* 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
* ->mmap_sem
* ->lock_page (access_process_vm)
*
- * ->mmap_sem
- * ->i_mutex (msync)
+ * ->i_mutex (generic_file_buffered_write)
+ * ->mmap_sem (fault_in_pages_readable->do_page_fault)
*
* ->i_mutex
* ->i_alloc_sem (various)
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)
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();
}
#ifdef CONFIG_NUMA
-struct page *page_cache_alloc(struct address_space *x)
+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, mapping_gfp_mask(x), 0);
+ return alloc_pages_node(n, gfp, 0);
}
- return alloc_pages(mapping_gfp_mask(x), 0);
+ return alloc_pages(gfp, 0);
}
-EXPORT_SYMBOL(page_cache_alloc);
+EXPORT_SYMBOL(__page_cache_alloc);
+#endif
-struct page *page_cache_alloc_cold(struct address_space *x)
+static int __sleep_on_page_lock(void *word)
{
- if (cpuset_do_page_mem_spread()) {
- int n = cpuset_mem_spread_node();
- return alloc_pages_node(n, mapping_gfp_mask(x)|__GFP_COLD, 0);
- }
- return alloc_pages(mapping_gfp_mask(x)|__GFP_COLD, 0);
+ io_schedule();
+ return 0;
}
-EXPORT_SYMBOL(page_cache_alloc_cold);
-#endif
/*
* In order to wait for pages to become available there must be
}
EXPORT_SYMBOL(__lock_page);
+/*
+ * Variant of lock_page that does not require the caller to hold a reference
+ * on the page's mapping.
+ */
+void fastcall __lock_page_nosync(struct page *page)
+{
+ DEFINE_WAIT_BIT(wait, &page->flags, PG_locked);
+ __wait_on_bit_lock(page_waitqueue(page), &wait, __sleep_on_page_lock,
+ TASK_UNINTERRUPTIBLE);
+}
+
/**
* 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.
+ * 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_get_page(struct address_space *mapping, unsigned long offset)
{
grab_cache_page_nowait(struct address_space *mapping, unsigned long index)
{
struct page *page = find_get_page(mapping, index);
- gfp_t 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;
}
}
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
/* 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);
}
unlock_page(page);
error = -EIO;
+ shrink_readahead_size_eio(filp, &ra);
goto readpage_error;
}
unlock_page(page);
}
/**
- * __generic_file_aio_read - generic filesystem read routine
+ * 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
+ * @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 *ppos)
+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;
for (seg = 0; seg < nr_segs; seg++) {
/* 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 (retval > 0)
*ppos = pos + retval;
}
- file_accessed(filp);
- goto out;
+ if (likely(retval != 0)) {
+ file_accessed(filp);
+ goto out;
+ }
}
retval = 0;
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;
*/
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);
* accessible..
*/
if (area->vm_mm == current->mm)
- return NULL;
+ return NOPAGE_SIGBUS;
/* Fall through to the non-read-ahead case */
no_cached_page:
/*
*/
if (error == -ENOMEM)
return NOPAGE_OOM;
- return NULL;
+ return NOPAGE_SIGBUS;
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;
+ return NOPAGE_SIGBUS;
}
EXPORT_SYMBOL(filemap_nopage);
page_not_uptodate:
lock_page(page);
- /* Did it get unhashed while we waited for it? */
+ /* Did it get truncated while we waited for it? */
if (!page->mapping) {
unlock_page(page);
goto err;
* 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;
+}
+
+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;
}
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;
}
{
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;
/* 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_file_range(file, 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);
-static 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);
mutex_lock(&inode->i_mutex);
- ret = __generic_file_aio_write_nolock(iocb, &local_iov, 1,
- &iocb->ki_pos);
+ 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))) {
}
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 };
-
- mutex_lock(&inode->i_mutex);
- ret = __generic_file_write_nolock(file, &local_iov, 1, ppos);
- mutex_unlock(&inode->i_mutex);
-
- 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;
-
- mutex_lock(&inode->i_mutex);
- ret = __generic_file_write_nolock(file, iov, nr_segs, ppos);
- mutex_unlock(&inode->i_mutex);
-
- 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_mutex for writes to S_ISREG files. Returns -EIO if something
* went wrong during pagecache shootdown.
}
return retval;
}
+
+/**
+ * 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