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Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 08/14] afs: Handle a short write to an AFS page From: David Howells To: viro@ZenIV.linux.org.uk Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-afs@lists.infradead.org Date: Fri, 24 Feb 2017 13:14:24 +0000 Message-ID: <148794206426.28770.6174886469916253725.stgit@warthog.procyon.org.uk> In-Reply-To: <148794199962.28770.5291326312391230868.stgit@warthog.procyon.org.uk> References: <148794199962.28770.5291326312391230868.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Fri, 24 Feb 2017 13:14:27 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Handle the situation where afs_write_begin() is told to expect that a full-page write will be made, but this doesn't happen (EFAULT, CTRL-C, etc.), and so afs_write_end() sees a partial write took place. Currently, no attempt is to deal with the discrepency. Fix this by loading the gap from the server. Reported-by: Al Viro Signed-off-by: David Howells --- fs/afs/fsclient.c | 4 +++- fs/afs/internal.h | 2 +- fs/afs/write.c | 28 +++++++++++++++++++--------- 3 files changed, 23 insertions(+), 11 deletions(-) diff --git a/fs/afs/fsclient.c b/fs/afs/fsclient.c index bf8904a1a58f..6f917dd1238c 100644 --- a/fs/afs/fsclient.c +++ b/fs/afs/fsclient.c @@ -393,8 +393,10 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call) if (req->remain > 0) { call->offset = 0; req->index++; - if (req->index >= req->nr_pages) + if (req->index >= req->nr_pages) { + call->unmarshall = 4; goto begin_discard; + } goto begin_page; } } diff --git a/fs/afs/internal.h b/fs/afs/internal.h index 4213aa35deed..4ffd50de9386 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -130,7 +130,7 @@ struct afs_call_type { */ struct afs_read { loff_t pos; /* Where to start reading */ - loff_t len; /* How much to read */ + loff_t len; /* How much we're asking for */ loff_t actual_len; /* How much we're actually getting */ atomic_t usage; unsigned int remain; /* Amount remaining */ diff --git a/fs/afs/write.c b/fs/afs/write.c index 3ac52f6a96ff..ea66890fc188 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -84,10 +84,9 @@ void afs_put_writeback(struct afs_writeback *wb) * partly or wholly fill a page that's under preparation for writing */ static int afs_fill_page(struct afs_vnode *vnode, struct key *key, - loff_t pos, struct page *page) + loff_t pos, unsigned int len, struct page *page) { struct afs_read *req; - loff_t i_size; int ret; _enter(",,%llu", (unsigned long long)pos); @@ -99,16 +98,11 @@ static int afs_fill_page(struct afs_vnode *vnode, struct key *key, atomic_set(&req->usage, 1); req->pos = pos; + req->len = len; req->nr_pages = 1; req->pages[0] = page; get_page(page); - i_size = i_size_read(&vnode->vfs_inode); - if (pos + PAGE_SIZE > i_size) - req->len = i_size - pos; - else - req->len = PAGE_SIZE; - ret = afs_vnode_fetch_data(vnode, key, req); afs_put_read(req); if (ret < 0) { @@ -164,7 +158,7 @@ int afs_write_begin(struct file *file, struct address_space *mapping, /* page won't leak in error case: it eventually gets cleaned off LRU */ if (!PageUptodate(page) && len != PAGE_SIZE) { - ret = afs_fill_page(vnode, key, index << PAGE_SHIFT, page); + ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page); if (ret < 0) { kfree(candidate); _leave(" = %d [prep]", ret); @@ -258,7 +252,9 @@ int afs_write_end(struct file *file, struct address_space *mapping, struct page *page, void *fsdata) { struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); + struct key *key = file->private_data; loff_t i_size, maybe_i_size; + int ret; _enter("{%x:%u},{%lx}", vnode->fid.vid, vnode->fid.vnode, page->index); @@ -274,6 +270,20 @@ int afs_write_end(struct file *file, struct address_space *mapping, spin_unlock(&vnode->writeback_lock); } + if (!PageUptodate(page)) { + if (copied < len) { + /* Try and load any missing data from the server. The + * unmarshalling routine will take care of clearing any + * bits that are beyond the EOF. + */ + ret = afs_fill_page(vnode, key, pos + copied, + len - copied, page); + if (ret < 0) + return ret; + } + SetPageUptodate(page); + } + set_page_dirty(page); if (PageDirty(page)) _debug("dirtied");