*/
/*
- * This file implements VFS file and inode operations of regular files, device
+ * This file implements VFS file and inode operations for regular files, device
* nodes and symlinks as well as address space operations.
*
- * UBIFS uses 2 page flags: PG_private and PG_checked. PG_private is set if the
- * page is dirty and is used for budgeting purposes - dirty pages should not be
- * budgeted. The PG_checked flag is set if full budgeting is required for the
- * page e.g., when it corresponds to a file hole or it is just beyond the file
- * size. The budgeting is done in 'ubifs_write_begin()', because it is OK to
- * fail in this function, and the budget is released in 'ubifs_write_end()'. So
- * the PG_private and PG_checked flags carry the information about how the page
- * was budgeted, to make it possible to release the budget properly.
+ * UBIFS uses 2 page flags: @PG_private and @PG_checked. @PG_private is set if
+ * the page is dirty and is used for optimization purposes - dirty pages are
+ * not budgeted so the flag shows that 'ubifs_write_end()' should not release
+ * the budget for this page. The @PG_checked flag is set if full budgeting is
+ * required for the page e.g., when it corresponds to a file hole or it is
+ * beyond the file size. The budgeting is done in 'ubifs_write_begin()', because
+ * it is OK to fail in this function, and the budget is released in
+ * 'ubifs_write_end()'. So the @PG_private and @PG_checked flags carry
+ * information about how the page was budgeted, to make it possible to release
+ * the budget properly.
*
- * A thing to keep in mind: inode's 'i_mutex' is locked in most VFS operations
- * we implement. However, this is not true for '->writepage()', which might be
- * called with 'i_mutex' unlocked. For example, when pdflush is performing
- * write-back, it calls 'writepage()' with unlocked 'i_mutex', although the
- * inode has 'I_LOCK' flag in this case. At "normal" work-paths 'i_mutex' is
- * locked in '->writepage', e.g. in "sys_write -> alloc_pages -> direct reclaim
- * path'. So, in '->writepage()' we are only guaranteed that the page is
- * locked.
+ * A thing to keep in mind: inode @i_mutex is locked in most VFS operations we
+ * implement. However, this is not true for 'ubifs_writepage()', which may be
+ * called with @i_mutex unlocked. For example, when pdflush is doing background
+ * write-back, it calls 'ubifs_writepage()' with unlocked @i_mutex. At "normal"
+ * work-paths the @i_mutex is locked in 'ubifs_writepage()', e.g. in the
+ * "sys_write -> alloc_pages -> direct reclaim path". So, in 'ubifs_writepage()'
+ * we are only guaranteed that the page is locked.
*
- * Similarly, 'i_mutex' does not have to be locked in readpage(), e.g.,
- * readahead path does not have it locked ("sys_read -> generic_file_aio_read
- * -> ondemand_readahead -> readpage"). In case of readahead, 'I_LOCK' flag is
- * not set as well. However, UBIFS disables readahead.
- *
- * This, for example means that there might be 2 concurrent '->writepage()'
- * calls for the same inode, but different inode dirty pages.
+ * Similarly, @i_mutex is not always locked in 'ubifs_readpage()', e.g., the
+ * read-ahead path does not lock it ("sys_read -> generic_file_aio_read ->
+ * ondemand_readahead -> readpage"). In case of readahead, @I_LOCK flag is not
+ * set as well. However, UBIFS disables readahead.
*/
#include "ubifs.h"
struct ubifs_inode *ui = ubifs_inode(inode);
pgoff_t index = pos >> PAGE_CACHE_SHIFT;
int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
+ int skipped_read = 0;
struct page *page;
-
ubifs_assert(ubifs_inode(inode)->ui_size == inode->i_size);
if (unlikely(c->ro_media))
if (!PageUptodate(page)) {
/* The page is not loaded from the flash */
- if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE)
+ if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE) {
/*
* We change whole page so no need to load it. But we
* have to set the @PG_checked flag to make the further
- * code the page is new. This might be not true, but it
- * is better to budget more that to read the page from
- * the media.
+ * code know that the page is new. This might be not
+ * true, but it is better to budget more than to read
+ * the page from the media.
*/
SetPageChecked(page);
- else {
+ skipped_read = 1;
+ } else {
err = do_readpage(page);
if (err) {
unlock_page(page);
if (unlikely(err)) {
ubifs_assert(err == -ENOSPC);
/*
+ * If we skipped reading the page because we were going to
+ * write all of it, then it is not up to date.
+ */
+ if (skipped_read) {
+ ClearPageChecked(page);
+ ClearPageUptodate(page);
+ }
+ /*
* Budgeting failed which means it would have to force
* write-back but didn't, because we set the @fast flag in the
* request. Write-back cannot be done now, while we have the
}
/*
- * Whee, we aquired budgeting quickly - without involving
- * garbage-collection, committing or forceing write-back. We return
+ * Whee, we acquired budgeting quickly - without involving
+ * garbage-collection, committing or forcing write-back. We return
* with @ui->ui_mutex locked if we are appending pages, and unlocked
* otherwise. This is an optimization (slightly hacky though).
*/
/*
* Return 0 to force VFS to repeat the whole operation, or the
- * error code if 'do_readpage()' failes.
+ * error code if 'do_readpage()' fails.
*/
copied = do_readpage(page);
goto out;
* whole index and correct all inode sizes, which is long an unacceptable.
*
* To prevent situations like this, UBIFS writes pages back only if they are
- * within last synchronized inode size, i.e. the the size which has been
+ * within the last synchronized inode size, i.e. the size which has been
* written to the flash media last time. Otherwise, UBIFS forces inode
* write-back, thus making sure the on-flash inode contains current inode size,
* and then keeps writing pages back.
ui->ui_size = inode->i_size;
/* Truncation changes inode [mc]time */
inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
- /* The other attributes may be changed at the same time as well */
+ /* Other attributes may be changed at the same time as well */
do_attr_changes(inode, attr);
-
err = ubifs_jnl_truncate(c, inode, old_size, new_size);
mutex_unlock(&ui->ui_mutex);
+
out_budg:
if (budgeted)
ubifs_release_budget(c, &req);
* mmap()d file has taken write protection fault and is being made
* writable. UBIFS must ensure page is budgeted for.
*/
-static int ubifs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page)
+static int ubifs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
+ struct page *page = vmf->page;
struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
struct ubifs_info *c = inode->i_sb->s_fs_info;
struct timespec now = ubifs_current_time(inode);
ubifs_assert(!(inode->i_sb->s_flags & MS_RDONLY));
if (unlikely(c->ro_media))
- return -EROFS;
+ return VM_FAULT_SIGBUS; /* -EROFS */
/*
* We have not locked @page so far so we may budget for changing the
if (err == -ENOSPC)
ubifs_warn("out of space for mmapped file "
"(inode number %lu)", inode->i_ino);
- return err;
+ return VM_FAULT_SIGBUS;
}
lock_page(page);
out_unlock:
unlock_page(page);
ubifs_release_budget(c, &req);
+ if (err)
+ err = VM_FAULT_SIGBUS;
return err;
}
return 0;
}
-struct address_space_operations ubifs_file_address_operations = {
+const struct address_space_operations ubifs_file_address_operations = {
.readpage = ubifs_readpage,
.writepage = ubifs_writepage,
.write_begin = ubifs_write_begin,
.releasepage = ubifs_releasepage,
};
-struct inode_operations ubifs_file_inode_operations = {
+const struct inode_operations ubifs_file_inode_operations = {
.setattr = ubifs_setattr,
.getattr = ubifs_getattr,
#ifdef CONFIG_UBIFS_FS_XATTR
#endif
};
-struct inode_operations ubifs_symlink_inode_operations = {
+const struct inode_operations ubifs_symlink_inode_operations = {
.readlink = generic_readlink,
.follow_link = ubifs_follow_link,
.setattr = ubifs_setattr,
.getattr = ubifs_getattr,
};
-struct file_operations ubifs_file_operations = {
+const struct file_operations ubifs_file_operations = {
.llseek = generic_file_llseek,
.read = do_sync_read,
.write = do_sync_write,
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff