trace of where it is allocated. The ref_tracker_dir object is embedded
in btrfs_delayed_node and keeps track of all current and some old/freed
ref_tracker objects. When a leak is detected we can print the stack
traces for all ref_trackers that have not yet been freed.
Here is a common example of taking a reference to a delayed_node and
freeing it with ref_tracker.
struct btrfs_ref_tracker tracker;
struct btrfs_delayed_node *node;
node = btrfs_get_delayed_node(inode, &tracker);
// use delayed_node...
btrfs_release_delayed_node(node, &tracker);
There are two special cases where the delayed_node reference is "long
lived", meaning that the thread that takes the reference and the thread
that releases the reference are different. The 'inode_cache_tracker'
tracks the delayed_node stored in btrfs_inode. The 'node_list_tracker'
tracks the delayed_node stored in the btrfs_delayed_root
node_list/prepare_list. These trackers are embedded in the
btrfs_delayed_node.
btrfs_ref_tracker and btrfs_ref_tracker_dir are wrappers that either
compile to the corresponding ref_tracker structs or empty structs
depending on CONFIG_BTRFS_DEBUG. There are also btrfs wrappers for
the ref_tracker API.
Signed-off-by: Leo Martins <loemra.dev@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
121 lines
3.7 KiB
Plaintext
121 lines
3.7 KiB
Plaintext
# SPDX-License-Identifier: GPL-2.0
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config BTRFS_FS
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tristate "Btrfs filesystem support"
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select BLK_CGROUP_PUNT_BIO
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select CRC32
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select CRYPTO
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select CRYPTO_CRC32C
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select CRYPTO_XXHASH
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select CRYPTO_SHA256
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select CRYPTO_BLAKE2B
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select ZLIB_INFLATE
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select ZLIB_DEFLATE
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select LZO_COMPRESS
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select LZO_DECOMPRESS
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select ZSTD_COMPRESS
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select ZSTD_DECOMPRESS
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select FS_IOMAP
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select RAID6_PQ
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select XOR_BLOCKS
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depends on PAGE_SIZE_LESS_THAN_256KB
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help
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Btrfs is a general purpose copy-on-write filesystem with extents,
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writable snapshotting, support for multiple devices and many more
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features focused on fault tolerance, repair and easy administration.
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The filesystem disk format is no longer unstable, and it's not
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expected to change unless there are strong reasons to do so. If there
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is a format change, file systems with a unchanged format will
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continue to be mountable and usable by newer kernels.
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For more information, please see the web pages at
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https://btrfs.readthedocs.io
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To compile this file system support as a module, choose M here. The
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module will be called btrfs.
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If unsure, say N.
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config BTRFS_FS_POSIX_ACL
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bool "Btrfs POSIX Access Control Lists"
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depends on BTRFS_FS
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select FS_POSIX_ACL
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help
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POSIX Access Control Lists (ACLs) support permissions for users and
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groups beyond the owner/group/world scheme.
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If you don't know what Access Control Lists are, say N
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config BTRFS_FS_RUN_SANITY_TESTS
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bool "Btrfs will run sanity tests upon loading"
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depends on BTRFS_FS
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help
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This will run sanity tests for core functionality like free space,
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extent maps, extent io, extent buffers, inodes, qgroups and others,
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at module load time. These are mostly regression tests and are only
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interesting to developers.
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If unsure, say N.
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config BTRFS_DEBUG
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bool "Btrfs debugging support"
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depends on BTRFS_FS
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select REF_TRACKER if STACKTRACE_SUPPORT
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help
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Enable run-time debugging support for the btrfs filesystem.
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Additional potentially expensive checks, debugging functionality or
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sysfs exported information is enabled, like leak checks of internal
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objects, optional forced space fragmentation and /sys/fs/btrfs/debug .
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This has negative impact on performance.
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If unsure, say N.
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config BTRFS_ASSERT
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bool "Btrfs assert support"
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depends on BTRFS_FS
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help
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Enable run-time assertion checking. Additional safety checks are
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done, simple enough not to affect performance but verify invariants
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and assumptions of code to run properly. This may result in panics,
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and is meant for developers but can be enabled in general.
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If unsure, say N.
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config BTRFS_EXPERIMENTAL
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bool "Btrfs experimental features"
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depends on BTRFS_FS
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default n
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help
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Enable experimental features. These features may not be stable enough
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for end users. This is meant for btrfs developers or users who wish
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to test the functionality and report problems.
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Current list:
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- COW fixup worker warning - last warning before removing the
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functionality catching out-of-band page
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dirtying, not necessary since 5.8
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- RAID mirror read policy - additional read policies for balancing
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reading from redundant block group
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profiles (currently: pid, round-robin,
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fixed devid)
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- send stream protocol v3 - fs-verity support
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- checksum offload mode - sysfs knob to affect when checksums are
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calculated (at IO time, or in a thread)
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- raid-stripe-tree - additional mapping of extents to devices to
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support RAID1* profiles on zoned devices,
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RAID56 not yet supported
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- extent tree v2 - complex rework of extent tracking
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- large folio support
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If unsure, say N.
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