diff options
Diffstat (limited to 'include/linux/buffer_head.h')
| -rw-r--r-- | include/linux/buffer_head.h | 394 |
1 files changed, 288 insertions, 106 deletions
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 91fa9a94ae92..b16b88bfbc3e 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ /* * include/linux/buffer_head.h * @@ -8,22 +9,18 @@ #define _LINUX_BUFFER_HEAD_H #include <linux/types.h> +#include <linux/blk_types.h> #include <linux/fs.h> #include <linux/linkage.h> #include <linux/pagemap.h> #include <linux/wait.h> #include <linux/atomic.h> -#ifdef CONFIG_BLOCK - enum bh_state_bits { BH_Uptodate, /* Contains valid data */ BH_Dirty, /* Is dirty */ BH_Lock, /* Is locked */ BH_Req, /* Has been submitted for I/O */ - BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise - * IO completion of other buffers in the page - */ BH_Mapped, /* Has a disk mapping */ BH_New, /* Disk mapping was newly created by get_block */ @@ -36,13 +33,15 @@ enum bh_state_bits { BH_Quiet, /* Buffer Error Prinks to be quiet */ BH_Meta, /* Buffer contains metadata */ BH_Prio, /* Buffer should be submitted with REQ_PRIO */ + BH_Defer_Completion, /* Defer AIO completion to workqueue */ + BH_Migrate, /* Buffer is being migrated (norefs) */ BH_PrivateStart,/* not a state bit, but the first bit available * for private allocation by other entities */ }; -#define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512) +#define MAX_BUF_PER_PAGE (PAGE_SIZE / 512) struct page; struct buffer_head; @@ -55,13 +54,16 @@ typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate); * filesystem and block layers. Nowadays the basic I/O unit * is the bio, and buffer_heads are used for extracting block * mappings (via a get_block_t call), for tracking state within - * a page (via a page_mapping) and for wrapping bio submission + * a folio (via a folio_mapping) and for wrapping bio submission * for backward compatibility reasons (e.g. submit_bh). */ struct buffer_head { unsigned long b_state; /* buffer state bitmap (see above) */ struct buffer_head *b_this_page;/* circular list of page's buffers */ - struct page *b_page; /* the page this bh is mapped to */ + union { + struct page *b_page; /* the page this bh is mapped to */ + struct folio *b_folio; /* the folio this bh is mapped to */ + }; sector_t b_blocknr; /* start block number */ size_t b_size; /* size of mapping */ @@ -74,22 +76,28 @@ struct buffer_head { struct address_space *b_assoc_map; /* mapping this buffer is associated with */ atomic_t b_count; /* users using this buffer_head */ + spinlock_t b_uptodate_lock; /* Used by the first bh in a page, to + * serialise IO completion of other + * buffers in the page */ }; /* * macro tricks to expand the set_buffer_foo(), clear_buffer_foo() * and buffer_foo() functions. + * To avoid reset buffer flags that are already set, because that causes + * a costly cache line transition, check the flag first. */ #define BUFFER_FNS(bit, name) \ -static inline void set_buffer_##name(struct buffer_head *bh) \ +static __always_inline void set_buffer_##name(struct buffer_head *bh) \ { \ - set_bit(BH_##bit, &(bh)->b_state); \ + if (!test_bit(BH_##bit, &(bh)->b_state)) \ + set_bit(BH_##bit, &(bh)->b_state); \ } \ -static inline void clear_buffer_##name(struct buffer_head *bh) \ +static __always_inline void clear_buffer_##name(struct buffer_head *bh) \ { \ clear_bit(BH_##bit, &(bh)->b_state); \ } \ -static inline int buffer_##name(const struct buffer_head *bh) \ +static __always_inline int buffer_##name(const struct buffer_head *bh) \ { \ return test_bit(BH_##bit, &(bh)->b_state); \ } @@ -98,11 +106,11 @@ static inline int buffer_##name(const struct buffer_head *bh) \ * test_set_buffer_foo() and test_clear_buffer_foo() */ #define TAS_BUFFER_FNS(bit, name) \ -static inline int test_set_buffer_##name(struct buffer_head *bh) \ +static __always_inline int test_set_buffer_##name(struct buffer_head *bh) \ { \ return test_and_set_bit(BH_##bit, &(bh)->b_state); \ } \ -static inline int test_clear_buffer_##name(struct buffer_head *bh) \ +static __always_inline int test_clear_buffer_##name(struct buffer_head *bh) \ { \ return test_and_clear_bit(BH_##bit, &(bh)->b_state); \ } \ @@ -112,7 +120,6 @@ static inline int test_clear_buffer_##name(struct buffer_head *bh) \ * of the form "mark_buffer_foo()". These are higher-level functions which * do something in addition to setting a b_state bit. */ -BUFFER_FNS(Uptodate, uptodate) BUFFER_FNS(Dirty, dirty) TAS_BUFFER_FNS(Dirty, dirty) BUFFER_FNS(Lock, locked) @@ -128,8 +135,47 @@ BUFFER_FNS(Write_EIO, write_io_error) BUFFER_FNS(Unwritten, unwritten) BUFFER_FNS(Meta, meta) BUFFER_FNS(Prio, prio) +BUFFER_FNS(Defer_Completion, defer_completion) + +static __always_inline void set_buffer_uptodate(struct buffer_head *bh) +{ + /* + * If somebody else already set this uptodate, they will + * have done the memory barrier, and a reader will thus + * see *some* valid buffer state. + * + * Any other serialization (with IO errors or whatever that + * might clear the bit) has to come from other state (eg BH_Lock). + */ + if (test_bit(BH_Uptodate, &bh->b_state)) + return; + + /* + * make it consistent with folio_mark_uptodate + * pairs with smp_load_acquire in buffer_uptodate + */ + smp_mb__before_atomic(); + set_bit(BH_Uptodate, &bh->b_state); +} + +static __always_inline void clear_buffer_uptodate(struct buffer_head *bh) +{ + clear_bit(BH_Uptodate, &bh->b_state); +} + +static __always_inline int buffer_uptodate(const struct buffer_head *bh) +{ + /* + * make it consistent with folio_test_uptodate + * pairs with smp_mb__before_atomic in set_buffer_uptodate + */ + return test_bit_acquire(BH_Uptodate, &bh->b_state); +} -#define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK) +static inline unsigned long bh_offset(const struct buffer_head *bh) +{ + return (unsigned long)(bh)->b_data & (page_size(bh->b_page) - 1); +} /* If we *know* page->private refers to buffer_heads */ #define page_buffers(page) \ @@ -137,9 +183,9 @@ BUFFER_FNS(Prio, prio) BUG_ON(!PagePrivate(page)); \ ((struct buffer_head *)page_private(page)); \ }) -#define page_has_buffers(page) PagePrivate(page) +#define folio_buffers(folio) folio_get_private(folio) -void buffer_check_dirty_writeback(struct page *page, +void buffer_check_dirty_writeback(struct folio *folio, bool *dirty, bool *writeback); /* @@ -147,128 +193,104 @@ void buffer_check_dirty_writeback(struct page *page, */ void mark_buffer_dirty(struct buffer_head *bh); -void init_buffer(struct buffer_head *, bh_end_io_t *, void *); +void mark_buffer_write_io_error(struct buffer_head *bh); void touch_buffer(struct buffer_head *bh); -void set_bh_page(struct buffer_head *bh, - struct page *page, unsigned long offset); -int try_to_free_buffers(struct page *); -struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, - int retry); -void create_empty_buffers(struct page *, unsigned long, - unsigned long b_state); +void folio_set_bh(struct buffer_head *bh, struct folio *folio, + unsigned long offset); +struct buffer_head *folio_alloc_buffers(struct folio *folio, unsigned long size, + gfp_t gfp); +struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size); +struct buffer_head *create_empty_buffers(struct folio *folio, + unsigned long blocksize, unsigned long b_state); void end_buffer_read_sync(struct buffer_head *bh, int uptodate); void end_buffer_write_sync(struct buffer_head *bh, int uptodate); -void end_buffer_async_write(struct buffer_head *bh, int uptodate); /* Things to do with buffers at mapping->private_list */ void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode); -int inode_has_buffers(struct inode *); -void invalidate_inode_buffers(struct inode *); -int remove_inode_buffers(struct inode *inode); -int sync_mapping_buffers(struct address_space *mapping); -void unmap_underlying_metadata(struct block_device *bdev, sector_t block); +int generic_buffers_fsync_noflush(struct file *file, loff_t start, loff_t end, + bool datasync); +int generic_buffers_fsync(struct file *file, loff_t start, loff_t end, + bool datasync); +void clean_bdev_aliases(struct block_device *bdev, sector_t block, + sector_t len); +static inline void clean_bdev_bh_alias(struct buffer_head *bh) +{ + clean_bdev_aliases(bh->b_bdev, bh->b_blocknr, 1); +} void mark_buffer_async_write(struct buffer_head *bh); void __wait_on_buffer(struct buffer_head *); wait_queue_head_t *bh_waitq_head(struct buffer_head *bh); struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block, unsigned size); -struct buffer_head *__getblk(struct block_device *bdev, sector_t block, - unsigned size); +struct buffer_head *__find_get_block_nonatomic(struct block_device *bdev, + sector_t block, unsigned size); +struct buffer_head *bdev_getblk(struct block_device *bdev, sector_t block, + unsigned size, gfp_t gfp); void __brelse(struct buffer_head *); void __bforget(struct buffer_head *); void __breadahead(struct block_device *, sector_t block, unsigned int size); -struct buffer_head *__bread(struct block_device *, sector_t block, unsigned size); -void invalidate_bh_lrus(void); +struct buffer_head *__bread_gfp(struct block_device *, + sector_t block, unsigned size, gfp_t gfp); struct buffer_head *alloc_buffer_head(gfp_t gfp_flags); void free_buffer_head(struct buffer_head * bh); void unlock_buffer(struct buffer_head *bh); void __lock_buffer(struct buffer_head *bh); -void ll_rw_block(int, int, struct buffer_head * bh[]); int sync_dirty_buffer(struct buffer_head *bh); -int __sync_dirty_buffer(struct buffer_head *bh, int rw); -void write_dirty_buffer(struct buffer_head *bh, int rw); -int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags); -int submit_bh(int, struct buffer_head *); +int __sync_dirty_buffer(struct buffer_head *bh, blk_opf_t op_flags); +void write_dirty_buffer(struct buffer_head *bh, blk_opf_t op_flags); +void submit_bh(blk_opf_t, struct buffer_head *); void write_boundary_block(struct block_device *bdev, sector_t bblock, unsigned blocksize); int bh_uptodate_or_lock(struct buffer_head *bh); -int bh_submit_read(struct buffer_head *bh); - -extern int buffer_heads_over_limit; +int __bh_read(struct buffer_head *bh, blk_opf_t op_flags, bool wait); +void __bh_read_batch(int nr, struct buffer_head *bhs[], + blk_opf_t op_flags, bool force_lock); /* * Generic address_space_operations implementations for buffer_head-backed * address_spaces. */ -void block_invalidatepage(struct page *page, unsigned int offset, - unsigned int length); -int block_write_full_page(struct page *page, get_block_t *get_block, - struct writeback_control *wbc); -int block_write_full_page_endio(struct page *page, get_block_t *get_block, - struct writeback_control *wbc, bh_end_io_t *handler); -int block_read_full_page(struct page*, get_block_t*); -int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc, - unsigned long from); +void block_invalidate_folio(struct folio *folio, size_t offset, size_t length); +int block_write_full_folio(struct folio *folio, struct writeback_control *wbc, + void *get_block); +int __block_write_full_folio(struct inode *inode, struct folio *folio, + get_block_t *get_block, struct writeback_control *wbc); +int block_read_full_folio(struct folio *, get_block_t *); +bool block_is_partially_uptodate(struct folio *, size_t from, size_t count); int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, - unsigned flags, struct page **pagep, get_block_t *get_block); -int __block_write_begin(struct page *page, loff_t pos, unsigned len, + struct folio **foliop, get_block_t *get_block); +int __block_write_begin(struct folio *folio, loff_t pos, unsigned len, get_block_t *get_block); -int block_write_end(struct file *, struct address_space *, - loff_t, unsigned, unsigned, - struct page *, void *); -int generic_write_end(struct file *, struct address_space *, - loff_t, unsigned, unsigned, - struct page *, void *); -void page_zero_new_buffers(struct page *page, unsigned from, unsigned to); -int cont_write_begin(struct file *, struct address_space *, loff_t, - unsigned, unsigned, struct page **, void **, +int block_write_end(loff_t pos, unsigned len, unsigned copied, struct folio *); +int generic_write_end(const struct kiocb *, struct address_space *, + loff_t, unsigned len, unsigned copied, + struct folio *, void *); +void folio_zero_new_buffers(struct folio *folio, size_t from, size_t to); +int cont_write_begin(const struct kiocb *, struct address_space *, loff_t, + unsigned, struct folio **, void **, get_block_t *, loff_t *); int generic_cont_expand_simple(struct inode *inode, loff_t size); -int block_commit_write(struct page *page, unsigned from, unsigned to); -int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, - get_block_t get_block); +void block_commit_write(struct folio *folio, size_t from, size_t to); int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, get_block_t get_block); -/* Convert errno to return value from ->page_mkwrite() call */ -static inline int block_page_mkwrite_return(int err) -{ - if (err == 0) - return VM_FAULT_LOCKED; - if (err == -EFAULT) - return VM_FAULT_NOPAGE; - if (err == -ENOMEM) - return VM_FAULT_OOM; - if (err == -EAGAIN) - return VM_FAULT_RETRY; - /* -ENOSPC, -EDQUOT, -EIO ... */ - return VM_FAULT_SIGBUS; -} sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *); int block_truncate_page(struct address_space *, loff_t, get_block_t *); -int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned, - struct page **, void **, get_block_t*); -int nobh_write_end(struct file *, struct address_space *, - loff_t, unsigned, unsigned, - struct page *, void *); -int nobh_truncate_page(struct address_space *, loff_t, get_block_t *); -int nobh_writepage(struct page *page, get_block_t *get_block, - struct writeback_control *wbc); -void buffer_init(void); +#ifdef CONFIG_MIGRATION +extern int buffer_migrate_folio(struct address_space *, + struct folio *dst, struct folio *src, enum migrate_mode); +extern int buffer_migrate_folio_norefs(struct address_space *, + struct folio *dst, struct folio *src, enum migrate_mode); +#else +#define buffer_migrate_folio NULL +#define buffer_migrate_folio_norefs NULL +#endif /* * inline definitions */ -static inline void attach_page_buffers(struct page *page, - struct buffer_head *head) -{ - page_cache_get(page); - SetPagePrivate(page); - set_page_private(page, (unsigned long)head); -} - static inline void get_bh(struct buffer_head *bh) { atomic_inc(&bh->b_count); @@ -276,16 +298,42 @@ static inline void get_bh(struct buffer_head *bh) static inline void put_bh(struct buffer_head *bh) { - smp_mb__before_atomic_dec(); + smp_mb__before_atomic(); atomic_dec(&bh->b_count); } +/** + * brelse - Release a buffer. + * @bh: The buffer to release. + * + * Decrement a buffer_head's reference count. If @bh is NULL, this + * function is a no-op. + * + * If all buffers on a folio have zero reference count, are clean + * and unlocked, and if the folio is unlocked and not under writeback + * then try_to_free_buffers() may strip the buffers from the folio in + * preparation for freeing it (sometimes, rarely, buffers are removed + * from a folio but it ends up not being freed, and buffers may later + * be reattached). + * + * Context: Any context. + */ static inline void brelse(struct buffer_head *bh) { if (bh) __brelse(bh); } +/** + * bforget - Discard any dirty data in a buffer. + * @bh: The buffer to forget. + * + * Call this function instead of brelse() if the data written to a buffer + * no longer needs to be written back. It will clear the buffer's dirty + * flag so writeback of this buffer will be skipped. + * + * Context: Any context. + */ static inline void bforget(struct buffer_head *bh) { if (bh) @@ -295,7 +343,13 @@ static inline void bforget(struct buffer_head *bh) static inline struct buffer_head * sb_bread(struct super_block *sb, sector_t block) { - return __bread(sb->s_bdev, block, sb->s_blocksize); + return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE); +} + +static inline struct buffer_head * +sb_bread_unmovable(struct super_block *sb, sector_t block) +{ + return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, 0); } static inline void @@ -304,18 +358,52 @@ sb_breadahead(struct super_block *sb, sector_t block) __breadahead(sb->s_bdev, block, sb->s_blocksize); } -static inline struct buffer_head * -sb_getblk(struct super_block *sb, sector_t block) +static inline struct buffer_head *getblk_unmovable(struct block_device *bdev, + sector_t block, unsigned size) +{ + gfp_t gfp; + + gfp = mapping_gfp_constraint(bdev->bd_mapping, ~__GFP_FS); + gfp |= __GFP_NOFAIL; + + return bdev_getblk(bdev, block, size, gfp); +} + +static inline struct buffer_head *__getblk(struct block_device *bdev, + sector_t block, unsigned size) +{ + gfp_t gfp; + + gfp = mapping_gfp_constraint(bdev->bd_mapping, ~__GFP_FS); + gfp |= __GFP_MOVABLE | __GFP_NOFAIL; + + return bdev_getblk(bdev, block, size, gfp); +} + +static inline struct buffer_head *sb_getblk(struct super_block *sb, + sector_t block) { return __getblk(sb->s_bdev, block, sb->s_blocksize); } +static inline struct buffer_head *sb_getblk_gfp(struct super_block *sb, + sector_t block, gfp_t gfp) +{ + return bdev_getblk(sb->s_bdev, block, sb->s_blocksize, gfp); +} + static inline struct buffer_head * sb_find_get_block(struct super_block *sb, sector_t block) { return __find_get_block(sb->s_bdev, block, sb->s_blocksize); } +static inline struct buffer_head * +sb_find_get_block_nonatomic(struct super_block *sb, sector_t block) +{ + return __find_get_block_nonatomic(sb->s_bdev, block, sb->s_blocksize); +} + static inline void map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block) { @@ -344,16 +432,110 @@ static inline void lock_buffer(struct buffer_head *bh) __lock_buffer(bh); } -extern int __set_page_dirty_buffers(struct page *page); +static inline void bh_readahead(struct buffer_head *bh, blk_opf_t op_flags) +{ + if (!buffer_uptodate(bh) && trylock_buffer(bh)) { + if (!buffer_uptodate(bh)) + __bh_read(bh, op_flags, false); + else + unlock_buffer(bh); + } +} + +static inline void bh_read_nowait(struct buffer_head *bh, blk_opf_t op_flags) +{ + if (!bh_uptodate_or_lock(bh)) + __bh_read(bh, op_flags, false); +} + +/* Returns 1 if buffer uptodated, 0 on success, and -EIO on error. */ +static inline int bh_read(struct buffer_head *bh, blk_opf_t op_flags) +{ + if (bh_uptodate_or_lock(bh)) + return 1; + return __bh_read(bh, op_flags, true); +} + +static inline void bh_read_batch(int nr, struct buffer_head *bhs[]) +{ + __bh_read_batch(nr, bhs, 0, true); +} + +static inline void bh_readahead_batch(int nr, struct buffer_head *bhs[], + blk_opf_t op_flags) +{ + __bh_read_batch(nr, bhs, op_flags, false); +} + +/** + * __bread() - Read a block. + * @bdev: The block device to read from. + * @block: Block number in units of block size. + * @size: The block size of this device in bytes. + * + * Read a specified block, and return the buffer head that refers + * to it. The memory is allocated from the movable area so that it can + * be migrated. The returned buffer head has its refcount increased. + * The caller should call brelse() when it has finished with the buffer. + * + * Context: May sleep waiting for I/O. + * Return: NULL if the block was unreadable. + */ +static inline struct buffer_head *__bread(struct block_device *bdev, + sector_t block, unsigned size) +{ + return __bread_gfp(bdev, block, size, __GFP_MOVABLE); +} + +/** + * get_nth_bh - Get a reference on the n'th buffer after this one. + * @bh: The buffer to start counting from. + * @count: How many buffers to skip. + * + * This is primarily useful for finding the nth buffer in a folio; in + * that case you pass the head buffer and the byte offset in the folio + * divided by the block size. It can be used for other purposes, but + * it will wrap at the end of the folio rather than returning NULL or + * proceeding to the next folio for you. + * + * Return: The requested buffer with an elevated refcount. + */ +static inline __must_check +struct buffer_head *get_nth_bh(struct buffer_head *bh, unsigned int count) +{ + while (count--) + bh = bh->b_this_page; + get_bh(bh); + return bh; +} + +bool block_dirty_folio(struct address_space *mapping, struct folio *folio); + +#ifdef CONFIG_BUFFER_HEAD + +void buffer_init(void); +bool try_to_free_buffers(struct folio *folio); +int inode_has_buffers(struct inode *inode); +void invalidate_inode_buffers(struct inode *inode); +int remove_inode_buffers(struct inode *inode); +int sync_mapping_buffers(struct address_space *mapping); +void invalidate_bh_lrus(void); +void invalidate_bh_lrus_cpu(void); +bool has_bh_in_lru(int cpu, void *dummy); +extern int buffer_heads_over_limit; -#else /* CONFIG_BLOCK */ +#else /* CONFIG_BUFFER_HEAD */ static inline void buffer_init(void) {} -static inline int try_to_free_buffers(struct page *page) { return 1; } +static inline bool try_to_free_buffers(struct folio *folio) { return true; } static inline int inode_has_buffers(struct inode *inode) { return 0; } static inline void invalidate_inode_buffers(struct inode *inode) {} static inline int remove_inode_buffers(struct inode *inode) { return 1; } static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; } +static inline void invalidate_bh_lrus(void) {} +static inline void invalidate_bh_lrus_cpu(void) {} +static inline bool has_bh_in_lru(int cpu, void *dummy) { return false; } +#define buffer_heads_over_limit 0 -#endif /* CONFIG_BLOCK */ +#endif /* CONFIG_BUFFER_HEAD */ #endif /* _LINUX_BUFFER_HEAD_H */ |