From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- fs/btrfs/extent_map.h | 195 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 195 insertions(+) create mode 100644 fs/btrfs/extent_map.h (limited to 'fs/btrfs/extent_map.h') diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h new file mode 100644 index 000000000..6f685f3c9 --- /dev/null +++ b/fs/btrfs/extent_map.h @@ -0,0 +1,195 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef BTRFS_EXTENT_MAP_H +#define BTRFS_EXTENT_MAP_H + +#include +#include +#include +#include +#include +#include "fs.h" + +struct btrfs_inode; +struct btrfs_fs_info; + +#define EXTENT_MAP_LAST_BYTE ((u64)-4) +#define EXTENT_MAP_HOLE ((u64)-3) +#define EXTENT_MAP_INLINE ((u64)-2) + +/* bits for the extent_map::flags field */ +enum { + /* this entry not yet on disk, don't free it */ + ENUM_BIT(EXTENT_FLAG_PINNED), + ENUM_BIT(EXTENT_FLAG_COMPRESS_ZLIB), + ENUM_BIT(EXTENT_FLAG_COMPRESS_LZO), + ENUM_BIT(EXTENT_FLAG_COMPRESS_ZSTD), + /* pre-allocated extent */ + ENUM_BIT(EXTENT_FLAG_PREALLOC), + /* Logging this extent */ + ENUM_BIT(EXTENT_FLAG_LOGGING), + /* This em is merged from two or more physically adjacent ems */ + ENUM_BIT(EXTENT_FLAG_MERGED), +}; + +/* + * This structure represents file extents and holes. + * + * Unlike on-disk file extent items, extent maps can be merged to save memory. + * This means members only match file extent items before any merging. + * + * Keep this structure as compact as possible, as we can have really large + * amounts of allocated extent maps at any time. + */ +struct extent_map { + struct rb_node rb_node; + + /* All of these are in bytes. */ + + /* File offset matching the offset of a BTRFS_EXTENT_ITEM_KEY key. */ + u64 start; + + /* + * Length of the file extent. + * + * For non-inlined file extents it's btrfs_file_extent_item::num_bytes. + * For inline extents it's sectorsize, since inline data starts at + * offsetof(struct btrfs_file_extent_item, disk_bytenr) thus + * btrfs_file_extent_item::num_bytes is not valid. + */ + u64 len; + + /* + * The bytenr of the full on-disk extent. + * + * For regular extents it's btrfs_file_extent_item::disk_bytenr. + * For holes it's EXTENT_MAP_HOLE and for inline extents it's + * EXTENT_MAP_INLINE. + */ + u64 disk_bytenr; + + /* + * The full on-disk extent length, matching + * btrfs_file_extent_item::disk_num_bytes. + */ + u64 disk_num_bytes; + + /* + * Offset inside the decompressed extent. + * + * For regular extents it's btrfs_file_extent_item::offset. + * For holes and inline extents it's 0. + */ + u64 offset; + + /* + * The decompressed size of the whole on-disk extent, matching + * btrfs_file_extent_item::ram_bytes. + */ + u64 ram_bytes; + + /* + * Generation of the extent map, for merged em it's the highest + * generation of all merged ems. + * For non-merged extents, it's from btrfs_file_extent_item::generation. + */ + u64 generation; + u32 flags; + refcount_t refs; + struct list_head list; +}; + +struct extent_map_tree { + struct rb_root root; + struct list_head modified_extents; + rwlock_t lock; +}; + +struct btrfs_inode; + +static inline void btrfs_extent_map_set_compression(struct extent_map *em, + enum btrfs_compression_type type) +{ + if (type == BTRFS_COMPRESS_ZLIB) + em->flags |= EXTENT_FLAG_COMPRESS_ZLIB; + else if (type == BTRFS_COMPRESS_LZO) + em->flags |= EXTENT_FLAG_COMPRESS_LZO; + else if (type == BTRFS_COMPRESS_ZSTD) + em->flags |= EXTENT_FLAG_COMPRESS_ZSTD; +} + +static inline enum btrfs_compression_type btrfs_extent_map_compression( + const struct extent_map *em) +{ + if (em->flags & EXTENT_FLAG_COMPRESS_ZLIB) + return BTRFS_COMPRESS_ZLIB; + + if (em->flags & EXTENT_FLAG_COMPRESS_LZO) + return BTRFS_COMPRESS_LZO; + + if (em->flags & EXTENT_FLAG_COMPRESS_ZSTD) + return BTRFS_COMPRESS_ZSTD; + + return BTRFS_COMPRESS_NONE; +} + +/* + * More efficient way to determine if extent is compressed, instead of using + * 'extent_map_compression() != BTRFS_COMPRESS_NONE'. + */ +static inline bool btrfs_extent_map_is_compressed(const struct extent_map *em) +{ + return (em->flags & (EXTENT_FLAG_COMPRESS_ZLIB | + EXTENT_FLAG_COMPRESS_LZO | + EXTENT_FLAG_COMPRESS_ZSTD)) != 0; +} + +static inline int btrfs_extent_map_in_tree(const struct extent_map *em) +{ + return !RB_EMPTY_NODE(&em->rb_node); +} + +static inline u64 btrfs_extent_map_block_start(const struct extent_map *em) +{ + if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE) { + if (btrfs_extent_map_is_compressed(em)) + return em->disk_bytenr; + return em->disk_bytenr + em->offset; + } + return em->disk_bytenr; +} + +static inline u64 btrfs_extent_map_end(const struct extent_map *em) +{ + if (em->start + em->len < em->start) + return (u64)-1; + return em->start + em->len; +} + +void btrfs_extent_map_tree_init(struct extent_map_tree *tree); +struct extent_map *btrfs_lookup_extent_mapping(struct extent_map_tree *tree, + u64 start, u64 len); +void btrfs_remove_extent_mapping(struct btrfs_inode *inode, struct extent_map *em); +int btrfs_split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre, + u64 new_logical); + +struct extent_map *btrfs_alloc_extent_map(void); +void btrfs_free_extent_map(struct extent_map *em); +int __init btrfs_extent_map_init(void); +void __cold btrfs_extent_map_exit(void); +int btrfs_unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen); +void btrfs_clear_em_logging(struct btrfs_inode *inode, struct extent_map *em); +struct extent_map *btrfs_search_extent_mapping(struct extent_map_tree *tree, + u64 start, u64 len); +int btrfs_add_extent_mapping(struct btrfs_inode *inode, + struct extent_map **em_in, u64 start, u64 len); +void btrfs_drop_extent_map_range(struct btrfs_inode *inode, + u64 start, u64 end, + bool skip_pinned); +int btrfs_replace_extent_map_range(struct btrfs_inode *inode, + struct extent_map *new_em, + bool modified); +void btrfs_free_extent_maps(struct btrfs_fs_info *fs_info, long nr_to_scan); +void btrfs_init_extent_map_shrinker_work(struct btrfs_fs_info *fs_info); + +#endif -- cgit v1.3.1