* 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/uaccess.h>
#include <linux/aio.h>
+#include <linux/capability.h>
#include <linux/kernel_stat.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/blkdev.h>
#include <linux/security.h>
#include <linux/syscalls.h>
+#include <linux/cpuset.h>
#include "filemap.h"
+#include "internal.h"
+
/*
* 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>
+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.
* ->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
* ->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
+ * ->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)
radix_tree_delete(&mapping->page_tree, page->index);
page->mapping = NULL;
mapping->nrpages--;
- pagecache_acct(-1);
+ __dec_zone_page_state(page, NR_FILE_PAGES);
+ BUG_ON(page_mapped(page));
}
void remove_from_page_cache(struct page *page)
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.
* 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
}
/**
- * filemap_fdatawrite_range - start writeback against all of a mapping's
- * dirty pages that lie within the byte offsets <start, end>
+ * __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 <start, end> 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))
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)
}
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.
*/
}
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;
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;
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);
}
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;
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)
{
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);
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)
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
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().
}
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)
{
}
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.
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.
*/
-struct page * find_get_page(struct address_space *mapping, unsigned long offset)
+void fastcall __lock_page_nosync(struct page *page)
{
- 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;
+ DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
+ __wait_on_bit_lock(page_waitqueue(page), &wait, __sleep_on_page_lock,
+ TASK_UNINTERRUPTIBLE);
}
-EXPORT_SYMBOL(find_get_page);
-
-/*
- * Same as above, but trylock it instead of incrementing the count.
+/**
+ * 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_trylock_page(struct address_space *mapping, unsigned long offset)
+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 && TestSetPageLocked(page))
- page = NULL;
+ if (page)
+ page_cache_get(page);
read_unlock_irq(&mapping->tree_lock);
return page;
}
-
-EXPORT_SYMBOL(find_trylock_page);
+EXPORT_SYMBOL(find_get_page);
/**
* find_lock_page - locate, pin and lock a pagecache page
- *
* @mapping: the address_space to search
* @offset: the page index
*
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;
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
* 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;
page = find_lock_page(mapping, index);
if (!page) {
if (!cached_page) {
- cached_page = alloc_page(gfp_mask);
+ cached_page =
+ __page_cache_alloc(gfp_mask);
if (!cached_page)
return NULL;
}
page_cache_release(cached_page);
return page;
}
-
EXPORT_SYMBOL(find_or_create_page);
/**
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;
+}
+EXPORT_SYMBOL(find_get_pages_contig);
+
+/**
+ * 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)
read_unlock_irq(&mapping->tree_lock);
return ret;
}
+EXPORT_SYMBOL(find_get_pages_tag);
-/*
- * Same as grab_cache_page, but do not wait if the page is unavailable.
+/**
+ * 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
* be safe to call while holding the lock for another 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))
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,
{
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;
+ unsigned int prev_offset;
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;
+ prev_index = ra.prev_index;
+ prev_offset = ra.prev_offset;
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 end_index;
+ loff_t isize;
unsigned long nr, ret;
+ cond_resched();
+find_page:
+ page = find_get_page(mapping, index);
+ if (!page) {
+ page_cache_sync_readahead(mapping,
+ &ra, filp,
+ index, last_index - index);
+ page = find_get_page(mapping, index);
+ if (unlikely(page == NULL))
+ goto no_cached_page;
+ }
+ if (PageReadahead(page)) {
+ page_cache_async_readahead(mapping,
+ &ra, filp, page,
+ index, last_index - index);
+ }
+ if (!PageUptodate(page))
+ goto page_not_up_to_date;
+page_ok:
+ /*
+ * i_size must be checked after we know the page is Uptodate.
+ *
+ * Checking i_size after the check allows us to calculate
+ * the correct value for "nr", which means the zero-filled
+ * part of the page is not copied back to userspace (unless
+ * another truncate extends the file - this is desired though).
+ */
+
+ isize = i_size_read(inode);
+ end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
+ if (unlikely(!isize || index > end_index)) {
+ page_cache_release(page);
+ goto out;
+ }
+
/* nr is the maximum number of bytes to copy from this page */
nr = PAGE_CACHE_SIZE;
- if (index >= end_index) {
- if (index > end_index)
- goto out;
+ if (index == end_index) {
nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
if (nr <= offset) {
+ page_cache_release(page);
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.
flush_dcache_page(page);
/*
- * When (part of) the same page is read multiple times
- * in succession, only mark it as accessed the first time.
+ * When a sequential read accesses a page several times,
+ * only mark it as accessed the first time.
*/
- if (prev_index != index)
+ if (prev_index != index || offset != prev_offset)
mark_page_accessed(page);
prev_index = index;
offset += ret;
index += offset >> PAGE_CACHE_SHIFT;
offset &= ~PAGE_CACHE_MASK;
+ prev_offset = offset;
+ ra.prev_offset = offset;
page_cache_release(page);
if (ret == nr && desc->count)
/* 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);
/* 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);
}
unlock_page(page);
error = -EIO;
+ shrink_readahead_size_eio(filp, &ra);
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:
out:
*_ra = ra;
+ _ra->prev_index = prev_index;
*ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
if (cached_page)
if (filp)
file_accessed(filp);
}
-
EXPORT_SYMBOL(do_generic_mapping_read);
int file_read_actor(read_descriptor_t *desc, struct page *page,
}
/*
- * This is the "read()" routine for all filesystems
- * that can use the page cache directly.
+ * Performs necessary checks before doing a write
+ * @iov: io vector request
+ * @nr_segs: number of segments in the iovec
+ * @count: number of bytes to write
+ * @access_flags: type of access: %VERIFY_READ or %VERIFY_WRITE
+ *
+ * Adjust number of segments and amount of bytes to write (nr_segs should be
+ * properly initialized first). Returns appropriate error code that caller
+ * should return or zero in case that write should be allowed.
*/
-ssize_t
-__generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t *ppos)
+int generic_segment_checks(const struct iovec *iov,
+ unsigned long *nr_segs, size_t *count, int access_flags)
{
- struct file *filp = iocb->ki_filp;
- ssize_t retval;
- unsigned long seg;
- size_t count;
-
- count = 0;
- for (seg = 0; seg < nr_segs; seg++) {
+ unsigned long seg;
+ size_t cnt = 0;
+ for (seg = 0; seg < *nr_segs; seg++) {
const struct iovec *iv = &iov[seg];
/*
* If any segment has a negative length, or the cumulative
* length ever wraps negative then return -EINVAL.
*/
- count += iv->iov_len;
- if (unlikely((ssize_t)(count|iv->iov_len) < 0))
+ cnt += iv->iov_len;
+ if (unlikely((ssize_t)(cnt|iv->iov_len) < 0))
return -EINVAL;
- if (access_ok(VERIFY_WRITE, iv->iov_base, iv->iov_len))
+ if (access_ok(access_flags, iv->iov_base, iv->iov_len))
continue;
if (seg == 0)
return -EFAULT;
- nr_segs = seg;
- count -= iv->iov_len; /* This segment is no good */
+ *nr_segs = seg;
+ cnt -= iv->iov_len; /* This segment is no good */
break;
}
+ *count = cnt;
+ return 0;
+}
+EXPORT_SYMBOL(generic_segment_checks);
+
+/**
+ * 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 pos)
+{
+ struct file *filp = iocb->ki_filp;
+ ssize_t retval;
+ unsigned long seg;
+ size_t count;
+ loff_t *ppos = &iocb->ki_pos;
+
+ count = 0;
+ retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
+ if (retval)
+ return retval;
/* 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;
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;
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;
}
+ if (desc.count > 0)
+ 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;
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)
}
#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() is invoked via the vma operations vector for a
+/**
+ * filemap_fault - read in file data for page fault handling
+ * @vma: vma in which the fault was taken
+ * @vmf: struct vm_fault containing details of the fault
+ *
+ * filemap_fault() 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 filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
int error;
- struct file *file = area->vm_file;
+ struct file *file = vma->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;
+ unsigned long size;
+ int did_readaround = 0;
+ int ret = 0;
-retry_all:
size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
- if (pgoff >= size)
+ if (vmf->pgoff >= size)
goto outside_data_content;
/* If we don't want any read-ahead, don't bother */
- if (VM_RandomReadHint(area))
+ if (VM_RandomReadHint(vma))
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);
+ page = find_lock_page(mapping, vmf->pgoff);
+ /*
+ * For sequential accesses, we use the generic readahead logic.
+ */
+ if (VM_SequentialReadHint(vma)) {
+ if (!page) {
+ page_cache_sync_readahead(mapping, ra, file,
+ vmf->pgoff, 1);
+ page = find_lock_page(mapping, vmf->pgoff);
+ if (!page)
+ goto no_cached_page;
+ }
+ if (PageReadahead(page)) {
+ page_cache_async_readahead(mapping, ra, file, page,
+ vmf->pgoff, 1);
+ }
+ }
+
if (!page) {
unsigned long ra_pages;
- if (VM_SequentialReadHint(area)) {
- handle_ra_miss(mapping, ra, pgoff);
- goto no_cached_page;
- }
ra->mmap_miss++;
/*
* check did_readaround, as this is an inner loop.
*/
if (!did_readaround) {
- majmin = VM_FAULT_MAJOR;
- inc_page_state(pgmajfault);
+ ret = VM_FAULT_MAJOR;
+ count_vm_event(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;
+ if (vmf->pgoff > ra_pages / 2)
+ start = vmf->pgoff - ra_pages / 2;
do_page_cache_readahead(mapping, file, start, ra_pages);
}
- page = find_get_page(mapping, pgoff);
+ page = find_lock_page(mapping, vmf->pgoff);
if (!page)
goto no_cached_page;
}
ra->mmap_hit++;
/*
- * Ok, found a page in the page cache, now we need to check
- * that it's up-to-date.
+ * We have a locked page in the page cache, now we need to check
+ * that it's up-to-date. If not, it is going to be due to an error.
*/
- if (!PageUptodate(page))
+ if (unlikely(!PageUptodate(page)))
goto page_not_uptodate;
-success:
+ /* Must recheck i_size under page lock */
+ size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ if (unlikely(vmf->pgoff >= size)) {
+ unlock_page(page);
+ goto outside_data_content;
+ }
+
/*
* Found the page and have a reference on it.
*/
mark_page_accessed(page);
- if (type)
- *type = majmin;
- return page;
+ ra->prev_index = page->index;
+ vmf->page = page;
+ return ret | VM_FAULT_LOCKED;
outside_data_content:
/*
* An external ptracer can access pages that normally aren't
* accessible..
*/
- if (area->vm_mm == current->mm)
- return NULL;
+ if (vma->vm_mm == current->mm)
+ return VM_FAULT_SIGBUS;
+
/* 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();
+ error = page_cache_read(file, vmf->pgoff);
/*
* The page we want has now been added to the page cache.
* to schedule I/O.
*/
if (error == -ENOMEM)
- return NOPAGE_OOM;
- return NULL;
+ return VM_FAULT_OOM;
+ return VM_FAULT_SIGBUS;
page_not_uptodate:
+ /* IO error path */
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;
+ ret = VM_FAULT_MAJOR;
+ count_vm_event(PGMAJFAULT);
}
/*
* 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.
- */
+ error = mapping->a_ops->readpage(file, page);
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)) {
- if (nonblock) {
- page_cache_release(page);
- return NULL;
- }
- 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)
+ if (!error || error == AOP_TRUNCATED_PAGE)
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);
-
- /* 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 {
- /* 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;
- }
-
- len -= PAGE_SIZE;
- addr += PAGE_SIZE;
- pgoff++;
- if (len)
- goto repeat;
-
- return 0;
+ /* Things didn't work out. Return zero to tell the mm layer so. */
+ shrink_readahead_size_eio(file, ra);
+ return VM_FAULT_SIGBUS;
}
+EXPORT_SYMBOL(filemap_fault);
struct vm_operations_struct generic_file_vm_ops = {
- .nopage = filemap_nopage,
- .populate = filemap_populate,
+ .fault = filemap_fault,
};
/* This is used for a general mmap of a disk file */
return -ENOEXEC;
file_accessed(file);
vma->vm_ops = &generic_file_vm_ops;
+ vma->vm_flags |= VM_CAN_NONLINEAR;
return 0;
}
-EXPORT_SYMBOL(filemap_populate);
/*
* This is for filesystems which do not implement ->writepage.
EXPORT_SYMBOL(generic_file_mmap);
EXPORT_SYMBOL(generic_file_readonly_mmap);
-static inline struct page *__read_cache_page(struct address_space *mapping,
+static struct page *__read_cache_page(struct address_space *mapping,
unsigned long index,
int (*filler)(void *,struct page*),
void *data)
}
/*
- * Read into the page cache. If a page already exists,
- * and PageUptodate() is not set, try to fill the page.
+ * Same as read_cache_page, but don't wait for page to become unlocked
+ * after submitting it to the filler.
*/
-struct page *read_cache_page(struct address_space *mapping,
+struct page *read_cache_page_async(struct address_space *mapping,
unsigned long index,
int (*filler)(void *,struct page*),
void *data)
retry:
page = __read_cache_page(mapping, index, filler, data);
if (IS_ERR(page))
- goto out;
- mark_page_accessed(page);
+ return page;
if (PageUptodate(page))
goto out;
err = filler(data, page);
if (err < 0) {
page_cache_release(page);
- page = ERR_PTR(err);
+ return ERR_PTR(err);
}
- out:
+out:
+ mark_page_accessed(page);
return page;
}
+EXPORT_SYMBOL(read_cache_page_async);
+
+/**
+ * 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 then wait for it to become unlocked.
+ *
+ * If the page does not get brought uptodate, return -EIO.
+ */
+struct page *read_cache_page(struct address_space *mapping,
+ unsigned long index,
+ int (*filler)(void *,struct page*),
+ void *data)
+{
+ struct page *page;
+ page = read_cache_page_async(mapping, index, filler, data);
+ if (IS_ERR(page))
+ goto out;
+ wait_on_page_locked(page);
+ if (!PageUptodate(page)) {
+ page_cache_release(page);
+ page = ERR_PTR(-EIO);
+ }
+ out:
+ return page;
+}
EXPORT_SYMBOL(read_cache_page);
/*
* 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))
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(should_remove_suid);
+
+int __remove_suid(struct dentry *dentry, int kill)
+{
+ struct iattr newattrs;
+
+ newattrs.ia_valid = ATTR_FORCE | kill;
+ return notify_change(dentry, &newattrs);
+}
+
+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);
size_t
-__filemap_copy_from_user_iovec(char *vaddr,
+__filemap_copy_from_user_iovec_inatomic(char *vaddr,
const struct iovec *iov, size_t base, size_t bytes)
{
size_t copied = 0, left = 0;
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;
}
/*
* 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.
*/
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) {
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 {
+#ifdef CONFIG_BLOCK
loff_t isize;
if (bdev_read_only(I_BDEV(inode)))
return -EPERM;
if (*pos + *count > isize)
*count = isize - *pos;
+#else
+ return -EPERM;
+#endif
}
return 0;
}
/*
* 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) || IS_SYNC(inode))) {
+ 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;
}
- if (written == count && !is_sync_kiocb(iocb))
- written = -EIOCBQUEUED;
return written;
}
EXPORT_SYMBOL(generic_file_direct_write);
{
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;
do {
unsigned long index;
unsigned long offset;
- unsigned long maxlen;
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.
+ /* Limit the size of the copy to the caller's write size */
+ bytes = min(bytes, count);
+
+ /* We only need to worry about prefaulting when writes are from
+ * user-space. NFSd uses vfs_writev with several non-aligned
+ * segments in the vector, and limiting to one segment a time is
+ * a noticeable performance for re-write
*/
- maxlen = cur_iov->iov_len - iov_base;
- if (maxlen > bytes)
- maxlen = bytes;
- fault_in_pages_readable(buf, maxlen);
+ if (!segment_eq(get_fs(), KERNEL_DS)) {
+ /*
+ * 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_. 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;
}
+ 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;
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;
}
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)
{
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;
- }
+ err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
+ if (err)
+ return err;
count = ocount;
pos = *ppos;
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;
/*
*/
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_mapping_range(file->f_mapping, 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)
}
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;
}
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)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
ssize_t retval;
- size_t write_len = 0;
+ size_t write_len;
+ pgoff_t end = 0; /* silence gcc */
/*
* If it's a write, unmap all mmappings of the file up-front. This
*/
if (rw == WRITE) {
write_len = iov_length(iov, nr_segs);
+ end = (offset + write_len - 1) >> PAGE_CACHE_SHIFT;
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,
+ if (retval)
+ goto out;
+
+ /*
+ * After a write we want buffered reads to be sure to go to disk to get
+ * the new data. We invalidate clean cached page from the region we're
+ * about to write. We do this *before* the write so that we can return
+ * -EIO without clobbering -EIOCBQUEUED from ->direct_IO().
+ */
+ if (rw == WRITE && mapping->nrpages) {
+ retval = invalidate_inode_pages2_range(mapping,
offset >> PAGE_CACHE_SHIFT, end);
- if (err)
- retval = err;
- }
+ if (retval)
+ goto out;
}
+
+ retval = mapping->a_ops->direct_IO(rw, iocb, iov, offset, nr_segs);
+ if (retval)
+ goto out;
+
+ /*
+ * Finally, try again to invalidate clean pages which might have been
+ * faulted in by get_user_pages() if the source of the write was an
+ * mmap()ed region of the file we're writing. That's a pretty crazy
+ * thing to do, so we don't support it 100%. If this invalidation
+ * fails and we have -EIOCBQUEUED we ignore the failure.
+ */
+ if (rw == WRITE && mapping->nrpages) {
+ int err = invalidate_inode_pages2_range(mapping,
+ offset >> PAGE_CACHE_SHIFT, end);
+ if (err && retval >= 0)
+ retval = err;
+ }
+out:
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);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff