diff options
| -rw-r--r-- | fs/cifs/file.c | 77 |
1 files changed, 56 insertions, 21 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c index b691b893a84..f0a81e631ae 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -1475,7 +1475,11 @@ static int cifs_write_end(struct file *file, struct address_space *mapping, cFYI(1, ("write_end for page %p from pos %lld with %d bytes", page, pos, copied)); - if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE) + if (PageChecked(page)) { + if (copied == len) + SetPageUptodate(page); + ClearPageChecked(page); + } else if (!PageUptodate(page) && copied == PAGE_CACHE_SIZE) SetPageUptodate(page); if (!PageUptodate(page)) { @@ -2062,39 +2066,70 @@ static int cifs_write_begin(struct file *file, struct address_space *mapping, { pgoff_t index = pos >> PAGE_CACHE_SHIFT; loff_t offset = pos & (PAGE_CACHE_SIZE - 1); + loff_t page_start = pos & PAGE_MASK; + loff_t i_size; + struct page *page; + int rc = 0; cFYI(1, ("write_begin from %lld len %d", (long long)pos, len)); - *pagep = __grab_cache_page(mapping, index); - if (!*pagep) - return -ENOMEM; - - if (PageUptodate(*pagep)) - return 0; + page = __grab_cache_page(mapping, index); + if (!page) { + rc = -ENOMEM; + goto out; + } - /* If we are writing a full page it will be up to date, - no need to read from the server */ - if (len == PAGE_CACHE_SIZE && flags & AOP_FLAG_UNINTERRUPTIBLE) - return 0; + if (PageUptodate(page)) + goto out; - if ((file->f_flags & O_ACCMODE) != O_WRONLY) { - int rc; + /* + * If we write a full page it will be up to date, no need to read from + * the server. If the write is short, we'll end up doing a sync write + * instead. + */ + if (len == PAGE_CACHE_SIZE) + goto out; - /* might as well read a page, it is fast enough */ - rc = cifs_readpage_worker(file, *pagep, &offset); + /* + * optimize away the read when we have an oplock, and we're not + * expecting to use any of the data we'd be reading in. That + * is, when the page lies beyond the EOF, or straddles the EOF + * and the write will cover all of the existing data. + */ + if (CIFS_I(mapping->host)->clientCanCacheRead) { + i_size = i_size_read(mapping->host); + if (page_start >= i_size || + (offset == 0 && (pos + len) >= i_size)) { + zero_user_segments(page, 0, offset, + offset + len, + PAGE_CACHE_SIZE); + /* + * PageChecked means that the parts of the page + * to which we're not writing are considered up + * to date. Once the data is copied to the + * page, it can be set uptodate. + */ + SetPageChecked(page); + goto out; + } + } - /* we do not need to pass errors back - e.g. if we do not have read access to the file - because cifs_write_end will attempt synchronous writes - -- shaggy */ + if ((file->f_flags & O_ACCMODE) != O_WRONLY) { + /* + * might as well read a page, it is fast enough. If we get + * an error, we don't need to return it. cifs_write_end will + * do a sync write instead since PG_uptodate isn't set. + */ + cifs_readpage_worker(file, page, &page_start); } else { /* we could try using another file handle if there is one - but how would we lock it to prevent close of that handle racing with this read? In any case this will be written out by write_end so is fine */ } - - return 0; +out: + *pagep = page; + return rc; } const struct address_space_operations cifs_addr_ops = { |