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authorMiklos Szeredi <mszeredi@suse.cz>2008-07-25 01:49:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-25 10:53:48 -0700
commitdbd561d236ff16f8143bc727d91758ddd190e8cb (patch)
treeaac8fb4d98c3f425b2f5bf404af7d82182f19bc0 /fs/fuse
parent0de6256daafa3a97a269995e9b29f956bd419bbf (diff)
downloadconfigs-dbd561d236ff16f8143bc727d91758ddd190e8cb.tar.gz
fuse: add export operations
Implement export_operations, to allow fuse filesystems to be exported to NFS. This feature has been in the out-of-tree fuse module, and is widely used and tested. It has not been originally merged into mainline, because doing the NFS export in userspace was thought to be a cleaner and more efficient way of doing it, than through the kernel. While that is true, it would also have involved a lot of duplicated effort at reimplementing NFS exporting (all the different versions of the protocol). This effort was unfortunately not undertaken by anyone, so we are left with doing it the easy but less efficient way. If this feature goes in, the out-of-tree fuse module can go away, which would have several advantages: - not having to maintain two versions - less confusion for users - no bugs due to kernel API changes Comment from hch: - Use the same fh_type values as XFS, since we use the same fh encoding. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> 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/dir.c4
-rw-r--r--fs/fuse/fuse_i.h4
-rw-r--r--fs/fuse/inode.c115
3 files changed, 121 insertions, 2 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index e5217b213b4..be5450dd638 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -97,7 +97,7 @@ void fuse_invalidate_attr(struct inode *inode)
* timeout is unknown (unlink, rmdir, rename and in some cases
* lookup)
*/
-static void fuse_invalidate_entry_cache(struct dentry *entry)
+void fuse_invalidate_entry_cache(struct dentry *entry)
{
fuse_dentry_settime(entry, 0);
}
@@ -225,7 +225,7 @@ static int invalid_nodeid(u64 nodeid)
return !nodeid || nodeid == FUSE_ROOT_ID;
}
-static struct dentry_operations fuse_dentry_operations = {
+struct dentry_operations fuse_dentry_operations = {
.d_revalidate = fuse_dentry_revalidate,
};
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index bae948657c4..5d3146da64e 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -464,6 +464,8 @@ static inline u64 get_node_id(struct inode *inode)
/** Device operations */
extern const struct file_operations fuse_dev_operations;
+extern struct dentry_operations fuse_dentry_operations;
+
/**
* Get a filled in inode
*/
@@ -604,6 +606,8 @@ void fuse_abort_conn(struct fuse_conn *fc);
*/
void fuse_invalidate_attr(struct inode *inode);
+void fuse_invalidate_entry_cache(struct dentry *entry);
+
/**
* Acquire reference to fuse_conn
*/
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 3141690558c..71fa76a48a3 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -18,6 +18,7 @@
#include <linux/statfs.h>
#include <linux/random.h>
#include <linux/sched.h>
+#include <linux/exportfs.h>
MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
MODULE_DESCRIPTION("Filesystem in Userspace");
@@ -552,6 +553,119 @@ static struct inode *get_root_inode(struct super_block *sb, unsigned mode)
return fuse_iget(sb, 1, 0, &attr, 0, 0);
}
+struct fuse_inode_handle
+{
+ u64 nodeid;
+ u32 generation;
+};
+
+static struct dentry *fuse_get_dentry(struct super_block *sb,
+ struct fuse_inode_handle *handle)
+{
+ struct inode *inode;
+ struct dentry *entry;
+ int err = -ESTALE;
+
+ if (handle->nodeid == 0)
+ goto out_err;
+
+ inode = ilookup5(sb, handle->nodeid, fuse_inode_eq, &handle->nodeid);
+ if (!inode)
+ goto out_err;
+ err = -ESTALE;
+ if (inode->i_generation != handle->generation)
+ goto out_iput;
+
+ entry = d_alloc_anon(inode);
+ err = -ENOMEM;
+ if (!entry)
+ goto out_iput;
+
+ if (get_node_id(inode) != FUSE_ROOT_ID) {
+ entry->d_op = &fuse_dentry_operations;
+ fuse_invalidate_entry_cache(entry);
+ }
+
+ return entry;
+
+ out_iput:
+ iput(inode);
+ out_err:
+ return ERR_PTR(err);
+}
+
+static int fuse_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,
+ int connectable)
+{
+ struct inode *inode = dentry->d_inode;
+ bool encode_parent = connectable && !S_ISDIR(inode->i_mode);
+ int len = encode_parent ? 6 : 3;
+ u64 nodeid;
+ u32 generation;
+
+ if (*max_len < len)
+ return 255;
+
+ nodeid = get_fuse_inode(inode)->nodeid;
+ generation = inode->i_generation;
+
+ fh[0] = (u32)(nodeid >> 32);
+ fh[1] = (u32)(nodeid & 0xffffffff);
+ fh[2] = generation;
+
+ if (encode_parent) {
+ struct inode *parent;
+
+ spin_lock(&dentry->d_lock);
+ parent = dentry->d_parent->d_inode;
+ nodeid = get_fuse_inode(parent)->nodeid;
+ generation = parent->i_generation;
+ spin_unlock(&dentry->d_lock);
+
+ fh[3] = (u32)(nodeid >> 32);
+ fh[4] = (u32)(nodeid & 0xffffffff);
+ fh[5] = generation;
+ }
+
+ *max_len = len;
+ return encode_parent ? 0x82 : 0x81;
+}
+
+static struct dentry *fuse_fh_to_dentry(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ struct fuse_inode_handle handle;
+
+ if ((fh_type != 0x81 && fh_type != 0x82) || fh_len < 3)
+ return NULL;
+
+ handle.nodeid = (u64) fid->raw[0] << 32;
+ handle.nodeid |= (u64) fid->raw[1];
+ handle.generation = fid->raw[2];
+ return fuse_get_dentry(sb, &handle);
+}
+
+static struct dentry *fuse_fh_to_parent(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ struct fuse_inode_handle parent;
+
+ if (fh_type != 0x82 || fh_len < 6)
+ return NULL;
+
+ parent.nodeid = (u64) fid->raw[3] << 32;
+ parent.nodeid |= (u64) fid->raw[4];
+ parent.generation = fid->raw[5];
+ return fuse_get_dentry(sb, &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,
+};
+
static const struct super_operations fuse_super_operations = {
.alloc_inode = fuse_alloc_inode,
.destroy_inode = fuse_destroy_inode,
@@ -652,6 +766,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
sb->s_magic = FUSE_SUPER_MAGIC;
sb->s_op = &fuse_super_operations;
sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_export_op = &fuse_export_operations;
file = fget(d.fd);
if (!file)