From 717d44e849219781ced028a40fcc59d3e1f49e4c Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Wed, 24 Jan 2007 11:54:55 -0800 Subject: [PATCH] NFS: Fix races in nfs_revalidate_mapping() Prevent the call to invalidate_inode_pages2() from racing with file writes by taking the inode->i_mutex across the page cache flush and invalidate. Signed-off-by: Trond Myklebust Signed-off-by: Linus Torvalds --- fs/nfs/dir.c | 2 +- fs/nfs/inode.c | 97 ++++++++++++++++++++++++++++++++++++++------------------ fs/nfs/symlink.c | 4 ++- 3 files changed, 71 insertions(+), 32 deletions(-) (limited to 'fs') diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index dee3d6c0f194..d9ba8cb0ee75 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -532,7 +532,7 @@ static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir) lock_kernel(); - res = nfs_revalidate_mapping(inode, filp->f_mapping); + res = nfs_revalidate_mapping_nolock(inode, filp->f_mapping); if (res < 0) { unlock_kernel(); return res; diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c index 63e470279309..d83498282837 100644 --- a/fs/nfs/inode.c +++ b/fs/nfs/inode.c @@ -665,49 +665,86 @@ int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode) return __nfs_revalidate_inode(server, inode); } +static int nfs_invalidate_mapping_nolock(struct inode *inode, struct address_space *mapping) +{ + struct nfs_inode *nfsi = NFS_I(inode); + + if (mapping->nrpages != 0) { + int ret = invalidate_inode_pages2(mapping); + if (ret < 0) + return ret; + } + spin_lock(&inode->i_lock); + nfsi->cache_validity &= ~NFS_INO_INVALID_DATA; + if (S_ISDIR(inode->i_mode)) { + memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf)); + /* This ensures we revalidate child dentries */ + nfsi->cache_change_attribute = jiffies; + } + spin_unlock(&inode->i_lock); + nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE); + dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n", + inode->i_sb->s_id, (long long)NFS_FILEID(inode)); + return 0; +} + +static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping) +{ + int ret = 0; + + mutex_lock(&inode->i_mutex); + if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_DATA) { + ret = nfs_sync_mapping(mapping); + if (ret == 0) + ret = nfs_invalidate_mapping_nolock(inode, mapping); + } + mutex_unlock(&inode->i_mutex); + return ret; +} + /** - * nfs_revalidate_mapping - Revalidate the pagecache + * nfs_revalidate_mapping_nolock - Revalidate the pagecache * @inode - pointer to host inode * @mapping - pointer to mapping */ -int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping) +int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping) { struct nfs_inode *nfsi = NFS_I(inode); int ret = 0; - if (NFS_STALE(inode)) - ret = -ESTALE; if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) - || nfs_attribute_timeout(inode)) + || nfs_attribute_timeout(inode) || NFS_STALE(inode)) { ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode); - if (ret < 0) - goto out; + if (ret < 0) + goto out; + } + if (nfsi->cache_validity & NFS_INO_INVALID_DATA) + ret = nfs_invalidate_mapping_nolock(inode, mapping); +out: + return ret; +} - if (nfsi->cache_validity & NFS_INO_INVALID_DATA) { - if (mapping->nrpages != 0) { - if (S_ISREG(inode->i_mode)) { - ret = nfs_sync_mapping(mapping); - if (ret < 0) - goto out; - } - ret = invalidate_inode_pages2(mapping); - if (ret < 0) - goto out; - } - spin_lock(&inode->i_lock); - nfsi->cache_validity &= ~NFS_INO_INVALID_DATA; - if (S_ISDIR(inode->i_mode)) { - memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf)); - /* This ensures we revalidate child dentries */ - nfsi->cache_change_attribute = jiffies; - } - spin_unlock(&inode->i_lock); +/** + * nfs_revalidate_mapping - Revalidate the pagecache + * @inode - pointer to host inode + * @mapping - pointer to mapping + * + * This version of the function will take the inode->i_mutex and attempt to + * flush out all dirty data if it needs to invalidate the page cache. + */ +int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping) +{ + struct nfs_inode *nfsi = NFS_I(inode); + int ret = 0; - nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE); - dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n", - inode->i_sb->s_id, - (long long)NFS_FILEID(inode)); + if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) + || nfs_attribute_timeout(inode) || NFS_STALE(inode)) { + ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode); + if (ret < 0) + goto out; } + if (nfsi->cache_validity & NFS_INO_INVALID_DATA) + ret = nfs_invalidate_mapping(inode, mapping); out: return ret; } diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c index 6c686112cc03..525c136c7d8c 100644 --- a/fs/nfs/symlink.c +++ b/fs/nfs/symlink.c @@ -50,7 +50,9 @@ static void *nfs_follow_link(struct dentry *dentry, struct nameidata *nd) { struct inode *inode = dentry->d_inode; struct page *page; - void *err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping)); + void *err; + + err = ERR_PTR(nfs_revalidate_mapping_nolock(inode, inode->i_mapping)); if (err) goto read_failed; page = read_cache_page(&inode->i_data, 0, -- cgit v1.2.3