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authorMiklos Szeredi <mszeredi@suse.cz>2008-07-25 01:49:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-25 10:53:48 -0700
commit33670fa296860283f04a7975b8c790f101e43a6e (patch)
tree61162737edbffe696f4f9b13998d192cd3be3f75 /fs/fuse
parentc180eebe1390c2076ead6a9bc95a02efb994edb7 (diff)
downloadconfigs-33670fa296860283f04a7975b8c790f101e43a6e.tar.gz
fuse: nfs export special lookups
Implement the get_parent export operation by sending a LOOKUP request with ".." as the name. Implement looking up an inode by node ID after it has been evicted from the cache. This is done by seding a LOOKUP request with "." as the name (for all file types, not just directories). The filesystem can set the FUSE_EXPORT_SUPPORT flag in the INIT reply, to indicate that it supports these special lookups. Thanks to John Muir for the original implementation of this feature. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Matthew Wilcox <matthew@wil.cx> Cc: David Teigland <teigland@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/fuse')
-rw-r--r--fs/fuse/fuse_i.h6
-rw-r--r--fs/fuse/inode.c66
2 files changed, 69 insertions, 3 deletions
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 5d3146da64e..3a876076bdd 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -363,6 +363,9 @@ struct fuse_conn {
/** Do not send separate SETATTR request before open(O_TRUNC) */
unsigned atomic_o_trunc : 1;
+ /** Filesystem supports NFS exporting. Only set in INIT */
+ unsigned export_support : 1;
+
/*
* The following bitfields are only for optimization purposes
* and hence races in setting them will not cause malfunction
@@ -473,6 +476,9 @@ struct inode *fuse_iget(struct super_block *sb, u64 nodeid,
int generation, struct fuse_attr *attr,
u64 attr_valid, u64 attr_version);
+int fuse_lookup_name(struct super_block *sb, u64 nodeid, struct qstr *name,
+ struct fuse_entry_out *outarg, struct inode **inode);
+
/**
* Send FORGET command
*/
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 71fa76a48a3..7d2f7d6e22e 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -562,6 +562,7 @@ struct fuse_inode_handle
static struct dentry *fuse_get_dentry(struct super_block *sb,
struct fuse_inode_handle *handle)
{
+ struct fuse_conn *fc = get_fuse_conn_super(sb);
struct inode *inode;
struct dentry *entry;
int err = -ESTALE;
@@ -570,8 +571,27 @@ static struct dentry *fuse_get_dentry(struct super_block *sb,
goto out_err;
inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
- if (!inode)
- goto out_err;
+ if (!inode) {
+ struct fuse_entry_out outarg;
+ struct qstr name;
+
+ if (!fc->export_support)
+ goto out_err;
+
+ name.len = 1;
+ name.name = ".";
+ err = fuse_lookup_name(sb, handle->nodeid, &name, &outarg,
+ &inode);
+ if (err && err != -ENOENT)
+ goto out_err;
+ if (err || !inode) {
+ err = -ESTALE;
+ goto out_err;
+ }
+ err = -EIO;
+ if (get_node_id(inode) != handle->nodeid)
+ goto out_iput;
+ }
err = -ESTALE;
if (inode->i_generation != handle->generation)
goto out_iput;
@@ -659,11 +679,46 @@ static struct dentry *fuse_fh_to_parent(struct super_block *sb,
return fuse_get_dentry(sb, &parent);
}
+static struct dentry *fuse_get_parent(struct dentry *child)
+{
+ struct inode *child_inode = child->d_inode;
+ struct fuse_conn *fc = get_fuse_conn(child_inode);
+ struct inode *inode;
+ struct dentry *parent;
+ struct fuse_entry_out outarg;
+ struct qstr name;
+ int err;
+
+ if (!fc->export_support)
+ return ERR_PTR(-ESTALE);
+
+ name.len = 2;
+ name.name = "..";
+ err = fuse_lookup_name(child_inode->i_sb, get_node_id(child_inode),
+ &name, &outarg, &inode);
+ if (err && err != -ENOENT)
+ return ERR_PTR(err);
+ if (err || !inode)
+ return ERR_PTR(-ESTALE);
+
+ parent = d_alloc_anon(inode);
+ if (!parent) {
+ iput(inode);
+ return ERR_PTR(-ENOMEM);
+ }
+ if (get_node_id(inode) != FUSE_ROOT_ID) {
+ parent->d_op = &fuse_dentry_operations;
+ fuse_invalidate_entry_cache(parent);
+ }
+
+ return parent;
+}
static const struct export_operations fuse_export_operations = {
.fh_to_dentry = fuse_fh_to_dentry,
.fh_to_parent = fuse_fh_to_parent,
.encode_fh = fuse_encode_fh,
+ .get_parent = fuse_get_parent,
};
static const struct super_operations fuse_super_operations = {
@@ -695,6 +750,11 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
fc->no_lock = 1;
if (arg->flags & FUSE_ATOMIC_O_TRUNC)
fc->atomic_o_trunc = 1;
+ if (arg->minor >= 9) {
+ /* LOOKUP has dependency on proto version */
+ if (arg->flags & FUSE_EXPORT_SUPPORT)
+ fc->export_support = 1;
+ }
if (arg->flags & FUSE_BIG_WRITES)
fc->big_writes = 1;
} else {
@@ -721,7 +781,7 @@ static void fuse_send_init(struct fuse_conn *fc, struct fuse_req *req)
arg->minor = FUSE_KERNEL_MINOR_VERSION;
arg->max_readahead = fc->bdi.ra_pages * PAGE_CACHE_SIZE;
arg->flags |= FUSE_ASYNC_READ | FUSE_POSIX_LOCKS | FUSE_ATOMIC_O_TRUNC |
- FUSE_BIG_WRITES;
+ FUSE_EXPORT_SUPPORT | FUSE_BIG_WRITES;
req->in.h.opcode = FUSE_INIT;
req->in.numargs = 1;
req->in.args[0].size = sizeof(*arg);