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 <[email protected]>
---
fs/nfs/inode.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++-----
fs/nfs/write.c | 2 ++
2 files changed, 63 insertions(+), 6 deletions(-)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 2c23d06..3adabd1 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -389,6 +389,62 @@ nfs_setattr(struct dentry *dentry, struct iattr *attr)
}
/**
+ * 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
* @attr: pointer to struct iattr
@@ -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 21d8a48..8f12157 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -145,7 +145,9 @@ static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int c
if (i_size >= end)
return;
nfs_inc_stats(inode, NFSIOS_EXTENDWRITE);
+ spin_lock(&inode->i_lock);
i_size_write(inode, end);
+ spin_unlock(&inode->i_lock);
}
/* A writeback failed: mark the page as bad, and invalidate the page cache */