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[PATCH] NFS: Fix races in nfs_revalidate_mapping()

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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>
This commit is contained in:
Trond Myklebust 2007-01-24 11:54:55 -08:00 committed by Linus Torvalds
parent bde8f00ce6
commit 717d44e849
4 changed files with 72 additions and 32 deletions
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2
fs/nfs/dir.c
View File

@ -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;

97
fs/nfs/inode.c
View File

@ -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_nolock - Revalidate the pagecache
* @inode - pointer to host inode
* @mapping - pointer to mapping
*/
int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)
{
struct nfs_inode *nfsi = NFS_I(inode);
int ret = 0;
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_nolock(inode, mapping);
out:
return ret;
}
/**
* 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;
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 (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_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 (ret < 0)
goto out;
}
if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
ret = nfs_invalidate_mapping(inode, mapping);
out:
return ret;
}

4
fs/nfs/symlink.c
View File

@ -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,

1
include/linux/nfs_fs.h
View File

@ -308,6 +308,7 @@ extern int nfs_attribute_timeout(struct inode *inode);
extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode);
extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
extern int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping);
extern int nfs_setattr(struct dentry *, struct iattr *);
extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr);
extern void nfs_begin_attr_update(struct inode *);