fs: Introduce filemap_range_has_page()
filemap_range_has_page() return true if the file's mapping has a page within the range mentioned. This function will be used to check if a write() call will cause a writeback of previous writes. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>hifive-unleashed-5.1
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fdd2f5b7de
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7fc9e47224
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@ -2518,6 +2518,8 @@ extern int filemap_fdatawait(struct address_space *);
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extern void filemap_fdatawait_keep_errors(struct address_space *);
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extern void filemap_fdatawait_keep_errors(struct address_space *);
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extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
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extern int filemap_fdatawait_range(struct address_space *, loff_t lstart,
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loff_t lend);
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loff_t lend);
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extern bool filemap_range_has_page(struct address_space *, loff_t lstart,
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loff_t lend);
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extern int filemap_write_and_wait(struct address_space *mapping);
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extern int filemap_write_and_wait(struct address_space *mapping);
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extern int filemap_write_and_wait_range(struct address_space *mapping,
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extern int filemap_write_and_wait_range(struct address_space *mapping,
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loff_t lstart, loff_t lend);
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loff_t lstart, loff_t lend);
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32
mm/filemap.c
32
mm/filemap.c
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@ -376,6 +376,38 @@ int filemap_flush(struct address_space *mapping)
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}
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}
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EXPORT_SYMBOL(filemap_flush);
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EXPORT_SYMBOL(filemap_flush);
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/**
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* filemap_range_has_page - check if a page exists in range.
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* @mapping: address space within which to check
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* @start_byte: offset in bytes where the range starts
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* @end_byte: offset in bytes where the range ends (inclusive)
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*
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* Find at least one page in the range supplied, usually used to check if
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* direct writing in this range will trigger a writeback.
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*/
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bool filemap_range_has_page(struct address_space *mapping,
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loff_t start_byte, loff_t end_byte)
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{
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pgoff_t index = start_byte >> PAGE_SHIFT;
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pgoff_t end = end_byte >> PAGE_SHIFT;
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struct pagevec pvec;
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bool ret;
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if (end_byte < start_byte)
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return false;
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if (mapping->nrpages == 0)
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return false;
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pagevec_init(&pvec, 0);
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if (!pagevec_lookup(&pvec, mapping, index, 1))
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return false;
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ret = (pvec.pages[0]->index <= end);
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pagevec_release(&pvec);
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return ret;
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}
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EXPORT_SYMBOL(filemap_range_has_page);
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static int __filemap_fdatawait_range(struct address_space *mapping,
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static int __filemap_fdatawait_range(struct address_space *mapping,
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loff_t start_byte, loff_t end_byte)
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loff_t start_byte, loff_t end_byte)
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{
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{
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