From 6db3ac3c4bc552837d232ec794559a2fae2815a0 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 16 Mar 2017 16:27:44 +0000 Subject: afs: Handle better the server returning excess or short data When an AFS server is given an FS.FetchData{,64} request to read data from a file, it is permitted by the protocol to return more or less than was requested. kafs currently relies on the latter behaviour in readpage{,s} to handle a partial page at the end of the file (we just ask for a whole page and clear space beyond the short read). However, we don't handle all cases. Add: (1) Handle excess data by discarding it rather than aborting. Note that we use a common static buffer to discard into so that the decryption algorithm advances the PCBC state. (2) Handle a short read that affects more than just the last page. Note that if a read comes up unexpectedly short of long, it's possible that the server's copy of the file changed - in which case the data version number will have been incremented and the callback will have been broken - in which case all the pages currently attached to the inode will be zapped anyway at some point. Signed-off-by: David Howells --- fs/afs/file.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'fs/afs/file.c') diff --git a/fs/afs/file.c b/fs/afs/file.c index ba7b71fba34b..a38e1c30d110 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -184,10 +184,13 @@ int afs_page_filler(void *data, struct page *page) if (!req) goto enomem; + /* We request a full page. If the page is a partial one at the + * end of the file, the server will return a short read and the + * unmarshalling code will clear the unfilled space. + */ atomic_set(&req->usage, 1); req->pos = (loff_t)page->index << PAGE_SHIFT; - req->len = min_t(size_t, i_size_read(inode) - req->pos, - PAGE_SIZE); + req->len = PAGE_SIZE; req->nr_pages = 1; req->pages[0] = page; get_page(page); -- cgit v1.2.3 From 58fed94dfb17e89556b5705f20f90e5b2971b6a1 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 16 Mar 2017 16:27:45 +0000 Subject: afs: Flush outstanding writes when an fd is closed Flush outstanding writes in afs when an fd is closed. This is what NFS and CIFS do. Reported-by: Marc Dionne Signed-off-by: David Howells --- fs/afs/file.c | 1 + fs/afs/internal.h | 1 + fs/afs/write.c | 14 ++++++++++++++ 3 files changed, 16 insertions(+) (limited to 'fs/afs/file.c') diff --git a/fs/afs/file.c b/fs/afs/file.c index a38e1c30d110..b5829443ff69 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -30,6 +30,7 @@ static int afs_readpages(struct file *filp, struct address_space *mapping, const struct file_operations afs_file_operations = { .open = afs_open, + .flush = afs_flush, .release = afs_release, .llseek = generic_file_llseek, .read_iter = generic_file_read_iter, diff --git a/fs/afs/internal.h b/fs/afs/internal.h index dc2cb486e127..af1d91ec7f2c 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -720,6 +720,7 @@ extern int afs_writepages(struct address_space *, struct writeback_control *); extern void afs_pages_written_back(struct afs_vnode *, struct afs_call *); extern ssize_t afs_file_write(struct kiocb *, struct iov_iter *); extern int afs_writeback_all(struct afs_vnode *); +extern int afs_flush(struct file *, fl_owner_t); extern int afs_fsync(struct file *, loff_t, loff_t, int); diff --git a/fs/afs/write.c b/fs/afs/write.c index ea66890fc188..f1450ea09406 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -757,6 +757,20 @@ out: return ret; } +/* + * Flush out all outstanding writes on a file opened for writing when it is + * closed. + */ +int afs_flush(struct file *file, fl_owner_t id) +{ + _enter(""); + + if ((file->f_mode & FMODE_WRITE) == 0) + return 0; + + return vfs_fsync(file, 0); +} + /* * notification that a previously read-only page is about to become writable * - if it returns an error, the caller will deliver a bus error signal -- cgit v1.2.3 From 68ae849d7e674b83610bc7fdf74b21621a09b9ac Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 16 Mar 2017 16:27:48 +0000 Subject: afs: Don't set PG_error on local EINTR or ENOMEM when filling a page Don't set PG_error on a page if we get local EINTR or ENOMEM when filling a page for writing. Signed-off-by: David Howells --- fs/afs/file.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'fs/afs/file.c') diff --git a/fs/afs/file.c b/fs/afs/file.c index b5829443ff69..0d5b8508869b 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -212,7 +212,13 @@ int afs_page_filler(void *data, struct page *page) fscache_uncache_page(vnode->cache, page); #endif BUG_ON(PageFsCache(page)); - goto error; + + if (ret == -EINTR || + ret == -ENOMEM || + ret == -ERESTARTSYS || + ret == -EAGAIN) + goto error; + goto io_error; } SetPageUptodate(page); @@ -231,10 +237,12 @@ int afs_page_filler(void *data, struct page *page) _leave(" = 0"); return 0; +io_error: + SetPageError(page); + goto error; enomem: ret = -ENOMEM; error: - SetPageError(page); unlock_page(page); _leave(" = %d", ret); return ret; -- cgit v1.2.3