#include <linux/uio.h>
#include <linux/hash.h>
#include <linux/writeback.h>
+#include <linux/backing-dev.h>
#include <linux/pagevec.h>
#include <linux/blkdev.h>
+#include <linux/backing-dev.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/cpuset.h>
-#include "filemap.h"
+#include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
#include "internal.h"
/*
* ->private_lock (__free_pte->__set_page_dirty_buffers)
* ->swap_lock (exclusive_swap_page, others)
* ->mapping->tree_lock
+ * ->zone.lock
*
* ->i_mutex
* ->i_mmap_lock (truncate->unmap_mapping_range)
mapping->nrpages--;
__dec_zone_page_state(page, NR_FILE_PAGES);
BUG_ON(page_mapped(page));
+
+ /*
+ * Some filesystems seem to re-dirty the page even after
+ * the VM has canceled the dirty bit (eg ext3 journaling).
+ *
+ * Fix it up by doing a final dirty accounting check after
+ * having removed the page entirely.
+ */
+ if (PageDirty(page) && mapping_cap_account_dirty(mapping)) {
+ dec_zone_page_state(page, NR_FILE_DIRTY);
+ dec_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE);
+ }
}
void remove_from_page_cache(struct page *page)
return 0;
}
+static int sync_page_killable(void *word)
+{
+ sync_page(word);
+ return fatal_signal_pending(current) ? -EINTR : 0;
+}
+
/**
* __filemap_fdatawrite_range - start writeback on mapping dirty pages in range
* @mapping: address space structure to write
}
EXPORT_SYMBOL(__lock_page);
+int fastcall __lock_page_killable(struct page *page)
+{
+ DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
+
+ return __wait_on_bit_lock(page_waitqueue(page), &wait,
+ sync_page_killable, TASK_KILLABLE);
+}
+
/*
* Variant of lock_page that does not require the caller to hold a reference
* on the page's mapping.
/**
* do_generic_mapping_read - generic file read routine
* @mapping: address_space to be read
- * @_ra: file's readahead state
+ * @ra: file's readahead state
* @filp: the file to read
* @ppos: current file position
* @desc: read_descriptor
page_not_up_to_date:
/* Get exclusive access to the page ... */
- lock_page(page);
+ if (lock_page_killable(page))
+ goto readpage_eio;
/* Did it get truncated before we got the lock? */
if (!page->mapping) {
}
if (!PageUptodate(page)) {
- lock_page(page);
+ if (lock_page_killable(page))
+ goto readpage_eio;
if (!PageUptodate(page)) {
if (page->mapping == NULL) {
/*
goto find_page;
}
unlock_page(page);
- error = -EIO;
shrink_readahead_size_eio(filp, ra);
- goto readpage_error;
+ goto readpage_eio;
}
unlock_page(page);
}
goto page_ok;
+readpage_eio:
+ error = -EIO;
readpage_error:
/* UHHUH! A synchronous read error occurred. Report it */
desc->error = error;
size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
if (vmf->pgoff >= size)
- goto outside_data_content;
+ return VM_FAULT_SIGBUS;
/* If we don't want any read-ahead, don't bother */
if (VM_RandomReadHint(vma))
if (unlikely(vmf->pgoff >= size)) {
unlock_page(page);
page_cache_release(page);
- goto outside_data_content;
+ return VM_FAULT_SIGBUS;
}
/*
vmf->page = page;
return ret | VM_FAULT_LOCKED;
-outside_data_content:
- /*
- * An external ptracer can access pages that normally aren't
- * accessible..
- */
- 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
int remove_suid(struct dentry *dentry)
{
- int kill = should_remove_suid(dentry);
+ int killsuid = should_remove_suid(dentry);
+ int killpriv = security_inode_need_killpriv(dentry);
+ int error = 0;
- if (unlikely(kill))
- return __remove_suid(dentry, kill);
+ if (killpriv < 0)
+ return killpriv;
+ if (killpriv)
+ error = security_inode_killpriv(dentry);
+ if (!error && killsuid)
+ error = __remove_suid(dentry, killsuid);
- return 0;
+ return error;
}
EXPORT_SYMBOL(remove_suid);
-size_t
-__filemap_copy_from_user_iovec_inatomic(char *vaddr,
+static size_t __iovec_copy_from_user_inatomic(char *vaddr,
const struct iovec *iov, size_t base, size_t bytes)
{
size_t copied = 0, left = 0;
return copied - left;
}
+/*
+ * Copy as much as we can into the page and return the number of bytes which
+ * were sucessfully copied. If a fault is encountered then return the number of
+ * bytes which were copied.
+ */
+size_t iov_iter_copy_from_user_atomic(struct page *page,
+ struct iov_iter *i, unsigned long offset, size_t bytes)
+{
+ char *kaddr;
+ size_t copied;
+
+ BUG_ON(!in_atomic());
+ kaddr = kmap_atomic(page, KM_USER0);
+ if (likely(i->nr_segs == 1)) {
+ int left;
+ char __user *buf = i->iov->iov_base + i->iov_offset;
+ left = __copy_from_user_inatomic_nocache(kaddr + offset,
+ buf, bytes);
+ copied = bytes - left;
+ } else {
+ copied = __iovec_copy_from_user_inatomic(kaddr + offset,
+ i->iov, i->iov_offset, bytes);
+ }
+ kunmap_atomic(kaddr, KM_USER0);
+
+ return copied;
+}
+EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
+
+/*
+ * This has the same sideeffects and return value as
+ * iov_iter_copy_from_user_atomic().
+ * The difference is that it attempts to resolve faults.
+ * Page must not be locked.
+ */
+size_t iov_iter_copy_from_user(struct page *page,
+ struct iov_iter *i, unsigned long offset, size_t bytes)
+{
+ char *kaddr;
+ size_t copied;
+
+ kaddr = kmap(page);
+ if (likely(i->nr_segs == 1)) {
+ int left;
+ char __user *buf = i->iov->iov_base + i->iov_offset;
+ left = __copy_from_user_nocache(kaddr + offset, buf, bytes);
+ copied = bytes - left;
+ } else {
+ copied = __iovec_copy_from_user_inatomic(kaddr + offset,
+ i->iov, i->iov_offset, bytes);
+ }
+ kunmap(page);
+ return copied;
+}
+EXPORT_SYMBOL(iov_iter_copy_from_user);
+
+static void __iov_iter_advance_iov(struct iov_iter *i, size_t bytes)
+{
+ if (likely(i->nr_segs == 1)) {
+ i->iov_offset += bytes;
+ } else {
+ const struct iovec *iov = i->iov;
+ size_t base = i->iov_offset;
+
+ while (bytes) {
+ int copy = min(bytes, iov->iov_len - base);
+
+ bytes -= copy;
+ base += copy;
+ if (iov->iov_len == base) {
+ iov++;
+ base = 0;
+ }
+ }
+ i->iov = iov;
+ i->iov_offset = base;
+ }
+}
+
+void iov_iter_advance(struct iov_iter *i, size_t bytes)
+{
+ BUG_ON(i->count < bytes);
+
+ __iov_iter_advance_iov(i, bytes);
+ i->count -= bytes;
+}
+EXPORT_SYMBOL(iov_iter_advance);
+
+/*
+ * Fault in the first iovec of the given iov_iter, to a maximum length
+ * of bytes. Returns 0 on success, or non-zero if the memory could not be
+ * accessed (ie. because it is an invalid address).
+ *
+ * writev-intensive code may want this to prefault several iovecs -- that
+ * would be possible (callers must not rely on the fact that _only_ the
+ * first iovec will be faulted with the current implementation).
+ */
+int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
+{
+ char __user *buf = i->iov->iov_base + i->iov_offset;
+ bytes = min(bytes, i->iov->iov_len - i->iov_offset);
+ return fault_in_pages_readable(buf, bytes);
+}
+EXPORT_SYMBOL(iov_iter_fault_in_readable);
+
+/*
+ * Return the count of just the current iov_iter segment.
+ */
+size_t iov_iter_single_seg_count(struct iov_iter *i)
+{
+ const struct iovec *iov = i->iov;
+ if (i->nr_segs == 1)
+ return i->count;
+ else
+ return min(i->count, iov->iov_len - i->iov_offset);
+}
+EXPORT_SYMBOL(iov_iter_single_seg_count);
+
/*
* Performs necessary checks before doing a write
*
}
EXPORT_SYMBOL(generic_write_checks);
+int pagecache_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
+{
+ const struct address_space_operations *aops = mapping->a_ops;
+
+ if (aops->write_begin) {
+ return aops->write_begin(file, mapping, pos, len, flags,
+ pagep, fsdata);
+ } else {
+ int ret;
+ pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+ unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
+ struct inode *inode = mapping->host;
+ struct page *page;
+again:
+ page = __grab_cache_page(mapping, index);
+ *pagep = page;
+ if (!page)
+ return -ENOMEM;
+
+ if (flags & AOP_FLAG_UNINTERRUPTIBLE && !PageUptodate(page)) {
+ /*
+ * There is no way to resolve a short write situation
+ * for a !Uptodate page (except by double copying in
+ * the caller done by generic_perform_write_2copy).
+ *
+ * Instead, we have to bring it uptodate here.
+ */
+ ret = aops->readpage(file, page);
+ page_cache_release(page);
+ if (ret) {
+ if (ret == AOP_TRUNCATED_PAGE)
+ goto again;
+ return ret;
+ }
+ goto again;
+ }
+
+ ret = aops->prepare_write(file, page, offset, offset+len);
+ if (ret) {
+ unlock_page(page);
+ page_cache_release(page);
+ if (pos + len > inode->i_size)
+ vmtruncate(inode, inode->i_size);
+ }
+ return ret;
+ }
+}
+EXPORT_SYMBOL(pagecache_write_begin);
+
+int pagecache_write_end(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
+{
+ const struct address_space_operations *aops = mapping->a_ops;
+ int ret;
+
+ if (aops->write_end) {
+ mark_page_accessed(page);
+ ret = aops->write_end(file, mapping, pos, len, copied,
+ page, fsdata);
+ } else {
+ unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
+ struct inode *inode = mapping->host;
+
+ flush_dcache_page(page);
+ ret = aops->commit_write(file, page, offset, offset+len);
+ unlock_page(page);
+ mark_page_accessed(page);
+ page_cache_release(page);
+
+ if (ret < 0) {
+ if (pos + len > inode->i_size)
+ vmtruncate(inode, inode->i_size);
+ } else if (ret > 0)
+ ret = min_t(size_t, copied, ret);
+ else
+ ret = copied;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(pagecache_write_end);
+
ssize_t
generic_file_direct_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long *nr_segs, loff_t pos, loff_t *ppos,
* Find or create a page at the given pagecache position. Return the locked
* page. This function is specifically for buffered writes.
*/
-static struct page *__grab_cache_page(struct address_space *mapping,
- pgoff_t index)
+struct page *__grab_cache_page(struct address_space *mapping, pgoff_t index)
{
int status;
struct page *page;
}
return page;
}
+EXPORT_SYMBOL(__grab_cache_page);
-ssize_t
-generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
- unsigned long nr_segs, loff_t pos, loff_t *ppos,
- size_t count, ssize_t written)
+static ssize_t generic_perform_write_2copy(struct file *file,
+ struct iov_iter *i, loff_t pos)
{
- struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
const struct address_space_operations *a_ops = mapping->a_ops;
- struct inode *inode = mapping->host;
- long status = 0;
- const struct iovec *cur_iov = iov; /* current iovec */
- size_t iov_offset = 0; /* offset in the current iovec */
- char __user *buf;
-
- /*
- * handle partial DIO write. Adjust cur_iov if needed.
- */
- filemap_set_next_iovec(&cur_iov, nr_segs, &iov_offset, written);
+ struct inode *inode = mapping->host;
+ long status = 0;
+ ssize_t written = 0;
do {
struct page *src_page;
struct page *page;
pgoff_t index; /* Pagecache index for current page */
unsigned long offset; /* Offset into pagecache page */
- unsigned long seglen; /* Bytes remaining in current iovec */
unsigned long bytes; /* Bytes to write to page */
size_t copied; /* Bytes copied from user */
- buf = cur_iov->iov_base + iov_offset;
offset = (pos & (PAGE_CACHE_SIZE - 1));
index = pos >> PAGE_CACHE_SHIFT;
- bytes = PAGE_CACHE_SIZE - offset;
- if (bytes > count)
- bytes = count;
+ bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
+ iov_iter_count(i));
/*
* a non-NULL src_page indicates that we're doing the
*/
src_page = NULL;
- seglen = cur_iov->iov_len - iov_offset;
- if (seglen > bytes)
- seglen = bytes;
-
/*
* Bring in the user page that we will copy from _first_.
* Otherwise there's a nasty deadlock on copying from the
* to check that the address is actually valid, when atomic
* usercopies are used, below.
*/
- if (unlikely(fault_in_pages_readable(buf, seglen))) {
+ if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
status = -EFAULT;
break;
}
* cannot take a pagefault with the destination page locked.
* So pin the source page to copy it.
*/
- if (!PageUptodate(page)) {
+ if (!PageUptodate(page) && !segment_eq(get_fs(), KERNEL_DS)) {
unlock_page(page);
src_page = alloc_page(GFP_KERNEL);
* same reason as we can't take a page fault with a
* page locked (as explained below).
*/
- copied = filemap_copy_from_user(src_page, offset,
- cur_iov, nr_segs, iov_offset, bytes);
+ copied = iov_iter_copy_from_user(src_page, i,
+ offset, bytes);
if (unlikely(copied == 0)) {
status = -EFAULT;
page_cache_release(page);
page_cache_release(src_page);
continue;
}
-
}
status = a_ops->prepare_write(file, page, offset, offset+bytes);
* really matter.
*/
pagefault_disable();
- copied = filemap_copy_from_user_atomic(page, offset,
- cur_iov, nr_segs, iov_offset, bytes);
+ copied = iov_iter_copy_from_user_atomic(page, i,
+ offset, bytes);
pagefault_enable();
} else {
void *src, *dst;
flush_dcache_page(page);
status = a_ops->commit_write(file, page, offset, offset+bytes);
- if (unlikely(status < 0 || status == AOP_TRUNCATED_PAGE))
+ if (unlikely(status < 0))
goto fs_write_aop_error;
if (unlikely(status > 0)) /* filesystem did partial write */
copied = min_t(size_t, copied, status);
if (src_page)
page_cache_release(src_page);
- written += copied;
- count -= copied;
+ iov_iter_advance(i, copied);
pos += copied;
- filemap_set_next_iovec(&cur_iov, nr_segs, &iov_offset, copied);
+ written += copied;
balance_dirty_pages_ratelimited(mapping);
cond_resched();
continue;
fs_write_aop_error:
- if (status != AOP_TRUNCATED_PAGE)
- unlock_page(page);
+ unlock_page(page);
page_cache_release(page);
if (src_page)
page_cache_release(src_page);
*/
if (pos + bytes > inode->i_size)
vmtruncate(inode, inode->i_size);
- if (status == AOP_TRUNCATED_PAGE)
- continue;
- else
- break;
- } while (count);
- *ppos = pos;
+ break;
+ } while (iov_iter_count(i));
+
+ return written ? written : status;
+}
+
+static ssize_t generic_perform_write(struct file *file,
+ struct iov_iter *i, loff_t pos)
+{
+ struct address_space *mapping = file->f_mapping;
+ const struct address_space_operations *a_ops = mapping->a_ops;
+ long status = 0;
+ ssize_t written = 0;
+ unsigned int flags = 0;
/*
- * For now, when the user asks for O_SYNC, we'll actually give O_DSYNC
+ * Copies from kernel address space cannot fail (NFSD is a big user).
*/
+ if (segment_eq(get_fs(), KERNEL_DS))
+ flags |= AOP_FLAG_UNINTERRUPTIBLE;
+
+ do {
+ struct page *page;
+ pgoff_t index; /* Pagecache index for current page */
+ unsigned long offset; /* Offset into pagecache page */
+ unsigned long bytes; /* Bytes to write to page */
+ size_t copied; /* Bytes copied from user */
+ void *fsdata;
+
+ offset = (pos & (PAGE_CACHE_SIZE - 1));
+ index = pos >> PAGE_CACHE_SHIFT;
+ bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
+ iov_iter_count(i));
+
+again:
+
+ /*
+ * 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.
+ *
+ * Not only is this an optimisation, but it is also required
+ * to check that the address is actually valid, when atomic
+ * usercopies are used, below.
+ */
+ if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
+ status = -EFAULT;
+ break;
+ }
+
+ status = a_ops->write_begin(file, mapping, pos, bytes, flags,
+ &page, &fsdata);
+ if (unlikely(status))
+ break;
+
+ pagefault_disable();
+ copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
+ pagefault_enable();
+ flush_dcache_page(page);
+
+ status = a_ops->write_end(file, mapping, pos, bytes, copied,
+ page, fsdata);
+ if (unlikely(status < 0))
+ break;
+ copied = status;
+
+ cond_resched();
+
+ if (unlikely(copied == 0)) {
+ /*
+ * If we were unable to copy any data at all, we must
+ * fall back to a single segment length write.
+ *
+ * If we didn't fallback here, we could livelock
+ * because not all segments in the iov can be copied at
+ * once without a pagefault.
+ */
+ bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
+ iov_iter_single_seg_count(i));
+ goto again;
+ }
+ iov_iter_advance(i, copied);
+ pos += copied;
+ written += copied;
+
+ balance_dirty_pages_ratelimited(mapping);
+
+ } while (iov_iter_count(i));
+
+ return written ? written : status;
+}
+
+ssize_t
+generic_file_buffered_write(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos, loff_t *ppos,
+ size_t count, ssize_t written)
+{
+ struct file *file = iocb->ki_filp;
+ struct address_space *mapping = file->f_mapping;
+ const struct address_space_operations *a_ops = mapping->a_ops;
+ struct inode *inode = mapping->host;
+ ssize_t status;
+ struct iov_iter i;
+
+ iov_iter_init(&i, iov, nr_segs, count, written);
+ if (a_ops->write_begin)
+ status = generic_perform_write(file, &i, pos);
+ else
+ status = generic_perform_write_2copy(file, &i, pos);
+
if (likely(status >= 0)) {
+ written += status;
+ *ppos = pos + status;
+
+ /*
+ * For now, when the user asks for O_SYNC, we'll actually give
+ * O_DSYNC
+ */
if (unlikely((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
if (!a_ops->writepage || !is_sync_kiocb(iocb))
status = generic_osync_inode(inode, mapping,
}
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.
+ * cached by non-direct readahead, or faulted in by get_user_pages()
+ * if the source of the write was an mmap'ed region of the file
+ * we're writing. Either one is a pretty crazy thing to do,
+ * so we don't support it 100%. If this invalidation
+ * fails, tough, the write still worked...
*/
if (rw == WRITE && mapping->nrpages) {
- int err = invalidate_inode_pages2_range(mapping,
- offset >> PAGE_CACHE_SHIFT, end);
- if (err && retval >= 0)
- retval = err;
+ invalidate_inode_pages2_range(mapping, offset >> PAGE_CACHE_SHIFT, end);
}
out:
return retval;
git.samba.org / sfrench / cifs-2.6.git / blobdiff