diff options
Diffstat (limited to 'fs/cifs/file.c')
| -rw-r--r-- | fs/cifs/file.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c index d210288e4a47..183381d9c4c1 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -2654,6 +2654,73 @@ cifs_readv_complete(struct work_struct *work) cifs_readdata_free(rdata); } +static int +cifs_readpages_marshal_iov(struct cifs_readdata *rdata, unsigned int remaining) +{ + int len = 0; + struct page *page, *tpage; + u64 eof; + pgoff_t eof_index; + + /* determine the eof that the server (probably) has */ + eof = CIFS_I(rdata->mapping->host)->server_eof; + eof_index = eof ? (eof - 1) >> PAGE_CACHE_SHIFT : 0; + cFYI(1, "eof=%llu eof_index=%lu", eof, eof_index); + + rdata->nr_iov = 1; + list_for_each_entry_safe(page, tpage, &rdata->pages, lru) { + if (remaining >= PAGE_CACHE_SIZE) { + /* enough data to fill the page */ + rdata->iov[rdata->nr_iov].iov_base = kmap(page); + rdata->iov[rdata->nr_iov].iov_len = PAGE_CACHE_SIZE; + cFYI(1, "%u: idx=%lu iov_base=%p iov_len=%zu", + rdata->nr_iov, page->index, + rdata->iov[rdata->nr_iov].iov_base, + rdata->iov[rdata->nr_iov].iov_len); + ++rdata->nr_iov; + len += PAGE_CACHE_SIZE; + remaining -= PAGE_CACHE_SIZE; + } else if (remaining > 0) { + /* enough for partial page, fill and zero the rest */ + rdata->iov[rdata->nr_iov].iov_base = kmap(page); + rdata->iov[rdata->nr_iov].iov_len = remaining; + cFYI(1, "%u: idx=%lu iov_base=%p iov_len=%zu", + rdata->nr_iov, page->index, + rdata->iov[rdata->nr_iov].iov_base, + rdata->iov[rdata->nr_iov].iov_len); + memset(rdata->iov[rdata->nr_iov].iov_base + remaining, + '\0', PAGE_CACHE_SIZE - remaining); + ++rdata->nr_iov; + len += remaining; + remaining = 0; + } else if (page->index > eof_index) { + /* + * The VFS will not try to do readahead past the + * i_size, but it's possible that we have outstanding + * writes with gaps in the middle and the i_size hasn't + * caught up yet. Populate those with zeroed out pages + * to prevent the VFS from repeatedly attempting to + * fill them until the writes are flushed. + */ + zero_user(page, 0, PAGE_CACHE_SIZE); + list_del(&page->lru); + lru_cache_add_file(page); + flush_dcache_page(page); + SetPageUptodate(page); + unlock_page(page); + page_cache_release(page); + } else { + /* no need to hold page hostage */ + list_del(&page->lru); + lru_cache_add_file(page); + unlock_page(page); + page_cache_release(page); + } + } + + return len; +} + static int cifs_readpages(struct file *file, struct address_space *mapping, struct list_head *page_list, unsigned num_pages) { @@ -2777,6 +2844,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping, rdata->offset = offset; rdata->bytes = bytes; rdata->pid = pid; + rdata->marshal_iov = cifs_readpages_marshal_iov; list_splice_init(&tmplist, &rdata->pages); do { |