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authorTrond Myklebust <Trond.Myklebust@netapp.com>2007-01-24 14:54:55 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-01-24 15:31:06 -0500
commit717d44e849219781ced028a40fcc59d3e1f49e4c (patch)
treeaa34a9b84377d18ff58901cc342b84c7e8b81dca /fs/nfs
parentbde8f00ce64d9824a4f227c8594e335a1a10d044 (diff)
[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 <Trond.Myklebust@netapp.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/dir.c2
-rw-r--r--fs/nfs/inode.c97
-rw-r--r--fs/nfs/symlink.c4
3 files changed, 71 insertions, 32 deletions
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)
532 532
533 lock_kernel(); 533 lock_kernel();
534 534
535 res = nfs_revalidate_mapping(inode, filp->f_mapping); 535 res = nfs_revalidate_mapping_nolock(inode, filp->f_mapping);
536 if (res < 0) { 536 if (res < 0) {
537 unlock_kernel(); 537 unlock_kernel();
538 return res; 538 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)
665 return __nfs_revalidate_inode(server, inode); 665 return __nfs_revalidate_inode(server, inode);
666} 666}
667 667
668static int nfs_invalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)
669{
670 struct nfs_inode *nfsi = NFS_I(inode);
671
672 if (mapping->nrpages != 0) {
673 int ret = invalidate_inode_pages2(mapping);
674 if (ret < 0)
675 return ret;
676 }
677 spin_lock(&inode->i_lock);
678 nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
679 if (S_ISDIR(inode->i_mode)) {
680 memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
681 /* This ensures we revalidate child dentries */
682 nfsi->cache_change_attribute = jiffies;
683 }
684 spin_unlock(&inode->i_lock);
685 nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
686 dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",
687 inode->i_sb->s_id, (long long)NFS_FILEID(inode));
688 return 0;
689}
690
691static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)
692{
693 int ret = 0;
694
695 mutex_lock(&inode->i_mutex);
696 if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_DATA) {
697 ret = nfs_sync_mapping(mapping);
698 if (ret == 0)
699 ret = nfs_invalidate_mapping_nolock(inode, mapping);
700 }
701 mutex_unlock(&inode->i_mutex);
702 return ret;
703}
704
668/** 705/**
669 * nfs_revalidate_mapping - Revalidate the pagecache 706 * nfs_revalidate_mapping_nolock - Revalidate the pagecache
670 * @inode - pointer to host inode 707 * @inode - pointer to host inode
671 * @mapping - pointer to mapping 708 * @mapping - pointer to mapping
672 */ 709 */
673int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping) 710int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)
674{ 711{
675 struct nfs_inode *nfsi = NFS_I(inode); 712 struct nfs_inode *nfsi = NFS_I(inode);
676 int ret = 0; 713 int ret = 0;
677 714
678 if (NFS_STALE(inode))
679 ret = -ESTALE;
680 if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) 715 if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
681 || nfs_attribute_timeout(inode)) 716 || nfs_attribute_timeout(inode) || NFS_STALE(inode)) {
682 ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode); 717 ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
683 if (ret < 0) 718 if (ret < 0)
684 goto out; 719 goto out;
720 }
721 if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
722 ret = nfs_invalidate_mapping_nolock(inode, mapping);
723out:
724 return ret;
725}
685 726
686 if (nfsi->cache_validity & NFS_INO_INVALID_DATA) { 727/**
687 if (mapping->nrpages != 0) { 728 * nfs_revalidate_mapping - Revalidate the pagecache
688 if (S_ISREG(inode->i_mode)) { 729 * @inode - pointer to host inode
689 ret = nfs_sync_mapping(mapping); 730 * @mapping - pointer to mapping
690 if (ret < 0) 731 *
691 goto out; 732 * This version of the function will take the inode->i_mutex and attempt to
692 } 733 * flush out all dirty data if it needs to invalidate the page cache.
693 ret = invalidate_inode_pages2(mapping); 734 */
694 if (ret < 0) 735int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
695 goto out; 736{
696 } 737 struct nfs_inode *nfsi = NFS_I(inode);
697 spin_lock(&inode->i_lock); 738 int ret = 0;
698 nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
699 if (S_ISDIR(inode->i_mode)) {
700 memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
701 /* This ensures we revalidate child dentries */
702 nfsi->cache_change_attribute = jiffies;
703 }
704 spin_unlock(&inode->i_lock);
705 739
706 nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE); 740 if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
707 dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n", 741 || nfs_attribute_timeout(inode) || NFS_STALE(inode)) {
708 inode->i_sb->s_id, 742 ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
709 (long long)NFS_FILEID(inode)); 743 if (ret < 0)
744 goto out;
710 } 745 }
746 if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
747 ret = nfs_invalidate_mapping(inode, mapping);
711out: 748out:
712 return ret; 749 return ret;
713} 750}
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)
50{ 50{
51 struct inode *inode = dentry->d_inode; 51 struct inode *inode = dentry->d_inode;
52 struct page *page; 52 struct page *page;
53 void *err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping)); 53 void *err;
54
55 err = ERR_PTR(nfs_revalidate_mapping_nolock(inode, inode->i_mapping));
54 if (err) 56 if (err)
55 goto read_failed; 57 goto read_failed;
56 page = read_cache_page(&inode->i_data, 0, 58 page = read_cache_page(&inode->i_data, 0,