* 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/buffer_head.h> /* for generic_osync_inode */
-#include <asm/uaccess.h>
#include <asm/mman.h>
static ssize_t
radix_tree_delete(&mapping->page_tree, page->index);
page->mapping = NULL;
mapping->nrpages--;
- pagecache_acct(-1);
+ __dec_zone_page_state(page, NR_FILE_PAGES);
}
void remove_from_page_cache(struct page *page)
}
/**
- * 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 (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.
*/
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)
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
*/
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.
}
EXPORT_SYMBOL(sync_page_range);
-/*
+/**
+ * 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.
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)
{
}
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
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().
*
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,
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
+/**
+ * find_get_page - find and get a page reference
+ * @mapping: the address_space to search
+ * @offset: the page index
+ *
+ * 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)
read_unlock_irq(&mapping->tree_lock);
return page;
}
-
EXPORT_SYMBOL(find_get_page);
-/*
- * Same as above, but trylock it instead of incrementing the count.
+/**
+ * find_trylock_page - find and lock a page
+ * @mapping: the address_space to search
+ * @offset: the page index
+ *
+ * Same as find_get_page(), but trylock it instead of incrementing the count.
*/
struct page *find_trylock_page(struct address_space *mapping, unsigned long offset)
{
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
*
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
page_cache_release(cached_page);
return page;
}
-
EXPORT_SYMBOL(find_or_create_page);
/**
return i;
}
-/*
+/**
+ * find_get_pages_tag - find and return pages that match @tag
+ * @mapping: the address_space to search
+ * @index: the starting page index
+ * @tag: the tag index
+ * @nr_pages: the maximum number of pages
+ * @pages: where the resulting pages are placed
+ *
* Like find_get_pages, except we only return pages which are tagged with
- * `tag'. We update *index to index the next page for the traversal.
+ * @tag. We update @index to index the next page for the traversal.
*/
unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
int tag, unsigned int nr_pages, struct page **pages)
return ret;
}
-/*
+/**
+ * grab_cache_page_nowait - returns locked page at given index in given cache
+ * @mapping: target address_space
+ * @index: the page index
+ *
* Same as grab_cache_page, but do not wait if the page is unavailable.
* This is intended for speculative data generators, where the data can
* be regenerated if the page couldn't be grabbed. This routine should
}
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;
+ printk(KERN_WARNING "Reducing readahead size to %luK\n",
+ ra->ra_pages << (PAGE_CACHE_SHIFT - 10));
+}
+
+/**
+ * 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,
}
unlock_page(page);
error = -EIO;
+ shrink_readahead_size_eio(filp, &ra);
goto readpage_error;
}
unlock_page(page);
if (filp)
file_accessed(filp);
}
-
EXPORT_SYMBOL(do_generic_mapping_read);
int file_read_actor(read_descriptor_t *desc, struct page *page,
}
EXPORT_SYMBOL_GPL(file_read_actor);
-/*
+/**
+ * __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
+ * @ppos: current file position
+ *
* This is the "read()" routine for all filesystems
* that can use the page cache directly.
*/
out:
return retval;
}
-
EXPORT_SYMBOL(__generic_file_aio_read);
ssize_t
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
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)
return desc.written;
return desc.error;
}
-
EXPORT_SYMBOL(generic_file_sendfile);
static ssize_t
}
#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;
#define MMAP_LOTSAMISS (100)
-/*
+/**
+ * filemap_nopage - read in file data for page fault handling
+ * @area: the applicable vm_area
+ * @address: target address to read in
+ * @type: returned with VM_FAULT_{MINOR,MAJOR} if not %NULL
+ *
* filemap_nopage() is invoked via the vma operations vector for a
* mapped memory region to read in file data during a page fault.
*
*/
if (!did_readaround) {
majmin = VM_FAULT_MAJOR;
- inc_page_state(pgmajfault);
+ count_vm_event(PGMAJFAULT);
}
did_readaround = 1;
ra_pages = max_sane_readahead(file->f_ra.ra_pages);
page_not_uptodate:
if (!did_readaround) {
majmin = VM_FAULT_MAJOR;
- inc_page_state(pgmajfault);
+ count_vm_event(PGMAJFAULT);
}
lock_page(page);
* Things didn't work out. Return zero to tell the
* mm layer so, possibly freeing the page cache page first.
*/
+ shrink_readahead_size_eio(file, ra);
page_cache_release(page);
return NULL;
}
-
EXPORT_SYMBOL(filemap_nopage);
static struct page * filemap_getpage(struct file *file, unsigned long pgoff,
return page;
}
-/*
+/**
+ * read_cache_page - read into page cache, fill it if needed
+ * @mapping: the page's address_space
+ * @index: the page index
+ * @filler: function to perform the read
+ * @data: destination for read data
+ *
* Read into the page cache. If a page already exists,
* and PageUptodate() is not set, try to fill the page.
*/
out:
return page;
}
-
EXPORT_SYMBOL(read_cache_page);
/*
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.
*/
{
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;
+
+ /* Limit the size of the copy to the caller's write size */
+ bytes = min(bytes, count);
+
+ /*
+ * Limit the size of the copy to that of the current segment,
+ * because fault_in_pages_readable() doesn't know how to walk
+ * segments.
+ */
+ bytes = min(bytes, cur_iov->iov_len - iov_base);
/*
* Bring in the user page that we will copy from _first_.
* same page as we're writing to, without it being marked
* up-to-date.
*/
- maxlen = cur_iov->iov_len - iov_base;
- if (maxlen > bytes)
- maxlen = bytes;
- fault_in_pages_readable(buf, maxlen);
+ fault_in_pages_readable(buf, bytes);
page = __grab_cache_page(mapping,index,&cached_page,&lru_pvec);
if (!page) {
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);
page_cache_release(page);
continue;
}
- if (likely(copied > 0)) {
+zero_length_segment:
+ if (likely(copied >= 0)) {
if (!status)
status = copied;
unsigned long nr_segs, loff_t *ppos)
{
struct file *file = iocb->ki_filp;
- struct address_space * mapping = file->f_mapping;
+ const struct address_space * mapping = file->f_mapping;
size_t ocount; /* original count */
size_t count; /* after file limit checks */
struct inode *inode = mapping->host;
git.openpandora.org / pandora-kernel.git / blobdiff