diff options
Diffstat (limited to 'include/linux/buffer_head.h')
| -rw-r--r-- | include/linux/buffer_head.h | 237 |
1 files changed, 149 insertions, 88 deletions
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 33fa5e94aa80..b16b88bfbc3e 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -16,8 +16,6 @@ #include <linux/wait.h> #include <linux/atomic.h> -#ifdef CONFIG_BLOCK - enum bh_state_bits { BH_Uptodate, /* Contains valid data */ BH_Dirty, /* Is dirty */ @@ -36,6 +34,7 @@ enum bh_state_bits { 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 @@ -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 */ @@ -170,7 +172,10 @@ static __always_inline int buffer_uptodate(const struct buffer_head *bh) 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) \ @@ -178,7 +183,6 @@ static __always_inline int buffer_uptodate(const struct buffer_head *bh) 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 folio *folio, @@ -191,23 +195,22 @@ void buffer_check_dirty_writeback(struct folio *folio, void mark_buffer_dirty(struct buffer_head *bh); 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); -bool try_to_free_buffers(struct folio *); -struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, - bool 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); +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) @@ -220,16 +223,15 @@ 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_gfp(struct block_device *bdev, sector_t block, - unsigned size, gfp_t gfp); +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_gfp(struct block_device *, sector_t block, unsigned size, gfp_t gfp); -void invalidate_bh_lrus(void); -void invalidate_bh_lrus_cpu(void); -bool has_bh_in_lru(int cpu, void *dummy); 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); @@ -245,51 +247,33 @@ 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); -extern int buffer_heads_over_limit; - /* * Generic address_space_operations implementations for buffer_head-backed * address_spaces. */ void block_invalidate_folio(struct folio *folio, size_t offset, size_t length); -int block_write_full_page(struct page *page, get_block_t *get_block, - struct writeback_control *wbc); -int __block_write_full_page(struct inode *inode, struct page *page, - get_block_t *get_block, struct writeback_control *wbc, - bh_end_io_t *handler); +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, - 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); -void clean_page_buffers(struct page *page); -int cont_write_begin(struct file *, struct address_space *, loff_t, - 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); +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 vm_fault_t block_page_mkwrite_return(int err) -{ - if (err == 0) - return VM_FAULT_LOCKED; - if (err == -EFAULT || err == -EAGAIN) - return VM_FAULT_NOPAGE; - if (err == -ENOMEM) - return VM_FAULT_OOM; - /* -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 *); @@ -303,8 +287,6 @@ extern int buffer_migrate_folio_norefs(struct address_space *, #define buffer_migrate_folio_norefs NULL #endif -void buffer_init(void); - /* * inline definitions */ @@ -320,12 +302,38 @@ static inline void put_bh(struct buffer_head *bh) 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) @@ -350,17 +358,38 @@ 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) { - return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE); + 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; -static inline struct buffer_head * -sb_getblk_gfp(struct super_block *sb, sector_t block, gfp_t gfp) + return bdev_getblk(bdev, block, size, gfp); +} + +static inline struct buffer_head *sb_getblk(struct super_block *sb, + sector_t block) { - return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, gfp); + 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 * @@ -369,6 +398,12 @@ 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) { @@ -397,20 +432,6 @@ static inline void lock_buffer(struct buffer_head *bh) __lock_buffer(bh); } -static inline struct buffer_head *getblk_unmovable(struct block_device *bdev, - sector_t block, - unsigned size) -{ - return __getblk_gfp(bdev, block, size, 0); -} - -static inline struct buffer_head *__getblk(struct block_device *bdev, - sector_t block, - unsigned size) -{ - return __getblk_gfp(bdev, block, size, __GFP_MOVABLE); -} - static inline void bh_readahead(struct buffer_head *bh, blk_opf_t op_flags) { if (!buffer_uptodate(bh) && trylock_buffer(bh)) { @@ -447,24 +468,63 @@ static inline void bh_readahead_batch(int nr, struct buffer_head *bhs[], } /** - * __bread() - reads a specified block and returns the bh - * @bdev: the block_device to read from - * @block: number of block - * @size: size (in bytes) to read + * __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. * - * Reads a specified block, and returns buffer head that contains it. - * The page cache is allocated from movable area so that it can be migrated. - * It returns NULL if the block was unreadable. + * 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) +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); -#else /* CONFIG_BLOCK */ +#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_BUFFER_HEAD */ static inline void buffer_init(void) {} static inline bool try_to_free_buffers(struct folio *folio) { return true; } @@ -472,9 +532,10 @@ 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 */ |