Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/mm/filemap.c b/mm/filemap.c
new file mode 100644
index 0000000..439b2be
--- /dev/null
+++ b/mm/filemap.c
@@ -0,0 +1,2306 @@
+/*
+ * 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)
+ */
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/compiler.h>
+#include <linux/fs.h>
+#include <linux/aio.h>
+#include <linux/kernel_stat.h>
+#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>
+#include <linux/pagevec.h>
+#include <linux/blkdev.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+/*
+ * This is needed for the following functions:
+ * - try_to_release_page
+ * - block_invalidatepage
+ * - generic_osync_inode
+ *
+ * FIXME: remove all knowledge of the buffer layer from the core VM
+ */
+#include <linux/buffer_head.h> /* for generic_osync_inode */
+
+#include <asm/uaccess.h>
+#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:
+ *
+ * ->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
+ *
+ * ->i_sem
+ * ->i_mmap_lock (truncate->unmap_mapping_range)
+ *
+ * ->mmap_sem
+ * ->i_mmap_lock
+ * ->page_table_lock (various places, mainly in mmap.c)
+ * ->mapping->tree_lock (arch-dependent flush_dcache_mmap_lock)
+ *
+ * ->mmap_sem
+ * ->lock_page (access_process_vm)
+ *
+ * ->mmap_sem
+ * ->i_sem (msync)
+ *
+ * ->i_sem
+ * ->i_alloc_sem (various)
+ *
+ * ->inode_lock
+ * ->sb_lock (fs/fs-writeback.c)
+ * ->mapping->tree_lock (__sync_single_inode)
+ *
+ * ->i_mmap_lock
+ * ->anon_vma.lock (vma_adjust)
+ *
+ * ->anon_vma.lock
+ * ->page_table_lock (anon_vma_prepare and various)
+ *
+ * ->page_table_lock
+ * ->swap_device_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)
+ * ->private_lock (page_remove_rmap->set_page_dirty)
+ * ->tree_lock (page_remove_rmap->set_page_dirty)
+ * ->inode_lock (page_remove_rmap->set_page_dirty)
+ * ->inode_lock (zap_pte_range->set_page_dirty)
+ * ->private_lock (zap_pte_range->__set_page_dirty_buffers)
+ *
+ * ->task->proc_lock
+ * ->dcache_lock (proc_pid_lookup)
+ */
+
+/*
+ * Remove a page from the page cache and free it. Caller has to make
+ * sure the page is locked and that nobody else uses it - or that usage
+ * is safe. The caller must hold a write_lock on the mapping's tree_lock.
+ */
+void __remove_from_page_cache(struct page *page)
+{
+ struct address_space *mapping = page->mapping;
+
+ radix_tree_delete(&mapping->page_tree, page->index);
+ page->mapping = NULL;
+ mapping->nrpages--;
+ pagecache_acct(-1);
+}
+
+void remove_from_page_cache(struct page *page)
+{
+ struct address_space *mapping = page->mapping;
+
+ if (unlikely(!PageLocked(page)))
+ PAGE_BUG(page);
+
+ write_lock_irq(&mapping->tree_lock);
+ __remove_from_page_cache(page);
+ write_unlock_irq(&mapping->tree_lock);
+}
+
+static int sync_page(void *word)
+{
+ struct address_space *mapping;
+ struct page *page;
+
+ page = container_of((page_flags_t *)word, struct page, flags);
+
+ /*
+ * FIXME, fercrissake. What is this barrier here for?
+ */
+ smp_mb();
+ mapping = page_mapping(page);
+ if (mapping && mapping->a_ops && mapping->a_ops->sync_page)
+ mapping->a_ops->sync_page(page);
+ io_schedule();
+ return 0;
+}
+
+/**
+ * filemap_fdatawrite_range - start writeback against all of a mapping's
+ * dirty pages that lie within the byte offsets <start, end>
+ * @mapping: address space structure to write
+ * @start: offset in bytes where the range starts
+ * @end : offset in bytes where the range ends
+ *
+ * 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
+ * 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 ret;
+ struct writeback_control wbc = {
+ .sync_mode = sync_mode,
+ .nr_to_write = mapping->nrpages * 2,
+ .start = start,
+ .end = end,
+ };
+
+ 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)
+{
+ return __filemap_fdatawrite_range(mapping, 0, 0, sync_mode);
+}
+
+int filemap_fdatawrite(struct address_space *mapping)
+{
+ return __filemap_fdatawrite(mapping, WB_SYNC_ALL);
+}
+EXPORT_SYMBOL(filemap_fdatawrite);
+
+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);
+}
+
+/*
+ * 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);
+
+/*
+ * Wait for writeback to complete against pages indexed by start->end
+ * inclusive
+ */
+static int wait_on_page_writeback_range(struct address_space *mapping,
+ pgoff_t start, pgoff_t end)
+{
+ struct pagevec pvec;
+ int nr_pages;
+ int ret = 0;
+ pgoff_t index;
+
+ if (end < start)
+ return 0;
+
+ pagevec_init(&pvec, 0);
+ index = start;
+ 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);
+ if (PageError(page))
+ 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;
+}
+
+/*
+ * 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
+ * it is otherwise livelockable.
+ */
+int sync_page_range(struct inode *inode, struct address_space *mapping,
+ loff_t pos, size_t count)
+{
+ pgoff_t start = pos >> PAGE_CACHE_SHIFT;
+ pgoff_t end = (pos + count - 1) >> PAGE_CACHE_SHIFT;
+ int ret;
+
+ if (!mapping_cap_writeback_dirty(mapping) || !count)
+ return 0;
+ ret = filemap_fdatawrite_range(mapping, pos, pos + count - 1);
+ if (ret == 0) {
+ down(&inode->i_sem);
+ ret = generic_osync_inode(inode, mapping, OSYNC_METADATA);
+ up(&inode->i_sem);
+ }
+ if (ret == 0)
+ ret = wait_on_page_writeback_range(mapping, start, end);
+ return ret;
+}
+EXPORT_SYMBOL(sync_page_range);
+
+/*
+ * Note: Holding i_sem 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)
+{
+ pgoff_t start = pos >> PAGE_CACHE_SHIFT;
+ pgoff_t end = (pos + count - 1) >> PAGE_CACHE_SHIFT;
+ int ret;
+
+ if (!mapping_cap_writeback_dirty(mapping) || !count)
+ return 0;
+ ret = filemap_fdatawrite_range(mapping, pos, pos + count - 1);
+ if (ret == 0)
+ ret = generic_osync_inode(inode, mapping, OSYNC_METADATA);
+ if (ret == 0)
+ ret = wait_on_page_writeback_range(mapping, start, end);
+ return ret;
+}
+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.
+ *
+ * @mapping: address space structure to wait for
+ */
+int filemap_fdatawait(struct address_space *mapping)
+{
+ loff_t i_size = i_size_read(mapping->host);
+
+ if (i_size == 0)
+ return 0;
+
+ return wait_on_page_writeback_range(mapping, 0,
+ (i_size - 1) >> PAGE_CACHE_SHIFT);
+}
+EXPORT_SYMBOL(filemap_fdatawait);
+
+int filemap_write_and_wait(struct address_space *mapping)
+{
+ int retval = 0;
+
+ if (mapping->nrpages) {
+ retval = filemap_fdatawrite(mapping);
+ if (retval == 0)
+ retval = filemap_fdatawait(mapping);
+ }
+ return retval;
+}
+
+int filemap_write_and_wait_range(struct address_space *mapping,
+ loff_t lstart, loff_t lend)
+{
+ int retval = 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);
+ }
+ return retval;
+}
+
+/*
+ * 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)
+{
+ int error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
+
+ if (error == 0) {
+ write_lock_irq(&mapping->tree_lock);
+ error = radix_tree_insert(&mapping->page_tree, offset, page);
+ if (!error) {
+ page_cache_get(page);
+ SetPageLocked(page);
+ page->mapping = mapping;
+ page->index = offset;
+ mapping->nrpages++;
+ pagecache_acct(1);
+ }
+ 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)
+{
+ int ret = add_to_page_cache(page, mapping, offset, gfp_mask);
+ if (ret == 0)
+ lru_cache_add(page);
+ return ret;
+}
+
+/*
+ * 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);
+}
+
+void fastcall wait_on_page_bit(struct page *page, int bit_nr)
+{
+ DEFINE_WAIT_BIT(wait, &page->flags, bit_nr);
+
+ if (test_bit(bit_nr, &page->flags))
+ __wait_on_bit(page_waitqueue(page), &wait, sync_page,
+ TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(wait_on_page_bit);
+
+/**
+ * unlock_page() - unlock a locked page
+ *
+ * @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.
+ *
+ * The first mb is necessary to safely close the critical section opened by the
+ * TestSetPageLocked(), the second 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()).
+ */
+void fastcall unlock_page(struct page *page)
+{
+ smp_mb__before_clear_bit();
+ if (!TestClearPageLocked(page))
+ BUG();
+ smp_mb__after_clear_bit();
+ wake_up_page(page, PG_locked);
+}
+EXPORT_SYMBOL(unlock_page);
+
+/*
+ * End writeback against a page.
+ */
+void end_page_writeback(struct page *page)
+{
+ if (!TestClearPageReclaim(page) || rotate_reclaimable_page(page)) {
+ if (!test_clear_page_writeback(page))
+ BUG();
+ }
+ smp_mb__after_clear_bit();
+ wake_up_page(page, PG_writeback);
+}
+EXPORT_SYMBOL(end_page_writeback);
+
+/*
+ * Get a lock on the page, assuming we need to sleep to get it.
+ *
+ * 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.
+ */
+void fastcall __lock_page(struct page *page)
+{
+ DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
+
+ __wait_on_bit_lock(page_waitqueue(page), &wait, sync_page,
+ TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(__lock_page);
+
+/*
+ * a rather lightweight function, finding and getting a reference to a
+ * hashed page atomically.
+ */
+struct page * find_get_page(struct address_space *mapping, unsigned long offset)
+{
+ struct page *page;
+
+ read_lock_irq(&mapping->tree_lock);
+ page = radix_tree_lookup(&mapping->page_tree, offset);
+ if (page)
+ page_cache_get(page);
+ read_unlock_irq(&mapping->tree_lock);
+ return page;
+}
+
+EXPORT_SYMBOL(find_get_page);
+
+/*
+ * Same as above, but trylock it instead of incrementing the count.
+ */
+struct page *find_trylock_page(struct address_space *mapping, unsigned long offset)
+{
+ struct page *page;
+
+ read_lock_irq(&mapping->tree_lock);
+ page = radix_tree_lookup(&mapping->page_tree, offset);
+ if (page && TestSetPageLocked(page))
+ page = NULL;
+ 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
+ *
+ * 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.
+ */
+struct page *find_lock_page(struct address_space *mapping,
+ unsigned long offset)
+{
+ struct page *page;
+
+ read_lock_irq(&mapping->tree_lock);
+repeat:
+ page = radix_tree_lookup(&mapping->page_tree, offset);
+ if (page) {
+ page_cache_get(page);
+ if (TestSetPageLocked(page)) {
+ read_unlock_irq(&mapping->tree_lock);
+ lock_page(page);
+ read_lock_irq(&mapping->tree_lock);
+
+ /* Has the page been truncated while we slept? */
+ if (page->mapping != mapping || page->index != offset) {
+ unlock_page(page);
+ page_cache_release(page);
+ goto 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
+ *
+ * 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,
+ unsigned long index, unsigned int gfp_mask)
+{
+ struct page *page, *cached_page = NULL;
+ int err;
+repeat:
+ page = find_lock_page(mapping, index);
+ if (!page) {
+ if (!cached_page) {
+ cached_page = alloc_page(gfp_mask);
+ if (!cached_page)
+ return NULL;
+ }
+ err = add_to_page_cache_lru(cached_page, mapping,
+ index, gfp_mask);
+ if (!err) {
+ page = cached_page;
+ cached_page = NULL;
+ } else if (err == -EEXIST)
+ goto repeat;
+ }
+ if (cached_page)
+ page_cache_release(cached_page);
+ return page;
+}
+
+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;
+
+ read_lock_irq(&mapping->tree_lock);
+ ret = radix_tree_gang_lookup(&mapping->page_tree,
+ (void **)pages, start, nr_pages);
+ for (i = 0; i < ret; i++)
+ page_cache_get(pages[i]);
+ read_unlock_irq(&mapping->tree_lock);
+ return ret;
+}
+
+/*
+ * 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.
+ */
+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;
+
+ read_lock_irq(&mapping->tree_lock);
+ ret = radix_tree_gang_lookup_tag(&mapping->page_tree,
+ (void **)pages, *index, nr_pages, tag);
+ for (i = 0; i < ret; i++)
+ page_cache_get(pages[i]);
+ if (ret)
+ *index = pages[ret - 1]->index + 1;
+ read_unlock_irq(&mapping->tree_lock);
+ return ret;
+}
+
+/*
+ * 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
+ * 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 *
+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))
+ return page;
+ 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_cache_release(page);
+ page = NULL;
+ }
+ return page;
+}
+
+EXPORT_SYMBOL(grab_cache_page_nowait);
+
+/*
+ * This is a generic file read routine, and uses the
+ * 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.
+ */
+void do_generic_mapping_read(struct address_space *mapping,
+ struct file_ra_state *_ra,
+ struct file *filp,
+ loff_t *ppos,
+ read_descriptor_t *desc,
+ read_actor_t actor)
+{
+ struct inode *inode = mapping->host;
+ unsigned long index;
+ unsigned long end_index;
+ unsigned long offset;
+ unsigned long last_index;
+ unsigned long next_index;
+ unsigned long prev_index;
+ loff_t isize;
+ struct page *cached_page;
+ int error;
+ struct file_ra_state ra = *_ra;
+
+ cached_page = NULL;
+ index = *ppos >> PAGE_CACHE_SHIFT;
+ next_index = index;
+ prev_index = ra.prev_page;
+ last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
+ offset = *ppos & ~PAGE_CACHE_MASK;
+
+ isize = i_size_read(inode);
+ if (!isize)
+ goto out;
+
+ end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
+ for (;;) {
+ struct page *page;
+ unsigned long nr, ret;
+
+ /* nr is the maximum number of bytes to copy from this page */
+ nr = PAGE_CACHE_SIZE;
+ if (index >= end_index) {
+ if (index > end_index)
+ goto out;
+ nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
+ if (nr <= offset) {
+ goto out;
+ }
+ }
+ nr = nr - offset;
+
+ cond_resched();
+ if (index == next_index)
+ next_index = page_cache_readahead(mapping, &ra, filp,
+ index, last_index - index);
+
+find_page:
+ page = find_get_page(mapping, index);
+ if (unlikely(page == NULL)) {
+ handle_ra_miss(mapping, &ra, index);
+ goto no_cached_page;
+ }
+ if (!PageUptodate(page))
+ goto page_not_up_to_date;
+page_ok:
+
+ /* 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);
+
+ /*
+ * When (part of) the same page is read multiple times
+ * in succession, only mark it as accessed the first time.
+ */
+ if (prev_index != index)
+ 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;
+
+ page_cache_release(page);
+ if (ret == nr && desc->count)
+ continue;
+ goto out;
+
+page_not_up_to_date:
+ /* Get exclusive access to the page ... */
+ lock_page(page);
+
+ /* Did it get unhashed before we got the lock? */
+ 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:
+ /* Start the actual read. The read will unlock the page. */
+ error = mapping->a_ops->readpage(filp, page);
+
+ if (unlikely(error))
+ goto readpage_error;
+
+ if (!PageUptodate(page)) {
+ lock_page(page);
+ if (!PageUptodate(page)) {
+ if (page->mapping == NULL) {
+ /*
+ * invalidate_inode_pages got it
+ */
+ unlock_page(page);
+ page_cache_release(page);
+ goto find_page;
+ }
+ unlock_page(page);
+ error = -EIO;
+ goto readpage_error;
+ }
+ unlock_page(page);
+ }
+
+ /*
+ * i_size must be checked after we have done ->readpage.
+ *
+ * Checking i_size after the readpage 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;
+ 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..
+ */
+ if (!cached_page) {
+ cached_page = page_cache_alloc_cold(mapping);
+ if (!cached_page) {
+ desc->error = -ENOMEM;
+ goto out;
+ }
+ }
+ error = add_to_page_cache_lru(cached_page, mapping,
+ index, GFP_KERNEL);
+ if (error) {
+ if (error == -EEXIST)
+ goto find_page;
+ desc->error = error;
+ goto out;
+ }
+ page = cached_page;
+ cached_page = NULL;
+ goto readpage;
+ }
+
+out:
+ *_ra = ra;
+
+ *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
+ if (cached_page)
+ page_cache_release(cached_page);
+ if (filp)
+ file_accessed(filp);
+}
+
+EXPORT_SYMBOL(do_generic_mapping_read);
+
+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;
+}
+
+/*
+ * 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)
+{
+ struct file *filp = iocb->ki_filp;
+ ssize_t retval;
+ unsigned long seg;
+ size_t count;
+
+ count = 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.
+ */
+ count += iv->iov_len;
+ if (unlikely((ssize_t)(count|iv->iov_len) < 0))
+ return -EINVAL;
+ if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len))
+ continue;
+ if (seg == 0)
+ return -EFAULT;
+ nr_segs = seg;
+ count -= iv->iov_len; /* This segment is no good */
+ break;
+ }
+
+ /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */
+ if (filp->f_flags & O_DIRECT) {
+ loff_t pos = *ppos, size;
+ struct address_space *mapping;
+ struct inode *inode;
+
+ mapping = filp->f_mapping;
+ inode = mapping->host;
+ retval = 0;
+ if (!count)
+ goto out; /* skip atime */
+ size = i_size_read(inode);
+ 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;
+ }
+
+ retval = 0;
+ if (count) {
+ for (seg = 0; seg < nr_segs; seg++) {
+ read_descriptor_t desc;
+
+ desc.written = 0;
+ desc.arg.buf = iov[seg].iov_base;
+ desc.count = iov[seg].iov_len;
+ if (desc.count == 0)
+ continue;
+ desc.error = 0;
+ do_generic_file_read(filp,ppos,&desc,file_read_actor);
+ retval += desc.written;
+ if (!retval) {
+ retval = desc.error;
+ break;
+ }
+ }
+ }
+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;
+ unsigned long count = desc->count;
+ struct file *file = desc->arg.data;
+
+ if (size > count)
+ size = count;
+
+ written = file->f_op->sendpage(file, page, offset,
+ size, &file->f_pos, size<count);
+ if (written < 0) {
+ desc->error = written;
+ written = 0;
+ }
+ desc->count = count - written;
+ desc->written += written;
+ return written;
+}
+
+ssize_t generic_file_sendfile(struct file *in_file, loff_t *ppos,
+ size_t count, read_actor_t actor, void *target)
+{
+ read_descriptor_t desc;
+
+ if (!count)
+ return 0;
+
+ desc.written = 0;
+ desc.count = count;
+ desc.arg.data = target;
+ desc.error = 0;
+
+ do_generic_file_read(in_file, ppos, &desc, actor);
+ if (desc.written)
+ return desc.written;
+ return desc.error;
+}
+
+EXPORT_SYMBOL(generic_file_sendfile);
+
+static ssize_t
+do_readahead(struct address_space *mapping, struct file *filp,
+ unsigned long index, unsigned long nr)
+{
+ if (!mapping || !mapping->a_ops || !mapping->a_ops->readpage)
+ return -EINVAL;
+
+ force_page_cache_readahead(mapping, filp, index,
+ max_sane_readahead(nr));
+ return 0;
+}
+
+asmlinkage ssize_t sys_readahead(int fd, loff_t offset, size_t count)
+{
+ 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;
+ unsigned long start = offset >> PAGE_CACHE_SHIFT;
+ unsigned long end = (offset + count - 1) >> PAGE_CACHE_SHIFT;
+ unsigned long len = end - start + 1;
+ ret = do_readahead(mapping, file, start, len);
+ }
+ fput(file);
+ }
+ return ret;
+}
+
+#ifdef CONFIG_MMU
+/*
+ * 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;
+
+ page = page_cache_alloc_cold(mapping);
+ if (!page)
+ return -ENOMEM;
+
+ 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;
+}
+
+#define MMAP_LOTSAMISS (100)
+
+/*
+ * filemap_nopage() is invoked via the vma operations vector for a
+ * 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.
+ */
+struct page *filemap_nopage(struct vm_area_struct *area,
+ unsigned long address, int *type)
+{
+ int error;
+ struct file *file = area->vm_file;
+ struct address_space *mapping = file->f_mapping;
+ struct file_ra_state *ra = &file->f_ra;
+ struct inode *inode = mapping->host;
+ struct page *page;
+ unsigned long size, pgoff;
+ int did_readaround = 0, majmin = VM_FAULT_MINOR;
+
+ pgoff = ((address-area->vm_start) >> PAGE_CACHE_SHIFT) + area->vm_pgoff;
+
+retry_all:
+ size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ if (pgoff >= size)
+ goto outside_data_content;
+
+ /* If we don't want any read-ahead, don't bother */
+ if (VM_RandomReadHint(area))
+ goto no_cached_page;
+
+ /*
+ * The readahead code wants to be told about each and every page
+ * so it can build and shrink its windows appropriately
+ *
+ * For sequential accesses, we use the generic readahead logic.
+ */
+ if (VM_SequentialReadHint(area))
+ page_cache_readahead(mapping, ra, file, pgoff, 1);
+
+ /*
+ * Do we have something in the page cache already?
+ */
+retry_find:
+ page = find_get_page(mapping, pgoff);
+ if (!page) {
+ unsigned long ra_pages;
+
+ if (VM_SequentialReadHint(area)) {
+ handle_ra_miss(mapping, ra, pgoff);
+ goto no_cached_page;
+ }
+ 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 > ra->mmap_hit + MMAP_LOTSAMISS)
+ goto no_cached_page;
+
+ /*
+ * To keep the pgmajfault counter straight, we need to
+ * check did_readaround, as this is an inner loop.
+ */
+ if (!did_readaround) {
+ majmin = VM_FAULT_MAJOR;
+ inc_page_state(pgmajfault);
+ }
+ did_readaround = 1;
+ ra_pages = max_sane_readahead(file->f_ra.ra_pages);
+ if (ra_pages) {
+ pgoff_t start = 0;
+
+ if (pgoff > ra_pages / 2)
+ start = pgoff - ra_pages / 2;
+ do_page_cache_readahead(mapping, file, start, ra_pages);
+ }
+ page = find_get_page(mapping, pgoff);
+ if (!page)
+ goto no_cached_page;
+ }
+
+ if (!did_readaround)
+ ra->mmap_hit++;
+
+ /*
+ * Ok, found a page in the page cache, now we need to check
+ * that it's up-to-date.
+ */
+ if (!PageUptodate(page))
+ goto page_not_uptodate;
+
+success:
+ /*
+ * Found the page and have a reference on it.
+ */
+ mark_page_accessed(page);
+ if (type)
+ *type = majmin;
+ return page;
+
+outside_data_content:
+ /*
+ * An external ptracer can access pages that normally aren't
+ * accessible..
+ */
+ if (area->vm_mm == current->mm)
+ return NULL;
+ /* Fall through to the non-read-ahead case */
+no_cached_page:
+ /*
+ * We're only likely to ever get here if MADV_RANDOM is in
+ * effect.
+ */
+ error = page_cache_read(file, pgoff);
+ grab_swap_token();
+
+ /*
+ * 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)
+ return NOPAGE_OOM;
+ return NULL;
+
+page_not_uptodate:
+ if (!did_readaround) {
+ majmin = VM_FAULT_MAJOR;
+ inc_page_state(pgmajfault);
+ }
+ lock_page(page);
+
+ /* Did it get unhashed while we waited for it? */
+ if (!page->mapping) {
+ unlock_page(page);
+ page_cache_release(page);
+ goto retry_all;
+ }
+
+ /* Did somebody else get it up-to-date? */
+ if (PageUptodate(page)) {
+ unlock_page(page);
+ goto success;
+ }
+
+ if (!mapping->a_ops->readpage(file, page)) {
+ wait_on_page_locked(page);
+ if (PageUptodate(page))
+ goto success;
+ }
+
+ /*
+ * 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.
+ */
+ lock_page(page);
+
+ /* Somebody truncated the page on us? */
+ if (!page->mapping) {
+ unlock_page(page);
+ page_cache_release(page);
+ goto retry_all;
+ }
+
+ /* Somebody else successfully read it in? */
+ if (PageUptodate(page)) {
+ unlock_page(page);
+ goto success;
+ }
+ ClearPageError(page);
+ if (!mapping->a_ops->readpage(file, page)) {
+ wait_on_page_locked(page);
+ if (PageUptodate(page))
+ goto success;
+ }
+
+ /*
+ * Things didn't work out. Return zero to tell the
+ * mm layer so, possibly freeing the page cache page first.
+ */
+ page_cache_release(page);
+ return NULL;
+}
+
+EXPORT_SYMBOL(filemap_nopage);
+
+static struct page * filemap_getpage(struct file *file, unsigned long pgoff,
+ int nonblock)
+{
+ struct address_space *mapping = file->f_mapping;
+ struct page *page;
+ int error;
+
+ /*
+ * Do we have something in the page cache already?
+ */
+retry_find:
+ page = find_get_page(mapping, pgoff);
+ if (!page) {
+ if (nonblock)
+ return NULL;
+ goto no_cached_page;
+ }
+
+ /*
+ * Ok, found a page in the page cache, now we need to check
+ * that it's up-to-date.
+ */
+ if (!PageUptodate(page))
+ goto page_not_uptodate;
+
+success:
+ /*
+ * Found the page and have a reference on it.
+ */
+ mark_page_accessed(page);
+ return page;
+
+no_cached_page:
+ error = page_cache_read(file, pgoff);
+
+ /*
+ * 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.
+ */
+ return NULL;
+
+page_not_uptodate:
+ lock_page(page);
+
+ /* Did it get unhashed while we waited for it? */
+ if (!page->mapping) {
+ unlock_page(page);
+ goto err;
+ }
+
+ /* Did somebody else get it up-to-date? */
+ if (PageUptodate(page)) {
+ unlock_page(page);
+ goto success;
+ }
+
+ if (!mapping->a_ops->readpage(file, page)) {
+ wait_on_page_locked(page);
+ if (PageUptodate(page))
+ goto success;
+ }
+
+ /*
+ * 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.
+ */
+ lock_page(page);
+
+ /* Somebody truncated the page on us? */
+ if (!page->mapping) {
+ unlock_page(page);
+ goto err;
+ }
+ /* Somebody else successfully read it in? */
+ if (PageUptodate(page)) {
+ unlock_page(page);
+ goto success;
+ }
+
+ ClearPageError(page);
+ if (!mapping->a_ops->readpage(file, page)) {
+ wait_on_page_locked(page);
+ if (PageUptodate(page))
+ goto success;
+ }
+
+ /*
+ * Things didn't work out. Return zero to tell the
+ * mm layer so, possibly freeing the page cache page first.
+ */
+err:
+ page_cache_release(page);
+
+ return NULL;
+}
+
+int filemap_populate(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long len, pgprot_t prot, unsigned long pgoff,
+ int nonblock)
+{
+ struct file *file = vma->vm_file;
+ struct address_space *mapping = file->f_mapping;
+ struct inode *inode = mapping->host;
+ unsigned long size;
+ struct mm_struct *mm = vma->vm_mm;
+ struct page *page;
+ int err;
+
+ if (!nonblock)
+ force_page_cache_readahead(mapping, vma->vm_file,
+ pgoff, len >> PAGE_CACHE_SHIFT);
+
+repeat:
+ size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ if (pgoff + (len >> PAGE_CACHE_SHIFT) > size)
+ return -EINVAL;
+
+ page = filemap_getpage(file, pgoff, nonblock);
+ if (!page && !nonblock)
+ return -ENOMEM;
+ if (page) {
+ err = install_page(mm, vma, addr, page, prot);
+ if (err) {
+ page_cache_release(page);
+ return err;
+ }
+ } else {
+ err = install_file_pte(mm, vma, addr, pgoff, prot);
+ if (err)
+ return err;
+ }
+
+ len -= PAGE_SIZE;
+ addr += PAGE_SIZE;
+ pgoff++;
+ if (len)
+ goto repeat;
+
+ return 0;
+}
+
+struct vm_operations_struct generic_file_vm_ops = {
+ .nopage = filemap_nopage,
+ .populate = filemap_populate,
+};
+
+/* 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;
+ return 0;
+}
+EXPORT_SYMBOL(filemap_populate);
+
+/*
+ * 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);
+
+static inline struct page *__read_cache_page(struct address_space *mapping,
+ unsigned long index,
+ int (*filler)(void *,struct page*),
+ void *data)
+{
+ struct page *page, *cached_page = NULL;
+ int err;
+repeat:
+ page = find_get_page(mapping, index);
+ if (!page) {
+ if (!cached_page) {
+ cached_page = page_cache_alloc_cold(mapping);
+ if (!cached_page)
+ return ERR_PTR(-ENOMEM);
+ }
+ err = add_to_page_cache_lru(cached_page, mapping,
+ index, GFP_KERNEL);
+ if (err == -EEXIST)
+ goto repeat;
+ if (err < 0) {
+ /* Presumably ENOMEM for radix tree node */
+ page_cache_release(cached_page);
+ return ERR_PTR(err);
+ }
+ page = cached_page;
+ cached_page = NULL;
+ err = filler(data, page);
+ if (err < 0) {
+ page_cache_release(page);
+ page = ERR_PTR(err);
+ }
+ }
+ if (cached_page)
+ page_cache_release(cached_page);
+ return page;
+}
+
+/*
+ * Read into the page cache. If a page already exists,
+ * and PageUptodate() is not set, try to fill the page.
+ */
+struct page *read_cache_page(struct address_space *mapping,
+ unsigned long index,
+ int (*filler)(void *,struct page*),
+ void *data)
+{
+ struct page *page;
+ int err;
+
+retry:
+ page = __read_cache_page(mapping, index, filler, data);
+ if (IS_ERR(page))
+ goto out;
+ mark_page_accessed(page);
+ 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);
+ page = ERR_PTR(err);
+ }
+ out:
+ return page;
+}
+
+EXPORT_SYMBOL(read_cache_page);
+
+/*
+ * If the page was newly created, increment its refcount and add it to the
+ * caller's lru-buffering pagevec. This function is specifically for
+ * generic_file_write().
+ */
+static inline struct page *
+__grab_cache_page(struct address_space *mapping, unsigned long index,
+ struct page **cached_page, struct pagevec *lru_pvec)
+{
+ int err;
+ struct page *page;
+repeat:
+ page = find_lock_page(mapping, index);
+ if (!page) {
+ if (!*cached_page) {
+ *cached_page = page_cache_alloc(mapping);
+ if (!*cached_page)
+ return NULL;
+ }
+ err = add_to_page_cache(*cached_page, mapping,
+ index, GFP_KERNEL);
+ if (err == -EEXIST)
+ goto repeat;
+ if (err == 0) {
+ page = *cached_page;
+ page_cache_get(page);
+ if (!pagevec_add(lru_pvec, page))
+ __pagevec_lru_add(lru_pvec);
+ *cached_page = NULL;
+ }
+ }
+ return page;
+}
+
+/*
+ * The logic we want is
+ *
+ * if suid or (sgid and xgrp)
+ * remove privs
+ */
+int 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))
+ 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;
+
+ if (unlikely(kill && !capable(CAP_FSETID))) {
+ struct iattr newattrs;
+
+ newattrs.ia_valid = ATTR_FORCE | kill;
+ result = notify_change(dentry, &newattrs);
+ }
+ return result;
+}
+EXPORT_SYMBOL(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)
+{
+ char *kaddr;
+ int left;
+
+ kaddr = kmap_atomic(page, KM_USER0);
+ left = __copy_from_user_inatomic(kaddr + offset, buf, bytes);
+ kunmap_atomic(kaddr, KM_USER0);
+
+ if (left != 0) {
+ /* Do it the slow way */
+ kaddr = kmap(page);
+ left = __copy_from_user(kaddr + offset, buf, bytes);
+ kunmap(page);
+ }
+ return bytes - left;
+}
+
+static size_t
+__filemap_copy_from_user_iovec(char *vaddr,
+ const struct iovec *iov, size_t base, size_t bytes)
+{
+ size_t copied = 0, left = 0;
+
+ while (bytes) {
+ char __user *buf = iov->iov_base + base;
+ int copy = min(bytes, iov->iov_len - base);
+
+ base = 0;
+ left = __copy_from_user_inatomic(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);
+ 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.
+ * 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;
+ unsigned long limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
+
+ 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)
+ *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) {
+ send_sig(SIGXFSZ, current, 0);
+ 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) {
+ send_sig(SIGXFSZ, current, 0);
+ 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 {
+ 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;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(generic_write_checks);
+
+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;
+
+ if (count != ocount)
+ *nr_segs = iov_shorten((struct iovec *)iov, *nr_segs, count);
+
+ written = generic_file_direct_IO(WRITE, iocb, iov, pos, *nr_segs);
+ if (written > 0) {
+ loff_t end = pos + written;
+ if (end > i_size_read(inode) && !S_ISBLK(inode->i_mode)) {
+ i_size_write(inode, end);
+ mark_inode_dirty(inode);
+ }
+ *ppos = end;
+ }
+
+ /*
+ * 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.
+ */
+ if (written >= 0 && file->f_flags & O_SYNC)
+ generic_osync_inode(inode, mapping, OSYNC_METADATA);
+ if (written == count && !is_sync_kiocb(iocb))
+ written = -EIOCBQUEUED;
+ return written;
+}
+EXPORT_SYMBOL(generic_file_direct_write);
+
+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;
+ struct address_space * mapping = file->f_mapping;
+ struct address_space_operations *a_ops = mapping->a_ops;
+ struct inode *inode = mapping->host;
+ long status = 0;
+ struct page *page;
+ struct page *cached_page = NULL;
+ size_t bytes;
+ struct pagevec lru_pvec;
+ const struct iovec *cur_iov = iov; /* current iovec */
+ size_t iov_base = 0; /* offset in the current iovec */
+ char __user *buf;
+
+ pagevec_init(&lru_pvec, 0);
+
+ /*
+ * handle partial DIO write. Adjust cur_iov if needed.
+ */
+ if (likely(nr_segs == 1))
+ buf = iov->iov_base + written;
+ else {
+ filemap_set_next_iovec(&cur_iov, &iov_base, written);
+ buf = iov->iov_base + iov_base;
+ }
+
+ do {
+ unsigned long index;
+ unsigned long offset;
+ size_t copied;
+
+ offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */
+ index = pos >> PAGE_CACHE_SHIFT;
+ bytes = PAGE_CACHE_SIZE - offset;
+ if (bytes > count)
+ bytes = count;
+
+ /*
+ * 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.
+ */
+ fault_in_pages_readable(buf, bytes);
+
+ page = __grab_cache_page(mapping,index,&cached_page,&lru_pvec);
+ if (!page) {
+ status = -ENOMEM;
+ break;
+ }
+
+ status = a_ops->prepare_write(file, page, offset, offset+bytes);
+ if (unlikely(status)) {
+ loff_t isize = i_size_read(inode);
+ /*
+ * 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;
+ }
+ if (likely(nr_segs == 1))
+ copied = filemap_copy_from_user(page, offset,
+ buf, bytes);
+ else
+ copied = filemap_copy_from_user_iovec(page, offset,
+ 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)
+ status = copied;
+
+ if (status >= 0) {
+ written += status;
+ count -= status;
+ pos += status;
+ buf += status;
+ if (unlikely(nr_segs > 1))
+ filemap_set_next_iovec(&cur_iov,
+ &iov_base, status);
+ }
+ }
+ if (unlikely(copied != bytes))
+ if (status >= 0)
+ status = -EFAULT;
+ unlock_page(page);
+ mark_page_accessed(page);
+ page_cache_release(page);
+ if (status < 0)
+ break;
+ balance_dirty_pages_ratelimited(mapping);
+ cond_resched();
+ } while (count);
+ *ppos = pos;
+
+ if (cached_page)
+ page_cache_release(cached_page);
+
+ /*
+ * For now, when the user asks for O_SYNC, we'll actually give O_DSYNC
+ */
+ if (likely(status >= 0)) {
+ if (unlikely((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+ if (!a_ops->writepage || !is_sync_kiocb(iocb))
+ status = generic_osync_inode(inode, mapping,
+ OSYNC_METADATA|OSYNC_DATA);
+ }
+ }
+
+ /*
+ * If we get here for O_DIRECT writes then we must have fallen through
+ * to buffered writes (block instantiation inside i_size). So we sync
+ * the file data here, to try to honour O_DIRECT expectations.
+ */
+ if (unlikely(file->f_flags & O_DIRECT) && written)
+ status = filemap_write_and_wait(mapping);
+
+ pagevec_lru_add(&lru_pvec);
+ return written ? written : status;
+}
+EXPORT_SYMBOL(generic_file_buffered_write);
+
+ssize_t
+__generic_file_aio_write_nolock(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t *ppos)
+{
+ struct file *file = iocb->ki_filp;
+ struct address_space * mapping = file->f_mapping;
+ size_t ocount; /* original count */
+ size_t count; /* after file limit checks */
+ struct inode *inode = mapping->host;
+ unsigned long seg;
+ loff_t pos;
+ ssize_t written;
+ ssize_t err;
+
+ ocount = 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.
+ */
+ ocount += iv->iov_len;
+ if (unlikely((ssize_t)(ocount|iv->iov_len) < 0))
+ return -EINVAL;
+ if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
+ continue;
+ if (seg == 0)
+ return -EFAULT;
+ nr_segs = seg;
+ ocount -= iv->iov_len; /* This segment is no good */
+ break;
+ }
+
+ 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;
+
+ err = remove_suid(file->f_dentry);
+ if (err)
+ goto out;
+
+ inode_update_time(inode, 1);
+
+ /* 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);
+ 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;
+ }
+
+ 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)
+{
+ 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);
+
+ if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+ int err;
+
+ err = sync_page_range_nolock(inode, mapping, pos, ret);
+ if (err < 0)
+ ret = err;
+ }
+ 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 (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)
+{
+ 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);
+
+ if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+ ssize_t err;
+
+ err = sync_page_range(inode, mapping, pos, ret);
+ if (err < 0)
+ ret = err;
+ }
+ return ret;
+}
+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
+ * went wrong during pagecache shootdown.
+ */
+ssize_t
+generic_file_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
+ loff_t offset, unsigned long nr_segs)
+{
+ struct file *file = iocb->ki_filp;
+ struct address_space *mapping = file->f_mapping;
+ ssize_t retval;
+ size_t write_len = 0;
+
+ /*
+ * If it's a write, unmap all mmappings of the file up-front. This
+ * will cause any pte dirty bits to be propagated into the pageframes
+ * for the subsequent filemap_write_and_wait().
+ */
+ if (rw == WRITE) {
+ write_len = iov_length(iov, nr_segs);
+ if (mapping_mapped(mapping))
+ unmap_mapping_range(mapping, offset, write_len, 0);
+ }
+
+ retval = filemap_write_and_wait(mapping);
+ if (retval == 0) {
+ retval = mapping->a_ops->direct_IO(rw, iocb, iov,
+ offset, nr_segs);
+ if (rw == WRITE && mapping->nrpages) {
+ pgoff_t end = (offset + write_len - 1)
+ >> PAGE_CACHE_SHIFT;
+ int err = invalidate_inode_pages2_range(mapping,
+ offset >> PAGE_CACHE_SHIFT, end);
+ if (err)
+ retval = err;
+ }
+ }
+ return retval;
+}
+EXPORT_SYMBOL_GPL(generic_file_direct_IO);
