From a3d01454bc58b5a211ef64a7670572a40b71e682 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 11 Jun 2008 12:21:19 -0400 Subject: [PATCH] NFS: Remove BKL requirement from attribute updates The main problem is dealing with inode->i_size: we need to set the inode->i_lock on all attribute updates, and so vmtruncate won't cut it. Make an NFS-private version of vmtruncate that has the necessary locking semantics. The result should be that the following inode attribute updates are protected by inode->i_lock nfsi->cache_validity nfsi->read_cache_jiffies nfsi->attrtimeo nfsi->attrtimeo_timestamp nfsi->change_attr nfsi->last_updated nfsi->cache_change_attribute nfsi->access_cache nfsi->access_cache_entry_lru nfsi->access_cache_inode_lru nfsi->acl_access nfsi->acl_default nfsi->nfs_page_tree nfsi->ncommit nfsi->npages nfsi->open_files nfsi->silly_list nfsi->acl nfsi->open_states inode->i_size inode->i_atime inode->i_mtime inode->i_ctime inode->i_nlink inode->i_uid inode->i_gid The following is protected by dir->i_mutex nfsi->cookieverf Signed-off-by: Trond Myklebust --- fs/nfs/inode.c | 67 +++++++++++++++++++++++++++++++++++++++++++++----- fs/nfs/write.c | 15 +++++++---- 2 files changed, 71 insertions(+), 11 deletions(-) diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 2c23d067e2a..3adabd15477 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -388,6 +388,62 @@ nfs_setattr(struct dentry *dentry, struct iattr *attr) return error; } +/** + * nfs_vmtruncate - unmap mappings "freed" by truncate() syscall + * @inode: inode of the file used + * @offset: file offset to start truncating + * + * This is a copy of the common vmtruncate, but with the locking + * corrected to take into account the fact that NFS requires + * inode->i_size to be updated under the inode->i_lock. + */ +static int nfs_vmtruncate(struct inode * inode, loff_t offset) +{ + if (i_size_read(inode) < offset) { + unsigned long limit; + + limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; + if (limit != RLIM_INFINITY && offset > limit) + goto out_sig; + if (offset > inode->i_sb->s_maxbytes) + goto out_big; + spin_lock(&inode->i_lock); + i_size_write(inode, offset); + spin_unlock(&inode->i_lock); + } else { + struct address_space *mapping = inode->i_mapping; + + /* + * truncation of in-use swapfiles is disallowed - it would + * cause subsequent swapout to scribble on the now-freed + * blocks. + */ + if (IS_SWAPFILE(inode)) + return -ETXTBSY; + spin_lock(&inode->i_lock); + i_size_write(inode, offset); + spin_unlock(&inode->i_lock); + + /* + * unmap_mapping_range is called twice, first simply for + * efficiency so that truncate_inode_pages does fewer + * single-page unmaps. However after this first call, and + * before truncate_inode_pages finishes, it is possible for + * private pages to be COWed, which remain after + * truncate_inode_pages finishes, hence the second + * unmap_mapping_range call must be made for correctness. + */ + unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); + truncate_inode_pages(mapping, offset); + unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); + } + return 0; +out_sig: + send_sig(SIGXFSZ, current, 0); +out_big: + return -EFBIG; +} + /** * nfs_setattr_update_inode - Update inode metadata after a setattr call. * @inode: pointer to struct inode @@ -414,8 +470,7 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr) } if ((attr->ia_valid & ATTR_SIZE) != 0) { nfs_inc_stats(inode, NFSIOS_SETATTRTRUNC); - inode->i_size = attr->ia_size; - vmtruncate(inode, attr->ia_size); + nfs_vmtruncate(inode, attr->ia_size); } } @@ -829,9 +884,9 @@ static void nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr) if (S_ISDIR(inode->i_mode)) nfsi->cache_validity |= NFS_INO_INVALID_DATA; } - if (inode->i_size == nfs_size_to_loff_t(fattr->pre_size) && + if (i_size_read(inode) == nfs_size_to_loff_t(fattr->pre_size) && nfsi->npages == 0) - inode->i_size = nfs_size_to_loff_t(fattr->size); + i_size_write(inode, nfs_size_to_loff_t(fattr->size)); } } @@ -972,7 +1027,7 @@ int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fa (fattr->valid & NFS_ATTR_WCC) == 0) { memcpy(&fattr->pre_ctime, &inode->i_ctime, sizeof(fattr->pre_ctime)); memcpy(&fattr->pre_mtime, &inode->i_mtime, sizeof(fattr->pre_mtime)); - fattr->pre_size = inode->i_size; + fattr->pre_size = i_size_read(inode); fattr->valid |= NFS_ATTR_WCC; } return nfs_post_op_update_inode(inode, fattr); @@ -1057,7 +1112,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr) /* Do we perhaps have any outstanding writes, or has * the file grown beyond our last write? */ if (nfsi->npages == 0 || new_isize > cur_isize) { - inode->i_size = new_isize; + i_size_write(inode, new_isize); invalid |= NFS_INO_INVALID_ATTR|NFS_INO_INVALID_DATA; } dprintk("NFS: isize change on server for file %s/%ld\n", diff --git a/fs/nfs/write.c b/fs/nfs/write.c index feca8c64876..3229e217c77 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -133,16 +133,21 @@ static struct nfs_page *nfs_page_find_request(struct page *page) static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int count) { struct inode *inode = page->mapping->host; - loff_t end, i_size = i_size_read(inode); - pgoff_t end_index = (i_size - 1) >> PAGE_CACHE_SHIFT; + loff_t end, i_size; + pgoff_t end_index; + spin_lock(&inode->i_lock); + i_size = i_size_read(inode); + end_index = (i_size - 1) >> PAGE_CACHE_SHIFT; if (i_size > 0 && page->index < end_index) - return; + goto out; end = ((loff_t)page->index << PAGE_CACHE_SHIFT) + ((loff_t)offset+count); if (i_size >= end) - return; - nfs_inc_stats(inode, NFSIOS_EXTENDWRITE); + goto out; i_size_write(inode, end); + nfs_inc_stats(inode, NFSIOS_EXTENDWRITE); +out: + spin_unlock(&inode->i_lock); } /* A writeback failed: mark the page as bad, and invalidate the page cache */ -- 2.41.1