afs: convert to new aops
Cannot assume writes will fully complete, so this conversion goes the easy way and always brings the page uptodate before the write. [dhowells@redhat.com: style tweaks] Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nick Piggin
Linus Torvalds
Родитель
8360e81b5d
Коммит
15b4650e55
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@ -50,8 +50,8 @@ const struct address_space_operations afs_fs_aops = {
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.launder_page = afs_launder_page,
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.releasepage = afs_releasepage,
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.invalidatepage = afs_invalidatepage,
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.prepare_write = afs_prepare_write,
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.commit_write = afs_commit_write,
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.write_begin = afs_write_begin,
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.write_end = afs_write_end,
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.writepage = afs_writepage,
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.writepages = afs_writepages,
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};
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@ -728,8 +728,12 @@ extern int afs_volume_release_fileserver(struct afs_vnode *,
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*/
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extern int afs_set_page_dirty(struct page *);
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extern void afs_put_writeback(struct afs_writeback *);
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extern int afs_prepare_write(struct file *, struct page *, unsigned, unsigned);
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extern int afs_commit_write(struct file *, struct page *, unsigned, unsigned);
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extern int afs_write_begin(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata);
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extern int afs_write_end(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata);
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extern int afs_writepage(struct page *, struct writeback_control *);
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extern int afs_writepages(struct address_space *, struct writeback_control *);
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extern int afs_write_inode(struct inode *, int);
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131
fs/afs/write.c
131
fs/afs/write.c
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@ -84,15 +84,23 @@ void afs_put_writeback(struct afs_writeback *wb)
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* partly or wholly fill a page that's under preparation for writing
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*/
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static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
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unsigned start, unsigned len, struct page *page)
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loff_t pos, unsigned len, struct page *page)
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{
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loff_t i_size;
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unsigned eof;
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int ret;
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_enter(",,%u,%u", start, len);
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_enter(",,%llu,%u", (unsigned long long)pos, len);
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ASSERTCMP(start + len, <=, PAGE_SIZE);
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ASSERTCMP(len, <=, PAGE_CACHE_SIZE);
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ret = afs_vnode_fetch_data(vnode, key, start, len, page);
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i_size = i_size_read(&vnode->vfs_inode);
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if (pos + len > i_size)
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eof = i_size;
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else
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eof = PAGE_CACHE_SIZE;
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ret = afs_vnode_fetch_data(vnode, key, 0, eof, page);
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if (ret < 0) {
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if (ret == -ENOENT) {
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_debug("got NOENT from server"
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@ -106,110 +114,56 @@ static int afs_fill_page(struct afs_vnode *vnode, struct key *key,
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return ret;
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}
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/*
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* prepare a page for being written to
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*/
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static int afs_prepare_page(struct afs_vnode *vnode, struct page *page,
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struct key *key, unsigned offset, unsigned to)
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{
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unsigned eof, tail, start, stop, len;
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loff_t i_size, pos;
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void *p;
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int ret;
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_enter("");
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if (offset == 0 && to == PAGE_SIZE)
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return 0;
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p = kmap_atomic(page, KM_USER0);
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i_size = i_size_read(&vnode->vfs_inode);
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pos = (loff_t) page->index << PAGE_SHIFT;
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if (pos >= i_size) {
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/* partial write, page beyond EOF */
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_debug("beyond");
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if (offset > 0)
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memset(p, 0, offset);
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if (to < PAGE_SIZE)
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memset(p + to, 0, PAGE_SIZE - to);
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kunmap_atomic(p, KM_USER0);
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return 0;
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}
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if (i_size - pos >= PAGE_SIZE) {
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/* partial write, page entirely before EOF */
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_debug("before");
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tail = eof = PAGE_SIZE;
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} else {
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/* partial write, page overlaps EOF */
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eof = i_size - pos;
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_debug("overlap %u", eof);
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tail = max(eof, to);
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if (tail < PAGE_SIZE)
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memset(p + tail, 0, PAGE_SIZE - tail);
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if (offset > eof)
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memset(p + eof, 0, PAGE_SIZE - eof);
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}
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kunmap_atomic(p, KM_USER0);
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ret = 0;
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if (offset > 0 || eof > to) {
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/* need to fill one or two bits that aren't going to be written
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* (cover both fillers in one read if there are two) */
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start = (offset > 0) ? 0 : to;
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stop = (eof > to) ? eof : offset;
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len = stop - start;
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_debug("wr=%u-%u av=0-%u rd=%u@%u",
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offset, to, eof, start, len);
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ret = afs_fill_page(vnode, key, start, len, page);
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}
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_leave(" = %d", ret);
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return ret;
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}
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/*
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* prepare to perform part of a write to a page
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* - the caller holds the page locked, preventing it from being written out or
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* modified by anyone else
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*/
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int afs_prepare_write(struct file *file, struct page *page,
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unsigned offset, unsigned to)
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int afs_write_begin(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata)
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{
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struct afs_writeback *candidate, *wb;
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struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode);
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struct page *page;
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struct key *key = file->private_data;
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pgoff_t index;
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unsigned from = pos & (PAGE_CACHE_SIZE - 1);
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unsigned to = from + len;
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pgoff_t index = pos >> PAGE_CACHE_SHIFT;
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int ret;
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_enter("{%x:%u},{%lx},%u,%u",
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vnode->fid.vid, vnode->fid.vnode, page->index, offset, to);
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vnode->fid.vid, vnode->fid.vnode, index, from, to);
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candidate = kzalloc(sizeof(*candidate), GFP_KERNEL);
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if (!candidate)
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return -ENOMEM;
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candidate->vnode = vnode;
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candidate->first = candidate->last = page->index;
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candidate->offset_first = offset;
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candidate->first = candidate->last = index;
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candidate->offset_first = from;
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candidate->to_last = to;
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candidate->usage = 1;
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candidate->state = AFS_WBACK_PENDING;
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init_waitqueue_head(&candidate->waitq);
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page = __grab_cache_page(mapping, index);
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if (!page) {
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kfree(candidate);
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return -ENOMEM;
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}
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*pagep = page;
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/* page won't leak in error case: it eventually gets cleaned off LRU */
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if (!PageUptodate(page)) {
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_debug("not up to date");
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ret = afs_prepare_page(vnode, page, key, offset, to);
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ret = afs_fill_page(vnode, key, pos, len, page);
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if (ret < 0) {
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kfree(candidate);
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_leave(" = %d [prep]", ret);
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return ret;
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}
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SetPageUptodate(page);
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}
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try_again:
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index = page->index;
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spin_lock(&vnode->writeback_lock);
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/* see if this page is already pending a writeback under a suitable key
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@ -242,8 +196,8 @@ try_again:
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subsume_in_current_wb:
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_debug("subsume");
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ASSERTRANGE(wb->first, <=, index, <=, wb->last);
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if (index == wb->first && offset < wb->offset_first)
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wb->offset_first = offset;
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if (index == wb->first && from < wb->offset_first)
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wb->offset_first = from;
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if (index == wb->last && to > wb->to_last)
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wb->to_last = to;
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spin_unlock(&vnode->writeback_lock);
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@ -289,17 +243,17 @@ flush_conflicting_wb:
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/*
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* finalise part of a write to a page
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*/
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int afs_commit_write(struct file *file, struct page *page,
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unsigned offset, unsigned to)
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int afs_write_end(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned copied,
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struct page *page, void *fsdata)
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{
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struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode);
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loff_t i_size, maybe_i_size;
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_enter("{%x:%u},{%lx},%u,%u",
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vnode->fid.vid, vnode->fid.vnode, page->index, offset, to);
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_enter("{%x:%u},{%lx}",
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vnode->fid.vid, vnode->fid.vnode, page->index);
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maybe_i_size = (loff_t) page->index << PAGE_SHIFT;
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maybe_i_size += to;
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maybe_i_size = pos + copied;
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i_size = i_size_read(&vnode->vfs_inode);
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if (maybe_i_size > i_size) {
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@ -310,12 +264,13 @@ int afs_commit_write(struct file *file, struct page *page,
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spin_unlock(&vnode->writeback_lock);
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}
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SetPageUptodate(page);
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set_page_dirty(page);
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if (PageDirty(page))
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_debug("dirtied");
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unlock_page(page);
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page_cache_release(page);
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return 0;
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return copied;
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}
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/*
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