From: Sage Weil Date: Mon, 5 Nov 2012 19:07:23 +0000 (-0800) Subject: ceph: Fix i_size update race X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=22cddde104;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git ceph: Fix i_size update race ceph_aio_write() has an optimization that marks cap EPH_CAP_FILE_WR dirty before data is copied to page cache and inode size is updated. If ceph_check_caps() flushes the dirty cap before the inode size is updated, MDS can miss the new inode size. The fix is move ceph_{get,put}_cap_refs() into ceph_write_{begin,end}() and call __ceph_mark_dirty_caps() after inode size is updated. Signed-off-by: Yan, Zheng Signed-off-by: Sage Weil --- diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index 22b6e4583faa..21a07187df05 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -1078,23 +1078,51 @@ static int ceph_write_begin(struct file *file, struct address_space *mapping, struct page **pagep, void **fsdata) { struct inode *inode = file->f_dentry->d_inode; + struct ceph_inode_info *ci = ceph_inode(inode); + struct ceph_file_info *fi = file->private_data; struct page *page; pgoff_t index = pos >> PAGE_CACHE_SHIFT; - int r; + int r, want, got = 0; + + if (fi->fmode & CEPH_FILE_MODE_LAZY) + want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO; + else + want = CEPH_CAP_FILE_BUFFER; + + dout("write_begin %p %llx.%llx %llu~%u getting caps. i_size %llu\n", + inode, ceph_vinop(inode), pos, len, inode->i_size); + r = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, pos+len); + if (r < 0) + return r; + dout("write_begin %p %llx.%llx %llu~%u got cap refs on %s\n", + inode, ceph_vinop(inode), pos, len, ceph_cap_string(got)); + if (!(got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO))) { + ceph_put_cap_refs(ci, got); + return -EAGAIN; + } do { /* get a page */ page = grab_cache_page_write_begin(mapping, index, 0); - if (!page) - return -ENOMEM; - *pagep = page; + if (!page) { + r = -ENOMEM; + break; + } dout("write_begin file %p inode %p page %p %d~%d\n", file, inode, page, (int)pos, (int)len); r = ceph_update_writeable_page(file, pos, len, page); + if (r) + page_cache_release(page); } while (r == -EAGAIN); + if (r) { + ceph_put_cap_refs(ci, got); + } else { + *pagep = page; + *(int *)fsdata = got; + } return r; } @@ -1108,10 +1136,12 @@ static int ceph_write_end(struct file *file, struct address_space *mapping, struct page *page, void *fsdata) { struct inode *inode = file->f_dentry->d_inode; + struct ceph_inode_info *ci = ceph_inode(inode); struct ceph_fs_client *fsc = ceph_inode_to_client(inode); struct ceph_mds_client *mdsc = fsc->mdsc; unsigned from = pos & (PAGE_CACHE_SIZE - 1); int check_cap = 0; + int got = (unsigned long)fsdata; dout("write_end file %p inode %p page %p %d~%d (%d)\n", file, inode, page, (int)pos, (int)copied, (int)len); @@ -1134,6 +1164,19 @@ static int ceph_write_end(struct file *file, struct address_space *mapping, up_read(&mdsc->snap_rwsem); page_cache_release(page); + if (copied > 0) { + int dirty; + spin_lock(&ci->i_ceph_lock); + dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR); + spin_unlock(&ci->i_ceph_lock); + if (dirty) + __mark_inode_dirty(inode, dirty); + } + + dout("write_end %p %llx.%llx %llu~%u dropping cap refs on %s\n", + inode, ceph_vinop(inode), pos, len, ceph_cap_string(got)); + ceph_put_cap_refs(ci, got); + if (check_cap) ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL); diff --git a/fs/ceph/file.c b/fs/ceph/file.c index 5840d2aaed15..d415096800a6 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -712,63 +712,53 @@ static ssize_t ceph_aio_write(struct kiocb *iocb, const struct iovec *iov, struct ceph_osd_client *osdc = &ceph_sb_to_client(inode->i_sb)->client->osdc; loff_t endoff = pos + iov->iov_len; - int want, got = 0; - int ret, err; + int got = 0; + int ret, err, written; if (ceph_snap(inode) != CEPH_NOSNAP) return -EROFS; retry_snap: + written = 0; if (ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_FULL)) return -ENOSPC; __ceph_do_pending_vmtruncate(inode); - dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n", - inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len, - inode->i_size); - if (fi->fmode & CEPH_FILE_MODE_LAZY) - want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO; - else - want = CEPH_CAP_FILE_BUFFER; - ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, endoff); - if (ret < 0) - goto out_put; - - dout("aio_write %p %llx.%llx %llu~%u got cap refs on %s\n", - inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len, - ceph_cap_string(got)); - - if ((got & (CEPH_CAP_FILE_BUFFER|CEPH_CAP_FILE_LAZYIO)) == 0 || - (iocb->ki_filp->f_flags & O_DIRECT) || - (inode->i_sb->s_flags & MS_SYNCHRONOUS) || - (fi->flags & CEPH_F_SYNC)) { - ret = ceph_sync_write(file, iov->iov_base, iov->iov_len, - &iocb->ki_pos); - } else { - /* - * buffered write; drop Fw early to avoid slow - * revocation if we get stuck on balance_dirty_pages - */ - int dirty; - - spin_lock(&ci->i_ceph_lock); - dirty = __ceph_mark_dirty_caps(ci, CEPH_CAP_FILE_WR); - spin_unlock(&ci->i_ceph_lock); - ceph_put_cap_refs(ci, got); + /* + * try to do a buffered write. if we don't have sufficient + * caps, we'll get -EAGAIN from generic_file_aio_write, or a + * short write if we only get caps for some pages. + */ + if (!(iocb->ki_filp->f_flags & O_DIRECT) && + !(inode->i_sb->s_flags & MS_SYNCHRONOUS) && + !(fi->flags & CEPH_F_SYNC)) { ret = generic_file_aio_write(iocb, iov, nr_segs, pos); + if (ret >= 0) + written = ret; + if ((ret >= 0 || ret == -EIOCBQUEUED) && ((file->f_flags & O_SYNC) || IS_SYNC(file->f_mapping->host) || ceph_osdmap_flag(osdc->osdmap, CEPH_OSDMAP_NEARFULL))) { - err = vfs_fsync_range(file, pos, pos + ret - 1, 1); + err = vfs_fsync_range(file, pos, pos + written - 1, 1); if (err < 0) ret = err; } + if ((ret < 0 && ret != -EAGAIN) || pos + written >= endoff) + goto out; + } - if (dirty) - __mark_inode_dirty(inode, dirty); + dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n", + inode, ceph_vinop(inode), pos + written, + (unsigned)iov->iov_len - written, inode->i_size); + ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, 0, &got, endoff); + if (ret < 0) goto out; - } + dout("aio_write %p %llx.%llx %llu~%u got cap refs on %s\n", + inode, ceph_vinop(inode), pos + written, + (unsigned)iov->iov_len - written, ceph_cap_string(got)); + ret = ceph_sync_write(file, iov->iov_base + written, + iov->iov_len - written, &iocb->ki_pos); if (ret >= 0) { int dirty; spin_lock(&ci->i_ceph_lock); @@ -777,13 +767,10 @@ retry_snap: if (dirty) __mark_inode_dirty(inode, dirty); } - -out_put: dout("aio_write %p %llx.%llx %llu~%u dropping cap refs on %s\n", - inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len, - ceph_cap_string(got)); + inode, ceph_vinop(inode), pos + written, + (unsigned)iov->iov_len - written, ceph_cap_string(got)); ceph_put_cap_refs(ci, got); - out: if (ret == -EOLDSNAPC) { dout("aio_write %p %llx.%llx %llu~%u got EOLDSNAPC, retrying\n",