static int
romfs_readpage(struct file *file, struct page * page)
{
struct inode *inode = page->mapping->host;
loff_t offset, avail, readlen;
void *buf;
int result = -EIO;
page_cache_get(page);
lock_kernel();
buf = kmap(page);
if (!buf)
goto err_out;
/* 32 bit warning -- but not for us :) */
offset = page_offset(page);
if (offset < i_size_read(inode)) {
avail = inode->i_size-offset;
readlen = min_t(unsigned long, avail, PAGE_SIZE);
if (romfs_copyfrom(inode, buf, ROMFS_I(inode)->i_dataoffset+offset, readlen) == readlen) {
if (readlen < PAGE_SIZE) {
memset(buf + readlen,0,PAGE_SIZE-readlen);
}
SetPageUptodate(page);
result = 0;
}
}
/*
* When an ext3-ordered file is truncated, it is possible that many pages are
* not successfully freed, because they are attached to a committing transaction.
* After the transaction commits, these pages are left on the LRU, with no
* ->mapping, and with attached buffers. These pages are trivially reclaimable
* by the VM, but their apparent absence upsets the VM accounting, and it makes
* the numbers in /proc/meminfo look odd.
*
* So here, we have a buffer which has just come off the forget list. Look to
* see if we can strip all buffers from the backing page.
*
* Called under journal->j_list_lock. The caller provided us with a ref
* against the buffer, and we drop that here.
*/
static void release_buffer_page(struct buffer_head *bh)
{
struct page *page;
if (buffer_dirty(bh))
goto nope;
if (atomic_read(&bh->b_count) != 1)
goto nope;
page = bh->b_page;
if (!page)
goto nope;
if (page->mapping)
goto nope;
/* OK, it's a truncated page */
if (!trylock_page(page))
goto nope;
page_cache_get(page);
__brelse(bh);
try_to_free_buffers(page);
unlock_page(page);
page_cache_release(page);
return;
nope:
__brelse(bh);
}
/*
* __add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,
* but sets SwapCache flag and private instead of mapping and index.
*/
int __add_to_swap_cache(struct page *page, swp_entry_t entry)
{
int error;
VM_BUG_ON(!PageLocked(page));
VM_BUG_ON(PageSwapCache(page));
VM_BUG_ON(!PageSwapBacked(page));
page_cache_get(page);
SetPageSwapCache(page);
set_page_private(page, entry.val);
spin_lock_irq(&swapper_space.tree_lock);
error = radix_tree_insert(&swapper_space.page_tree, entry.val, page);
if (likely(!error)) {
total_swapcache_pages++;
__inc_zone_page_state(page, NR_FILE_PAGES);
INC_CACHE_INFO(add_total);
}
spin_unlock_irq(&swapper_space.tree_lock);
if (unlikely(error)) {
/*
* Only the context which have set SWAP_HAS_CACHE flag
* would call add_to_swap_cache().
* So add_to_swap_cache() doesn't returns -EEXIST.
*/
VM_BUG_ON(error == -EEXIST);
set_page_private(page, 0UL);
ClearPageSwapCache(page);
page_cache_release(page);
}
return error;
}
/*
* Writeback is about to end against a page which has been marked for immediate
* reclaim. If it still appears to be reclaimable, move it to the tail of the
* inactive list.
*
* Returns zero if it cleared PG_writeback.
*/
int rotate_reclaimable_page(struct page *page)
{
struct pagevec *pvec;
unsigned long flags;
if (PageLocked(page))
return 1;
if (PageDirty(page))
return 1;
if (PageActive(page))
return 1;
if (!PageLRU(page))
return 1;
page_cache_get(page);
local_irq_save(flags);
pvec = &__get_cpu_var(lru_rotate_pvecs);
if (!pagevec_add(pvec, page))
pagevec_move_tail(pvec);
local_irq_restore(flags);
if (!test_clear_page_writeback(page))
BUG();
return 0;
}
/*
* Write a page to the server. This will be used for NFS swapping only
* (for now), and we currently do this synchronously only.
*
* We are called with the page locked and we unlock it when done.
*/
static int
smb_writepage(struct page *page, struct writeback_control *wbc)
{
struct address_space *mapping = page->mapping;
struct inode *inode;
unsigned long end_index;
unsigned offset = PAGE_CACHE_SIZE;
int err;
BUG_ON(!mapping);
inode = mapping->host;
BUG_ON(!inode);
end_index = inode->i_size >> PAGE_CACHE_SHIFT;
/* easy case */
if (page->index < end_index)
goto do_it;
/* things got complicated... */
offset = inode->i_size & (PAGE_CACHE_SIZE-1);
/* OK, are we completely out? */
if (page->index >= end_index+1 || !offset)
return 0; /* truncated - don't care */
do_it:
page_cache_get(page);
err = smb_writepage_sync(inode, page, 0, offset);
SetPageUptodate(page);
unlock_page(page);
page_cache_release(page);
return err;
}
/*
* __add_to_swap_cache resembles add_to_page_cache on swapper_space,
* but sets SwapCache flag and private instead of mapping and index.
*/
static int __add_to_swap_cache(struct page *page, swp_entry_t entry,
gfp_t gfp_mask)
{
int error;
BUG_ON(PageSwapCache(page));
BUG_ON(PagePrivate(page));
error = radix_tree_preload(gfp_mask);
if (!error) {
write_lock_irq(&swapper_space.tree_lock);
error = radix_tree_insert(&swapper_space.page_tree,
entry.val, page);
if (!error) {
page_cache_get(page);
SetPageLocked(page);
SetPageSwapCache(page);
set_page_private(page, entry.val);
total_swapcache_pages++;
pagecache_acct(1);
}
write_unlock_irq(&swapper_space.tree_lock);
radix_tree_preload_end();
}
return error;
}
/**
* get the page associated with the block inside our dedup structure
*/
struct page* dedup_get_block_page(sector_t block)
{
struct page *res = NULL;
// Check if the block is inside our range
if (dedup_is_in_range(block)) {
// Get the page pointer stored inside the dedup structure
res = blocksArray.pages[block - start_block];
if (res != NULL) {
// If its not NULL, check if the page is up to date and used
if (PageLRU(res) && PageUptodate(res)) {
page_cache_get(res);
}
else {
// Cannot use page, need to read from bdev
blocksArray.pages[block - start_block] = NULL;
res = NULL;
}
}
}
else
printk("get_block_page: block not in range.\n");
return res;
}
/*
* This routine handles present pages, when users try to write
* to a shared page. It is done by copying the page to a new address
* and decrementing the shared-page counter for the old page.
*
* Goto-purists beware: the only reason for goto's here is that it results
* in better assembly code.. The "default" path will see no jumps at all.
*
* Note that this routine assumes that the protection checks have been
* done by the caller (the low-level page fault routine in most cases).
* Thus we can safely just mark it writable once we've done any necessary
* COW.
*
* We also mark the page dirty at this point even though the page will
* change only once the write actually happens. This avoids a few races,
* and potentially makes it more efficient.
*
* We hold the mm semaphore and the page_table_lock on entry and exit
* with the page_table_lock released.
*/
static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma,
unsigned long address, pte_t *page_table, pte_t pte)
{
struct page *old_page, *new_page;
old_page = pte_page(pte);
if (!VALID_PAGE(old_page))
goto bad_wp_page;
if (!TryLockPage(old_page)) {
int reuse = can_share_swap_page(old_page);
unlock_page(old_page);
if (reuse) {
#ifndef CONFIG_SUPERH
/* Not needed for VIPT cache */
flush_cache_page(vma, address);
#endif
establish_pte(vma, address, page_table, pte_mkyoung(pte_mkdirty(pte_mkwrite(pte))));
spin_unlock(&mm->page_table_lock);
return 1; /* Minor fault */
}
}
/*
* Ok, we need to copy. Oh, well..
*/
page_cache_get(old_page);
spin_unlock(&mm->page_table_lock);
new_page = alloc_page(GFP_HIGHUSER);
if (!new_page)
goto no_mem;
copy_cow_page(old_page,new_page,address);
/*
* Re-check the pte - we dropped the lock
*/
spin_lock(&mm->page_table_lock);
if (pte_same(*page_table, pte)) {
if (PageReserved(old_page))
++mm->rss;
break_cow(vma, new_page, address, page_table);
lru_cache_add(new_page);
/* Free the old page.. */
new_page = old_page;
}
spin_unlock(&mm->page_table_lock);
page_cache_release(new_page);
page_cache_release(old_page);
return 1; /* Minor fault */
bad_wp_page:
spin_unlock(&mm->page_table_lock);
printk("do_wp_page: bogus page at address %08lx (page 0x%lx)\n",address,(unsigned long)old_page);
return -1;
no_mem:
page_cache_release(old_page);
return -1;
}
/*
* add_to_swap_cache resembles add_to_page_cache_locked on swapper_space,
* but sets SwapCache flag and private instead of mapping and index.
*/
int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask)
{
int error;
BUG_ON(!PageLocked(page));
BUG_ON(PageSwapCache(page));
BUG_ON(PagePrivate(page));
BUG_ON(!PageSwapBacked(page));
error = radix_tree_preload(gfp_mask);
if (!error) {
page_cache_get(page);
SetPageSwapCache(page);
set_page_private(page, entry.val);
spin_lock_irq(&swapper_space.tree_lock);
error = radix_tree_insert(&swapper_space.page_tree,
entry.val, page);
if (likely(!error)) {
total_swapcache_pages++;
__inc_zone_page_state(page, NR_FILE_PAGES);
INC_CACHE_INFO(add_total);
}
spin_unlock_irq(&swapper_space.tree_lock);
radix_tree_preload_end();
if (unlikely(error)) {
set_page_private(page, 0UL);
ClearPageSwapCache(page);
page_cache_release(page);
}
}
return error;
}
/**
* lru_cache_add: add a page to the page lists
* @page: the page to add
*/
void lru_cache_add(struct page *page)
{
struct pagevec *pvec = &get_cpu_var(lru_add_pvecs);
page_cache_get(page);
if (!pagevec_add(pvec, page))
__pagevec_lru_add(pvec);
put_cpu_var(lru_add_pvecs);
}
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start,
int len, int write, int force, struct page **pages, struct vm_area_struct **vmas)
{
int i = 0;
do {
struct vm_area_struct * vma;
vma = find_extend_vma(mm, start);
if ( !vma ||
(!force &&
((write && (!(vma->vm_flags & VM_WRITE))) ||
(!write && (!(vma->vm_flags & VM_READ))) ) )) {
if (i) return i;
return -EFAULT;
}
spin_lock(&mm->page_table_lock);
do {
struct page *map;
while (!(map = follow_page(mm, start, write))) {
spin_unlock(&mm->page_table_lock);
switch (handle_mm_fault(mm, vma, start, write)) {
case 1:
tsk->min_flt++;
break;
case 2:
tsk->maj_flt++;
break;
case 0:
if (i) return i;
return -EFAULT;
default:
if (i) return i;
return -ENOMEM;
}
spin_lock(&mm->page_table_lock);
}
if (pages) {
pages[i] = get_page_map(map);
/* FIXME: call the correct function,
* depending on the type of the found page
*/
if (pages[i])
page_cache_get(pages[i]);
}
if (vmas)
vmas[i] = vma;
i++;
start += PAGE_SIZE;
len--;
} while(len && start < vma->vm_end);
spin_unlock(&mm->page_table_lock);
} while(len);
return i;
}
void fastcall lru_cache_add_active(struct page *page)
{
struct pagevec *pvec = &get_cpu_var(lru_add_active_pvecs);
page_cache_get(page);
if (!pagevec_add(pvec, page))
__pagevec_lru_add_active(pvec);
put_cpu_var(lru_add_active_pvecs);
}
void __lru_cache_add(struct page *page, enum lru_list lru)
{
struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
page_cache_get(page);
if (!pagevec_add(pvec, page))
____pagevec_lru_add(pvec, lru);
put_cpu_var(lru_add_pvecs);
}
/*
* Order of operations is important: flush the pagevec when it's already
* full, not when adding the last page, to make sure that last page is
* not added to the LRU directly when passed to this function. Because
* mark_page_accessed() (called after this when writing) only activates
* pages that are on the LRU, linear writes in subpage chunks would see
* every PAGEVEC_SIZE page activated, which is unexpected.
*/
void __lru_cache_add(struct page *page, enum lru_list lru)
{
struct pagevec *pvec = &get_locked_var(swapvec_lock, lru_add_pvecs)[lru];
page_cache_get(page);
if (!pagevec_space(pvec))
__pagevec_lru_add(pvec, lru);
pagevec_add(pvec, page);
put_locked_var(swapvec_lock, lru_add_pvecs);
}
/**
* __lru_cache_add:page加入到lru类型的lru_add_pvecs页缓存中
*/
void __lru_cache_add(struct page *page, enum lru_list lru)
{
struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
page_cache_get(page);
/*加入页缓存中,当也缓存满时,才加入到page对应
* 的zone的lru链表中*/
if (!pagevec_add(pvec, page))
____pagevec_lru_add(pvec, lru);
put_cpu_var(lru_add_pvecs);
}
/**
* lru_cache_add: add a page to the page lists
* @page: the page to add
*/
void fastcall lru_cache_add(struct page *page)
{
struct pagevec *pvec = &get_cpu_var(lru_add_pvecs);
page_cache_get(page);
// dyc: if no space left in pvec, add all pages into zone's inactive list
if (!pagevec_add(pvec, page)) {
__pagevec_lru_add(pvec);
}
put_cpu_var(lru_add_pvecs);
}
void activate_page(struct page *page)
{
if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
struct pagevec *pvec = &get_cpu_var(activate_page_pvecs);
page_cache_get(page);
if (!pagevec_add(pvec, page))
pagevec_lru_move_fn(pvec, __activate_page, NULL);
put_cpu_var(activate_page_pvecs);
}
}
/*
* We are called with the page locked and we unlock it when done.
*/
static int
smb_readpage(struct file *file, struct page *page)
{
int error;
struct dentry *dentry = file->f_path.dentry;
page_cache_get(page);
error = smb_readpage_sync(dentry, page);
page_cache_release(page);
return error;
}
void __lru_cache_add(struct page *page, enum lru_list lru)
{
struct pagevec *pvec;
int cpu;
pvec = swap_get_cpu_var(lru_add_pvecs, cpu)[lru];
page_cache_get(page);
if (!pagevec_add(pvec, page))
____pagevec_lru_add(pvec, lru);
swap_put_cpu_var(lru_add_pvecs, cpu);
}
/*
* Writeback is about to end against a page which has been marked for immediate
* reclaim. If it still appears to be reclaimable, move it to the tail of the
* inactive list.
*/
void rotate_reclaimable_page(struct page *page)
{
if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) &&
!PageUnevictable(page) && PageLRU(page)) {
struct pagevec *pvec;
unsigned long flags;
page_cache_get(page);
local_irq_save(flags);
pvec = &__get_cpu_var(lru_rotate_pvecs);
if (!pagevec_add(pvec, page))
pagevec_move_tail(pvec);
local_irq_restore(flags);
}
}
/*
* get_kernel_pages() - pin kernel pages in memory
* @kiov: An array of struct kvec structures
* @nr_segs: number of segments to pin
* @write: pinning for read/write, currently ignored
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_segs long.
*
* Returns number of pages pinned. This may be fewer than the number
* requested. If nr_pages is 0 or negative, returns 0. If no pages
* were pinned, returns -errno. Each page returned must be released
* with a put_page() call when it is finished with.
*/
int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write,
struct page **pages)
{
int seg;
for (seg = 0; seg < nr_segs; seg++) {
if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE))
return seg;
pages[seg] = kmap_to_page(kiov[seg].iov_base);
page_cache_get(pages[seg]);
}
return seg;
}
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, int len, int write, int force,
struct page **pages, struct vm_area_struct **vmas)
{
int i;
static struct vm_area_struct dummy_vma;
for (i = 0; i < len; i++) {
if (pages) {
pages[i] = virt_to_page(start);
if (pages[i])
page_cache_get(pages[i]);
}
if (vmas)
vmas[i] = &dummy_vma;
start += PAGE_SIZE;
}
return(i);
}
long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int foll_flags, struct page **pages,
struct vm_area_struct **vmas, int *nonblocking)
{
struct vm_area_struct *vma;
unsigned long vm_flags;
int i;
/* calculate required read or write permissions.
* If FOLL_FORCE is set, we only require the "MAY" flags.
*/
vm_flags = (foll_flags & FOLL_WRITE) ?
(VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
vm_flags &= (foll_flags & FOLL_FORCE) ?
(VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
for (i = 0; i < nr_pages; i++) {
vma = find_vma(mm, start);
if (!vma)
goto finish_or_fault;
/* protect what we can, including chardevs */
if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
!(vm_flags & vma->vm_flags))
goto finish_or_fault;
if (pages) {
pages[i] = virt_to_page(start);
if (pages[i])
page_cache_get(pages[i]);
}
if (vmas)
vmas[i] = vma;
start = (start + PAGE_SIZE) & PAGE_MASK;
}
return i;
finish_or_fault:
return i ? : -EFAULT;
}
void nilfs_btnode_delete(struct buffer_head *bh)
{
struct address_space *mapping;
struct page *page = bh->b_page;
pgoff_t index = page_index(page);
int still_dirty;
page_cache_get(page);
lock_page(page);
wait_on_page_writeback(page);
nilfs_forget_buffer(bh);
still_dirty = PageDirty(page);
mapping = page->mapping;
unlock_page(page);
page_cache_release(page);
if (!still_dirty && mapping)
invalidate_inode_pages2_range(mapping, index, index);
}
/**
* nfs_create_request - Create an NFS read/write request.
* @file: file descriptor to use
* @inode: inode to which the request is attached
* @page: page to write
* @offset: starting offset within the page for the write
* @count: number of bytes to read/write
*
* The page must be locked by the caller. This makes sure we never
* create two different requests for the same page, and avoids
* a possible deadlock when we reach the hard limit on the number
* of dirty pages.
* User should ensure it is safe to sleep in this function.
*/
struct nfs_page *
nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
struct page *page,
unsigned int offset, unsigned int count)
{
struct nfs_server *server = NFS_SERVER(inode);
struct nfs_page *req;
/* Deal with hard limits. */
for (;;) {
/* try to allocate the request struct */
req = nfs_page_alloc();
if (req != NULL)
break;
/* Try to free up at least one request in order to stay
* below the hard limit
*/
if (signalled() && (server->flags & NFS_MOUNT_INTR))
return ERR_PTR(-ERESTARTSYS);
yield();
}
/* Initialize the request struct. Initially, we assume a
* long write-back delay. This will be adjusted in
* update_nfs_request below if the region is not locked. */
req->wb_page = page;
atomic_set(&req->wb_complete, 0);
req->wb_index = page->index;
page_cache_get(page);
BUG_ON(PagePrivate(page));
BUG_ON(!PageLocked(page));
BUG_ON(page->mapping->host != inode);
req->wb_offset = offset;
req->wb_pgbase = offset;
req->wb_bytes = count;
atomic_set(&req->wb_count, 1);
req->wb_context = get_nfs_open_context(ctx);
return req;
}
/*
* Free the swap entry like above, but also try to
* free the page cache entry if it is the last user.
*/
void free_swap_and_cache(swp_entry_t entry)
{
struct swap_info_struct * p;
struct page *page = NULL;
p = swap_info_get(entry);
if (p) {
if (swap_entry_free(p, SWP_OFFSET(entry)) == 1)
page = find_trylock_page(&swapper_space, entry.val);
swap_info_put(p);
}
if (page) {
page_cache_get(page);
/* Only cache user (+us), or swap space full? Free it! */
if (page_count(page) - !!page->buffers == 2 || vm_swap_full()) {
delete_from_swap_cache(page);
SetPageDirty(page);
}
UnlockPage(page);
page_cache_release(page);
}
}
static int
HgfsReadpage(struct file *file, // IN: File to read from
struct page *page) // IN/OUT: Page to write to
{
int result = 0;
HgfsHandle handle;
ASSERT(file);
ASSERT(file->f_dentry);
ASSERT(file->f_dentry->d_inode);
ASSERT(page);
handle = FILE_GET_FI_P(file)->handle;
LOG(6, (KERN_WARNING "VMware hgfs: HgfsReadPage: reading from handle %u\n",
handle));
page_cache_get(page);
result = HgfsDoReadpage(handle, page, 0, PAGE_CACHE_SIZE);
page_cache_release(page);
compat_unlock_page(page);
return result;
}
/**
* nfs_create_request - Create an NFS read/write request.
* @ctx: open context to use
* @page: page to write
* @last: last nfs request created for this page group or NULL if head
* @offset: starting offset within the page for the write
* @count: number of bytes to read/write
*
* The page must be locked by the caller. This makes sure we never
* create two different requests for the same page.
* User should ensure it is safe to sleep in this function.
*/
struct nfs_page *
nfs_create_request(struct nfs_open_context *ctx, struct page *page,
struct nfs_page *last, unsigned int offset,
unsigned int count)
{
struct nfs_page *req;
struct nfs_lock_context *l_ctx;
if (test_bit(NFS_CONTEXT_BAD, &ctx->flags))
return ERR_PTR(-EBADF);
/* try to allocate the request struct */
req = nfs_page_alloc();
if (req == NULL)
return ERR_PTR(-ENOMEM);
/* get lock context early so we can deal with alloc failures */
l_ctx = nfs_get_lock_context(ctx);
if (IS_ERR(l_ctx)) {
nfs_page_free(req);
return ERR_CAST(l_ctx);
}
req->wb_lock_context = l_ctx;
nfs_iocounter_inc(&l_ctx->io_count);
/* Initialize the request struct. Initially, we assume a
* long write-back delay. This will be adjusted in
* update_nfs_request below if the region is not locked. */
req->wb_page = page;
req->wb_index = page_file_index(page);
page_cache_get(page);
req->wb_offset = offset;
req->wb_pgbase = offset;
req->wb_bytes = count;
req->wb_context = get_nfs_open_context(ctx);
kref_init(&req->wb_kref);
nfs_page_group_init(req, last);
return req;
}
/**
* nfs_create_request - Create an NFS read/write request.
* @file: file descriptor to use
* @inode: inode to which the request is attached
* @page: page to write
* @offset: starting offset within the page for the write
* @count: number of bytes to read/write
*
* The page must be locked by the caller. This makes sure we never
* create two different requests for the same page.
* User should ensure it is safe to sleep in this function.
*/
struct nfs_page *
nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
struct page *page,
unsigned int offset, unsigned int count)
{
struct nfs_page *req;
/* try to allocate the request struct */
req = nfs_page_alloc();
if (req == NULL)
return ERR_PTR(-ENOMEM);
/* get lock context early so we can deal with alloc failures */
req->wb_lock_context = nfs_get_lock_context(ctx);
if (req->wb_lock_context == NULL) {
nfs_page_free(req);
return ERR_PTR(-ENOMEM);
}
/* Initialize the request struct. Initially, we assume a
* long write-back delay. This will be adjusted in
* update_nfs_request below if the region is not locked. */
req->wb_page = page;
atomic_set(&req->wb_complete, 0);
req->wb_index = page->index;
page_cache_get(page);
BUG_ON(PagePrivate(page));
BUG_ON(!PageLocked(page));
BUG_ON(page->mapping->host != inode);
req->wb_offset = offset;
req->wb_pgbase = offset;
req->wb_bytes = count;
req->wb_context = get_nfs_open_context(ctx);
kref_init(&req->wb_kref);
return req;
}
/**
* write_one_page - write out a single page and optionally wait on I/O
* @page: the page to write
* @wait: if true, wait on writeout
*
* The page must be locked by the caller and will be unlocked upon return.
*
* write_one_page() returns a negative error code if I/O failed.
*/
int write_one_page(struct page *page, int wait)
{
struct address_space *mapping = page->mapping;
int ret = 0;
struct writeback_control wbc = {
.sync_mode = WB_SYNC_ALL,
.nr_to_write = 1,
};
BUG_ON(!PageLocked(page));
if (wait)
wait_on_page_writeback(page);
if (clear_page_dirty_for_io(page)) {
page_cache_get(page);
ret = mapping->a_ops->writepage(page, &wbc);
if (ret == 0 && wait) {
wait_on_page_writeback(page);
if (PageError(page))
ret = -EIO;
}
page_cache_release(page);
} else {
unlock_page(page);
}
return ret;
}
EXPORT_SYMBOL(write_one_page);
/*
* For address_spaces which do not use buffers nor write back.
*/
int __set_page_dirty_no_writeback(struct page *page)
{
if (!PageDirty(page))
SetPageDirty(page);
return 0;
}
/*
* For address_spaces which do not use buffers. Just tag the page as dirty in
* its radix tree.
*
* This is also used when a single buffer is being dirtied: we want to set the
* page dirty in that case, but not all the buffers. This is a "bottom-up"
* dirtying, whereas __set_page_dirty_buffers() is a "top-down" dirtying.
*
* Most callers have locked the page, which pins the address_space in memory.
* But zap_pte_range() does not lock the page, however in that case the
* mapping is pinned by the vma's ->vm_file reference.
*
* We take care to handle the case where the page was truncated from the
* mapping by re-checking page_mapping() inside tree_lock.
*/
int __set_page_dirty_nobuffers(struct page *page)
{
if (!TestSetPageDirty(page)) {
struct address_space *mapping = page_mapping(page);
struct address_space *mapping2;
if (!mapping)
return 1;
spin_lock_irq(&mapping->tree_lock);
mapping2 = page_mapping(page);
if (mapping2) { /* Race with truncate? */
BUG_ON(mapping2 != mapping);
WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(page));
if (mapping_cap_account_dirty(mapping)) {
__inc_zone_page_state(page, NR_FILE_DIRTY);
__inc_bdi_stat(mapping->backing_dev_info,
BDI_RECLAIMABLE);
task_io_account_write(PAGE_CACHE_SIZE);
}
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
}
spin_unlock_irq(&mapping->tree_lock);
if (mapping->host) {
/* !PageAnon && !swapper_space */
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
}
return 1;
}
return 0;
}
EXPORT_SYMBOL(__set_page_dirty_nobuffers);
/*
* When a writepage implementation decides that it doesn't want to write this
* page for some reason, it should redirty the locked page via
* redirty_page_for_writepage() and it should then unlock the page and return 0
*/
int redirty_page_for_writepage(struct writeback_control *wbc, struct page *page)
{
wbc->pages_skipped++;
return __set_page_dirty_nobuffers(page);
}