X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Ffilemap.c;h=8332c77b1bd123fdd76b2a9b2d966711a45b124b;hb=87c18aa95199b4b7dd9510b2b927a5e30083da01;hp=1d33fec7bac615ed864a504bf99c9e899c5d85f7;hpb=b5c44c2147a447f77e07fecdb087ae288e1f4e40;p=safe%2Fjmp%2Flinux-2.6 diff --git a/mm/filemap.c b/mm/filemap.c index 1d33fec..8332c77 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -9,12 +9,13 @@ * most "normal" filesystems (but you don't /have/ to use this: * the NFS filesystem used to do this differently, for example) */ -#include #include #include #include #include +#include #include +#include #include #include #include @@ -28,14 +29,21 @@ #include #include #include +#include +#include "filemap.h" +#include "internal.h" + /* * FIXME: remove all knowledge of the buffer layer from the core VM */ #include /* for generic_osync_inode */ -#include #include +static ssize_t +generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, + loff_t offset, unsigned long nr_segs); + /* * Shared mappings implemented 30.11.1994. It's not fully working yet, * though. @@ -53,25 +61,24 @@ * * ->i_mmap_lock (vmtruncate) * ->private_lock (__free_pte->__set_page_dirty_buffers) - * ->swap_list_lock - * ->swap_device_lock (exclusive_swap_page, others) - * ->mapping->tree_lock + * ->swap_lock (exclusive_swap_page, others) + * ->mapping->tree_lock * - * ->i_sem + * ->i_mutex * ->i_mmap_lock (truncate->unmap_mapping_range) * * ->mmap_sem * ->i_mmap_lock - * ->page_table_lock (various places, mainly in mmap.c) + * ->page_table_lock or pte_lock (various, mainly in memory.c) * ->mapping->tree_lock (arch-dependent flush_dcache_mmap_lock) * * ->mmap_sem * ->lock_page (access_process_vm) * - * ->mmap_sem - * ->i_sem (msync) + * ->i_mutex (generic_file_buffered_write) + * ->mmap_sem (fault_in_pages_readable->do_page_fault) * - * ->i_sem + * ->i_mutex * ->i_alloc_sem (various) * * ->inode_lock @@ -82,13 +89,14 @@ * ->anon_vma.lock (vma_adjust) * * ->anon_vma.lock - * ->page_table_lock (anon_vma_prepare and various) + * ->page_table_lock or pte_lock (anon_vma_prepare and various) * - * ->page_table_lock - * ->swap_device_lock (try_to_unmap_one) + * ->page_table_lock or pte_lock + * ->swap_lock (try_to_unmap_one) * ->private_lock (try_to_unmap_one) * ->tree_lock (try_to_unmap_one) * ->zone.lru_lock (follow_page->mark_page_accessed) + * ->zone.lru_lock (check_pte_range->isolate_lru_page) * ->private_lock (page_remove_rmap->set_page_dirty) * ->tree_lock (page_remove_rmap->set_page_dirty) * ->inode_lock (page_remove_rmap->set_page_dirty) @@ -111,7 +119,7 @@ void __remove_from_page_cache(struct page *page) radix_tree_delete(&mapping->page_tree, page->index); page->mapping = NULL; mapping->nrpages--; - pagecache_acct(-1); + __dec_zone_page_state(page, NR_FILE_PAGES); } void remove_from_page_cache(struct page *page) @@ -130,7 +138,7 @@ static int sync_page(void *word) struct address_space *mapping; struct page *page; - page = container_of((page_flags_t *)word, struct page, flags); + page = container_of((unsigned long *)word, struct page, flags); /* * page_mapping() is being called without PG_locked held. @@ -148,7 +156,7 @@ static int sync_page(void *word) * in the ->sync_page() methods make essential use of the * page_mapping(), merely passing the page down to the backing * device's unplug functions when it's non-NULL, which in turn - * ignore it for all cases but swap, where only page->private is + * ignore it for all cases but swap, where only page_private(page) is * of interest. When page_mapping() does go NULL, the entire * call stack gracefully ignores the page and returns. * -- wli @@ -162,27 +170,29 @@ static int sync_page(void *word) } /** - * filemap_fdatawrite_range - start writeback against all of a mapping's - * dirty pages that lie within the byte offsets + * __filemap_fdatawrite_range - start writeback on mapping dirty pages in range * @mapping: address space structure to write * @start: offset in bytes where the range starts - * @end: offset in bytes where the range ends + * @end: offset in bytes where the range ends (inclusive) * @sync_mode: enable synchronous operation * + * Start writeback against all of a mapping's dirty pages that lie + * within the byte offsets inclusive. + * * If sync_mode is WB_SYNC_ALL then this is a "data integrity" operation, as - * opposed to a regular memory * cleansing writeback. The difference between + * opposed to a regular memory cleansing writeback. The difference between * these two operations is that if a dirty page/buffer is encountered, it must * be waited upon, and not just skipped over. */ -static int __filemap_fdatawrite_range(struct address_space *mapping, - loff_t start, loff_t end, int sync_mode) +int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start, + loff_t end, int sync_mode) { int ret; struct writeback_control wbc = { .sync_mode = sync_mode, .nr_to_write = mapping->nrpages * 2, - .start = start, - .end = end, + .range_start = start, + .range_end = end, }; if (!mapping_cap_writeback_dirty(mapping)) @@ -195,7 +205,7 @@ static int __filemap_fdatawrite_range(struct address_space *mapping, static inline int __filemap_fdatawrite(struct address_space *mapping, int sync_mode) { - return __filemap_fdatawrite_range(mapping, 0, 0, sync_mode); + return __filemap_fdatawrite_range(mapping, 0, LLONG_MAX, sync_mode); } int filemap_fdatawrite(struct address_space *mapping) @@ -204,13 +214,16 @@ int filemap_fdatawrite(struct address_space *mapping) } EXPORT_SYMBOL(filemap_fdatawrite); -static int filemap_fdatawrite_range(struct address_space *mapping, - loff_t start, loff_t end) +static int filemap_fdatawrite_range(struct address_space *mapping, loff_t start, + loff_t end) { return __filemap_fdatawrite_range(mapping, start, end, WB_SYNC_ALL); } -/* +/** + * filemap_flush - mostly a non-blocking flush + * @mapping: target address_space + * * This is a mostly non-blocking flush. Not suitable for data-integrity * purposes - I/O may not be started against all dirty pages. */ @@ -220,11 +233,16 @@ int filemap_flush(struct address_space *mapping) } EXPORT_SYMBOL(filemap_flush); -/* +/** + * wait_on_page_writeback_range - wait for writeback to complete + * @mapping: target address_space + * @start: beginning page index + * @end: ending page index + * * Wait for writeback to complete against pages indexed by start->end * inclusive */ -static int wait_on_page_writeback_range(struct address_space *mapping, +int wait_on_page_writeback_range(struct address_space *mapping, pgoff_t start, pgoff_t end) { struct pagevec pvec; @@ -267,16 +285,22 @@ static int wait_on_page_writeback_range(struct address_space *mapping, return ret; } -/* +/** + * sync_page_range - write and wait on all pages in the passed range + * @inode: target inode + * @mapping: target address_space + * @pos: beginning offset in pages to write + * @count: number of bytes to write + * * Write and wait upon all the pages in the passed range. This is a "data * integrity" operation. It waits upon in-flight writeout before starting and * waiting upon new writeout. If there was an IO error, return it. * - * We need to re-take i_sem during the generic_osync_inode list walk because + * We need to re-take i_mutex during the generic_osync_inode list walk because * it is otherwise livelockable. */ int sync_page_range(struct inode *inode, struct address_space *mapping, - loff_t pos, size_t count) + loff_t pos, loff_t count) { pgoff_t start = pos >> PAGE_CACHE_SHIFT; pgoff_t end = (pos + count - 1) >> PAGE_CACHE_SHIFT; @@ -286,9 +310,9 @@ int sync_page_range(struct inode *inode, struct address_space *mapping, return 0; ret = filemap_fdatawrite_range(mapping, pos, pos + count - 1); if (ret == 0) { - down(&inode->i_sem); + mutex_lock(&inode->i_mutex); ret = generic_osync_inode(inode, mapping, OSYNC_METADATA); - up(&inode->i_sem); + mutex_unlock(&inode->i_mutex); } if (ret == 0) ret = wait_on_page_writeback_range(mapping, start, end); @@ -296,13 +320,19 @@ int sync_page_range(struct inode *inode, struct address_space *mapping, } EXPORT_SYMBOL(sync_page_range); -/* - * Note: Holding i_sem across sync_page_range_nolock is not a good idea +/** + * sync_page_range_nolock + * @inode: target inode + * @mapping: target address_space + * @pos: beginning offset in pages to write + * @count: number of bytes to write + * + * Note: Holding i_mutex across sync_page_range_nolock is not a good idea * as it forces O_SYNC writers to different parts of the same file * to be serialised right until io completion. */ int sync_page_range_nolock(struct inode *inode, struct address_space *mapping, - loff_t pos, size_t count) + loff_t pos, loff_t count) { pgoff_t start = pos >> PAGE_CACHE_SHIFT; pgoff_t end = (pos + count - 1) >> PAGE_CACHE_SHIFT; @@ -320,10 +350,11 @@ int sync_page_range_nolock(struct inode *inode, struct address_space *mapping, EXPORT_SYMBOL(sync_page_range_nolock); /** - * filemap_fdatawait - walk the list of under-writeback pages of the given - * address space and wait for all of them. - * + * filemap_fdatawait - wait for all under-writeback pages to complete * @mapping: address space structure to wait for + * + * Walk the list of under-writeback pages of the given address space + * and wait for all of them. */ int filemap_fdatawait(struct address_space *mapping) { @@ -339,41 +370,72 @@ EXPORT_SYMBOL(filemap_fdatawait); int filemap_write_and_wait(struct address_space *mapping) { - int retval = 0; + int err = 0; if (mapping->nrpages) { - retval = filemap_fdatawrite(mapping); - if (retval == 0) - retval = filemap_fdatawait(mapping); + 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; + } } - return retval; + return err; } +EXPORT_SYMBOL(filemap_write_and_wait); +/** + * 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) + * + * 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). + */ int filemap_write_and_wait_range(struct address_space *mapping, loff_t lstart, loff_t lend) { - int retval = 0; + int err = 0; if (mapping->nrpages) { - retval = __filemap_fdatawrite_range(mapping, lstart, lend, - WB_SYNC_ALL); - if (retval == 0) - retval = wait_on_page_writeback_range(mapping, - lstart >> PAGE_CACHE_SHIFT, - lend >> PAGE_CACHE_SHIFT); + err = __filemap_fdatawrite_range(mapping, lstart, lend, + WB_SYNC_ALL); + /* See comment of filemap_write_and_wait() */ + if (err != -EIO) { + int err2 = wait_on_page_writeback_range(mapping, + lstart >> PAGE_CACHE_SHIFT, + lend >> PAGE_CACHE_SHIFT); + if (!err) + err = err2; + } } - return retval; + return err; } -/* - * This function is used to add newly allocated pagecache pages: +/** + * add_to_page_cache - add newly allocated pagecache pages + * @page: page to add + * @mapping: the page's address_space + * @offset: page index + * @gfp_mask: page allocation mode + * + * This function is used to add newly allocated pagecache pages; * the page is new, so we can just run SetPageLocked() against it. * The other page state flags were set by rmqueue(). * * This function does not add the page to the LRU. The caller must do that. */ int add_to_page_cache(struct page *page, struct address_space *mapping, - pgoff_t offset, int gfp_mask) + pgoff_t offset, gfp_t gfp_mask) { int error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); @@ -386,18 +448,17 @@ int add_to_page_cache(struct page *page, struct address_space *mapping, page->mapping = mapping; page->index = offset; mapping->nrpages++; - pagecache_acct(1); + __inc_zone_page_state(page, NR_FILE_PAGES); } write_unlock_irq(&mapping->tree_lock); radix_tree_preload_end(); } return error; } - EXPORT_SYMBOL(add_to_page_cache); int add_to_page_cache_lru(struct page *page, struct address_space *mapping, - pgoff_t offset, int gfp_mask) + pgoff_t offset, gfp_t gfp_mask) { int ret = add_to_page_cache(page, mapping, offset, gfp_mask); if (ret == 0) @@ -405,6 +466,24 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping, return ret; } +#ifdef CONFIG_NUMA +struct page *__page_cache_alloc(gfp_t gfp) +{ + if (cpuset_do_page_mem_spread()) { + int n = cpuset_mem_spread_node(); + return alloc_pages_node(n, gfp, 0); + } + return alloc_pages(gfp, 0); +} +EXPORT_SYMBOL(__page_cache_alloc); +#endif + +static int __sleep_on_page_lock(void *word) +{ + io_schedule(); + return 0; +} + /* * In order to wait for pages to become available there must be * waitqueues associated with pages. By using a hash table of @@ -438,8 +517,7 @@ void fastcall wait_on_page_bit(struct page *page, int bit_nr) EXPORT_SYMBOL(wait_on_page_bit); /** - * unlock_page() - unlock a locked page - * + * unlock_page - unlock a locked page * @page: the page * * Unlocks the page and wakes up sleepers in ___wait_on_page_locked(). @@ -462,8 +540,9 @@ void fastcall unlock_page(struct page *page) } EXPORT_SYMBOL(unlock_page); -/* - * End writeback against a page. +/** + * end_page_writeback - end writeback against a page + * @page: the page */ void end_page_writeback(struct page *page) { @@ -476,10 +555,11 @@ void end_page_writeback(struct page *page) } EXPORT_SYMBOL(end_page_writeback); -/* - * Get a lock on the page, assuming we need to sleep to get it. +/** + * __lock_page - get a lock on the page, assuming we need to sleep to get it + * @page: the page to lock * - * Ugly: running sync_page() in state TASK_UNINTERRUPTIBLE is scary. If some + * Ugly. Running sync_page() in state TASK_UNINTERRUPTIBLE is scary. If some * random driver's requestfn sets TASK_RUNNING, we could busywait. However * chances are that on the second loop, the block layer's plug list is empty, * so sync_page() will then return in state TASK_UNINTERRUPTIBLE. @@ -494,8 +574,23 @@ void fastcall __lock_page(struct page *page) EXPORT_SYMBOL(__lock_page); /* - * a rather lightweight function, finding and getting a reference to a - * hashed page atomically. + * Variant of lock_page that does not require the caller to hold a reference + * on the page's mapping. + */ +void fastcall __lock_page_nosync(struct page *page) +{ + DEFINE_WAIT_BIT(wait, &page->flags, PG_locked); + __wait_on_bit_lock(page_waitqueue(page), &wait, __sleep_on_page_lock, + TASK_UNINTERRUPTIBLE); +} + +/** + * find_get_page - find and get a page reference + * @mapping: the address_space to search + * @offset: the page index + * + * Is there a pagecache struct page at the given (mapping, offset) tuple? + * If yes, increment its refcount and return it; if no, return NULL. */ struct page * find_get_page(struct address_space *mapping, unsigned long offset) { @@ -508,11 +603,14 @@ struct page * find_get_page(struct address_space *mapping, unsigned long offset) read_unlock_irq(&mapping->tree_lock); return page; } - EXPORT_SYMBOL(find_get_page); -/* - * Same as above, but trylock it instead of incrementing the count. +/** + * find_trylock_page - find and lock a page + * @mapping: the address_space to search + * @offset: the page index + * + * Same as find_get_page(), but trylock it instead of incrementing the count. */ struct page *find_trylock_page(struct address_space *mapping, unsigned long offset) { @@ -525,12 +623,10 @@ struct page *find_trylock_page(struct address_space *mapping, unsigned long offs read_unlock_irq(&mapping->tree_lock); return page; } - EXPORT_SYMBOL(find_trylock_page); /** * find_lock_page - locate, pin and lock a pagecache page - * * @mapping: the address_space to search * @offset: the page index * @@ -551,11 +647,12 @@ repeat: page_cache_get(page); if (TestSetPageLocked(page)) { read_unlock_irq(&mapping->tree_lock); - lock_page(page); + __lock_page(page); read_lock_irq(&mapping->tree_lock); /* Has the page been truncated while we slept? */ - if (page->mapping != mapping || page->index != offset) { + if (unlikely(page->mapping != mapping || + page->index != offset)) { unlock_page(page); page_cache_release(page); goto repeat; @@ -565,12 +662,10 @@ repeat: read_unlock_irq(&mapping->tree_lock); return page; } - EXPORT_SYMBOL(find_lock_page); /** * find_or_create_page - locate or add a pagecache page - * * @mapping: the page's address_space * @index: the page's index into the mapping * @gfp_mask: page allocation mode @@ -587,7 +682,7 @@ EXPORT_SYMBOL(find_lock_page); * memory exhaustion. */ struct page *find_or_create_page(struct address_space *mapping, - unsigned long index, unsigned int gfp_mask) + unsigned long index, gfp_t gfp_mask) { struct page *page, *cached_page = NULL; int err; @@ -611,7 +706,6 @@ repeat: page_cache_release(cached_page); return page; } - EXPORT_SYMBOL(find_or_create_page); /** @@ -645,9 +739,48 @@ unsigned find_get_pages(struct address_space *mapping, pgoff_t start, return ret; } -/* +/** + * 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; + + read_lock_irq(&mapping->tree_lock); + ret = radix_tree_gang_lookup(&mapping->page_tree, + (void **)pages, index, nr_pages); + for (i = 0; i < ret; i++) { + if (pages[i]->mapping == NULL || pages[i]->index != index) + break; + + page_cache_get(pages[i]); + index++; + } + read_unlock_irq(&mapping->tree_lock); + return i; +} + +/** + * 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 + * * Like find_get_pages, except we only return pages which are tagged with - * `tag'. We update *index to index the next page for the traversal. + * @tag. We update @index to index the next page for the traversal. */ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, int tag, unsigned int nr_pages, struct page **pages) @@ -666,7 +799,11 @@ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, return ret; } -/* +/** + * grab_cache_page_nowait - returns locked page at given index in given cache + * @mapping: target address_space + * @index: the page index + * * Same as grab_cache_page, but do not wait if the page is unavailable. * This is intended for speculative data generators, where the data can * be regenerated if the page couldn't be grabbed. This routine should @@ -679,7 +816,6 @@ struct page * grab_cache_page_nowait(struct address_space *mapping, unsigned long index) { struct page *page = find_get_page(mapping, index); - unsigned int gfp_mask; if (page) { if (!TestSetPageLocked(page)) @@ -687,27 +823,56 @@ grab_cache_page_nowait(struct address_space *mapping, unsigned long index) page_cache_release(page); return NULL; } - gfp_mask = mapping_gfp_mask(mapping) & ~__GFP_FS; - page = alloc_pages(gfp_mask, 0); - if (page && add_to_page_cache_lru(page, mapping, index, gfp_mask)) { + page = __page_cache_alloc(mapping_gfp_mask(mapping) & ~__GFP_FS); + if (page && add_to_page_cache_lru(page, mapping, index, GFP_KERNEL)) { page_cache_release(page); page = NULL; } return page; } - EXPORT_SYMBOL(grab_cache_page_nowait); /* + * 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) +{ + if (!ra->ra_pages) + return; + + ra->ra_pages /= 4; +} + +/** + * do_generic_mapping_read - generic file read routine + * @mapping: address_space to be read + * @_ra: file's readahead state + * @filp: the file to read + * @ppos: current file position + * @desc: read_descriptor + * @actor: read method + * * This is a generic file read routine, and uses the - * mapping->a_ops->readpage() function for the actual low-level - * stuff. + * mapping->a_ops->readpage() function for the actual low-level stuff. * * This is really ugly. But the goto's actually try to clarify some * of the logic when it comes to error handling etc. * - * Note the struct file* is only passed for the use of readpage. It may be - * NULL. + * Note the struct file* is only passed for the use of readpage. + * It may be NULL. */ void do_generic_mapping_read(struct address_space *mapping, struct file_ra_state *_ra, @@ -810,7 +975,7 @@ page_not_up_to_date: /* Get exclusive access to the page ... */ lock_page(page); - /* Did it get unhashed before we got the lock? */ + /* Did it get truncated before we got the lock? */ if (!page->mapping) { unlock_page(page); page_cache_release(page); @@ -827,8 +992,13 @@ readpage: /* Start the actual read. The read will unlock the page. */ error = mapping->a_ops->readpage(filp, page); - if (unlikely(error)) + if (unlikely(error)) { + if (error == AOP_TRUNCATED_PAGE) { + page_cache_release(page); + goto find_page; + } goto readpage_error; + } if (!PageUptodate(page)) { lock_page(page); @@ -843,6 +1013,7 @@ readpage: } unlock_page(page); error = -EIO; + shrink_readahead_size_eio(filp, &ra); goto readpage_error; } unlock_page(page); @@ -915,7 +1086,6 @@ out: if (filp) file_accessed(filp); } - EXPORT_SYMBOL(do_generic_mapping_read); int file_read_actor(read_descriptor_t *desc, struct page *page, @@ -956,18 +1126,25 @@ success: return size; } -/* +/** + * generic_file_aio_read - generic filesystem read routine + * @iocb: kernel I/O control block + * @iov: io vector request + * @nr_segs: number of segments in the iovec + * @pos: current file position + * * This is the "read()" routine for all filesystems * that can use the page cache directly. */ ssize_t -__generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t *ppos) +generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) { struct file *filp = iocb->ki_filp; ssize_t retval; unsigned long seg; size_t count; + loff_t *ppos = &iocb->ki_pos; count = 0; for (seg = 0; seg < nr_segs; seg++) { @@ -991,7 +1168,7 @@ __generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ if (filp->f_flags & O_DIRECT) { - loff_t pos = *ppos, size; + loff_t size; struct address_space *mapping; struct inode *inode; @@ -1004,13 +1181,13 @@ __generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, if (pos < size) { retval = generic_file_direct_IO(READ, iocb, iov, pos, nr_segs); - if (retval > 0 && !is_sync_kiocb(iocb)) - retval = -EIOCBQUEUED; if (retval > 0) *ppos = pos + retval; } - file_accessed(filp); - goto out; + if (likely(retval != 0)) { + file_accessed(filp); + goto out; + } } retval = 0; @@ -1026,8 +1203,8 @@ __generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, desc.error = 0; do_generic_file_read(filp,ppos,&desc,file_read_actor); retval += desc.written; - if (!retval) { - retval = desc.error; + if (desc.error) { + retval = retval ?: desc.error; break; } } @@ -1035,36 +1212,8 @@ __generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, out: return retval; } - -EXPORT_SYMBOL(__generic_file_aio_read); - -ssize_t -generic_file_aio_read(struct kiocb *iocb, char __user *buf, size_t count, loff_t pos) -{ - struct iovec local_iov = { .iov_base = buf, .iov_len = count }; - - BUG_ON(iocb->ki_pos != pos); - return __generic_file_aio_read(iocb, &local_iov, 1, &iocb->ki_pos); -} - EXPORT_SYMBOL(generic_file_aio_read); -ssize_t -generic_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) -{ - struct iovec local_iov = { .iov_base = buf, .iov_len = count }; - struct kiocb kiocb; - ssize_t ret; - - init_sync_kiocb(&kiocb, filp); - ret = __generic_file_aio_read(&kiocb, &local_iov, 1, ppos); - if (-EIOCBQUEUED == ret) - ret = wait_on_sync_kiocb(&kiocb); - return ret; -} - -EXPORT_SYMBOL(generic_file_read); - int file_send_actor(read_descriptor_t * desc, struct page *page, unsigned long offset, unsigned long size) { ssize_t written; @@ -1103,7 +1252,6 @@ ssize_t generic_file_sendfile(struct file *in_file, loff_t *ppos, return desc.written; return desc.error; } - EXPORT_SYMBOL(generic_file_sendfile); static ssize_t @@ -1139,40 +1287,47 @@ asmlinkage ssize_t sys_readahead(int fd, loff_t offset, size_t count) } #ifdef CONFIG_MMU -/* +static int FASTCALL(page_cache_read(struct file * file, unsigned long offset)); +/** + * page_cache_read - adds requested page to the page cache if not already there + * @file: file to read + * @offset: page index + * * 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. */ -static int FASTCALL(page_cache_read(struct file * file, unsigned long offset)); static int fastcall page_cache_read(struct file * file, unsigned long offset) { struct address_space *mapping = file->f_mapping; struct page *page; - int error; + int ret; - page = page_cache_alloc_cold(mapping); - if (!page) - return -ENOMEM; + 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 */ - error = add_to_page_cache_lru(page, mapping, offset, GFP_KERNEL); - if (!error) { - error = mapping->a_ops->readpage(file, page); page_cache_release(page); - return error; - } - /* - * We arrive here in the unlikely event that someone - * raced with us and added our page to the cache first - * or we are out of memory for radix-tree nodes. - */ - page_cache_release(page); - return error == -EEXIST ? 0 : error; + } while (ret == AOP_TRUNCATED_PAGE); + + return ret; } #define MMAP_LOTSAMISS (100) -/* +/** + * filemap_nopage - read in file data for page fault handling + * @area: the applicable vm_area + * @address: target address to read in + * @type: returned with VM_FAULT_{MINOR,MAJOR} if not %NULL + * * filemap_nopage() is invoked via the vma operations vector for a * mapped memory region to read in file data during a page fault. * @@ -1239,7 +1394,7 @@ retry_find: */ if (!did_readaround) { majmin = VM_FAULT_MAJOR; - inc_page_state(pgmajfault); + count_vm_event(PGMAJFAULT); } did_readaround = 1; ra_pages = max_sane_readahead(file->f_ra.ra_pages); @@ -1280,7 +1435,7 @@ outside_data_content: * accessible.. */ if (area->vm_mm == current->mm) - return NULL; + return NOPAGE_SIGBUS; /* Fall through to the non-read-ahead case */ no_cached_page: /* @@ -1288,7 +1443,6 @@ no_cached_page: * effect. */ error = page_cache_read(file, pgoff); - grab_swap_token(); /* * The page we want has now been added to the page cache. @@ -1305,12 +1459,12 @@ no_cached_page: */ if (error == -ENOMEM) return NOPAGE_OOM; - return NULL; + return NOPAGE_SIGBUS; page_not_uptodate: if (!did_readaround) { majmin = VM_FAULT_MAJOR; - inc_page_state(pgmajfault); + count_vm_event(PGMAJFAULT); } lock_page(page); @@ -1327,10 +1481,14 @@ page_not_uptodate: goto success; } - if (!mapping->a_ops->readpage(file, page)) { + error = mapping->a_ops->readpage(file, page); + if (!error) { wait_on_page_locked(page); if (PageUptodate(page)) goto success; + } else if (error == AOP_TRUNCATED_PAGE) { + page_cache_release(page); + goto retry_find; } /* @@ -1354,20 +1512,24 @@ page_not_uptodate: goto success; } ClearPageError(page); - if (!mapping->a_ops->readpage(file, page)) { + error = mapping->a_ops->readpage(file, page); + if (!error) { wait_on_page_locked(page); if (PageUptodate(page)) goto success; + } else if (error == AOP_TRUNCATED_PAGE) { + page_cache_release(page); + goto retry_find; } /* * Things didn't work out. Return zero to tell the * mm layer so, possibly freeing the page cache page first. */ + shrink_readahead_size_eio(file, ra); page_cache_release(page); - return NULL; + return NOPAGE_SIGBUS; } - EXPORT_SYMBOL(filemap_nopage); static struct page * filemap_getpage(struct file *file, unsigned long pgoff, @@ -1428,7 +1590,7 @@ no_cached_page: page_not_uptodate: lock_page(page); - /* Did it get unhashed while we waited for it? */ + /* Did it get truncated while we waited for it? */ if (!page->mapping) { unlock_page(page); goto err; @@ -1440,10 +1602,14 @@ page_not_uptodate: goto success; } - if (!mapping->a_ops->readpage(file, page)) { + error = mapping->a_ops->readpage(file, page); + if (!error) { wait_on_page_locked(page); if (PageUptodate(page)) goto success; + } else if (error == AOP_TRUNCATED_PAGE) { + page_cache_release(page); + goto retry_find; } /* @@ -1466,10 +1632,14 @@ page_not_uptodate: } ClearPageError(page); - if (!mapping->a_ops->readpage(file, page)) { + error = mapping->a_ops->readpage(file, page); + if (!error) { wait_on_page_locked(page); if (PageUptodate(page)) goto success; + } else if (error == AOP_TRUNCATED_PAGE) { + page_cache_release(page); + goto retry_find; } /* @@ -1504,15 +1674,22 @@ repeat: return -EINVAL; page = filemap_getpage(file, pgoff, nonblock); + + /* XXX: This is wrong, a filesystem I/O error may have happened. Fix that as + * done in shmem_populate calling shmem_getpage */ if (!page && !nonblock) return -ENOMEM; + if (page) { err = install_page(mm, vma, addr, page, prot); if (err) { page_cache_release(page); return err; } - } else { + } else if (vma->vm_flags & VM_NONLINEAR) { + /* No page was found just because we can't read it in now (being + * here implies nonblock != 0), but the page may exist, so set + * the PTE to fault it in later. */ err = install_file_pte(mm, vma, addr, pgoff, prot); if (err) return err; @@ -1526,6 +1703,7 @@ repeat: return 0; } +EXPORT_SYMBOL(filemap_populate); struct vm_operations_struct generic_file_vm_ops = { .nopage = filemap_nopage, @@ -1544,7 +1722,6 @@ int generic_file_mmap(struct file * file, struct vm_area_struct * vma) vma->vm_ops = &generic_file_vm_ops; return 0; } -EXPORT_SYMBOL(filemap_populate); /* * This is for filesystems which do not implement ->writepage. @@ -1606,7 +1783,13 @@ repeat: return page; } -/* +/** + * 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 + * @data: destination for read data + * * Read into the page cache. If a page already exists, * and PageUptodate() is not set, try to fill the page. */ @@ -1644,7 +1827,6 @@ retry: out: return page; } - EXPORT_SYMBOL(read_cache_page); /* @@ -1687,11 +1869,10 @@ repeat: * if suid or (sgid and xgrp) * remove privs */ -int remove_suid(struct dentry *dentry) +int should_remove_suid(struct dentry *dentry) { mode_t mode = dentry->d_inode->i_mode; int kill = 0; - int result = 0; /* suid always must be killed */ if (unlikely(mode & S_ISUID)) @@ -1704,43 +1885,34 @@ int remove_suid(struct dentry *dentry) if (unlikely((mode & S_ISGID) && (mode & S_IXGRP))) kill |= ATTR_KILL_SGID; - if (unlikely(kill && !capable(CAP_FSETID))) { - struct iattr newattrs; + if (unlikely(kill && !capable(CAP_FSETID))) + return kill; - newattrs.ia_valid = ATTR_FORCE | kill; - result = notify_change(dentry, &newattrs); - } - return result; + return 0; } -EXPORT_SYMBOL(remove_suid); +EXPORT_SYMBOL(should_remove_suid); -/* - * Copy as much as we can into the page and return the number of bytes which - * were sucessfully copied. If a fault is encountered then clear the page - * out to (offset+bytes) and return the number of bytes which were copied. - */ -static inline size_t -filemap_copy_from_user(struct page *page, unsigned long offset, - const char __user *buf, unsigned bytes) +int __remove_suid(struct dentry *dentry, int kill) { - char *kaddr; - int left; + struct iattr newattrs; - kaddr = kmap_atomic(page, KM_USER0); - left = __copy_from_user_inatomic(kaddr + offset, buf, bytes); - kunmap_atomic(kaddr, KM_USER0); + newattrs.ia_valid = ATTR_FORCE | kill; + return notify_change(dentry, &newattrs); +} - if (left != 0) { - /* Do it the slow way */ - kaddr = kmap(page); - left = __copy_from_user(kaddr + offset, buf, bytes); - kunmap(page); - } - return bytes - left; +int remove_suid(struct dentry *dentry) +{ + int kill = should_remove_suid(dentry); + + if (unlikely(kill)) + return __remove_suid(dentry, kill); + + return 0; } +EXPORT_SYMBOL(remove_suid); -static size_t -__filemap_copy_from_user_iovec(char *vaddr, +size_t +__filemap_copy_from_user_iovec_inatomic(char *vaddr, const struct iovec *iov, size_t base, size_t bytes) { size_t copied = 0, left = 0; @@ -1750,72 +1922,22 @@ __filemap_copy_from_user_iovec(char *vaddr, int copy = min(bytes, iov->iov_len - base); base = 0; - left = __copy_from_user_inatomic(vaddr, buf, copy); + left = __copy_from_user_inatomic_nocache(vaddr, buf, copy); copied += copy; bytes -= copy; vaddr += copy; iov++; - if (unlikely(left)) { - /* zero the rest of the target like __copy_from_user */ - if (bytes) - memset(vaddr, 0, bytes); + if (unlikely(left)) break; - } } return copied - left; } /* - * This has the same sideeffects and return value as filemap_copy_from_user(). - * The difference is that on a fault we need to memset the remainder of the - * page (out to offset+bytes), to emulate filemap_copy_from_user()'s - * single-segment behaviour. - */ -static inline size_t -filemap_copy_from_user_iovec(struct page *page, unsigned long offset, - const struct iovec *iov, size_t base, size_t bytes) -{ - char *kaddr; - size_t copied; - - kaddr = kmap_atomic(page, KM_USER0); - copied = __filemap_copy_from_user_iovec(kaddr + offset, iov, - base, bytes); - kunmap_atomic(kaddr, KM_USER0); - if (copied != bytes) { - kaddr = kmap(page); - copied = __filemap_copy_from_user_iovec(kaddr + offset, iov, - base, bytes); - kunmap(page); - } - return copied; -} - -static inline void -filemap_set_next_iovec(const struct iovec **iovp, size_t *basep, size_t bytes) -{ - const struct iovec *iov = *iovp; - size_t base = *basep; - - while (bytes) { - int copy = min(bytes, iov->iov_len - base); - - bytes -= copy; - base += copy; - if (iov->iov_len == base) { - iov++; - base = 0; - } - } - *iovp = iov; - *basep = base; -} - -/* * Performs necessary checks before doing a write * - * Can adjust writing position aor amount of bytes to write. + * Can adjust writing position or amount of bytes to write. * Returns appropriate error code that caller should return or * zero in case that write should be allowed. */ @@ -1827,12 +1949,6 @@ inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, i if (unlikely(*pos < 0)) return -EINVAL; - if (unlikely(file->f_error)) { - int err = file->f_error; - file->f_error = 0; - return err; - } - if (!isblk) { /* FIXME: this is for backwards compatibility with 2.4 */ if (file->f_flags & O_APPEND) @@ -1882,6 +1998,7 @@ inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, i if (unlikely(*pos + *count > inode->i_sb->s_maxbytes)) *count = inode->i_sb->s_maxbytes - *pos; } else { +#ifdef CONFIG_BLOCK loff_t isize; if (bdev_read_only(I_BDEV(inode))) return -EPERM; @@ -1893,6 +2010,9 @@ inline int generic_write_checks(struct file *file, loff_t *pos, size_t *count, i if (*pos + *count > isize) *count = isize - *pos; +#else + return -EPERM; +#endif } return 0; } @@ -1924,13 +2044,15 @@ generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov, /* * Sync the fs metadata but not the minor inode changes and * of course not the data as we did direct DMA for the IO. - * i_sem is held, which protects generic_osync_inode() from - * livelocking. + * i_mutex is held, which protects generic_osync_inode() from + * livelocking. AIO O_DIRECT ops attempt to sync metadata here. */ - if (written >= 0 && file->f_flags & O_SYNC) - generic_osync_inode(inode, mapping, OSYNC_METADATA); - if (written == count && !is_sync_kiocb(iocb)) - written = -EIOCBQUEUED; + if ((written >= 0 || written == -EIOCBQUEUED) && + ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { + int err = generic_osync_inode(inode, mapping, OSYNC_METADATA); + if (err < 0) + written = err; + } return written; } EXPORT_SYMBOL(generic_file_direct_write); @@ -1942,7 +2064,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, { struct file *file = iocb->ki_filp; struct address_space * mapping = file->f_mapping; - struct address_space_operations *a_ops = mapping->a_ops; + const struct address_space_operations *a_ops = mapping->a_ops; struct inode *inode = mapping->host; long status = 0; struct page *page; @@ -1973,8 +2095,16 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ index = pos >> PAGE_CACHE_SHIFT; bytes = PAGE_CACHE_SIZE - offset; - if (bytes > count) - bytes = count; + + /* Limit the size of the copy to the caller's write size */ + bytes = min(bytes, count); + + /* + * Limit the size of the copy to that of the current segment, + * because fault_in_pages_readable() doesn't know how to walk + * segments. + */ + bytes = min(bytes, cur_iov->iov_len - iov_base); /* * Bring in the user page that we will copy from _first_. @@ -1990,15 +2120,25 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, break; } + if (unlikely(bytes == 0)) { + status = 0; + copied = 0; + goto zero_length_segment; + } + status = a_ops->prepare_write(file, page, offset, offset+bytes); if (unlikely(status)) { loff_t isize = i_size_read(inode); + + if (status != AOP_TRUNCATED_PAGE) + unlock_page(page); + page_cache_release(page); + if (status == AOP_TRUNCATED_PAGE) + continue; /* * prepare_write() may have instantiated a few blocks * outside i_size. Trim these off again. */ - unlock_page(page); - page_cache_release(page); if (pos + bytes > isize) vmtruncate(inode, isize); break; @@ -2011,7 +2151,12 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, cur_iov, iov_base, bytes); flush_dcache_page(page); status = a_ops->commit_write(file, page, offset, offset+bytes); - if (likely(copied > 0)) { + if (status == AOP_TRUNCATED_PAGE) { + page_cache_release(page); + continue; + } +zero_length_segment: + if (likely(copied >= 0)) { if (!status) status = copied; @@ -2023,7 +2168,11 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, if (unlikely(nr_segs > 1)) { filemap_set_next_iovec(&cur_iov, &iov_base, status); - buf = cur_iov->iov_base + iov_base; + if (count) + buf = cur_iov->iov_base + + iov_base; + } else { + iov_base += status; } } } @@ -2067,7 +2216,7 @@ generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov, } EXPORT_SYMBOL(generic_file_buffered_write); -ssize_t +static ssize_t __generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t *ppos) { @@ -2117,16 +2266,19 @@ __generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, if (count == 0) goto out; - err = remove_suid(file->f_dentry); + err = remove_suid(file->f_path.dentry); if (err) goto out; - inode_update_time(inode, 1); + file_update_time(file); /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ if (unlikely(file->f_flags & O_DIRECT)) { - written = generic_file_direct_write(iocb, iov, - &nr_segs, pos, ppos, count, ocount); + loff_t endbyte; + ssize_t written_buffered; + + written = generic_file_direct_write(iocb, iov, &nr_segs, pos, + ppos, count, ocount); if (written < 0 || written == count) goto out; /* @@ -2135,30 +2287,66 @@ __generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, */ pos += written; count -= written; - } + 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; + } - written = generic_file_buffered_write(iocb, iov, nr_segs, - pos, ppos, count, written); + /* + * 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; + err = do_sync_file_range(file, pos, endbyte, + SYNC_FILE_RANGE_WAIT_BEFORE| + SYNC_FILE_RANGE_WRITE| + SYNC_FILE_RANGE_WAIT_AFTER); + 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); + } out: current->backing_dev_info = NULL; return written ? written : err; } -EXPORT_SYMBOL(generic_file_aio_write_nolock); -ssize_t -generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t *ppos) +ssize_t generic_file_aio_write_nolock(struct kiocb *iocb, + const struct iovec *iov, unsigned long nr_segs, loff_t pos) { struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; ssize_t ret; - loff_t pos = *ppos; - ret = __generic_file_aio_write_nolock(iocb, iov, nr_segs, ppos); + BUG_ON(iocb->ki_pos != pos); + + ret = __generic_file_aio_write_nolock(iocb, iov, nr_segs, + &iocb->ki_pos); if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { - int err; + ssize_t err; err = sync_page_range_nolock(inode, mapping, pos, ret); if (err < 0) @@ -2166,52 +2354,22 @@ generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov, } return ret; } +EXPORT_SYMBOL(generic_file_aio_write_nolock); -ssize_t -__generic_file_write_nolock(struct file *file, const struct iovec *iov, - unsigned long nr_segs, loff_t *ppos) -{ - struct kiocb kiocb; - ssize_t ret; - - init_sync_kiocb(&kiocb, file); - ret = __generic_file_aio_write_nolock(&kiocb, iov, nr_segs, ppos); - if (ret == -EIOCBQUEUED) - ret = wait_on_sync_kiocb(&kiocb); - return ret; -} - -ssize_t -generic_file_write_nolock(struct file *file, const struct iovec *iov, - unsigned long nr_segs, loff_t *ppos) -{ - struct kiocb kiocb; - ssize_t ret; - - init_sync_kiocb(&kiocb, file); - ret = generic_file_aio_write_nolock(&kiocb, iov, nr_segs, ppos); - if (-EIOCBQUEUED == ret) - ret = wait_on_sync_kiocb(&kiocb); - return ret; -} -EXPORT_SYMBOL(generic_file_write_nolock); - -ssize_t generic_file_aio_write(struct kiocb *iocb, const char __user *buf, - size_t count, loff_t pos) +ssize_t generic_file_aio_write(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) { struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; ssize_t ret; - struct iovec local_iov = { .iov_base = (void __user *)buf, - .iov_len = count }; BUG_ON(iocb->ki_pos != pos); - down(&inode->i_sem); - ret = __generic_file_aio_write_nolock(iocb, &local_iov, 1, - &iocb->ki_pos); - up(&inode->i_sem); + mutex_lock(&inode->i_mutex); + ret = __generic_file_aio_write_nolock(iocb, iov, nr_segs, + &iocb->ki_pos); + mutex_unlock(&inode->i_mutex); if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { ssize_t err; @@ -2224,71 +2382,11 @@ ssize_t generic_file_aio_write(struct kiocb *iocb, const char __user *buf, } EXPORT_SYMBOL(generic_file_aio_write); -ssize_t generic_file_write(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) -{ - struct address_space *mapping = file->f_mapping; - struct inode *inode = mapping->host; - ssize_t ret; - struct iovec local_iov = { .iov_base = (void __user *)buf, - .iov_len = count }; - - down(&inode->i_sem); - ret = __generic_file_write_nolock(file, &local_iov, 1, ppos); - up(&inode->i_sem); - - if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { - ssize_t err; - - err = sync_page_range(inode, mapping, *ppos - ret, ret); - if (err < 0) - ret = err; - } - return ret; -} -EXPORT_SYMBOL(generic_file_write); - -ssize_t generic_file_readv(struct file *filp, const struct iovec *iov, - unsigned long nr_segs, loff_t *ppos) -{ - struct kiocb kiocb; - ssize_t ret; - - init_sync_kiocb(&kiocb, filp); - ret = __generic_file_aio_read(&kiocb, iov, nr_segs, ppos); - if (-EIOCBQUEUED == ret) - ret = wait_on_sync_kiocb(&kiocb); - return ret; -} -EXPORT_SYMBOL(generic_file_readv); - -ssize_t generic_file_writev(struct file *file, const struct iovec *iov, - unsigned long nr_segs, loff_t *ppos) -{ - struct address_space *mapping = file->f_mapping; - struct inode *inode = mapping->host; - ssize_t ret; - - down(&inode->i_sem); - ret = __generic_file_write_nolock(file, iov, nr_segs, ppos); - up(&inode->i_sem); - - if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) { - int err; - - err = sync_page_range(inode, mapping, *ppos - ret, ret); - if (err < 0) - ret = err; - } - return ret; -} -EXPORT_SYMBOL(generic_file_writev); - /* - * Called under i_sem for writes to S_ISREG files. Returns -EIO if something + * Called under i_mutex for writes to S_ISREG files. Returns -EIO if something * went wrong during pagecache shootdown. */ -ssize_t +static ssize_t generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t offset, unsigned long nr_segs) { @@ -2323,4 +2421,33 @@ generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, } return retval; } -EXPORT_SYMBOL_GPL(generic_file_direct_IO); + +/** + * 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. + * + * The @gfp_mask argument specifies whether I/O may be performed to release + * this page (__GFP_IO), and whether the call may block (__GFP_WAIT). + * + * NOTE: @gfp_mask may go away, and this function may become non-blocking. + */ +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);