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authorDavid Howells <dhowells@redhat.com>2019-12-10 15:31:13 +0300
committerAnna Schumaker <Anna.Schumaker@Netapp.com>2020-01-15 18:15:17 +0300
commitf2aedb713c284429987dc66c7aaf38decfc8da2a (patch)
tree01978da583f0b64bb524dde8825dbaeb0934c615 /fs/nfs/nfs4namespace.c
parente38bb238ed8ce280a217629294ba51dc217c5a2c (diff)
downloadlinux-f2aedb713c284429987dc66c7aaf38decfc8da2a.tar.xz
NFS: Add fs_context support.
Add filesystem context support to NFS, parsing the options in advance and attaching the information to struct nfs_fs_context. The highlights are: (*) Merge nfs_mount_info and nfs_clone_mount into nfs_fs_context. This structure represents NFS's superblock config. (*) Make use of the VFS's parsing support to split comma-separated lists (*) Pin the NFS protocol module in the nfs_fs_context. (*) Attach supplementary error information to fs_context. This has the downside that these strings must be static and can't be formatted. (*) Remove the auxiliary file_system_type structs since the information necessary can be conveyed in the nfs_fs_context struct instead. (*) Root mounts are made by duplicating the config for the requested mount so as to have the same parameters. Submounts pick up their parameters from the parent superblock. [AV -- retrans is u32, not string] [SM -- Renamed cfg to ctx in a few functions in an earlier patch] [SM -- Moved fs_context mount option parsing to an earlier patch] [SM -- Moved fs_context error logging to a later patch] [SM -- Fixed printks in nfs4_try_get_tree() and nfs4_get_referral_tree()] [SM -- Added is_remount_fc() helper] [SM -- Deferred some refactoring to a later patch] [SM -- Fixed referral mounts, which were broken in the original patch] [SM -- Fixed leak of nfs_fattr when fs_context is freed] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Scott Mayhew <smayhew@redhat.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'fs/nfs/nfs4namespace.c')
-rw-r--r--fs/nfs/nfs4namespace.c293
1 files changed, 172 insertions, 121 deletions
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 2e460c33ae48..a1a0c4c53ce1 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -8,6 +8,7 @@
* NFSv4 namespace
*/
+#include <linux/module.h>
#include <linux/dcache.h>
#include <linux/mount.h>
#include <linux/namei.h>
@@ -21,37 +22,64 @@
#include <linux/inet.h>
#include "internal.h"
#include "nfs4_fs.h"
+#include "nfs.h"
#include "dns_resolve.h"
#define NFSDBG_FACILITY NFSDBG_VFS
/*
+ * Work out the length that an NFSv4 path would render to as a standard posix
+ * path, with a leading slash but no terminating slash.
+ */
+static ssize_t nfs4_pathname_len(const struct nfs4_pathname *pathname)
+{
+ ssize_t len = 0;
+ int i;
+
+ for (i = 0; i < pathname->ncomponents; i++) {
+ const struct nfs4_string *component = &pathname->components[i];
+
+ if (component->len > NAME_MAX)
+ goto too_long;
+ len += 1 + component->len; /* Adding "/foo" */
+ if (len > PATH_MAX)
+ goto too_long;
+ }
+ return len;
+
+too_long:
+ return -ENAMETOOLONG;
+}
+
+/*
* Convert the NFSv4 pathname components into a standard posix path.
- *
- * Note that the resulting string will be placed at the end of the buffer
*/
-static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
- char *buffer, ssize_t buflen)
+static char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
+ unsigned short *_len)
{
- char *end = buffer + buflen;
- int n;
+ ssize_t len;
+ char *buf, *p;
+ int i;
+
+ len = nfs4_pathname_len(pathname);
+ if (len < 0)
+ return ERR_PTR(len);
+ *_len = len;
+
+ p = buf = kmalloc(len + 1, GFP_KERNEL);
+ if (!buf)
+ return ERR_PTR(-ENOMEM);
+
+ for (i = 0; i < pathname->ncomponents; i++) {
+ const struct nfs4_string *component = &pathname->components[i];
- *--end = '\0';
- buflen--;
-
- n = pathname->ncomponents;
- while (--n >= 0) {
- const struct nfs4_string *component = &pathname->components[n];
- buflen -= component->len + 1;
- if (buflen < 0)
- goto Elong;
- end -= component->len;
- memcpy(end, component->data, component->len);
- *--end = '/';
+ *p++ = '/';
+ memcpy(p, component->data, component->len);
+ p += component->len;
}
- return end;
-Elong:
- return ERR_PTR(-ENAMETOOLONG);
+
+ *p = 0;
+ return buf;
}
/*
@@ -100,21 +128,32 @@ static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
*/
static int nfs4_validate_fspath(struct dentry *dentry,
const struct nfs4_fs_locations *locations,
- char *page, char *page2)
+ struct nfs_fs_context *ctx)
{
const char *path, *fs_path;
+ char *buf;
+ unsigned short len;
+ int n;
- path = nfs4_path(dentry, page, PAGE_SIZE);
- if (IS_ERR(path))
+ buf = kmalloc(4096, GFP_KERNEL);
+ path = nfs4_path(dentry, buf, 4096);
+ if (IS_ERR(path)) {
+ kfree(buf);
return PTR_ERR(path);
+ }
- fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
- if (IS_ERR(fs_path))
+ fs_path = nfs4_pathname_string(&locations->fs_path, &len);
+ if (IS_ERR(fs_path)) {
+ kfree(buf);
return PTR_ERR(fs_path);
+ }
- if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
+ n = strncmp(path, fs_path, len);
+ kfree(buf);
+ kfree(fs_path);
+ if (n != 0) {
dprintk("%s: path %s does not begin with fsroot %s\n",
- __func__, path, fs_path);
+ __func__, path, ctx->nfs_server.export_path);
return -ENOENT;
}
@@ -236,55 +275,83 @@ out:
return new;
}
-static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
- char *page, char *page2,
- const struct nfs4_fs_location *location)
+static int try_location(struct fs_context *fc,
+ const struct nfs4_fs_location *location)
{
const size_t addr_bufsize = sizeof(struct sockaddr_storage);
- struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
- struct vfsmount *mnt = ERR_PTR(-ENOENT);
- char *mnt_path;
- unsigned int maxbuflen;
- unsigned int s;
+ struct nfs_fs_context *ctx = nfs_fc2context(fc);
+ unsigned int len, s;
+ char *export_path, *source, *p;
+ int ret = -ENOENT;
+
+ /* Allocate a buffer big enough to hold any of the hostnames plus a
+ * terminating char and also a buffer big enough to hold the hostname
+ * plus a colon plus the path.
+ */
+ len = 0;
+ for (s = 0; s < location->nservers; s++) {
+ const struct nfs4_string *buf = &location->servers[s];
+ if (buf->len > len)
+ len = buf->len;
+ }
- mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
- if (IS_ERR(mnt_path))
- return ERR_CAST(mnt_path);
- mountdata->mnt_path = mnt_path;
- maxbuflen = mnt_path - 1 - page2;
+ kfree(ctx->nfs_server.hostname);
+ ctx->nfs_server.hostname = kmalloc(len + 1, GFP_KERNEL);
+ if (!ctx->nfs_server.hostname)
+ return -ENOMEM;
- mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
- if (mountdata->addr == NULL)
- return ERR_PTR(-ENOMEM);
+ export_path = nfs4_pathname_string(&location->rootpath,
+ &ctx->nfs_server.export_path_len);
+ if (IS_ERR(export_path))
+ return PTR_ERR(export_path);
+ ctx->nfs_server.export_path = export_path;
+
+ source = kmalloc(len + 1 + ctx->nfs_server.export_path_len + 1,
+ GFP_KERNEL);
+ if (!source)
+ return -ENOMEM;
+
+ kfree(fc->source);
+ fc->source = source;
+
+ ctx->clone_data.addr = kmalloc(addr_bufsize, GFP_KERNEL);
+ if (ctx->clone_data.addr == NULL)
+ return -ENOMEM;
for (s = 0; s < location->nservers; s++) {
const struct nfs4_string *buf = &location->servers[s];
- if (buf->len <= 0 || buf->len >= maxbuflen)
- continue;
-
if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
continue;
- mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
- mountdata->addr, addr_bufsize, net);
- if (mountdata->addrlen == 0)
+ ctx->clone_data.addrlen =
+ nfs_parse_server_name(buf->data, buf->len,
+ ctx->clone_data.addr,
+ addr_bufsize,
+ fc->net_ns);
+ if (ctx->clone_data.addrlen == 0)
continue;
- memcpy(page2, buf->data, buf->len);
- page2[buf->len] = '\0';
- mountdata->hostname = page2;
+ rpc_set_port(ctx->clone_data.addr, NFS_PORT);
- snprintf(page, PAGE_SIZE, "%s:%s",
- mountdata->hostname,
- mountdata->mnt_path);
+ memcpy(ctx->nfs_server.hostname, buf->data, buf->len);
+ ctx->nfs_server.hostname[buf->len] = '\0';
+ ctx->clone_data.hostname = ctx->nfs_server.hostname;
- mnt = vfs_submount(mountdata->dentry, &nfs4_referral_fs_type, page, mountdata);
- if (!IS_ERR(mnt))
- break;
+ p = source;
+ memcpy(p, buf->data, buf->len);
+ p += buf->len;
+ *p++ = ':';
+ memcpy(p, ctx->nfs_server.export_path, ctx->nfs_server.export_path_len);
+ p += ctx->nfs_server.export_path_len;
+ *p = 0;
+
+ ret = nfs4_get_referral_tree(fc);
+ if (ret == 0)
+ return 0;
}
- kfree(mountdata->addr);
- return mnt;
+
+ return ret;
}
/**
@@ -293,38 +360,23 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
* @locations: array of NFSv4 server location information
*
*/
-static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
- const struct nfs4_fs_locations *locations)
+static int nfs_follow_referral(struct fs_context *fc,
+ const struct nfs4_fs_locations *locations)
{
- struct vfsmount *mnt = ERR_PTR(-ENOENT);
- struct nfs_clone_mount mountdata = {
- .sb = dentry->d_sb,
- .dentry = dentry,
- .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
- };
- char *page = NULL, *page2 = NULL;
+ struct nfs_fs_context *ctx = nfs_fc2context(fc);
int loc, error;
if (locations == NULL || locations->nlocations <= 0)
- goto out;
-
- dprintk("%s: referral at %pd2\n", __func__, dentry);
-
- page = (char *) __get_free_page(GFP_USER);
- if (!page)
- goto out;
+ return -ENOENT;
- page2 = (char *) __get_free_page(GFP_USER);
- if (!page2)
- goto out;
+ dprintk("%s: referral at %pd2\n", __func__, ctx->clone_data.dentry);
/* Ensure fs path is a prefix of current dentry path */
- error = nfs4_validate_fspath(dentry, locations, page, page2);
- if (error < 0) {
- mnt = ERR_PTR(error);
- goto out;
- }
+ error = nfs4_validate_fspath(ctx->clone_data.dentry, locations, ctx);
+ if (error < 0)
+ return error;
+ error = -ENOENT;
for (loc = 0; loc < locations->nlocations; loc++) {
const struct nfs4_fs_location *location = &locations->locations[loc];
@@ -332,15 +384,12 @@ static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
location->rootpath.ncomponents == 0)
continue;
- mnt = try_location(&mountdata, page, page2, location);
- if (!IS_ERR(mnt))
- break;
+ error = try_location(fc, location);
+ if (error == 0)
+ return 0;
}
-out:
- free_page((unsigned long) page);
- free_page((unsigned long) page2);
- return mnt;
+ return error;
}
/*
@@ -348,71 +397,73 @@ out:
* @dentry - dentry of referral
*
*/
-static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
+static int nfs_do_refmount(struct fs_context *fc, struct rpc_clnt *client)
{
- struct vfsmount *mnt = ERR_PTR(-ENOMEM);
- struct dentry *parent;
+ struct nfs_fs_context *ctx = nfs_fc2context(fc);
+ struct dentry *dentry, *parent;
struct nfs4_fs_locations *fs_locations = NULL;
struct page *page;
- int err;
+ int err = -ENOMEM;
/* BUG_ON(IS_ROOT(dentry)); */
page = alloc_page(GFP_KERNEL);
- if (page == NULL)
- return mnt;
+ if (!page)
+ return -ENOMEM;
fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
- if (fs_locations == NULL)
+ if (!fs_locations)
goto out_free;
/* Get locations */
- mnt = ERR_PTR(-ENOENT);
-
+ dentry = ctx->clone_data.dentry;
parent = dget_parent(dentry);
dprintk("%s: getting locations for %pd2\n",
__func__, dentry);
err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page);
dput(parent);
- if (err != 0 ||
- fs_locations->nlocations <= 0 ||
+ if (err != 0)
+ goto out_free_2;
+
+ err = -ENOENT;
+ if (fs_locations->nlocations <= 0 ||
fs_locations->fs_path.ncomponents <= 0)
- goto out_free;
+ goto out_free_2;
- mnt = nfs_follow_referral(dentry, fs_locations);
+ err = nfs_follow_referral(fc, fs_locations);
+out_free_2:
+ kfree(fs_locations);
out_free:
__free_page(page);
- kfree(fs_locations);
- return mnt;
+ return err;
}
-struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
- struct nfs_fh *fh, struct nfs_fattr *fattr)
+int nfs4_submount(struct fs_context *fc, struct nfs_server *server)
{
- rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
+ struct nfs_fs_context *ctx = nfs_fc2context(fc);
+ struct dentry *dentry = ctx->clone_data.dentry;
struct dentry *parent = dget_parent(dentry);
struct inode *dir = d_inode(parent);
const struct qstr *name = &dentry->d_name;
struct rpc_clnt *client;
- struct vfsmount *mnt;
+ int ret;
/* Look it up again to get its attributes and sec flavor */
- client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
+ client = nfs4_proc_lookup_mountpoint(dir, name, ctx->mount_info.mntfh,
+ ctx->clone_data.fattr);
dput(parent);
if (IS_ERR(client))
- return ERR_CAST(client);
+ return PTR_ERR(client);
- if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
- mnt = nfs_do_refmount(client, dentry);
- goto out;
+ ctx->selected_flavor = client->cl_auth->au_flavor;
+ if (ctx->clone_data.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
+ ret = nfs_do_refmount(fc, client);
+ } else {
+ ret = nfs_do_submount(fc);
}
- if (client->cl_auth->au_flavor != flavor)
- flavor = client->cl_auth->au_flavor;
- mnt = nfs_do_submount(dentry, fh, fattr, flavor);
-out:
rpc_shutdown_client(client);
- return mnt;
+ return ret;
}
/*