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Date: Thu, 20 Sep 2007 17:13:05 -0700
From: akpm@...ux-foundation.org
To: mm-commits@...r.kernel.org
Cc: hch@....de, aia21@...tab.net, bfields@...ldses.org, dgc@....com,
hirofumi@...l.parknet.co.jp, hugh@...itas.com, jeffm@...e.com,
linux-ext4@...r.kernel.org, mark.fasheh@...cle.com, mason@...e.com,
neilb@...e.de, shaggy@...tin.ibm.com, swhiteho@...hat.com,
tes@....com, vs@...esys.com
Subject: + exportfs-add-new-methods.patch added to -mm tree
The patch titled
exportfs: add new methods
has been added to the -mm tree. Its filename is
exportfs-add-new-methods.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: exportfs: add new methods
From: Christoph Hellwig <hch@....de>
Add the guts for the new filesystem API to exportfs.
There's now a fh_to_dentry method that returns a dentry for the object looked
for given a filehandle fragment, and a fh_to_parent operation that returns the
dentry for the encoded parent directory in case the file handle contains it.
There are default implementations for these methods that only take a callback
for an nfs-enhanced iget variant and implement the rest of the semantics.
Signed-off-by: Christoph Hellwig <hch@....de>
Cc: Neil Brown <neilb@...e.de>
Cc: "J. Bruce Fields" <bfields@...ldses.org>
Cc: <linux-ext4@...r.kernel.org>
Cc: Dave Kleikamp <shaggy@...tin.ibm.com>
Cc: Anton Altaparmakov <aia21@...tab.net>
Cc: David Chinner <dgc@....com>
Cc: Timothy Shimmin <tes@....com>
Cc: OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
Cc: Hugh Dickins <hugh@...itas.com>
Cc: Chris Mason <mason@...e.com>
Cc: Jeff Mahoney <jeffm@...e.com>
Cc: "Vladimir V. Saveliev" <vs@...esys.com>
Cc: Steven Whitehouse <swhiteho@...hat.com>
Cc: Mark Fasheh <mark.fasheh@...cle.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
---
fs/exportfs/expfs.c | 136 +++++++++++++++++++++++++++++++++++--
fs/libfs.c | 88 +++++++++++++++++++++++
include/linux/exportfs.h | 30 ++++++++
3 files changed, 248 insertions(+), 6 deletions(-)
diff -puN fs/exportfs/expfs.c~exportfs-add-new-methods fs/exportfs/expfs.c
--- a/fs/exportfs/expfs.c~exportfs-add-new-methods
+++ a/fs/exportfs/expfs.c
@@ -514,17 +514,141 @@ struct dentry *exportfs_decode_fh(struct
int (*acceptable)(void *, struct dentry *), void *context)
{
struct export_operations *nop = mnt->mnt_sb->s_export_op;
- struct dentry *result;
+ struct dentry *result, *alias;
+ int err;
- if (nop->decode_fh) {
- result = nop->decode_fh(mnt->mnt_sb, fid->raw, fh_len,
+ /*
+ * Old way of doing things. Will go away soon.
+ */
+ if (!nop->fh_to_dentry) {
+ if (nop->decode_fh) {
+ return nop->decode_fh(mnt->mnt_sb, fid->raw, fh_len,
fileid_type, acceptable, context);
+ } else {
+ return export_decode_fh(mnt->mnt_sb, fid->raw, fh_len,
+ fileid_type, acceptable, context);
+ }
+ }
+
+ /*
+ * Try to get any dentry for the given file handle from the filesystem.
+ */
+ result = nop->fh_to_dentry(mnt->mnt_sb, fid, fh_len, fileid_type);
+ if (!result)
+ result = ERR_PTR(-ESTALE);
+ if (IS_ERR(result))
+ return result;
+
+ if (S_ISDIR(result->d_inode->i_mode)) {
+ /*
+ * This request is for a directory.
+ *
+ * On the positive side there is only one dentry for each
+ * directory inode. On the negative side this implies that we
+ * to ensure our dentry is connected all the way up to the
+ * filesystem root.
+ */
+ if (result->d_flags & DCACHE_DISCONNECTED) {
+ err = reconnect_path(mnt->mnt_sb, result);
+ if (err)
+ goto err_result;
+ }
+
+ if (!acceptable(context, result)) {
+ err = -EACCES;
+ goto err_result;
+ }
+
+ return result;
} else {
- result = export_decode_fh(mnt->mnt_sb, fid->raw, fh_len,
- fileid_type, acceptable, context);
+ /*
+ * It's not a directory. Life is a little more complicated.
+ */
+ struct dentry *target_dir, *nresult;
+ char nbuf[NAME_MAX+1];
+
+ /*
+ * See if either the dentry we just got from the filesystem
+ * or any alias for it is acceptable. This is always true
+ * if this filesystem is exported without the subtreecheck
+ * option. If the filesystem is exported with the subtree
+ * check option there's a fair chance we need to look at
+ * the parent directory in the file handle and make sure
+ * it's connected to the filesystem root.
+ */
+ alias = find_acceptable_alias(result, acceptable, context);
+ if (alias)
+ return alias;
+
+ /*
+ * Try to extract a dentry for the parent directory from the
+ * file handle. If this fails we'll have to give up.
+ */
+ err = -ESTALE;
+ if (!nop->fh_to_parent)
+ goto err_result;
+
+ target_dir = nop->fh_to_parent(mnt->mnt_sb, fid,
+ fh_len, fileid_type);
+ if (!target_dir)
+ goto err_result;
+ err = PTR_ERR(target_dir);
+ if (IS_ERR(target_dir))
+ goto err_result;
+
+ /*
+ * And as usual we need to make sure the parent directory is
+ * connected to the filesystem root. The VFS really doesn't
+ * like disconnected directories..
+ */
+ err = reconnect_path(mnt->mnt_sb, target_dir);
+ if (err) {
+ dput(target_dir);
+ goto err_result;
+ }
+
+ /*
+ * Now that we've got both a well-connected parent and a
+ * dentry for the inode we're after, make sure that our
+ * inode is actually connected to the parent.
+ */
+ err = exportfs_get_name(target_dir, nbuf, result);
+ if (!err) {
+ mutex_lock(&target_dir->d_inode->i_mutex);
+ nresult = lookup_one_len(nbuf, target_dir,
+ strlen(nbuf));
+ mutex_unlock(&target_dir->d_inode->i_mutex);
+ if (!IS_ERR(nresult)) {
+ if (nresult->d_inode) {
+ dput(result);
+ result = nresult;
+ } else
+ dput(nresult);
+ }
+ }
+
+ /*
+ * At this point we are done with the parent, but it's pinned
+ * by the child dentry anyway.
+ */
+ dput(target_dir);
+
+ /*
+ * And finally make sure the dentry is actually acceptable
+ * to NFSD.
+ */
+ alias = find_acceptable_alias(result, acceptable, context);
+ if (!alias) {
+ err = -EACCES;
+ goto err_result;
+ }
+
+ return alias;
}
- return result;
+ err_result:
+ dput(result);
+ return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(exportfs_decode_fh);
diff -puN fs/libfs.c~exportfs-add-new-methods fs/libfs.c
--- a/fs/libfs.c~exportfs-add-new-methods
+++ a/fs/libfs.c
@@ -8,6 +8,7 @@
#include <linux/mount.h>
#include <linux/vfs.h>
#include <linux/mutex.h>
+#include <linux/exportfs.h>
#include <asm/uaccess.h>
@@ -678,6 +679,93 @@ out:
return ret;
}
+/*
+ * This is what d_alloc_anon should have been. Once the exportfs
+ * argument transition has been finished I will update d_alloc_anon
+ * to this prototype and this wrapper will go away. --hch
+ */
+static struct dentry *exportfs_d_alloc(struct inode *inode)
+{
+ struct dentry *dentry;
+
+ if (!inode)
+ return NULL;
+ if (IS_ERR(inode))
+ return ERR_PTR(PTR_ERR(inode));
+
+ dentry = d_alloc_anon(inode);
+ if (!dentry) {
+ iput(inode);
+ dentry = ERR_PTR(-ENOMEM);
+ }
+ return dentry;
+}
+
+/**
+ * generic_fh_to_dentry - generic helper for the fh_to_dentry export operation
+ * @sb: filesystem to do the file handle conversion on
+ * @fid: file handle to convert
+ * @fh_len: length of the file handle in bytes
+ * @fh_type: type of file handle
+ * @get_inode: filesystem callback to retrieve inode
+ *
+ * This function decodes @fid as long as it has one of the well-known
+ * Linux filehandle types and calls @get_inode on it to retrieve the
+ * inode for the object specified in the file handle.
+ */
+struct dentry *generic_fh_to_dentry(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type, struct inode *(*get_inode)
+ (struct super_block *sb, u64 ino, u32 gen))
+{
+ struct inode *inode = NULL;
+
+ if (fh_len < 2)
+ return NULL;
+
+ switch (fh_type) {
+ case FILEID_INO32_GEN:
+ case FILEID_INO32_GEN_PARENT:
+ inode = get_inode(sb, fid->i32.ino, fid->i32.gen);
+ break;
+ }
+
+ return exportfs_d_alloc(inode);
+}
+EXPORT_SYMBOL_GPL(generic_fh_to_dentry);
+
+/**
+ * generic_fh_to_dentry - generic helper for the fh_to_parent export operation
+ * @sb: filesystem to do the file handle conversion on
+ * @fid: file handle to convert
+ * @fh_len: length of the file handle in bytes
+ * @fh_type: type of file handle
+ * @get_inode: filesystem callback to retrieve inode
+ *
+ * This function decodes @fid as long as it has one of the well-known
+ * Linux filehandle types and calls @get_inode on it to retrieve the
+ * inode for the _parent_ object specified in the file handle if it
+ * is specified in the file handle, or NULL otherwise.
+ */
+struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type, struct inode *(*get_inode)
+ (struct super_block *sb, u64 ino, u32 gen))
+{
+ struct inode *inode = NULL;
+
+ if (fh_len <= 2)
+ return NULL;
+
+ switch (fh_type) {
+ case FILEID_INO32_GEN_PARENT:
+ inode = get_inode(sb, fid->i32.parent_ino,
+ (fh_len > 3 ? fid->i32.parent_gen : 0));
+ break;
+ }
+
+ return exportfs_d_alloc(inode);
+}
+EXPORT_SYMBOL_GPL(generic_fh_to_parent);
+
EXPORT_SYMBOL(dcache_dir_close);
EXPORT_SYMBOL(dcache_dir_lseek);
EXPORT_SYMBOL(dcache_dir_open);
diff -puN include/linux/exportfs.h~exportfs-add-new-methods include/linux/exportfs.h
--- a/include/linux/exportfs.h~exportfs-add-new-methods
+++ a/include/linux/exportfs.h
@@ -4,6 +4,7 @@
#include <linux/types.h>
struct dentry;
+struct inode;
struct super_block;
struct vfsmount;
@@ -101,6 +102,21 @@ struct fid {
* the filehandle fragment. encode_fh() should return the number of bytes
* stored or a negative error code such as %-ENOSPC
*
+ * fh_to_dentry:
+ * @fh_to_dentry is given a &struct super_block (@sb) and a file handle
+ * fragment (@fh, @fh_len). It should return a &struct dentry which refers
+ * to the same file that the file handle fragment refers to. If it cannot,
+ * it should return a %NULL pointer if the file was found but no acceptable
+ * &dentries were available, or an %ERR_PTR error code indicating why it
+ * couldn't be found (e.g. %ENOENT or %ENOMEM). Any suitable dentry can be
+ * returned including, if necessary, a new dentry created with d_alloc_root.
+ * The caller can then find any other extant dentries by following the
+ * d_alias links.
+ *
+ * fh_to_parent:
+ * Same as @fh_to_dentry, except that it returns a pointer to the parent
+ * dentry if it was encoded into the filehandle fragment by @encode_fh.
+ *
* get_name:
* @get_name should find a name for the given @child in the given @parent
* directory. The name should be stored in the @name (with the
@@ -139,6 +155,10 @@ struct export_operations {
void *context);
int (*encode_fh)(struct dentry *de, __u32 *fh, int *max_len,
int connectable);
+ struct dentry * (*fh_to_dentry)(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type);
+ struct dentry * (*fh_to_parent)(struct super_block *sb, struct fid *fid,
+ int fh_len, int fh_type);
int (*get_name)(struct dentry *parent, char *name,
struct dentry *child);
struct dentry * (*get_parent)(struct dentry *child);
@@ -161,4 +181,14 @@ extern struct dentry *exportfs_decode_fh
int fh_len, int fileid_type, int (*acceptable)(void *, struct dentry *),
void *context);
+/*
+ * Generic helpers for filesystems.
+ */
+extern struct dentry *generic_fh_to_dentry(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type,
+ struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
+extern struct dentry *generic_fh_to_parent(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type,
+ struct inode *(*get_inode) (struct super_block *sb, u64 ino, u32 gen));
+
#endif /* LINUX_EXPORTFS_H */
_
Patches currently in -mm which might be from hch@....de are
git-nfs.patch
git-nfsd.patch
partially-fix-up-the-lookup_one_noperm-mess.patch
optimize-x86-page-faults-like-all-other-achitectures-and-kill-notifier-cruft.patch
optimize-x86-page-faults-like-all-other-achitectures-and-kill-notifier-cruft-fix.patch
git-xfs.patch
sysv-convert-to-new-aops.patch
alpha-convert-to-generic-sys_ptrace.patch
kill-declare_mutex_locked.patch
remove-unneded-lock_kernel-in-driver-block-loopc.patch
ufs-move-non-layout-parts-of-ufs_fsh-to-fs-ufs.patch
fix-execute-checking-in-permission.patch
exec-remove-unnecessary-check-for-mnt_noexec.patch
fix-f_version-type-should-be-u64-instead-of-unsigned-long.patch
unprivileged-mounts-add-user-mounts-to-the-kernel.patch
unprivileged-mounts-allow-unprivileged-umount.patch
unprivileged-mounts-account-user-mounts.patch
unprivileged-mounts-propagate-error-values-from-clone_mnt.patch
unprivileged-mounts-allow-unprivileged-bind-mounts.patch
unprivileged-mounts-put-declaration-of-put_filesystem-in-fsh.patch
unprivileged-mounts-allow-unprivileged-mounts.patch
unprivileged-mounts-allow-unprivileged-fuse-mounts.patch
unprivileged-mounts-propagation-inherit-owner-from-parent.patch
unprivileged-mounts-add-no-submounts-flag.patch
revoke-special-mmap-handling.patch
revoke-core-code.patch
revoke-support-for-ext2-and-ext3.patch
revoke-add-documentation.patch
revoke-wire-up-i386-system-calls.patch
exportfs-add-fid-type.patch
exportfs-add-new-methods.patch
ext2-new-export-ops.patch
ext3-new-export-ops.patch
ext4-new-export-ops.patch
efs-new-export-ops.patch
jfs-new-export-ops.patch
ntfs-new-export-ops.patch
xfs-new-export-ops.patch
fat-new-export-ops.patch
isofs-new-export-ops.patch
shmem-new-export-ops.patch
reiserfs-new-export-ops.patch
gfs2-new-export-ops.patch
ocfs2-new-export-ops.patch
exportfs-remove-old-methods.patch
exportfs-make-struct-export_operations-const.patch
exportfs-update-documentation.patch
-
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