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mm/filemap.c
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/* * linux/mm/filemap.c * * Copyright (C) 1994-1999 Linus Torvalds */ /* * This file handles the generic file mmap semantics used by * most "normal" filesystems (but you don't /have/ to use this: * the NFS filesystem used to do this differently, for example) */ |
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#include <linux/export.h> |
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#include <linux/compiler.h> #include <linux/fs.h> |
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#include <linux/uaccess.h> |
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#include <linux/aio.h> |
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#include <linux/capability.h> |
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#include <linux/kernel_stat.h> |
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#include <linux/gfp.h> |
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#include <linux/mm.h> #include <linux/swap.h> #include <linux/mman.h> #include <linux/pagemap.h> #include <linux/file.h> #include <linux/uio.h> #include <linux/hash.h> #include <linux/writeback.h> |
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#include <linux/backing-dev.h> |
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#include <linux/pagevec.h> #include <linux/blkdev.h> #include <linux/security.h> #include <linux/syscalls.h> |
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#include <linux/cpuset.h> |
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#include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */ |
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#include <linux/memcontrol.h> |
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#include <linux/cleancache.h> |
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#include "internal.h" |
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/* |
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* FIXME: remove all knowledge of the buffer layer from the core VM */ |
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#include <linux/buffer_head.h> /* for try_to_free_buffers */ |
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#include <asm/mman.h> /* * Shared mappings implemented 30.11.1994. It's not fully working yet, * though. * * Shared mappings now work. 15.8.1995 Bruno. * * finished 'unifying' the page and buffer cache and SMP-threaded the * page-cache, 21.05.1999, Ingo Molnar <mingo@redhat.com> * * SMP-threaded pagemap-LRU 1999, Andrea Arcangeli <andrea@suse.de> */ /* * Lock ordering: * |
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* ->i_mmap_mutex (truncate_pagecache) |
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* ->private_lock (__free_pte->__set_page_dirty_buffers) |
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* ->swap_lock (exclusive_swap_page, others) * ->mapping->tree_lock |
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* |
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* ->i_mutex |
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* ->i_mmap_mutex (truncate->unmap_mapping_range) |
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* * ->mmap_sem |
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* ->i_mmap_mutex |
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* ->page_table_lock or pte_lock (various, mainly in memory.c) |
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* ->mapping->tree_lock (arch-dependent flush_dcache_mmap_lock) * * ->mmap_sem * ->lock_page (access_process_vm) * |
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* ->i_mutex (generic_file_buffered_write) * ->mmap_sem (fault_in_pages_readable->do_page_fault) |
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* |
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* bdi->wb.list_lock |
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* sb_lock (fs/fs-writeback.c) |
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* ->mapping->tree_lock (__sync_single_inode) * |
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* ->i_mmap_mutex |
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* ->anon_vma.lock (vma_adjust) * * ->anon_vma.lock |
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* ->page_table_lock or pte_lock (anon_vma_prepare and various) |
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* |
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* ->page_table_lock or pte_lock |
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* ->swap_lock (try_to_unmap_one) |
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* ->private_lock (try_to_unmap_one) * ->tree_lock (try_to_unmap_one) * ->zone.lru_lock (follow_page->mark_page_accessed) |
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* ->zone.lru_lock (check_pte_range->isolate_lru_page) |
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* ->private_lock (page_remove_rmap->set_page_dirty) * ->tree_lock (page_remove_rmap->set_page_dirty) |
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* bdi.wb->list_lock (page_remove_rmap->set_page_dirty) |
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* ->inode->i_lock (page_remove_rmap->set_page_dirty) |
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* bdi.wb->list_lock (zap_pte_range->set_page_dirty) |
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* ->inode->i_lock (zap_pte_range->set_page_dirty) |
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* ->private_lock (zap_pte_range->__set_page_dirty_buffers) * |
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* (code doesn't rely on that order, so you could switch it around) * ->tasklist_lock (memory_failure, collect_procs_ao) |
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* ->i_mmap_mutex |
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*/ /* |
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* Delete a page from the page cache and free it. Caller has to make |
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* sure the page is locked and that nobody else uses it - or that usage |
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* is safe. The caller must hold the mapping's tree_lock. |
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*/ |
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void __delete_from_page_cache(struct page *page) |
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{ struct address_space *mapping = page->mapping; |
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/* * if we're uptodate, flush out into the cleancache, otherwise * invalidate any existing cleancache entries. We can't leave * stale data around in the cleancache once our page is gone */ if (PageUptodate(page) && PageMappedToDisk(page)) cleancache_put_page(page); else cleancache_flush_page(mapping, page); |
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radix_tree_delete(&mapping->page_tree, page->index); page->mapping = NULL; |
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/* Leave page->index set: truncation lookup relies upon it */ |
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mapping->nrpages--; |
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__dec_zone_page_state(page, NR_FILE_PAGES); |
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if (PageSwapBacked(page)) __dec_zone_page_state(page, NR_SHMEM); |
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BUG_ON(page_mapped(page)); |
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/* * Some filesystems seem to re-dirty the page even after * the VM has canceled the dirty bit (eg ext3 journaling). * * Fix it up by doing a final dirty accounting check after * having removed the page entirely. */ if (PageDirty(page) && mapping_cap_account_dirty(mapping)) { dec_zone_page_state(page, NR_FILE_DIRTY); dec_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE); } |
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} |
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/** * delete_from_page_cache - delete page from page cache * @page: the page which the kernel is trying to remove from page cache * * This must be called only on pages that have been verified to be in the page * cache and locked. It will never put the page into the free list, the caller * has a reference on the page. */ void delete_from_page_cache(struct page *page) |
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{ struct address_space *mapping = page->mapping; |
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void (*freepage)(struct page *); |
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|
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BUG_ON(!PageLocked(page)); |
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|
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freepage = mapping->a_ops->freepage; |
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spin_lock_irq(&mapping->tree_lock); |
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__delete_from_page_cache(page); |
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spin_unlock_irq(&mapping->tree_lock); |
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mem_cgroup_uncharge_cache_page(page); |
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if (freepage) freepage(page); |
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page_cache_release(page); } EXPORT_SYMBOL(delete_from_page_cache); |
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static int sleep_on_page(void *word) |
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{ |
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io_schedule(); return 0; } |
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static int sleep_on_page_killable(void *word) |
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{ |
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sleep_on_page(word); |
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return fatal_signal_pending(current) ? -EINTR : 0; } |
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/** |
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* __filemap_fdatawrite_range - start writeback on mapping dirty pages in range |
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* @mapping: address space structure to write * @start: offset in bytes where the range starts |
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* @end: offset in bytes where the range ends (inclusive) |
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* @sync_mode: enable synchronous operation |
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* |
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* Start writeback against all of a mapping's dirty pages that lie * within the byte offsets <start, end> inclusive. * |
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* If sync_mode is WB_SYNC_ALL then this is a "data integrity" operation, as |
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* opposed to a regular memory cleansing writeback. The difference between |
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* these two operations is that if a dirty page/buffer is encountered, it must * be waited upon, and not just skipped over. */ |
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int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start, loff_t end, int sync_mode) |
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{ int ret; struct writeback_control wbc = { .sync_mode = sync_mode, |
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.nr_to_write = LONG_MAX, |
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.range_start = start, .range_end = end, |
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}; if (!mapping_cap_writeback_dirty(mapping)) return 0; ret = do_writepages(mapping, &wbc); return ret; } static inline int __filemap_fdatawrite(struct address_space *mapping, int sync_mode) { |
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return __filemap_fdatawrite_range(mapping, 0, LLONG_MAX, sync_mode); |
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} int filemap_fdatawrite(struct address_space *mapping) { return __filemap_fdatawrite(mapping, WB_SYNC_ALL); } EXPORT_SYMBOL(filemap_fdatawrite); |
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int filemap_fdatawrite_range(struct address_space *mapping, loff_t start, |
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loff_t end) |
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{ return __filemap_fdatawrite_range(mapping, start, end, WB_SYNC_ALL); } |
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EXPORT_SYMBOL(filemap_fdatawrite_range); |
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|
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/** * filemap_flush - mostly a non-blocking flush * @mapping: target address_space * |
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* This is a mostly non-blocking flush. Not suitable for data-integrity * purposes - I/O may not be started against all dirty pages. */ int filemap_flush(struct address_space *mapping) { return __filemap_fdatawrite(mapping, WB_SYNC_NONE); } EXPORT_SYMBOL(filemap_flush); |
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/** |
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* filemap_fdatawait_range - wait for writeback to complete * @mapping: address space structure to wait for * @start_byte: offset in bytes where the range starts * @end_byte: offset in bytes where the range ends (inclusive) |
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* |
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* Walk the list of under-writeback pages of the given address space * in the given range and wait for all of them. |
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*/ |
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int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte, loff_t end_byte) |
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{ |
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pgoff_t index = start_byte >> PAGE_CACHE_SHIFT; pgoff_t end = end_byte >> PAGE_CACHE_SHIFT; |
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struct pagevec pvec; int nr_pages; int ret = 0; |
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|
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if (end_byte < start_byte) |
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return 0; pagevec_init(&pvec, 0); |
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while ((index <= end) && (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index, PAGECACHE_TAG_WRITEBACK, min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1)) != 0) { unsigned i; for (i = 0; i < nr_pages; i++) { struct page *page = pvec.pages[i]; /* until radix tree lookup accepts end_index */ if (page->index > end) continue; wait_on_page_writeback(page); |
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if (TestClearPageError(page)) |
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ret = -EIO; } pagevec_release(&pvec); cond_resched(); } /* Check for outstanding write errors */ if (test_and_clear_bit(AS_ENOSPC, &mapping->flags)) ret = -ENOSPC; if (test_and_clear_bit(AS_EIO, &mapping->flags)) ret = -EIO; return ret; } |
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EXPORT_SYMBOL(filemap_fdatawait_range); /** |
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* filemap_fdatawait - wait for all under-writeback pages to complete |
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* @mapping: address space structure to wait for |
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* * Walk the list of under-writeback pages of the given address space * and wait for all of them. |
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*/ int filemap_fdatawait(struct address_space *mapping) { loff_t i_size = i_size_read(mapping->host); if (i_size == 0) return 0; |
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return filemap_fdatawait_range(mapping, 0, i_size - 1); |
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} EXPORT_SYMBOL(filemap_fdatawait); int filemap_write_and_wait(struct address_space *mapping) { |
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int err = 0; |
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if (mapping->nrpages) { |
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err = filemap_fdatawrite(mapping); /* * Even if the above returned error, the pages may be * written partially (e.g. -ENOSPC), so we wait for it. * But the -EIO is special case, it may indicate the worst * thing (e.g. bug) happened, so we avoid waiting for it. */ if (err != -EIO) { int err2 = filemap_fdatawait(mapping); if (!err) err = err2; } |
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} |
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return err; |
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} |
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EXPORT_SYMBOL(filemap_write_and_wait); |
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|
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/** * filemap_write_and_wait_range - write out & wait on a file range * @mapping: the address_space for the pages * @lstart: offset in bytes where the range starts * @lend: offset in bytes where the range ends (inclusive) * |
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* Write out and wait upon file offsets lstart->lend, inclusive. * * Note that `lend' is inclusive (describes the last byte to be written) so * that this function can be used to write to the very end-of-file (end = -1). */ |
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int filemap_write_and_wait_range(struct address_space *mapping, loff_t lstart, loff_t lend) { |
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int err = 0; |
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if (mapping->nrpages) { |
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err = __filemap_fdatawrite_range(mapping, lstart, lend, WB_SYNC_ALL); /* See comment of filemap_write_and_wait() */ if (err != -EIO) { |
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int err2 = filemap_fdatawait_range(mapping, lstart, lend); |
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if (!err) err = err2; } |
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} |
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return err; |
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} |
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EXPORT_SYMBOL(filemap_write_and_wait_range); |
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|
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/** |
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* replace_page_cache_page - replace a pagecache page with a new one * @old: page to be replaced * @new: page to replace with * @gfp_mask: allocation mode * * This function replaces a page in the pagecache with a new one. On * success it acquires the pagecache reference for the new page and * drops it for the old page. Both the old and new pages must be * locked. This function does not add the new page to the LRU, the * caller must do that. * * The remove + add is atomic. The only way this function can fail is * memory allocation failure. */ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask) { int error; |
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VM_BUG_ON(!PageLocked(old)); VM_BUG_ON(!PageLocked(new)); VM_BUG_ON(new->mapping); |
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error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); if (!error) { struct address_space *mapping = old->mapping; void (*freepage)(struct page *); pgoff_t offset = old->index; freepage = mapping->a_ops->freepage; page_cache_get(new); new->mapping = mapping; new->index = offset; spin_lock_irq(&mapping->tree_lock); |
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__delete_from_page_cache(old); |
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error = radix_tree_insert(&mapping->page_tree, offset, new); BUG_ON(error); mapping->nrpages++; __inc_zone_page_state(new, NR_FILE_PAGES); if (PageSwapBacked(new)) __inc_zone_page_state(new, NR_SHMEM); spin_unlock_irq(&mapping->tree_lock); |
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/* mem_cgroup codes must not be called under tree_lock */ mem_cgroup_replace_page_cache(old, new); |
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radix_tree_preload_end(); if (freepage) freepage(old); page_cache_release(old); |
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} return error; } EXPORT_SYMBOL_GPL(replace_page_cache_page); /** |
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* add_to_page_cache_locked - add a locked page to the pagecache |
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* @page: page to add * @mapping: the page's address_space * @offset: page index * @gfp_mask: page allocation mode * |
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* This function is used to add a page to the pagecache. It must be locked. |
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* This function does not add the page to the LRU. The caller must do that. */ |
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int add_to_page_cache_locked(struct page *page, struct address_space *mapping, |
6daa0e286 [PATCH] gfp_t: mm... |
434 |
pgoff_t offset, gfp_t gfp_mask) |
1da177e4c Linux-2.6.12-rc2 |
435 |
{ |
e286781d5 mm: speculative p... |
436 437 438 |
int error; VM_BUG_ON(!PageLocked(page)); |
31475dd61 mm: a few small u... |
439 |
VM_BUG_ON(PageSwapBacked(page)); |
e286781d5 mm: speculative p... |
440 441 |
error = mem_cgroup_cache_charge(page, current->mm, |
2c26fdd70 memcg: revert gfp... |
442 |
gfp_mask & GFP_RECLAIM_MASK); |
35c754d79 memory controller... |
443 444 |
if (error) goto out; |
1da177e4c Linux-2.6.12-rc2 |
445 |
|
35c754d79 memory controller... |
446 |
error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); |
1da177e4c Linux-2.6.12-rc2 |
447 |
if (error == 0) { |
e286781d5 mm: speculative p... |
448 449 450 |
page_cache_get(page); page->mapping = mapping; page->index = offset; |
19fd62312 mm: spinlock tree... |
451 |
spin_lock_irq(&mapping->tree_lock); |
1da177e4c Linux-2.6.12-rc2 |
452 |
error = radix_tree_insert(&mapping->page_tree, offset, page); |
e286781d5 mm: speculative p... |
453 |
if (likely(!error)) { |
1da177e4c Linux-2.6.12-rc2 |
454 |
mapping->nrpages++; |
347ce434d [PATCH] zoned vm ... |
455 |
__inc_zone_page_state(page, NR_FILE_PAGES); |
e767e0561 memcg: fix deadlo... |
456 |
spin_unlock_irq(&mapping->tree_lock); |
e286781d5 mm: speculative p... |
457 458 |
} else { page->mapping = NULL; |
b85e0effd mm: consistent tr... |
459 |
/* Leave page->index set: truncation relies upon it */ |
e767e0561 memcg: fix deadlo... |
460 |
spin_unlock_irq(&mapping->tree_lock); |
69029cd55 memcg: remove ref... |
461 |
mem_cgroup_uncharge_cache_page(page); |
e286781d5 mm: speculative p... |
462 463 |
page_cache_release(page); } |
1da177e4c Linux-2.6.12-rc2 |
464 |
radix_tree_preload_end(); |
35c754d79 memory controller... |
465 |
} else |
69029cd55 memcg: remove ref... |
466 |
mem_cgroup_uncharge_cache_page(page); |
8a9f3ccd2 Memory controller... |
467 |
out: |
1da177e4c Linux-2.6.12-rc2 |
468 469 |
return error; } |
e286781d5 mm: speculative p... |
470 |
EXPORT_SYMBOL(add_to_page_cache_locked); |
1da177e4c Linux-2.6.12-rc2 |
471 472 |
int add_to_page_cache_lru(struct page *page, struct address_space *mapping, |
6daa0e286 [PATCH] gfp_t: mm... |
473 |
pgoff_t offset, gfp_t gfp_mask) |
1da177e4c Linux-2.6.12-rc2 |
474 |
{ |
4f98a2fee vmscan: split LRU... |
475 |
int ret; |
4f98a2fee vmscan: split LRU... |
476 |
ret = add_to_page_cache(page, mapping, offset, gfp_mask); |
31475dd61 mm: a few small u... |
477 478 |
if (ret == 0) lru_cache_add_file(page); |
1da177e4c Linux-2.6.12-rc2 |
479 480 |
return ret; } |
18bc0bbd1 Staging: pohmelfs... |
481 |
EXPORT_SYMBOL_GPL(add_to_page_cache_lru); |
1da177e4c Linux-2.6.12-rc2 |
482 |
|
44110fe38 [PATCH] cpuset me... |
483 |
#ifdef CONFIG_NUMA |
2ae88149a [PATCH] mm: clean... |
484 |
struct page *__page_cache_alloc(gfp_t gfp) |
44110fe38 [PATCH] cpuset me... |
485 |
{ |
c0ff7453b cpuset,mm: fix no... |
486 487 |
int n; struct page *page; |
44110fe38 [PATCH] cpuset me... |
488 |
if (cpuset_do_page_mem_spread()) { |
c0ff7453b cpuset,mm: fix no... |
489 490 491 492 493 |
get_mems_allowed(); n = cpuset_mem_spread_node(); page = alloc_pages_exact_node(n, gfp, 0); put_mems_allowed(); return page; |
44110fe38 [PATCH] cpuset me... |
494 |
} |
2ae88149a [PATCH] mm: clean... |
495 |
return alloc_pages(gfp, 0); |
44110fe38 [PATCH] cpuset me... |
496 |
} |
2ae88149a [PATCH] mm: clean... |
497 |
EXPORT_SYMBOL(__page_cache_alloc); |
44110fe38 [PATCH] cpuset me... |
498 |
#endif |
1da177e4c Linux-2.6.12-rc2 |
499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 |
/* * In order to wait for pages to become available there must be * waitqueues associated with pages. By using a hash table of * waitqueues where the bucket discipline is to maintain all * waiters on the same queue and wake all when any of the pages * become available, and for the woken contexts to check to be * sure the appropriate page became available, this saves space * at a cost of "thundering herd" phenomena during rare hash * collisions. */ static wait_queue_head_t *page_waitqueue(struct page *page) { const struct zone *zone = page_zone(page); return &zone->wait_table[hash_ptr(page, zone->wait_table_bits)]; } static inline void wake_up_page(struct page *page, int bit) { __wake_up_bit(page_waitqueue(page), &page->flags, bit); } |
920c7a5d0 mm: remove fastca... |
520 |
void wait_on_page_bit(struct page *page, int bit_nr) |
1da177e4c Linux-2.6.12-rc2 |
521 522 523 524 |
{ DEFINE_WAIT_BIT(wait, &page->flags, bit_nr); if (test_bit(bit_nr, &page->flags)) |
7eaceacca block: remove per... |
525 |
__wait_on_bit(page_waitqueue(page), &wait, sleep_on_page, |
1da177e4c Linux-2.6.12-rc2 |
526 527 528 |
TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL(wait_on_page_bit); |
f62e00cc3 mm: introduce wai... |
529 530 531 532 533 534 535 536 537 538 |
int wait_on_page_bit_killable(struct page *page, int bit_nr) { DEFINE_WAIT_BIT(wait, &page->flags, bit_nr); if (!test_bit(bit_nr, &page->flags)) return 0; return __wait_on_bit(page_waitqueue(page), &wait, sleep_on_page_killable, TASK_KILLABLE); } |
1da177e4c Linux-2.6.12-rc2 |
539 |
/** |
385e1ca5f CacheFiles: Permi... |
540 |
* add_page_wait_queue - Add an arbitrary waiter to a page's wait queue |
697f619fc filemap: fix kern... |
541 542 |
* @page: Page defining the wait queue of interest * @waiter: Waiter to add to the queue |
385e1ca5f CacheFiles: Permi... |
543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 |
* * Add an arbitrary @waiter to the wait queue for the nominated @page. */ void add_page_wait_queue(struct page *page, wait_queue_t *waiter) { wait_queue_head_t *q = page_waitqueue(page); unsigned long flags; spin_lock_irqsave(&q->lock, flags); __add_wait_queue(q, waiter); spin_unlock_irqrestore(&q->lock, flags); } EXPORT_SYMBOL_GPL(add_page_wait_queue); /** |
485bb99b4 [PATCH] kernel-do... |
558 |
* unlock_page - unlock a locked page |
1da177e4c Linux-2.6.12-rc2 |
559 560 561 562 563 564 565 |
* @page: the page * * Unlocks the page and wakes up sleepers in ___wait_on_page_locked(). * Also wakes sleepers in wait_on_page_writeback() because the wakeup * mechananism between PageLocked pages and PageWriteback pages is shared. * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep. * |
8413ac9d8 mm: page lock use... |
566 567 |
* The mb is necessary to enforce ordering between the clear_bit and the read * of the waitqueue (to avoid SMP races with a parallel wait_on_page_locked()). |
1da177e4c Linux-2.6.12-rc2 |
568 |
*/ |
920c7a5d0 mm: remove fastca... |
569 |
void unlock_page(struct page *page) |
1da177e4c Linux-2.6.12-rc2 |
570 |
{ |
8413ac9d8 mm: page lock use... |
571 572 573 |
VM_BUG_ON(!PageLocked(page)); clear_bit_unlock(PG_locked, &page->flags); smp_mb__after_clear_bit(); |
1da177e4c Linux-2.6.12-rc2 |
574 575 576 |
wake_up_page(page, PG_locked); } EXPORT_SYMBOL(unlock_page); |
485bb99b4 [PATCH] kernel-do... |
577 578 579 |
/** * end_page_writeback - end writeback against a page * @page: the page |
1da177e4c Linux-2.6.12-rc2 |
580 581 582 |
*/ void end_page_writeback(struct page *page) { |
ac6aadb24 mm: rotate_reclai... |
583 584 585 586 587 |
if (TestClearPageReclaim(page)) rotate_reclaimable_page(page); if (!test_clear_page_writeback(page)) BUG(); |
1da177e4c Linux-2.6.12-rc2 |
588 589 590 591 |
smp_mb__after_clear_bit(); wake_up_page(page, PG_writeback); } EXPORT_SYMBOL(end_page_writeback); |
485bb99b4 [PATCH] kernel-do... |
592 593 594 |
/** * __lock_page - get a lock on the page, assuming we need to sleep to get it * @page: the page to lock |
1da177e4c Linux-2.6.12-rc2 |
595 |
*/ |
920c7a5d0 mm: remove fastca... |
596 |
void __lock_page(struct page *page) |
1da177e4c Linux-2.6.12-rc2 |
597 598 |
{ DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); |
7eaceacca block: remove per... |
599 |
__wait_on_bit_lock(page_waitqueue(page), &wait, sleep_on_page, |
1da177e4c Linux-2.6.12-rc2 |
600 601 602 |
TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL(__lock_page); |
b5606c2d4 remove final fast... |
603 |
int __lock_page_killable(struct page *page) |
2687a3569 Add lock_page_kil... |
604 605 606 607 |
{ DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); return __wait_on_bit_lock(page_waitqueue(page), &wait, |
7eaceacca block: remove per... |
608 |
sleep_on_page_killable, TASK_KILLABLE); |
2687a3569 Add lock_page_kil... |
609 |
} |
18bc0bbd1 Staging: pohmelfs... |
610 |
EXPORT_SYMBOL_GPL(__lock_page_killable); |
2687a3569 Add lock_page_kil... |
611 |
|
d065bd810 mm: retry page fa... |
612 613 614 |
int __lock_page_or_retry(struct page *page, struct mm_struct *mm, unsigned int flags) { |
37b23e052 x86,mm: make page... |
615 616 617 618 619 620 621 622 623 624 625 626 |
if (flags & FAULT_FLAG_ALLOW_RETRY) { /* * CAUTION! In this case, mmap_sem is not released * even though return 0. */ if (flags & FAULT_FLAG_RETRY_NOWAIT) return 0; up_read(&mm->mmap_sem); if (flags & FAULT_FLAG_KILLABLE) wait_on_page_locked_killable(page); else |
318b275fb mm: allow GUP to ... |
627 |
wait_on_page_locked(page); |
d065bd810 mm: retry page fa... |
628 |
return 0; |
37b23e052 x86,mm: make page... |
629 630 631 632 633 634 635 636 637 638 639 640 |
} else { if (flags & FAULT_FLAG_KILLABLE) { int ret; ret = __lock_page_killable(page); if (ret) { up_read(&mm->mmap_sem); return 0; } } else __lock_page(page); return 1; |
d065bd810 mm: retry page fa... |
641 642 |
} } |
485bb99b4 [PATCH] kernel-do... |
643 644 645 646 647 |
/** * find_get_page - find and get a page reference * @mapping: the address_space to search * @offset: the page index * |
da6052f7b [PATCH] update so... |
648 649 |
* Is there a pagecache struct page at the given (mapping, offset) tuple? * If yes, increment its refcount and return it; if no, return NULL. |
1da177e4c Linux-2.6.12-rc2 |
650 |
*/ |
a60637c85 mm: lockless page... |
651 |
struct page *find_get_page(struct address_space *mapping, pgoff_t offset) |
1da177e4c Linux-2.6.12-rc2 |
652 |
{ |
a60637c85 mm: lockless page... |
653 |
void **pagep; |
1da177e4c Linux-2.6.12-rc2 |
654 |
struct page *page; |
a60637c85 mm: lockless page... |
655 656 657 658 659 660 |
rcu_read_lock(); repeat: page = NULL; pagep = radix_tree_lookup_slot(&mapping->page_tree, offset); if (pagep) { page = radix_tree_deref_slot(pagep); |
27d20fddc radix-tree: fix R... |
661 662 |
if (unlikely(!page)) goto out; |
a2c16d6cb mm: let swap use ... |
663 |
if (radix_tree_exception(page)) { |
8079b1c85 mm: clarify the r... |
664 665 666 667 668 669 670 671 |
if (radix_tree_deref_retry(page)) goto repeat; /* * Otherwise, shmem/tmpfs must be storing a swap entry * here as an exceptional entry: so return it without * attempting to raise page count. */ goto out; |
a2c16d6cb mm: let swap use ... |
672 |
} |
a60637c85 mm: lockless page... |
673 674 675 676 677 678 679 680 681 682 683 684 685 |
if (!page_cache_get_speculative(page)) goto repeat; /* * Has the page moved? * This is part of the lockless pagecache protocol. See * include/linux/pagemap.h for details. */ if (unlikely(page != *pagep)) { page_cache_release(page); goto repeat; } } |
27d20fddc radix-tree: fix R... |
686 |
out: |
a60637c85 mm: lockless page... |
687 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
688 689 |
return page; } |
1da177e4c Linux-2.6.12-rc2 |
690 |
EXPORT_SYMBOL(find_get_page); |
485bb99b4 [PATCH] kernel-do... |
691 |
/** |
1da177e4c Linux-2.6.12-rc2 |
692 |
* find_lock_page - locate, pin and lock a pagecache page |
67be2dd1b [PATCH] DocBook: ... |
693 694 |
* @mapping: the address_space to search * @offset: the page index |
1da177e4c Linux-2.6.12-rc2 |
695 696 697 698 699 700 |
* * Locates the desired pagecache page, locks it, increments its reference * count and returns its address. * * Returns zero if the page was not present. find_lock_page() may sleep. */ |
a60637c85 mm: lockless page... |
701 |
struct page *find_lock_page(struct address_space *mapping, pgoff_t offset) |
1da177e4c Linux-2.6.12-rc2 |
702 703 |
{ struct page *page; |
1da177e4c Linux-2.6.12-rc2 |
704 |
repeat: |
a60637c85 mm: lockless page... |
705 |
page = find_get_page(mapping, offset); |
a2c16d6cb mm: let swap use ... |
706 |
if (page && !radix_tree_exception(page)) { |
a60637c85 mm: lockless page... |
707 708 709 710 711 712 |
lock_page(page); /* Has the page been truncated? */ if (unlikely(page->mapping != mapping)) { unlock_page(page); page_cache_release(page); goto repeat; |
1da177e4c Linux-2.6.12-rc2 |
713 |
} |
a60637c85 mm: lockless page... |
714 |
VM_BUG_ON(page->index != offset); |
1da177e4c Linux-2.6.12-rc2 |
715 |
} |
1da177e4c Linux-2.6.12-rc2 |
716 717 |
return page; } |
1da177e4c Linux-2.6.12-rc2 |
718 719 720 721 |
EXPORT_SYMBOL(find_lock_page); /** * find_or_create_page - locate or add a pagecache page |
67be2dd1b [PATCH] DocBook: ... |
722 723 724 |
* @mapping: the page's address_space * @index: the page's index into the mapping * @gfp_mask: page allocation mode |
1da177e4c Linux-2.6.12-rc2 |
725 726 727 728 729 730 731 732 733 734 735 736 737 |
* * Locates a page in the pagecache. If the page is not present, a new page * is allocated using @gfp_mask and is added to the pagecache and to the VM's * LRU list. The returned page is locked and has its reference count * incremented. * * find_or_create_page() may sleep, even if @gfp_flags specifies an atomic * allocation! * * find_or_create_page() returns the desired page's address, or zero on * memory exhaustion. */ struct page *find_or_create_page(struct address_space *mapping, |
57f6b96c0 filemap: convert ... |
738 |
pgoff_t index, gfp_t gfp_mask) |
1da177e4c Linux-2.6.12-rc2 |
739 |
{ |
eb2be1893 mm: buffered writ... |
740 |
struct page *page; |
1da177e4c Linux-2.6.12-rc2 |
741 742 743 744 |
int err; repeat: page = find_lock_page(mapping, index); if (!page) { |
eb2be1893 mm: buffered writ... |
745 746 747 |
page = __page_cache_alloc(gfp_mask); if (!page) return NULL; |
67d58ac47 mm: pagecache gfp... |
748 749 750 751 752 753 754 755 |
/* * We want a regular kernel memory (not highmem or DMA etc) * allocation for the radix tree nodes, but we need to honour * the context-specific requirements the caller has asked for. * GFP_RECLAIM_MASK collects those requirements. */ err = add_to_page_cache_lru(page, mapping, index, (gfp_mask & GFP_RECLAIM_MASK)); |
eb2be1893 mm: buffered writ... |
756 757 758 759 760 |
if (unlikely(err)) { page_cache_release(page); page = NULL; if (err == -EEXIST) goto repeat; |
1da177e4c Linux-2.6.12-rc2 |
761 |
} |
1da177e4c Linux-2.6.12-rc2 |
762 |
} |
1da177e4c Linux-2.6.12-rc2 |
763 764 |
return page; } |
1da177e4c Linux-2.6.12-rc2 |
765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 |
EXPORT_SYMBOL(find_or_create_page); /** * find_get_pages - gang pagecache lookup * @mapping: The address_space to search * @start: The starting page index * @nr_pages: The maximum number of pages * @pages: Where the resulting pages are placed * * find_get_pages() will search for and return a group of up to * @nr_pages pages in the mapping. The pages are placed at @pages. * find_get_pages() takes a reference against the returned pages. * * The search returns a group of mapping-contiguous pages with ascending * indexes. There may be holes in the indices due to not-present pages. * * find_get_pages() returns the number of pages which were found. */ unsigned find_get_pages(struct address_space *mapping, pgoff_t start, unsigned int nr_pages, struct page **pages) { unsigned int i; unsigned int ret; |
cc39c6a9b mm: account skipp... |
788 |
unsigned int nr_found, nr_skip; |
a60637c85 mm: lockless page... |
789 790 791 792 |
rcu_read_lock(); restart: nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, |
6328650bb radix_tree: excep... |
793 |
(void ***)pages, NULL, start, nr_pages); |
a60637c85 mm: lockless page... |
794 |
ret = 0; |
cc39c6a9b mm: account skipp... |
795 |
nr_skip = 0; |
a60637c85 mm: lockless page... |
796 797 798 799 800 801 |
for (i = 0; i < nr_found; i++) { struct page *page; repeat: page = radix_tree_deref_slot((void **)pages[i]); if (unlikely(!page)) continue; |
9d8aa4ea8 mm: remove worryi... |
802 |
|
a2c16d6cb mm: let swap use ... |
803 |
if (radix_tree_exception(page)) { |
8079b1c85 mm: clarify the r... |
804 805 806 807 808 809 810 811 812 |
if (radix_tree_deref_retry(page)) { /* * Transient condition which can only trigger * when entry at index 0 moves out of or back * to root: none yet gotten, safe to restart. */ WARN_ON(start | i); goto restart; } |
a2c16d6cb mm: let swap use ... |
813 |
/* |
8079b1c85 mm: clarify the r... |
814 815 816 |
* Otherwise, shmem/tmpfs must be storing a swap entry * here as an exceptional entry: so skip over it - * we only reach this from invalidate_mapping_pages(). |
a2c16d6cb mm: let swap use ... |
817 |
*/ |
cc39c6a9b mm: account skipp... |
818 |
nr_skip++; |
8079b1c85 mm: clarify the r... |
819 |
continue; |
27d20fddc radix-tree: fix R... |
820 |
} |
a60637c85 mm: lockless page... |
821 822 823 824 825 826 827 828 829 |
if (!page_cache_get_speculative(page)) goto repeat; /* Has the page moved? */ if (unlikely(page != *((void **)pages[i]))) { page_cache_release(page); goto repeat; } |
1da177e4c Linux-2.6.12-rc2 |
830 |
|
a60637c85 mm: lockless page... |
831 832 833 |
pages[ret] = page; ret++; } |
5b280c0cc mm: don't return ... |
834 835 836 837 838 |
/* * If all entries were removed before we could secure them, * try again, because callers stop trying once 0 is returned. */ |
cc39c6a9b mm: account skipp... |
839 |
if (unlikely(!ret && nr_found > nr_skip)) |
5b280c0cc mm: don't return ... |
840 |
goto restart; |
a60637c85 mm: lockless page... |
841 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
842 843 |
return ret; } |
ebf43500e [PATCH] Add find_... |
844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 |
/** * find_get_pages_contig - gang contiguous pagecache lookup * @mapping: The address_space to search * @index: The starting page index * @nr_pages: The maximum number of pages * @pages: Where the resulting pages are placed * * find_get_pages_contig() works exactly like find_get_pages(), except * that the returned number of pages are guaranteed to be contiguous. * * find_get_pages_contig() returns the number of pages which were found. */ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, unsigned int nr_pages, struct page **pages) { unsigned int i; unsigned int ret; |
a60637c85 mm: lockless page... |
861 862 863 864 865 |
unsigned int nr_found; rcu_read_lock(); restart: nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, |
6328650bb radix_tree: excep... |
866 |
(void ***)pages, NULL, index, nr_pages); |
a60637c85 mm: lockless page... |
867 868 869 870 871 872 873 |
ret = 0; for (i = 0; i < nr_found; i++) { struct page *page; repeat: page = radix_tree_deref_slot((void **)pages[i]); if (unlikely(!page)) continue; |
9d8aa4ea8 mm: remove worryi... |
874 |
|
a2c16d6cb mm: let swap use ... |
875 |
if (radix_tree_exception(page)) { |
8079b1c85 mm: clarify the r... |
876 877 878 879 880 881 882 883 |
if (radix_tree_deref_retry(page)) { /* * Transient condition which can only trigger * when entry at index 0 moves out of or back * to root: none yet gotten, safe to restart. */ goto restart; } |
a2c16d6cb mm: let swap use ... |
884 |
/* |
8079b1c85 mm: clarify the r... |
885 886 887 |
* Otherwise, shmem/tmpfs must be storing a swap entry * here as an exceptional entry: so stop looking for * contiguous pages. |
a2c16d6cb mm: let swap use ... |
888 |
*/ |
8079b1c85 mm: clarify the r... |
889 |
break; |
a2c16d6cb mm: let swap use ... |
890 |
} |
ebf43500e [PATCH] Add find_... |
891 |
|
a60637c85 mm: lockless page... |
892 893 894 895 896 897 898 899 |
if (!page_cache_get_speculative(page)) goto repeat; /* Has the page moved? */ if (unlikely(page != *((void **)pages[i]))) { page_cache_release(page); goto repeat; } |
9cbb4cb21 mm: find_get_page... |
900 901 902 903 904 905 906 907 908 |
/* * must check mapping and index after taking the ref. * otherwise we can get both false positives and false * negatives, which is just confusing to the caller. */ if (page->mapping == NULL || page->index != index) { page_cache_release(page); break; } |
a60637c85 mm: lockless page... |
909 910 |
pages[ret] = page; ret++; |
ebf43500e [PATCH] Add find_... |
911 912 |
index++; } |
a60637c85 mm: lockless page... |
913 914 |
rcu_read_unlock(); return ret; |
ebf43500e [PATCH] Add find_... |
915 |
} |
ef71c15c4 AFS: export a cou... |
916 |
EXPORT_SYMBOL(find_get_pages_contig); |
ebf43500e [PATCH] Add find_... |
917 |
|
485bb99b4 [PATCH] kernel-do... |
918 919 920 921 922 923 924 925 |
/** * find_get_pages_tag - find and return pages that match @tag * @mapping: the address_space to search * @index: the starting page index * @tag: the tag index * @nr_pages: the maximum number of pages * @pages: where the resulting pages are placed * |
1da177e4c Linux-2.6.12-rc2 |
926 |
* Like find_get_pages, except we only return pages which are tagged with |
485bb99b4 [PATCH] kernel-do... |
927 |
* @tag. We update @index to index the next page for the traversal. |
1da177e4c Linux-2.6.12-rc2 |
928 929 930 931 932 933 |
*/ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, int tag, unsigned int nr_pages, struct page **pages) { unsigned int i; unsigned int ret; |
a60637c85 mm: lockless page... |
934 935 936 937 938 939 940 941 942 943 944 945 946 |
unsigned int nr_found; rcu_read_lock(); restart: nr_found = radix_tree_gang_lookup_tag_slot(&mapping->page_tree, (void ***)pages, *index, nr_pages, tag); ret = 0; for (i = 0; i < nr_found; i++) { struct page *page; repeat: page = radix_tree_deref_slot((void **)pages[i]); if (unlikely(!page)) continue; |
9d8aa4ea8 mm: remove worryi... |
947 |
|
a2c16d6cb mm: let swap use ... |
948 |
if (radix_tree_exception(page)) { |
8079b1c85 mm: clarify the r... |
949 950 951 952 953 954 955 956 |
if (radix_tree_deref_retry(page)) { /* * Transient condition which can only trigger * when entry at index 0 moves out of or back * to root: none yet gotten, safe to restart. */ goto restart; } |
a2c16d6cb mm: let swap use ... |
957 |
/* |
8079b1c85 mm: clarify the r... |
958 959 |
* This function is never used on a shmem/tmpfs * mapping, so a swap entry won't be found here. |
a2c16d6cb mm: let swap use ... |
960 |
*/ |
8079b1c85 mm: clarify the r... |
961 |
BUG(); |
a2c16d6cb mm: let swap use ... |
962 |
} |
a60637c85 mm: lockless page... |
963 964 965 966 967 968 969 970 971 972 973 974 975 |
if (!page_cache_get_speculative(page)) goto repeat; /* Has the page moved? */ if (unlikely(page != *((void **)pages[i]))) { page_cache_release(page); goto repeat; } pages[ret] = page; ret++; } |
5b280c0cc mm: don't return ... |
976 977 978 979 980 981 982 |
/* * If all entries were removed before we could secure them, * try again, because callers stop trying once 0 is returned. */ if (unlikely(!ret && nr_found)) goto restart; |
a60637c85 mm: lockless page... |
983 |
rcu_read_unlock(); |
1da177e4c Linux-2.6.12-rc2 |
984 |
|
1da177e4c Linux-2.6.12-rc2 |
985 986 |
if (ret) *index = pages[ret - 1]->index + 1; |
a60637c85 mm: lockless page... |
987 |
|
1da177e4c Linux-2.6.12-rc2 |
988 989 |
return ret; } |
ef71c15c4 AFS: export a cou... |
990 |
EXPORT_SYMBOL(find_get_pages_tag); |
1da177e4c Linux-2.6.12-rc2 |
991 |
|
485bb99b4 [PATCH] kernel-do... |
992 993 994 995 996 |
/** * grab_cache_page_nowait - returns locked page at given index in given cache * @mapping: target address_space * @index: the page index * |
72fd4a35a [PATCH] Numerous ... |
997 |
* Same as grab_cache_page(), but do not wait if the page is unavailable. |
1da177e4c Linux-2.6.12-rc2 |
998 999 1000 1001 1002 1003 1004 1005 |
* This is intended for speculative data generators, where the data can * be regenerated if the page couldn't be grabbed. This routine should * be safe to call while holding the lock for another page. * * Clear __GFP_FS when allocating the page to avoid recursion into the fs * and deadlock against the caller's locked page. */ struct page * |
57f6b96c0 filemap: convert ... |
1006 |
grab_cache_page_nowait(struct address_space *mapping, pgoff_t index) |
1da177e4c Linux-2.6.12-rc2 |
1007 1008 |
{ struct page *page = find_get_page(mapping, index); |
1da177e4c Linux-2.6.12-rc2 |
1009 1010 |
if (page) { |
529ae9aaa mm: rename page t... |
1011 |
if (trylock_page(page)) |
1da177e4c Linux-2.6.12-rc2 |
1012 1013 1014 1015 |
return page; page_cache_release(page); return NULL; } |
2ae88149a [PATCH] mm: clean... |
1016 |
page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~__GFP_FS); |
67d58ac47 mm: pagecache gfp... |
1017 |
if (page && add_to_page_cache_lru(page, mapping, index, GFP_NOFS)) { |
1da177e4c Linux-2.6.12-rc2 |
1018 1019 1020 1021 1022 |
page_cache_release(page); page = NULL; } return page; } |
1da177e4c Linux-2.6.12-rc2 |
1023 |
EXPORT_SYMBOL(grab_cache_page_nowait); |
76d42bd96 [PATCH] readahead... |
1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 |
/* * CD/DVDs are error prone. When a medium error occurs, the driver may fail * a _large_ part of the i/o request. Imagine the worst scenario: * * ---R__________________________________________B__________ * ^ reading here ^ bad block(assume 4k) * * read(R) => miss => readahead(R...B) => media error => frustrating retries * => failing the whole request => read(R) => read(R+1) => * readahead(R+1...B+1) => bang => read(R+2) => read(R+3) => * readahead(R+3...B+2) => bang => read(R+3) => read(R+4) => * readahead(R+4...B+3) => bang => read(R+4) => read(R+5) => ...... * * It is going insane. Fix it by quickly scaling down the readahead size. */ static void shrink_readahead_size_eio(struct file *filp, struct file_ra_state *ra) { |
76d42bd96 [PATCH] readahead... |
1042 |
ra->ra_pages /= 4; |
76d42bd96 [PATCH] readahead... |
1043 |
} |
485bb99b4 [PATCH] kernel-do... |
1044 |
/** |
36e789144 kill do_generic_m... |
1045 |
* do_generic_file_read - generic file read routine |
485bb99b4 [PATCH] kernel-do... |
1046 1047 1048 1049 1050 |
* @filp: the file to read * @ppos: current file position * @desc: read_descriptor * @actor: read method * |
1da177e4c Linux-2.6.12-rc2 |
1051 |
* This is a generic file read routine, and uses the |
485bb99b4 [PATCH] kernel-do... |
1052 |
* mapping->a_ops->readpage() function for the actual low-level stuff. |
1da177e4c Linux-2.6.12-rc2 |
1053 1054 1055 |
* * This is really ugly. But the goto's actually try to clarify some * of the logic when it comes to error handling etc. |
1da177e4c Linux-2.6.12-rc2 |
1056 |
*/ |
36e789144 kill do_generic_m... |
1057 1058 |
static void do_generic_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1da177e4c Linux-2.6.12-rc2 |
1059 |
{ |
36e789144 kill do_generic_m... |
1060 |
struct address_space *mapping = filp->f_mapping; |
1da177e4c Linux-2.6.12-rc2 |
1061 |
struct inode *inode = mapping->host; |
36e789144 kill do_generic_m... |
1062 |
struct file_ra_state *ra = &filp->f_ra; |
57f6b96c0 filemap: convert ... |
1063 1064 1065 1066 |
pgoff_t index; pgoff_t last_index; pgoff_t prev_index; unsigned long offset; /* offset into pagecache page */ |
ec0f16372 readahead: improv... |
1067 |
unsigned int prev_offset; |
1da177e4c Linux-2.6.12-rc2 |
1068 |
int error; |
1da177e4c Linux-2.6.12-rc2 |
1069 |
|
1da177e4c Linux-2.6.12-rc2 |
1070 |
index = *ppos >> PAGE_CACHE_SHIFT; |
7ff81078d readahead: remove... |
1071 1072 |
prev_index = ra->prev_pos >> PAGE_CACHE_SHIFT; prev_offset = ra->prev_pos & (PAGE_CACHE_SIZE-1); |
1da177e4c Linux-2.6.12-rc2 |
1073 1074 |
last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; offset = *ppos & ~PAGE_CACHE_MASK; |
1da177e4c Linux-2.6.12-rc2 |
1075 1076 |
for (;;) { struct page *page; |
57f6b96c0 filemap: convert ... |
1077 |
pgoff_t end_index; |
a32ea1e1f Fix read/truncate... |
1078 |
loff_t isize; |
1da177e4c Linux-2.6.12-rc2 |
1079 |
unsigned long nr, ret; |
1da177e4c Linux-2.6.12-rc2 |
1080 |
cond_resched(); |
1da177e4c Linux-2.6.12-rc2 |
1081 1082 |
find_page: page = find_get_page(mapping, index); |
3ea89ee86 readahead: conver... |
1083 |
if (!page) { |
cf914a7d6 readahead: split ... |
1084 |
page_cache_sync_readahead(mapping, |
7ff81078d readahead: remove... |
1085 |
ra, filp, |
3ea89ee86 readahead: conver... |
1086 1087 1088 1089 1090 1091 |
index, last_index - index); page = find_get_page(mapping, index); if (unlikely(page == NULL)) goto no_cached_page; } if (PageReadahead(page)) { |
cf914a7d6 readahead: split ... |
1092 |
page_cache_async_readahead(mapping, |
7ff81078d readahead: remove... |
1093 |
ra, filp, page, |
3ea89ee86 readahead: conver... |
1094 |
index, last_index - index); |
1da177e4c Linux-2.6.12-rc2 |
1095 |
} |
8ab22b9ab vfs: pagecache us... |
1096 1097 1098 1099 |
if (!PageUptodate(page)) { if (inode->i_blkbits == PAGE_CACHE_SHIFT || !mapping->a_ops->is_partially_uptodate) goto page_not_up_to_date; |
529ae9aaa mm: rename page t... |
1100 |
if (!trylock_page(page)) |
8ab22b9ab vfs: pagecache us... |
1101 |
goto page_not_up_to_date; |
8d056cb96 mm/vfs: revalidat... |
1102 1103 1104 |
/* Did it get truncated before we got the lock? */ if (!page->mapping) goto page_not_up_to_date_locked; |
8ab22b9ab vfs: pagecache us... |
1105 1106 1107 1108 1109 |
if (!mapping->a_ops->is_partially_uptodate(page, desc, offset)) goto page_not_up_to_date_locked; unlock_page(page); } |
1da177e4c Linux-2.6.12-rc2 |
1110 |
page_ok: |
a32ea1e1f Fix read/truncate... |
1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 |
/* * i_size must be checked after we know the page is Uptodate. * * Checking i_size after the check allows us to calculate * the correct value for "nr", which means the zero-filled * part of the page is not copied back to userspace (unless * another truncate extends the file - this is desired though). */ isize = i_size_read(inode); end_index = (isize - 1) >> PAGE_CACHE_SHIFT; if (unlikely(!isize || index > end_index)) { page_cache_release(page); goto out; } /* nr is the maximum number of bytes to copy from this page */ nr = PAGE_CACHE_SIZE; if (index == end_index) { nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; if (nr <= offset) { page_cache_release(page); goto out; } } nr = nr - offset; |
1da177e4c Linux-2.6.12-rc2 |
1137 1138 1139 1140 1141 1142 1143 1144 1145 |
/* If users can be writing to this page using arbitrary * virtual addresses, take care about potential aliasing * before reading the page on the kernel side. */ if (mapping_writably_mapped(mapping)) flush_dcache_page(page); /* |
ec0f16372 readahead: improv... |
1146 1147 |
* When a sequential read accesses a page several times, * only mark it as accessed the first time. |
1da177e4c Linux-2.6.12-rc2 |
1148 |
*/ |
ec0f16372 readahead: improv... |
1149 |
if (prev_index != index || offset != prev_offset) |
1da177e4c Linux-2.6.12-rc2 |
1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 |
mark_page_accessed(page); prev_index = index; /* * Ok, we have the page, and it's up-to-date, so * now we can copy it to user space... * * The actor routine returns how many bytes were actually used.. * NOTE! This may not be the same as how much of a user buffer * we filled up (we may be padding etc), so we can only update * "pos" here (the actor routine has to update the user buffer * pointers and the remaining count). */ ret = actor(desc, page, offset, nr); offset += ret; index += offset >> PAGE_CACHE_SHIFT; offset &= ~PAGE_CACHE_MASK; |
6ce745ed3 readahead: code c... |
1167 |
prev_offset = offset; |
1da177e4c Linux-2.6.12-rc2 |
1168 1169 1170 1171 1172 1173 1174 1175 |
page_cache_release(page); if (ret == nr && desc->count) continue; goto out; page_not_up_to_date: /* Get exclusive access to the page ... */ |
854623235 do_generic_file_r... |
1176 1177 1178 |
error = lock_page_killable(page); if (unlikely(error)) goto readpage_error; |
1da177e4c Linux-2.6.12-rc2 |
1179 |
|
8ab22b9ab vfs: pagecache us... |
1180 |
page_not_up_to_date_locked: |
da6052f7b [PATCH] update so... |
1181 |
/* Did it get truncated before we got the lock? */ |
1da177e4c Linux-2.6.12-rc2 |
1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 |
if (!page->mapping) { unlock_page(page); page_cache_release(page); continue; } /* Did somebody else fill it already? */ if (PageUptodate(page)) { unlock_page(page); goto page_ok; } readpage: |
91803b499 do_generic_file_r... |
1195 1196 1197 1198 1199 1200 |
/* * A previous I/O error may have been due to temporary * failures, eg. multipath errors. * PG_error will be set again if readpage fails. */ ClearPageError(page); |
1da177e4c Linux-2.6.12-rc2 |
1201 1202 |
/* Start the actual read. The read will unlock the page. */ error = mapping->a_ops->readpage(filp, page); |
994fc28c7 [PATCH] add AOP_T... |
1203 1204 1205 1206 1207 |
if (unlikely(error)) { if (error == AOP_TRUNCATED_PAGE) { page_cache_release(page); goto find_page; } |
1da177e4c Linux-2.6.12-rc2 |
1208 |
goto readpage_error; |
994fc28c7 [PATCH] add AOP_T... |
1209 |
} |
1da177e4c Linux-2.6.12-rc2 |
1210 1211 |
if (!PageUptodate(page)) { |
854623235 do_generic_file_r... |
1212 1213 1214 |
error = lock_page_killable(page); if (unlikely(error)) goto readpage_error; |
1da177e4c Linux-2.6.12-rc2 |
1215 1216 1217 |
if (!PageUptodate(page)) { if (page->mapping == NULL) { /* |
2ecdc82ef kill unused inval... |
1218 |
* invalidate_mapping_pages got it |
1da177e4c Linux-2.6.12-rc2 |
1219 1220 1221 1222 1223 1224 |
*/ unlock_page(page); page_cache_release(page); goto find_page; } unlock_page(page); |
7ff81078d readahead: remove... |
1225 |
shrink_readahead_size_eio(filp, ra); |
854623235 do_generic_file_r... |
1226 1227 |
error = -EIO; goto readpage_error; |
1da177e4c Linux-2.6.12-rc2 |
1228 1229 1230 |
} unlock_page(page); } |
1da177e4c Linux-2.6.12-rc2 |
1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 |
goto page_ok; readpage_error: /* UHHUH! A synchronous read error occurred. Report it */ desc->error = error; page_cache_release(page); goto out; no_cached_page: /* * Ok, it wasn't cached, so we need to create a new * page.. */ |
eb2be1893 mm: buffered writ... |
1244 1245 1246 1247 |
page = page_cache_alloc_cold(mapping); if (!page) { desc->error = -ENOMEM; goto out; |
1da177e4c Linux-2.6.12-rc2 |
1248 |
} |
eb2be1893 mm: buffered writ... |
1249 |
error = add_to_page_cache_lru(page, mapping, |
1da177e4c Linux-2.6.12-rc2 |
1250 1251 |
index, GFP_KERNEL); if (error) { |
eb2be1893 mm: buffered writ... |
1252 |
page_cache_release(page); |
1da177e4c Linux-2.6.12-rc2 |
1253 1254 1255 1256 1257 |
if (error == -EEXIST) goto find_page; desc->error = error; goto out; } |
1da177e4c Linux-2.6.12-rc2 |
1258 1259 1260 1261 |
goto readpage; } out: |
7ff81078d readahead: remove... |
1262 1263 1264 |
ra->prev_pos = prev_index; ra->prev_pos <<= PAGE_CACHE_SHIFT; ra->prev_pos |= prev_offset; |
1da177e4c Linux-2.6.12-rc2 |
1265 |
|
f4e6b498d readahead: combin... |
1266 |
*ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset; |
0c6aa2639 mm: do_generic_fi... |
1267 |
file_accessed(filp); |
1da177e4c Linux-2.6.12-rc2 |
1268 |
} |
1da177e4c Linux-2.6.12-rc2 |
1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 |
int file_read_actor(read_descriptor_t *desc, struct page *page, unsigned long offset, unsigned long size) { char *kaddr; unsigned long left, count = desc->count; if (size > count) size = count; /* * Faults on the destination of a read are common, so do it before * taking the kmap. */ if (!fault_in_pages_writeable(desc->arg.buf, size)) { kaddr = kmap_atomic(page, KM_USER0); left = __copy_to_user_inatomic(desc->arg.buf, kaddr + offset, size); kunmap_atomic(kaddr, KM_USER0); if (left == 0) goto success; } /* Do it the slow way */ kaddr = kmap(page); left = __copy_to_user(desc->arg.buf, kaddr + offset, size); kunmap(page); if (left) { size -= left; desc->error = -EFAULT; } success: desc->count = count - size; desc->written += size; desc->arg.buf += size; return size; } |
0ceb33143 mm: move common s... |
1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 |
/* * Performs necessary checks before doing a write * @iov: io vector request * @nr_segs: number of segments in the iovec * @count: number of bytes to write * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE * * Adjust number of segments and amount of bytes to write (nr_segs should be * properly initialized first). Returns appropriate error code that caller * should return or zero in case that write should be allowed. */ int generic_segment_checks(const struct iovec *iov, unsigned long *nr_segs, size_t *count, int access_flags) { unsigned long seg; size_t cnt = 0; for (seg = 0; seg < *nr_segs; seg++) { const struct iovec *iv = &iov[seg]; /* * If any segment has a negative length, or the cumulative * length ever wraps negative then return -EINVAL. */ cnt += iv->iov_len; if (unlikely((ssize_t)(cnt|iv->iov_len) < 0)) return -EINVAL; if (access_ok(access_flags, iv->iov_base, iv->iov_len)) continue; if (seg == 0) return -EFAULT; *nr_segs = seg; cnt -= iv->iov_len; /* This segment is no good */ break; } *count = cnt; return 0; } EXPORT_SYMBOL(generic_segment_checks); |
485bb99b4 [PATCH] kernel-do... |
1345 |
/** |
b2abacf3a [PATCH] mm: fix i... |
1346 |
* generic_file_aio_read - generic filesystem read routine |
485bb99b4 [PATCH] kernel-do... |
1347 1348 1349 |
* @iocb: kernel I/O control block * @iov: io vector request * @nr_segs: number of segments in the iovec |
b2abacf3a [PATCH] mm: fix i... |
1350 |
* @pos: current file position |
485bb99b4 [PATCH] kernel-do... |
1351 |
* |
1da177e4c Linux-2.6.12-rc2 |
1352 1353 1354 1355 |
* This is the "read()" routine for all filesystems * that can use the page cache directly. */ ssize_t |
543ade1fc [PATCH] Streamlin... |
1356 1357 |
generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos) |
1da177e4c Linux-2.6.12-rc2 |
1358 1359 1360 |
{ struct file *filp = iocb->ki_filp; ssize_t retval; |
66f998f61 fs: allow short d... |
1361 |
unsigned long seg = 0; |
1da177e4c Linux-2.6.12-rc2 |
1362 |
size_t count; |
543ade1fc [PATCH] Streamlin... |
1363 |
loff_t *ppos = &iocb->ki_pos; |
55602dd66 fs: make generic ... |
1364 |
struct blk_plug plug; |
1da177e4c Linux-2.6.12-rc2 |
1365 1366 |
count = 0; |
0ceb33143 mm: move common s... |
1367 1368 1369 |
retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); if (retval) return retval; |
1da177e4c Linux-2.6.12-rc2 |
1370 |
|
55602dd66 fs: make generic ... |
1371 |
blk_start_plug(&plug); |
1da177e4c Linux-2.6.12-rc2 |
1372 1373 |
/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ if (filp->f_flags & O_DIRECT) { |
543ade1fc [PATCH] Streamlin... |
1374 |
loff_t size; |
1da177e4c Linux-2.6.12-rc2 |
1375 1376 1377 1378 1379 |
struct address_space *mapping; struct inode *inode; mapping = filp->f_mapping; inode = mapping->host; |
1da177e4c Linux-2.6.12-rc2 |
1380 1381 1382 1383 |
if (!count) goto out; /* skip atime */ size = i_size_read(inode); if (pos < size) { |
48b47c561 mm: direct IO sta... |
1384 1385 |
retval = filemap_write_and_wait_range(mapping, pos, pos + iov_length(iov, nr_segs) - 1); |
a969e903a kill generic_file... |
1386 1387 1388 1389 |
if (!retval) { retval = mapping->a_ops->direct_IO(READ, iocb, iov, pos, nr_segs); } |
66f998f61 fs: allow short d... |
1390 |
if (retval > 0) { |
1da177e4c Linux-2.6.12-rc2 |
1391 |
*ppos = pos + retval; |
66f998f61 fs: allow short d... |
1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 |
count -= retval; } /* * Btrfs can have a short DIO read if we encounter * compressed extents, so if there was an error, or if * we've already read everything we wanted to, or if * there was a short read because we hit EOF, go ahead * and return. Otherwise fallthrough to buffered io for * the rest of the read. */ if (retval < 0 || !count || *ppos >= size) { |
11fa977ec generic_file_aio_... |
1404 1405 1406 |
file_accessed(filp); goto out; } |
0e0bcae3b [GFS2] Fix direct... |
1407 |
} |
1da177e4c Linux-2.6.12-rc2 |
1408 |
} |
66f998f61 fs: allow short d... |
1409 |
count = retval; |
11fa977ec generic_file_aio_... |
1410 1411 |
for (seg = 0; seg < nr_segs; seg++) { read_descriptor_t desc; |
66f998f61 fs: allow short d... |
1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 |
loff_t offset = 0; /* * If we did a short DIO read we need to skip the section of the * iov that we've already read data into. */ if (count) { if (count > iov[seg].iov_len) { count -= iov[seg].iov_len; continue; } offset = count; count = 0; } |
1da177e4c Linux-2.6.12-rc2 |
1426 |
|
11fa977ec generic_file_aio_... |
1427 |
desc.written = 0; |
66f998f61 fs: allow short d... |
1428 1429 |
desc.arg.buf = iov[seg].iov_base + offset; desc.count = iov[seg].iov_len - offset; |
11fa977ec generic_file_aio_... |
1430 1431 1432 1433 1434 1435 1436 1437 |
if (desc.count == 0) continue; desc.error = 0; do_generic_file_read(filp, ppos, &desc, file_read_actor); retval += desc.written; if (desc.error) { retval = retval ?: desc.error; break; |
1da177e4c Linux-2.6.12-rc2 |
1438 |
} |
11fa977ec generic_file_aio_... |
1439 1440 |
if (desc.count > 0) break; |
1da177e4c Linux-2.6.12-rc2 |
1441 1442 |
} out: |
55602dd66 fs: make generic ... |
1443 |
blk_finish_plug(&plug); |
1da177e4c Linux-2.6.12-rc2 |
1444 1445 |
return retval; } |
1da177e4c Linux-2.6.12-rc2 |
1446 |
EXPORT_SYMBOL(generic_file_aio_read); |
1da177e4c Linux-2.6.12-rc2 |
1447 1448 |
static ssize_t do_readahead(struct address_space *mapping, struct file *filp, |
57f6b96c0 filemap: convert ... |
1449 |
pgoff_t index, unsigned long nr) |
1da177e4c Linux-2.6.12-rc2 |
1450 1451 1452 |
{ if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage) return -EINVAL; |
f7e839dd3 readahead: move m... |
1453 |
force_page_cache_readahead(mapping, filp, index, nr); |
1da177e4c Linux-2.6.12-rc2 |
1454 1455 |
return 0; } |
6673e0c3f [CVE-2009-0029] S... |
1456 |
SYSCALL_DEFINE(readahead)(int fd, loff_t offset, size_t count) |
1da177e4c Linux-2.6.12-rc2 |
1457 1458 1459 1460 1461 1462 1463 1464 1465 |
{ ssize_t ret; struct file *file; ret = -EBADF; file = fget(fd); if (file) { if (file->f_mode & FMODE_READ) { struct address_space *mapping = file->f_mapping; |
57f6b96c0 filemap: convert ... |
1466 1467 |
pgoff_t start = offset >> PAGE_CACHE_SHIFT; pgoff_t end = (offset + count - 1) >> PAGE_CACHE_SHIFT; |
1da177e4c Linux-2.6.12-rc2 |
1468 1469 1470 1471 1472 1473 1474 |
unsigned long len = end - start + 1; ret = do_readahead(mapping, file, start, len); } fput(file); } return ret; } |
6673e0c3f [CVE-2009-0029] S... |
1475 1476 1477 1478 1479 1480 1481 |
#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS asmlinkage long SyS_readahead(long fd, loff_t offset, long count) { return SYSC_readahead((int) fd, offset, (size_t) count); } SYSCALL_ALIAS(sys_readahead, SyS_readahead); #endif |
1da177e4c Linux-2.6.12-rc2 |
1482 1483 |
#ifdef CONFIG_MMU |
485bb99b4 [PATCH] kernel-do... |
1484 1485 1486 1487 1488 |
/** * page_cache_read - adds requested page to the page cache if not already there * @file: file to read * @offset: page index * |
1da177e4c Linux-2.6.12-rc2 |
1489 1490 1491 |
* This adds the requested page to the page cache if it isn't already there, * and schedules an I/O to read in its contents from disk. */ |
920c7a5d0 mm: remove fastca... |
1492 |
static int page_cache_read(struct file *file, pgoff_t offset) |
1da177e4c Linux-2.6.12-rc2 |
1493 1494 1495 |
{ struct address_space *mapping = file->f_mapping; struct page *page; |
994fc28c7 [PATCH] add AOP_T... |
1496 |
int ret; |
1da177e4c Linux-2.6.12-rc2 |
1497 |
|
994fc28c7 [PATCH] add AOP_T... |
1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 |
do { page = page_cache_alloc_cold(mapping); if (!page) return -ENOMEM; ret = add_to_page_cache_lru(page, mapping, offset, GFP_KERNEL); if (ret == 0) ret = mapping->a_ops->readpage(file, page); else if (ret == -EEXIST) ret = 0; /* losing race to add is OK */ |
1da177e4c Linux-2.6.12-rc2 |
1508 |
|
1da177e4c Linux-2.6.12-rc2 |
1509 |
page_cache_release(page); |
1da177e4c Linux-2.6.12-rc2 |
1510 |
|
994fc28c7 [PATCH] add AOP_T... |
1511 1512 1513 |
} while (ret == AOP_TRUNCATED_PAGE); return ret; |
1da177e4c Linux-2.6.12-rc2 |
1514 1515 1516 |
} #define MMAP_LOTSAMISS (100) |
ef00e08e2 readahead: clean ... |
1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 |
/* * Synchronous readahead happens when we don't even find * a page in the page cache at all. */ static void do_sync_mmap_readahead(struct vm_area_struct *vma, struct file_ra_state *ra, struct file *file, pgoff_t offset) { unsigned long ra_pages; struct address_space *mapping = file->f_mapping; /* If we don't want any read-ahead, don't bother */ if (VM_RandomReadHint(vma)) return; |
275b12bf5 readahead: return... |
1532 1533 |
if (!ra->ra_pages) return; |
ef00e08e2 readahead: clean ... |
1534 |
|
2cbea1d3a readahead: trigge... |
1535 |
if (VM_SequentialReadHint(vma)) { |
7ffc59b4d readahead: enforc... |
1536 1537 |
page_cache_sync_readahead(mapping, ra, file, offset, ra->ra_pages); |
ef00e08e2 readahead: clean ... |
1538 1539 |
return; } |
207d04baa readahead: reduce... |
1540 1541 |
/* Avoid banging the cache line if not needed */ if (ra->mmap_miss < MMAP_LOTSAMISS * 10) |
ef00e08e2 readahead: clean ... |
1542 1543 1544 1545 1546 1547 1548 1549 |
ra->mmap_miss++; /* * Do we miss much more than hit in this file? If so, * stop bothering with read-ahead. It will only hurt. */ if (ra->mmap_miss > MMAP_LOTSAMISS) return; |
d30a11004 readahead: record... |
1550 1551 1552 |
/* * mmap read-around */ |
ef00e08e2 readahead: clean ... |
1553 |
ra_pages = max_sane_readahead(ra->ra_pages); |
275b12bf5 readahead: return... |
1554 1555 |
ra->start = max_t(long, 0, offset - ra_pages / 2); ra->size = ra_pages; |
2cbea1d3a readahead: trigge... |
1556 |
ra->async_size = ra_pages / 4; |
275b12bf5 readahead: return... |
1557 |
ra_submit(ra, mapping, file); |
ef00e08e2 readahead: clean ... |
1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 |
} /* * Asynchronous readahead happens when we find the page and PG_readahead, * so we want to possibly extend the readahead further.. */ static void do_async_mmap_readahead(struct vm_area_struct *vma, struct file_ra_state *ra, struct file *file, struct page *page, pgoff_t offset) { struct address_space *mapping = file->f_mapping; /* If we don't want any read-ahead, don't bother */ if (VM_RandomReadHint(vma)) return; if (ra->mmap_miss > 0) ra->mmap_miss--; if (PageReadahead(page)) |
2fad6f5de readahead: enforc... |
1578 1579 |
page_cache_async_readahead(mapping, ra, file, page, offset, ra->ra_pages); |
ef00e08e2 readahead: clean ... |
1580 |
} |
485bb99b4 [PATCH] kernel-do... |
1581 |
/** |
54cb8821d mm: merge populat... |
1582 |
* filemap_fault - read in file data for page fault handling |
d0217ac04 mm: fault feedbac... |
1583 1584 |
* @vma: vma in which the fault was taken * @vmf: struct vm_fault containing details of the fault |
485bb99b4 [PATCH] kernel-do... |
1585 |
* |
54cb8821d mm: merge populat... |
1586 |
* filemap_fault() is invoked via the vma operations vector for a |
1da177e4c Linux-2.6.12-rc2 |
1587 1588 1589 1590 1591 1592 |
* mapped memory region to read in file data during a page fault. * * The goto's are kind of ugly, but this streamlines the normal case of having * it in the page cache, and handles the special cases reasonably without * having a lot of duplicated code. */ |
d0217ac04 mm: fault feedbac... |
1593 |
int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4c Linux-2.6.12-rc2 |
1594 1595 |
{ int error; |
54cb8821d mm: merge populat... |
1596 |
struct file *file = vma->vm_file; |
1da177e4c Linux-2.6.12-rc2 |
1597 1598 1599 |
struct address_space *mapping = file->f_mapping; struct file_ra_state *ra = &file->f_ra; struct inode *inode = mapping->host; |
ef00e08e2 readahead: clean ... |
1600 |
pgoff_t offset = vmf->pgoff; |
1da177e4c Linux-2.6.12-rc2 |
1601 |
struct page *page; |
2004dc8ee Use pgoff_t inste... |
1602 |
pgoff_t size; |
83c54070e mm: fault feedbac... |
1603 |
int ret = 0; |
1da177e4c Linux-2.6.12-rc2 |
1604 |
|
1da177e4c Linux-2.6.12-rc2 |
1605 |
size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
ef00e08e2 readahead: clean ... |
1606 |
if (offset >= size) |
5307cc1aa Remove broken ptr... |
1607 |
return VM_FAULT_SIGBUS; |
1da177e4c Linux-2.6.12-rc2 |
1608 |
|
1da177e4c Linux-2.6.12-rc2 |
1609 |
/* |
1da177e4c Linux-2.6.12-rc2 |
1610 1611 |
* Do we have something in the page cache already? */ |
ef00e08e2 readahead: clean ... |
1612 1613 |
page = find_get_page(mapping, offset); if (likely(page)) { |
1da177e4c Linux-2.6.12-rc2 |
1614 |
/* |
ef00e08e2 readahead: clean ... |
1615 1616 |
* We found the page, so try async readahead before * waiting for the lock. |
1da177e4c Linux-2.6.12-rc2 |
1617 |
*/ |
ef00e08e2 readahead: clean ... |
1618 |
do_async_mmap_readahead(vma, ra, file, page, offset); |
ef00e08e2 readahead: clean ... |
1619 1620 1621 1622 |
} else { /* No page in the page cache at all */ do_sync_mmap_readahead(vma, ra, file, offset); count_vm_event(PGMAJFAULT); |
456f998ec memcg: add the pa... |
1623 |
mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); |
ef00e08e2 readahead: clean ... |
1624 1625 |
ret = VM_FAULT_MAJOR; retry_find: |
b522c94da mm: filemap_fault... |
1626 |
page = find_get_page(mapping, offset); |
1da177e4c Linux-2.6.12-rc2 |
1627 1628 1629 |
if (!page) goto no_cached_page; } |
d88c0922f Release page refe... |
1630 1631 |
if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) { page_cache_release(page); |
d065bd810 mm: retry page fa... |
1632 |
return ret | VM_FAULT_RETRY; |
d88c0922f Release page refe... |
1633 |
} |
b522c94da mm: filemap_fault... |
1634 1635 1636 1637 1638 1639 1640 1641 |
/* Did it get truncated? */ if (unlikely(page->mapping != mapping)) { unlock_page(page); put_page(page); goto retry_find; } VM_BUG_ON(page->index != offset); |
1da177e4c Linux-2.6.12-rc2 |
1642 |
/* |
d00806b18 mm: fix fault vs ... |
1643 1644 |
* We have a locked page in the page cache, now we need to check * that it's up-to-date. If not, it is going to be due to an error. |
1da177e4c Linux-2.6.12-rc2 |
1645 |
*/ |
d00806b18 mm: fix fault vs ... |
1646 |
if (unlikely(!PageUptodate(page))) |
1da177e4c Linux-2.6.12-rc2 |
1647 |
goto page_not_uptodate; |
ef00e08e2 readahead: clean ... |
1648 1649 1650 1651 |
/* * Found the page and have a reference on it. * We must recheck i_size under page lock. */ |
d00806b18 mm: fix fault vs ... |
1652 |
size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
ef00e08e2 readahead: clean ... |
1653 |
if (unlikely(offset >= size)) { |
d00806b18 mm: fix fault vs ... |
1654 |
unlock_page(page); |
745ad48e8 fix page release ... |
1655 |
page_cache_release(page); |
5307cc1aa Remove broken ptr... |
1656 |
return VM_FAULT_SIGBUS; |
d00806b18 mm: fix fault vs ... |
1657 |
} |
d0217ac04 mm: fault feedbac... |
1658 |
vmf->page = page; |
83c54070e mm: fault feedbac... |
1659 |
return ret | VM_FAULT_LOCKED; |
1da177e4c Linux-2.6.12-rc2 |
1660 |
|
1da177e4c Linux-2.6.12-rc2 |
1661 1662 1663 1664 1665 |
no_cached_page: /* * We're only likely to ever get here if MADV_RANDOM is in * effect. */ |
ef00e08e2 readahead: clean ... |
1666 |
error = page_cache_read(file, offset); |
1da177e4c Linux-2.6.12-rc2 |
1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 |
/* * The page we want has now been added to the page cache. * In the unlikely event that someone removed it in the * meantime, we'll just come back here and read it again. */ if (error >= 0) goto retry_find; /* * An error return from page_cache_read can result if the * system is low on memory, or a problem occurs while trying * to schedule I/O. */ if (error == -ENOMEM) |
d0217ac04 mm: fault feedbac... |
1682 1683 |
return VM_FAULT_OOM; return VM_FAULT_SIGBUS; |
1da177e4c Linux-2.6.12-rc2 |
1684 1685 |
page_not_uptodate: |
1da177e4c Linux-2.6.12-rc2 |
1686 1687 1688 1689 1690 1691 |
/* * Umm, take care of errors if the page isn't up-to-date. * Try to re-read it _once_. We do this synchronously, * because there really aren't any performance issues here * and we need to check for errors. */ |
1da177e4c Linux-2.6.12-rc2 |
1692 |
ClearPageError(page); |
994fc28c7 [PATCH] add AOP_T... |
1693 |
error = mapping->a_ops->readpage(file, page); |
3ef0f720e mm: fix infinite ... |
1694 1695 1696 1697 1698 |
if (!error) { wait_on_page_locked(page); if (!PageUptodate(page)) error = -EIO; } |
d00806b18 mm: fix fault vs ... |
1699 1700 1701 |
page_cache_release(page); if (!error || error == AOP_TRUNCATED_PAGE) |
994fc28c7 [PATCH] add AOP_T... |
1702 |
goto retry_find; |
1da177e4c Linux-2.6.12-rc2 |
1703 |
|
d00806b18 mm: fix fault vs ... |
1704 |
/* Things didn't work out. Return zero to tell the mm layer so. */ |
76d42bd96 [PATCH] readahead... |
1705 |
shrink_readahead_size_eio(file, ra); |
d0217ac04 mm: fault feedbac... |
1706 |
return VM_FAULT_SIGBUS; |
54cb8821d mm: merge populat... |
1707 1708 |
} EXPORT_SYMBOL(filemap_fault); |
f0f37e2f7 const: mark struc... |
1709 |
const struct vm_operations_struct generic_file_vm_ops = { |
54cb8821d mm: merge populat... |
1710 |
.fault = filemap_fault, |
1da177e4c Linux-2.6.12-rc2 |
1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 |
}; /* This is used for a general mmap of a disk file */ int generic_file_mmap(struct file * file, struct vm_area_struct * vma) { struct address_space *mapping = file->f_mapping; if (!mapping->a_ops->readpage) return -ENOEXEC; file_accessed(file); vma->vm_ops = &generic_file_vm_ops; |
d0217ac04 mm: fault feedbac... |
1723 |
vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4c Linux-2.6.12-rc2 |
1724 1725 |
return 0; } |
1da177e4c Linux-2.6.12-rc2 |
1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 |
/* * This is for filesystems which do not implement ->writepage. */ int generic_file_readonly_mmap(struct file *file, struct vm_area_struct *vma) { if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) return -EINVAL; return generic_file_mmap(file, vma); } #else int generic_file_mmap(struct file * file, struct vm_area_struct * vma) { return -ENOSYS; } int generic_file_readonly_mmap(struct file * file, struct vm_area_struct * vma) { return -ENOSYS; } #endif /* CONFIG_MMU */ EXPORT_SYMBOL(generic_file_mmap); EXPORT_SYMBOL(generic_file_readonly_mmap); |
6fe6900e1 mm: make read_cac... |
1749 |
static struct page *__read_cache_page(struct address_space *mapping, |
57f6b96c0 filemap: convert ... |
1750 |
pgoff_t index, |
5e5358e7c mm: cleanup descr... |
1751 |
int (*filler)(void *, struct page *), |
0531b2aac mm: add new 'read... |
1752 1753 |
void *data, gfp_t gfp) |
1da177e4c Linux-2.6.12-rc2 |
1754 |
{ |
eb2be1893 mm: buffered writ... |
1755 |
struct page *page; |
1da177e4c Linux-2.6.12-rc2 |
1756 1757 1758 1759 |
int err; repeat: page = find_get_page(mapping, index); if (!page) { |
0531b2aac mm: add new 'read... |
1760 |
page = __page_cache_alloc(gfp | __GFP_COLD); |
eb2be1893 mm: buffered writ... |
1761 1762 |
if (!page) return ERR_PTR(-ENOMEM); |
e6f67b8c0 vfs: __read_cache... |
1763 |
err = add_to_page_cache_lru(page, mapping, index, gfp); |
eb2be1893 mm: buffered writ... |
1764 1765 1766 1767 |
if (unlikely(err)) { page_cache_release(page); if (err == -EEXIST) goto repeat; |
1da177e4c Linux-2.6.12-rc2 |
1768 |
/* Presumably ENOMEM for radix tree node */ |
1da177e4c Linux-2.6.12-rc2 |
1769 1770 |
return ERR_PTR(err); } |
1da177e4c Linux-2.6.12-rc2 |
1771 1772 1773 1774 1775 1776 |
err = filler(data, page); if (err < 0) { page_cache_release(page); page = ERR_PTR(err); } } |
1da177e4c Linux-2.6.12-rc2 |
1777 1778 |
return page; } |
0531b2aac mm: add new 'read... |
1779 |
static struct page *do_read_cache_page(struct address_space *mapping, |
57f6b96c0 filemap: convert ... |
1780 |
pgoff_t index, |
5e5358e7c mm: cleanup descr... |
1781 |
int (*filler)(void *, struct page *), |
0531b2aac mm: add new 'read... |
1782 1783 |
void *data, gfp_t gfp) |
1da177e4c Linux-2.6.12-rc2 |
1784 1785 1786 1787 1788 |
{ struct page *page; int err; retry: |
0531b2aac mm: add new 'read... |
1789 |
page = __read_cache_page(mapping, index, filler, data, gfp); |
1da177e4c Linux-2.6.12-rc2 |
1790 |
if (IS_ERR(page)) |
c855ff371 Fix a bad error c... |
1791 |
return page; |
1da177e4c Linux-2.6.12-rc2 |
1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 |
if (PageUptodate(page)) goto out; lock_page(page); if (!page->mapping) { unlock_page(page); page_cache_release(page); goto retry; } if (PageUptodate(page)) { unlock_page(page); goto out; } err = filler(data, page); if (err < 0) { page_cache_release(page); |
c855ff371 Fix a bad error c... |
1808 |
return ERR_PTR(err); |
1da177e4c Linux-2.6.12-rc2 |
1809 |
} |
c855ff371 Fix a bad error c... |
1810 |
out: |
6fe6900e1 mm: make read_cac... |
1811 1812 1813 |
mark_page_accessed(page); return page; } |
0531b2aac mm: add new 'read... |
1814 1815 1816 1817 1818 1819 |
/** * read_cache_page_async - read into page cache, fill it if needed * @mapping: the page's address_space * @index: the page index * @filler: function to perform the read |
5e5358e7c mm: cleanup descr... |
1820 |
* @data: first arg to filler(data, page) function, often left as NULL |
0531b2aac mm: add new 'read... |
1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 |
* * Same as read_cache_page, but don't wait for page to become unlocked * after submitting it to the filler. * * Read into the page cache. If a page already exists, and PageUptodate() is * not set, try to fill the page but don't wait for it to become unlocked. * * If the page does not get brought uptodate, return -EIO. */ struct page *read_cache_page_async(struct address_space *mapping, pgoff_t index, |
5e5358e7c mm: cleanup descr... |
1832 |
int (*filler)(void *, struct page *), |
0531b2aac mm: add new 'read... |
1833 1834 1835 1836 |
void *data) { return do_read_cache_page(mapping, index, filler, data, mapping_gfp_mask(mapping)); } |
6fe6900e1 mm: make read_cac... |
1837 |
EXPORT_SYMBOL(read_cache_page_async); |
0531b2aac mm: add new 'read... |
1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 |
static struct page *wait_on_page_read(struct page *page) { if (!IS_ERR(page)) { wait_on_page_locked(page); if (!PageUptodate(page)) { page_cache_release(page); page = ERR_PTR(-EIO); } } return page; } /** * read_cache_page_gfp - read into page cache, using specified page allocation flags. * @mapping: the page's address_space * @index: the page index * @gfp: the page allocator flags to use if allocating * * This is the same as "read_mapping_page(mapping, index, NULL)", but with |
e6f67b8c0 vfs: __read_cache... |
1857 |
* any new page allocations done using the specified allocation flags. |
0531b2aac mm: add new 'read... |
1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 |
* * If the page does not get brought uptodate, return -EIO. */ struct page *read_cache_page_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp) { filler_t *filler = (filler_t *)mapping->a_ops->readpage; return wait_on_page_read(do_read_cache_page(mapping, index, filler, NULL, gfp)); } EXPORT_SYMBOL(read_cache_page_gfp); |
6fe6900e1 mm: make read_cac... |
1870 1871 1872 1873 1874 |
/** * read_cache_page - read into page cache, fill it if needed * @mapping: the page's address_space * @index: the page index * @filler: function to perform the read |
5e5358e7c mm: cleanup descr... |
1875 |
* @data: first arg to filler(data, page) function, often left as NULL |
6fe6900e1 mm: make read_cac... |
1876 1877 1878 1879 1880 1881 1882 |
* * Read into the page cache. If a page already exists, and PageUptodate() is * not set, try to fill the page then wait for it to become unlocked. * * If the page does not get brought uptodate, return -EIO. */ struct page *read_cache_page(struct address_space *mapping, |
57f6b96c0 filemap: convert ... |
1883 |
pgoff_t index, |
5e5358e7c mm: cleanup descr... |
1884 |
int (*filler)(void *, struct page *), |
6fe6900e1 mm: make read_cac... |
1885 1886 |
void *data) { |
0531b2aac mm: add new 'read... |
1887 |
return wait_on_page_read(read_cache_page_async(mapping, index, filler, data)); |
1da177e4c Linux-2.6.12-rc2 |
1888 |
} |
1da177e4c Linux-2.6.12-rc2 |
1889 1890 1891 |
EXPORT_SYMBOL(read_cache_page); /* |
1da177e4c Linux-2.6.12-rc2 |
1892 1893 1894 1895 1896 |
* The logic we want is * * if suid or (sgid and xgrp) * remove privs */ |
01de85e05 [PATCH] Add lockl... |
1897 |
int should_remove_suid(struct dentry *dentry) |
1da177e4c Linux-2.6.12-rc2 |
1898 |
{ |
649fc7b1b should_remove_sui... |
1899 |
umode_t mode = dentry->d_inode->i_mode; |
1da177e4c Linux-2.6.12-rc2 |
1900 |
int kill = 0; |
1da177e4c Linux-2.6.12-rc2 |
1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 |
/* suid always must be killed */ if (unlikely(mode & S_ISUID)) kill = ATTR_KILL_SUID; /* * sgid without any exec bits is just a mandatory locking mark; leave * it alone. If some exec bits are set, it's a real sgid; kill it. */ if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) kill |= ATTR_KILL_SGID; |
7f5ff766a kill suid bit onl... |
1912 |
if (unlikely(kill && !capable(CAP_FSETID) && S_ISREG(mode))) |
01de85e05 [PATCH] Add lockl... |
1913 |
return kill; |
1da177e4c Linux-2.6.12-rc2 |
1914 |
|
01de85e05 [PATCH] Add lockl... |
1915 1916 |
return 0; } |
d23a147bb [PATCH] Export sh... |
1917 |
EXPORT_SYMBOL(should_remove_suid); |
01de85e05 [PATCH] Add lockl... |
1918 |
|
7f3d4ee10 vfs: splice remov... |
1919 |
static int __remove_suid(struct dentry *dentry, int kill) |
01de85e05 [PATCH] Add lockl... |
1920 1921 1922 1923 1924 1925 |
{ struct iattr newattrs; newattrs.ia_valid = ATTR_FORCE | kill; return notify_change(dentry, &newattrs); } |
2f1936b87 [patch 3/5] vfs: ... |
1926 |
int file_remove_suid(struct file *file) |
01de85e05 [PATCH] Add lockl... |
1927 |
{ |
2f1936b87 [patch 3/5] vfs: ... |
1928 |
struct dentry *dentry = file->f_path.dentry; |
69b457329 Cache xattr secur... |
1929 1930 1931 |
struct inode *inode = dentry->d_inode; int killsuid; int killpriv; |
b53767719 Implement file po... |
1932 |
int error = 0; |
01de85e05 [PATCH] Add lockl... |
1933 |
|
69b457329 Cache xattr secur... |
1934 1935 1936 1937 1938 1939 |
/* Fast path for nothing security related */ if (IS_NOSEC(inode)) return 0; killsuid = should_remove_suid(dentry); killpriv = security_inode_need_killpriv(dentry); |
b53767719 Implement file po... |
1940 1941 1942 1943 1944 1945 |
if (killpriv < 0) return killpriv; if (killpriv) error = security_inode_killpriv(dentry); if (!error && killsuid) error = __remove_suid(dentry, killsuid); |
9e1f1de02 more conservative... |
1946 |
if (!error && (inode->i_sb->s_flags & MS_NOSEC)) |
69b457329 Cache xattr secur... |
1947 |
inode->i_flags |= S_NOSEC; |
01de85e05 [PATCH] Add lockl... |
1948 |
|
b53767719 Implement file po... |
1949 |
return error; |
1da177e4c Linux-2.6.12-rc2 |
1950 |
} |
2f1936b87 [patch 3/5] vfs: ... |
1951 |
EXPORT_SYMBOL(file_remove_suid); |
1da177e4c Linux-2.6.12-rc2 |
1952 |
|
2f718ffc1 mm: buffered writ... |
1953 |
static size_t __iovec_copy_from_user_inatomic(char *vaddr, |
1da177e4c Linux-2.6.12-rc2 |
1954 1955 |
const struct iovec *iov, size_t base, size_t bytes) { |
f18005369 x86, mm: dont use... |
1956 |
size_t copied = 0, left = 0; |
1da177e4c Linux-2.6.12-rc2 |
1957 1958 1959 1960 1961 1962 |
while (bytes) { char __user *buf = iov->iov_base + base; int copy = min(bytes, iov->iov_len - base); base = 0; |
f18005369 x86, mm: dont use... |
1963 |
left = __copy_from_user_inatomic(vaddr, buf, copy); |
1da177e4c Linux-2.6.12-rc2 |
1964 1965 1966 1967 |
copied += copy; bytes -= copy; vaddr += copy; iov++; |
01408c493 [PATCH] Prepare f... |
1968 |
if (unlikely(left)) |
1da177e4c Linux-2.6.12-rc2 |
1969 |
break; |
1da177e4c Linux-2.6.12-rc2 |
1970 1971 1972 1973 1974 |
} return copied - left; } /* |
2f718ffc1 mm: buffered writ... |
1975 |
* Copy as much as we can into the page and return the number of bytes which |
af901ca18 tree-wide: fix as... |
1976 |
* were successfully copied. If a fault is encountered then return the number of |
2f718ffc1 mm: buffered writ... |
1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 |
* bytes which were copied. */ size_t iov_iter_copy_from_user_atomic(struct page *page, struct iov_iter *i, unsigned long offset, size_t bytes) { char *kaddr; size_t copied; BUG_ON(!in_atomic()); kaddr = kmap_atomic(page, KM_USER0); if (likely(i->nr_segs == 1)) { int left; char __user *buf = i->iov->iov_base + i->iov_offset; |
f18005369 x86, mm: dont use... |
1990 |
left = __copy_from_user_inatomic(kaddr + offset, buf, bytes); |
2f718ffc1 mm: buffered writ... |
1991 1992 1993 1994 1995 1996 1997 1998 1999 |
copied = bytes - left; } else { copied = __iovec_copy_from_user_inatomic(kaddr + offset, i->iov, i->iov_offset, bytes); } kunmap_atomic(kaddr, KM_USER0); return copied; } |
89e107877 fs: new cont helpers |
2000 |
EXPORT_SYMBOL(iov_iter_copy_from_user_atomic); |
2f718ffc1 mm: buffered writ... |
2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 |
/* * This has the same sideeffects and return value as * iov_iter_copy_from_user_atomic(). * The difference is that it attempts to resolve faults. * Page must not be locked. */ size_t iov_iter_copy_from_user(struct page *page, struct iov_iter *i, unsigned long offset, size_t bytes) { char *kaddr; size_t copied; kaddr = kmap(page); if (likely(i->nr_segs == 1)) { int left; char __user *buf = i->iov->iov_base + i->iov_offset; |
f18005369 x86, mm: dont use... |
2018 |
left = __copy_from_user(kaddr + offset, buf, bytes); |
2f718ffc1 mm: buffered writ... |
2019 2020 2021 2022 2023 2024 2025 2026 |
copied = bytes - left; } else { copied = __iovec_copy_from_user_inatomic(kaddr + offset, i->iov, i->iov_offset, bytes); } kunmap(page); return copied; } |
89e107877 fs: new cont helpers |
2027 |
EXPORT_SYMBOL(iov_iter_copy_from_user); |
2f718ffc1 mm: buffered writ... |
2028 |
|
f7009264c iov_iter_advance(... |
2029 |
void iov_iter_advance(struct iov_iter *i, size_t bytes) |
2f718ffc1 mm: buffered writ... |
2030 |
{ |
f7009264c iov_iter_advance(... |
2031 |
BUG_ON(i->count < bytes); |
2f718ffc1 mm: buffered writ... |
2032 2033 |
if (likely(i->nr_segs == 1)) { i->iov_offset += bytes; |
f7009264c iov_iter_advance(... |
2034 |
i->count -= bytes; |
2f718ffc1 mm: buffered writ... |
2035 2036 2037 |
} else { const struct iovec *iov = i->iov; size_t base = i->iov_offset; |
39be79c16 vfs: iov_iter: ha... |
2038 |
unsigned long nr_segs = i->nr_segs; |
2f718ffc1 mm: buffered writ... |
2039 |
|
124d3b704 fix writev regres... |
2040 2041 |
/* * The !iov->iov_len check ensures we skip over unlikely |
f7009264c iov_iter_advance(... |
2042 |
* zero-length segments (without overruning the iovec). |
124d3b704 fix writev regres... |
2043 |
*/ |
94ad374a0 Fix off-by-one er... |
2044 |
while (bytes || unlikely(i->count && !iov->iov_len)) { |
f7009264c iov_iter_advance(... |
2045 |
int copy; |
2f718ffc1 mm: buffered writ... |
2046 |
|
f7009264c iov_iter_advance(... |
2047 2048 2049 |
copy = min(bytes, iov->iov_len - base); BUG_ON(!i->count || i->count < copy); i->count -= copy; |
2f718ffc1 mm: buffered writ... |
2050 2051 2052 2053 |
bytes -= copy; base += copy; if (iov->iov_len == base) { iov++; |
39be79c16 vfs: iov_iter: ha... |
2054 |
nr_segs--; |
2f718ffc1 mm: buffered writ... |
2055 2056 2057 2058 2059 |
base = 0; } } i->iov = iov; i->iov_offset = base; |
39be79c16 vfs: iov_iter: ha... |
2060 |
i->nr_segs = nr_segs; |
2f718ffc1 mm: buffered writ... |
2061 2062 |
} } |
89e107877 fs: new cont helpers |
2063 |
EXPORT_SYMBOL(iov_iter_advance); |
2f718ffc1 mm: buffered writ... |
2064 |
|
afddba49d fs: introduce wri... |
2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 |
/* * Fault in the first iovec of the given iov_iter, to a maximum length * of bytes. Returns 0 on success, or non-zero if the memory could not be * accessed (ie. because it is an invalid address). * * writev-intensive code may want this to prefault several iovecs -- that * would be possible (callers must not rely on the fact that _only_ the * first iovec will be faulted with the current implementation). */ int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) |
2f718ffc1 mm: buffered writ... |
2075 |
{ |
2f718ffc1 mm: buffered writ... |
2076 |
char __user *buf = i->iov->iov_base + i->iov_offset; |
afddba49d fs: introduce wri... |
2077 2078 |
bytes = min(bytes, i->iov->iov_len - i->iov_offset); return fault_in_pages_readable(buf, bytes); |
2f718ffc1 mm: buffered writ... |
2079 |
} |
89e107877 fs: new cont helpers |
2080 |
EXPORT_SYMBOL(iov_iter_fault_in_readable); |
2f718ffc1 mm: buffered writ... |
2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 |
/* * Return the count of just the current iov_iter segment. */ size_t iov_iter_single_seg_count(struct iov_iter *i) { const struct iovec *iov = i->iov; if (i->nr_segs == 1) return i->count; else return min(i->count, iov->iov_len - i->iov_offset); } |
89e107877 fs: new cont helpers |
2093 |
EXPORT_SYMBOL(iov_iter_single_seg_count); |
2f718ffc1 mm: buffered writ... |
2094 2095 |
/* |
1da177e4c Linux-2.6.12-rc2 |
2096 2097 |
* Performs necessary checks before doing a write * |
485bb99b4 [PATCH] kernel-do... |
2098 |
* Can adjust writing position or amount of bytes to write. |
1da177e4c Linux-2.6.12-rc2 |
2099 2100 2101 2102 2103 2104 |
* Returns appropriate error code that caller should return or * zero in case that write should be allowed. */ inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, int isblk) { struct inode *inode = file->f_mapping->host; |
59e99e5b9 mm: use rlimit he... |
2105 |
unsigned long limit = rlimit(RLIMIT_FSIZE); |
1da177e4c Linux-2.6.12-rc2 |
2106 2107 2108 |
if (unlikely(*pos < 0)) return -EINVAL; |
1da177e4c Linux-2.6.12-rc2 |
2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 |
if (!isblk) { /* FIXME: this is for backwards compatibility with 2.4 */ if (file->f_flags & O_APPEND) *pos = i_size_read(inode); if (limit != RLIM_INFINITY) { if (*pos >= limit) { send_sig(SIGXFSZ, current, 0); return -EFBIG; } if (*count > limit - (typeof(limit))*pos) { *count = limit - (typeof(limit))*pos; } } } /* * LFS rule */ if (unlikely(*pos + *count > MAX_NON_LFS && !(file->f_flags & O_LARGEFILE))) { if (*pos >= MAX_NON_LFS) { |
1da177e4c Linux-2.6.12-rc2 |
2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 |
return -EFBIG; } if (*count > MAX_NON_LFS - (unsigned long)*pos) { *count = MAX_NON_LFS - (unsigned long)*pos; } } /* * Are we about to exceed the fs block limit ? * * If we have written data it becomes a short write. If we have * exceeded without writing data we send a signal and return EFBIG. * Linus frestrict idea will clean these up nicely.. */ if (likely(!isblk)) { if (unlikely(*pos >= inode->i_sb->s_maxbytes)) { if (*count || *pos > inode->i_sb->s_maxbytes) { |
1da177e4c Linux-2.6.12-rc2 |
2148 2149 2150 2151 2152 2153 2154 2155 |
return -EFBIG; } /* zero-length writes at ->s_maxbytes are OK */ } if (unlikely(*pos + *count > inode->i_sb->s_maxbytes)) *count = inode->i_sb->s_maxbytes - *pos; } else { |
9361401eb [PATCH] BLOCK: Ma... |
2156 |
#ifdef CONFIG_BLOCK |
1da177e4c Linux-2.6.12-rc2 |
2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 |
loff_t isize; if (bdev_read_only(I_BDEV(inode))) return -EPERM; isize = i_size_read(inode); if (*pos >= isize) { if (*count || *pos > isize) return -ENOSPC; } if (*pos + *count > isize) *count = isize - *pos; |
9361401eb [PATCH] BLOCK: Ma... |
2168 2169 2170 |
#else return -EPERM; #endif |
1da177e4c Linux-2.6.12-rc2 |
2171 2172 2173 2174 |
} return 0; } EXPORT_SYMBOL(generic_write_checks); |
afddba49d fs: introduce wri... |
2175 2176 2177 2178 2179 |
int pagecache_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { const struct address_space_operations *aops = mapping->a_ops; |
4e02ed4b4 fs: remove prepar... |
2180 |
return aops->write_begin(file, mapping, pos, len, flags, |
afddba49d fs: introduce wri... |
2181 |
pagep, fsdata); |
afddba49d fs: introduce wri... |
2182 2183 2184 2185 2186 2187 2188 2189 |
} EXPORT_SYMBOL(pagecache_write_begin); int pagecache_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { const struct address_space_operations *aops = mapping->a_ops; |
afddba49d fs: introduce wri... |
2190 |
|
4e02ed4b4 fs: remove prepar... |
2191 2192 |
mark_page_accessed(page); return aops->write_end(file, mapping, pos, len, copied, page, fsdata); |
afddba49d fs: introduce wri... |
2193 2194 |
} EXPORT_SYMBOL(pagecache_write_end); |
1da177e4c Linux-2.6.12-rc2 |
2195 2196 2197 2198 2199 2200 2201 2202 2203 |
ssize_t generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, unsigned long *nr_segs, loff_t pos, loff_t *ppos, size_t count, size_t ocount) { struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; ssize_t written; |
a969e903a kill generic_file... |
2204 2205 |
size_t write_len; pgoff_t end; |
1da177e4c Linux-2.6.12-rc2 |
2206 2207 2208 |
if (count != ocount) *nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count); |
a969e903a kill generic_file... |
2209 2210 |
write_len = iov_length(iov, *nr_segs); end = (pos + write_len - 1) >> PAGE_CACHE_SHIFT; |
a969e903a kill generic_file... |
2211 |
|
48b47c561 mm: direct IO sta... |
2212 |
written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1); |
a969e903a kill generic_file... |
2213 2214 2215 2216 2217 2218 2219 |
if (written) goto out; /* * After a write we want buffered reads to be sure to go to disk to get * the new data. We invalidate clean cached page from the region we're * about to write. We do this *before* the write so that we can return |
6ccfa806a VFS: fix dio writ... |
2220 |
* without clobbering -EIOCBQUEUED from ->direct_IO(). |
a969e903a kill generic_file... |
2221 2222 2223 2224 |
*/ if (mapping->nrpages) { written = invalidate_inode_pages2_range(mapping, pos >> PAGE_CACHE_SHIFT, end); |
6ccfa806a VFS: fix dio writ... |
2225 2226 2227 2228 2229 2230 2231 |
/* * If a page can not be invalidated, return 0 to fall back * to buffered write. */ if (written) { if (written == -EBUSY) return 0; |
a969e903a kill generic_file... |
2232 |
goto out; |
6ccfa806a VFS: fix dio writ... |
2233 |
} |
a969e903a kill generic_file... |
2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 |
} written = mapping->a_ops->direct_IO(WRITE, iocb, iov, pos, *nr_segs); /* * Finally, try again to invalidate clean pages which might have been * cached by non-direct readahead, or faulted in by get_user_pages() * if the source of the write was an mmap'ed region of the file * we're writing. Either one is a pretty crazy thing to do, * so we don't support it 100%. If this invalidation * fails, tough, the write still worked... */ if (mapping->nrpages) { invalidate_inode_pages2_range(mapping, pos >> PAGE_CACHE_SHIFT, end); } |
1da177e4c Linux-2.6.12-rc2 |
2250 |
if (written > 0) { |
0116651c8 mm: remove tempor... |
2251 2252 2253 |
pos += written; if (pos > i_size_read(inode) && !S_ISBLK(inode->i_mode)) { i_size_write(inode, pos); |
1da177e4c Linux-2.6.12-rc2 |
2254 2255 |
mark_inode_dirty(inode); } |
0116651c8 mm: remove tempor... |
2256 |
*ppos = pos; |
1da177e4c Linux-2.6.12-rc2 |
2257 |
} |
a969e903a kill generic_file... |
2258 |
out: |
1da177e4c Linux-2.6.12-rc2 |
2259 2260 2261 |
return written; } EXPORT_SYMBOL(generic_file_direct_write); |
eb2be1893 mm: buffered writ... |
2262 2263 2264 2265 |
/* * Find or create a page at the given pagecache position. Return the locked * page. This function is specifically for buffered writes. */ |
54566b2c1 fs: symlink write... |
2266 2267 |
struct page *grab_cache_page_write_begin(struct address_space *mapping, pgoff_t index, unsigned flags) |
eb2be1893 mm: buffered writ... |
2268 2269 |
{ int status; |
0faa70cb0 mm: filemap: pass... |
2270 |
gfp_t gfp_mask; |
eb2be1893 mm: buffered writ... |
2271 |
struct page *page; |
54566b2c1 fs: symlink write... |
2272 |
gfp_t gfp_notmask = 0; |
0faa70cb0 mm: filemap: pass... |
2273 2274 |
gfp_mask = mapping_gfp_mask(mapping) | __GFP_WRITE; |
54566b2c1 fs: symlink write... |
2275 2276 |
if (flags & AOP_FLAG_NOFS) gfp_notmask = __GFP_FS; |
eb2be1893 mm: buffered writ... |
2277 2278 |
repeat: page = find_lock_page(mapping, index); |
c585a2678 mm: remove likely... |
2279 |
if (page) |
3d08bcc88 mm: Wait for writ... |
2280 |
goto found; |
eb2be1893 mm: buffered writ... |
2281 |
|
0faa70cb0 mm: filemap: pass... |
2282 |
page = __page_cache_alloc(gfp_mask & ~gfp_notmask); |
eb2be1893 mm: buffered writ... |
2283 2284 |
if (!page) return NULL; |
54566b2c1 fs: symlink write... |
2285 2286 |
status = add_to_page_cache_lru(page, mapping, index, GFP_KERNEL & ~gfp_notmask); |
eb2be1893 mm: buffered writ... |
2287 2288 2289 2290 2291 2292 |
if (unlikely(status)) { page_cache_release(page); if (status == -EEXIST) goto repeat; return NULL; } |
3d08bcc88 mm: Wait for writ... |
2293 2294 |
found: wait_on_page_writeback(page); |
eb2be1893 mm: buffered writ... |
2295 2296 |
return page; } |
54566b2c1 fs: symlink write... |
2297 |
EXPORT_SYMBOL(grab_cache_page_write_begin); |
eb2be1893 mm: buffered writ... |
2298 |
|
afddba49d fs: introduce wri... |
2299 2300 2301 2302 2303 2304 2305 |
static ssize_t generic_perform_write(struct file *file, struct iov_iter *i, loff_t pos) { struct address_space *mapping = file->f_mapping; const struct address_space_operations *a_ops = mapping->a_ops; long status = 0; ssize_t written = 0; |
674b892ed mm: restore KERNE... |
2306 2307 2308 2309 2310 2311 2312 |
unsigned int flags = 0; /* * Copies from kernel address space cannot fail (NFSD is a big user). */ if (segment_eq(get_fs(), KERNEL_DS)) flags |= AOP_FLAG_UNINTERRUPTIBLE; |
afddba49d fs: introduce wri... |
2313 2314 2315 |
do { struct page *page; |
afddba49d fs: introduce wri... |
2316 2317 2318 2319 2320 2321 |
unsigned long offset; /* Offset into pagecache page */ unsigned long bytes; /* Bytes to write to page */ size_t copied; /* Bytes copied from user */ void *fsdata; offset = (pos & (PAGE_CACHE_SIZE - 1)); |
afddba49d fs: introduce wri... |
2322 2323 2324 2325 |
bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset, iov_iter_count(i)); again: |
afddba49d fs: introduce wri... |
2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 |
/* * Bring in the user page that we will copy from _first_. * Otherwise there's a nasty deadlock on copying from the * same page as we're writing to, without it being marked * up-to-date. * * Not only is this an optimisation, but it is also required * to check that the address is actually valid, when atomic * usercopies are used, below. */ if (unlikely(iov_iter_fault_in_readable(i, bytes))) { status = -EFAULT; break; } |
674b892ed mm: restore KERNE... |
2340 |
status = a_ops->write_begin(file, mapping, pos, bytes, flags, |
afddba49d fs: introduce wri... |
2341 2342 2343 |
&page, &fsdata); if (unlikely(status)) break; |
931e80e4b mm: flush dcache ... |
2344 2345 |
if (mapping_writably_mapped(mapping)) flush_dcache_page(page); |
afddba49d fs: introduce wri... |
2346 2347 2348 2349 |
pagefault_disable(); copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); pagefault_enable(); flush_dcache_page(page); |
c8236db9c mm: mark page acc... |
2350 |
mark_page_accessed(page); |
afddba49d fs: introduce wri... |
2351 2352 2353 2354 2355 2356 2357 |
status = a_ops->write_end(file, mapping, pos, bytes, copied, page, fsdata); if (unlikely(status < 0)) break; copied = status; cond_resched(); |
124d3b704 fix writev regres... |
2358 |
iov_iter_advance(i, copied); |
afddba49d fs: introduce wri... |
2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 |
if (unlikely(copied == 0)) { /* * If we were unable to copy any data at all, we must * fall back to a single segment length write. * * If we didn't fallback here, we could livelock * because not all segments in the iov can be copied at * once without a pagefault. */ bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset, iov_iter_single_seg_count(i)); goto again; } |
afddba49d fs: introduce wri... |
2372 2373 2374 2375 |
pos += copied; written += copied; balance_dirty_pages_ratelimited(mapping); |
a50527b19 fs: Make write(2)... |
2376 2377 2378 2379 |
if (fatal_signal_pending(current)) { status = -EINTR; break; } |
afddba49d fs: introduce wri... |
2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 |
} while (iov_iter_count(i)); return written ? written : status; } ssize_t generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos, loff_t *ppos, size_t count, ssize_t written) { struct file *file = iocb->ki_filp; |
afddba49d fs: introduce wri... |
2391 2392 2393 2394 |
ssize_t status; struct iov_iter i; iov_iter_init(&i, iov, nr_segs, count, written); |
4e02ed4b4 fs: remove prepar... |
2395 |
status = generic_perform_write(file, &i, pos); |
1da177e4c Linux-2.6.12-rc2 |
2396 |
|
1da177e4c Linux-2.6.12-rc2 |
2397 |
if (likely(status >= 0)) { |
afddba49d fs: introduce wri... |
2398 2399 |
written += status; *ppos = pos + status; |
1da177e4c Linux-2.6.12-rc2 |
2400 2401 |
} |
1da177e4c Linux-2.6.12-rc2 |
2402 2403 2404 |
return written ? written : status; } EXPORT_SYMBOL(generic_file_buffered_write); |
e4dd9de3c vfs: Export __gen... |
2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 |
/** * __generic_file_aio_write - write data to a file * @iocb: IO state structure (file, offset, etc.) * @iov: vector with data to write * @nr_segs: number of segments in the vector * @ppos: position where to write * * This function does all the work needed for actually writing data to a * file. It does all basic checks, removes SUID from the file, updates * modification times and calls proper subroutines depending on whether we * do direct IO or a standard buffered write. * * It expects i_mutex to be grabbed unless we work on a block device or similar * object which does not need locking at all. * * This function does *not* take care of syncing data in case of O_SYNC write. * A caller has to handle it. This is mainly due to the fact that we want to * avoid syncing under i_mutex. */ ssize_t __generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t *ppos) |
1da177e4c Linux-2.6.12-rc2 |
2426 2427 |
{ struct file *file = iocb->ki_filp; |
fb5527e68 [PATCH] direct-io... |
2428 |
struct address_space * mapping = file->f_mapping; |
1da177e4c Linux-2.6.12-rc2 |
2429 2430 2431 |
size_t ocount; /* original count */ size_t count; /* after file limit checks */ struct inode *inode = mapping->host; |
1da177e4c Linux-2.6.12-rc2 |
2432 2433 2434 2435 2436 |
loff_t pos; ssize_t written; ssize_t err; ocount = 0; |
0ceb33143 mm: move common s... |
2437 2438 2439 |
err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ); if (err) return err; |
1da177e4c Linux-2.6.12-rc2 |
2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 |
count = ocount; pos = *ppos; vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE); /* We can write back this queue in page reclaim */ current->backing_dev_info = mapping->backing_dev_info; written = 0; err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode)); if (err) goto out; if (count == 0) goto out; |
2f1936b87 [patch 3/5] vfs: ... |
2456 |
err = file_remove_suid(file); |
1da177e4c Linux-2.6.12-rc2 |
2457 2458 |
if (err) goto out; |
870f48179 [PATCH] replace i... |
2459 |
file_update_time(file); |
1da177e4c Linux-2.6.12-rc2 |
2460 2461 2462 |
/* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ if (unlikely(file->f_flags & O_DIRECT)) { |
fb5527e68 [PATCH] direct-io... |
2463 2464 2465 2466 2467 |
loff_t endbyte; ssize_t written_buffered; written = generic_file_direct_write(iocb, iov, &nr_segs, pos, ppos, count, ocount); |
1da177e4c Linux-2.6.12-rc2 |
2468 2469 2470 2471 2472 2473 2474 2475 |
if (written < 0 || written == count) goto out; /* * direct-io write to a hole: fall through to buffered I/O * for completing the rest of the request. */ pos += written; count -= written; |
fb5527e68 [PATCH] direct-io... |
2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 |
written_buffered = generic_file_buffered_write(iocb, iov, nr_segs, pos, ppos, count, written); /* * If generic_file_buffered_write() retuned a synchronous error * then we want to return the number of bytes which were * direct-written, or the error code if that was zero. Note * that this differs from normal direct-io semantics, which * will return -EFOO even if some bytes were written. */ if (written_buffered < 0) { err = written_buffered; goto out; } |
1da177e4c Linux-2.6.12-rc2 |
2490 |
|
fb5527e68 [PATCH] direct-io... |
2491 2492 2493 2494 2495 2496 |
/* * We need to ensure that the page cache pages are written to * disk and invalidated to preserve the expected O_DIRECT * semantics. */ endbyte = pos + written_buffered - written - 1; |
c05c4edd8 direct I/O fallba... |
2497 |
err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte); |
fb5527e68 [PATCH] direct-io... |
2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 |
if (err == 0) { written = written_buffered; invalidate_mapping_pages(mapping, pos >> PAGE_CACHE_SHIFT, endbyte >> PAGE_CACHE_SHIFT); } else { /* * We don't know how much we wrote, so just return * the number of bytes which were direct-written */ } } else { written = generic_file_buffered_write(iocb, iov, nr_segs, pos, ppos, count, written); } |
1da177e4c Linux-2.6.12-rc2 |
2513 2514 2515 2516 |
out: current->backing_dev_info = NULL; return written ? written : err; } |
e4dd9de3c vfs: Export __gen... |
2517 |
EXPORT_SYMBOL(__generic_file_aio_write); |
e4dd9de3c vfs: Export __gen... |
2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 |
/** * generic_file_aio_write - write data to a file * @iocb: IO state structure * @iov: vector with data to write * @nr_segs: number of segments in the vector * @pos: position in file where to write * * This is a wrapper around __generic_file_aio_write() to be used by most * filesystems. It takes care of syncing the file in case of O_SYNC file * and acquires i_mutex as needed. */ |
027445c37 [PATCH] Vectorize... |
2529 2530 |
ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos) |
1da177e4c Linux-2.6.12-rc2 |
2531 2532 |
{ struct file *file = iocb->ki_filp; |
148f948ba vfs: Introduce ne... |
2533 |
struct inode *inode = file->f_mapping->host; |
55602dd66 fs: make generic ... |
2534 |
struct blk_plug plug; |
1da177e4c Linux-2.6.12-rc2 |
2535 |
ssize_t ret; |
1da177e4c Linux-2.6.12-rc2 |
2536 2537 |
BUG_ON(iocb->ki_pos != pos); |
1b1dcc1b5 [PATCH] mutex sub... |
2538 |
mutex_lock(&inode->i_mutex); |
55602dd66 fs: make generic ... |
2539 |
blk_start_plug(&plug); |
e4dd9de3c vfs: Export __gen... |
2540 |
ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos); |
1b1dcc1b5 [PATCH] mutex sub... |
2541 |
mutex_unlock(&inode->i_mutex); |
1da177e4c Linux-2.6.12-rc2 |
2542 |
|
148f948ba vfs: Introduce ne... |
2543 |
if (ret > 0 || ret == -EIOCBQUEUED) { |
1da177e4c Linux-2.6.12-rc2 |
2544 |
ssize_t err; |
148f948ba vfs: Introduce ne... |
2545 |
err = generic_write_sync(file, pos, ret); |
c7b50db21 vfs: Remove synci... |
2546 |
if (err < 0 && ret > 0) |
1da177e4c Linux-2.6.12-rc2 |
2547 2548 |
ret = err; } |
55602dd66 fs: make generic ... |
2549 |
blk_finish_plug(&plug); |
1da177e4c Linux-2.6.12-rc2 |
2550 2551 2552 |
return ret; } EXPORT_SYMBOL(generic_file_aio_write); |
cf9a2ae8d [PATCH] BLOCK: Mo... |
2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 |
/** * try_to_release_page() - release old fs-specific metadata on a page * * @page: the page which the kernel is trying to free * @gfp_mask: memory allocation flags (and I/O mode) * * The address_space is to try to release any data against the page * (presumably at page->private). If the release was successful, return `1'. * Otherwise return zero. * |
266cf658e FS-Cache: Recruit... |
2563 2564 2565 |
* This may also be called if PG_fscache is set on a page, indicating that the * page is known to the local caching routines. * |
cf9a2ae8d [PATCH] BLOCK: Mo... |
2566 |
* The @gfp_mask argument specifies whether I/O may be performed to release |
3f31fddfa jbd: fix race bet... |
2567 |
* this page (__GFP_IO), and whether the call may block (__GFP_WAIT & __GFP_FS). |
cf9a2ae8d [PATCH] BLOCK: Mo... |
2568 |
* |
cf9a2ae8d [PATCH] BLOCK: Mo... |
2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 |
*/ int try_to_release_page(struct page *page, gfp_t gfp_mask) { struct address_space * const mapping = page->mapping; BUG_ON(!PageLocked(page)); if (PageWriteback(page)) return 0; if (mapping && mapping->a_ops->releasepage) return mapping->a_ops->releasepage(page, gfp_mask); return try_to_free_buffers(page); } EXPORT_SYMBOL(try_to_release_page); |