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authorNeilBrown <neilb@cse.unsw.edu.au>2005-06-23 22:04:25 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-24 00:06:35 -0700
commit190e4fbf96037e5e526ba3210f2bcc2a3b6fe964 (patch)
tree957fb35a6a2895622c4db0052160fd91d06153e8 /fs/nfsd/nfs4recover.c
parentcb36d6345752fa24827044c68e15f6708a40d9f6 (diff)
[PATCH] knfsd: nfsd4: initialize recovery directory
NFSv4 clients are required to know what state they have on the server so that they can reclaim it on server reboot. However, it is possible for pathalogical combinations of server reboots and network partitions to leave a client in a state where it cannot know whether it has lost its state on the server. For this reason, rfc3530 requires that we store some information about clients to stable storage. So we maintain a directory /var/lib/nfs/v4recovery with a subdirectory for each client with active state. We leave open the possibility of including files underneath each such subdirectory with information about the client, but for now the subdirectories are empty. We create a client subdirectory whenever a client makes its first non-reclaim open_confirm. We remove a client subdirectory whenever either a) its lease expires, or b) the grace period ends without it reclaiming anything. When handling reclaims, we allow the reclaim if and only if the client doing the reclaim has a subdirectory. This patch adds just the code to scan the recovery directory on nfsd startup. Signed-off-by: Andy Adamson <andros@citi.umich.edu> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/nfsd/nfs4recover.c')
-rw-r--r--fs/nfsd/nfs4recover.c166
1 files changed, 166 insertions, 0 deletions
diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c
index 841a305d794..2dc9851a1d3 100644
--- a/fs/nfsd/nfs4recover.c
+++ b/fs/nfsd/nfs4recover.c
@@ -39,6 +39,9 @@
#include <linux/nfs4.h>
#include <linux/nfsd/state.h>
#include <linux/nfsd/xdr4.h>
+#include <linux/param.h>
+#include <linux/file.h>
+#include <linux/namei.h>
#include <asm/uaccess.h>
#include <asm/scatterlist.h>
#include <linux/crypto.h>
@@ -46,6 +49,27 @@
#define NFSDDBG_FACILITY NFSDDBG_PROC
+/* Globals */
+char recovery_dirname[PATH_MAX] = "/var/lib/nfs/v4recovery";
+static struct nameidata rec_dir;
+static int rec_dir_init = 0;
+
+static void
+nfs4_save_user(uid_t *saveuid, gid_t *savegid)
+{
+ *saveuid = current->fsuid;
+ *savegid = current->fsgid;
+ current->fsuid = 0;
+ current->fsgid = 0;
+}
+
+static void
+nfs4_reset_user(uid_t saveuid, gid_t savegid)
+{
+ current->fsuid = saveuid;
+ current->fsgid = savegid;
+}
+
static void
md5_to_hex(char *out, char *md5)
{
@@ -95,3 +119,145 @@ out:
crypto_free_tfm(tfm);
return status;
}
+
+typedef int (recdir_func)(struct dentry *, struct dentry *);
+
+struct dentry_list {
+ struct dentry *dentry;
+ struct list_head list;
+};
+
+struct dentry_list_arg {
+ struct list_head dentries;
+ struct dentry *parent;
+};
+
+static int
+nfsd4_build_dentrylist(void *arg, const char *name, int namlen,
+ loff_t offset, ino_t ino, unsigned int d_type)
+{
+ struct dentry_list_arg *dla = arg;
+ struct list_head *dentries = &dla->dentries;
+ struct dentry *parent = dla->parent;
+ struct dentry *dentry;
+ struct dentry_list *child;
+
+ if (name && isdotent(name, namlen))
+ return nfs_ok;
+ dentry = lookup_one_len(name, parent, namlen);
+ if (IS_ERR(dentry))
+ return PTR_ERR(dentry);
+ child = kmalloc(sizeof(*child), GFP_KERNEL);
+ if (child == NULL)
+ return -ENOMEM;
+ child->dentry = dentry;
+ list_add(&child->list, dentries);
+ return 0;
+}
+
+static int
+nfsd4_list_rec_dir(struct dentry *dir, recdir_func *f)
+{
+ struct file *filp;
+ struct dentry_list_arg dla = {
+ .parent = dir,
+ };
+ struct list_head *dentries = &dla.dentries;
+ struct dentry_list *child;
+ uid_t uid;
+ gid_t gid;
+ int status;
+
+ if (!rec_dir_init)
+ return 0;
+
+ nfs4_save_user(&uid, &gid);
+
+ filp = dentry_open(dget(dir), mntget(rec_dir.mnt),
+ O_RDWR);
+ status = PTR_ERR(filp);
+ if (IS_ERR(filp))
+ goto out;
+ INIT_LIST_HEAD(dentries);
+ status = vfs_readdir(filp, nfsd4_build_dentrylist, &dla);
+ fput(filp);
+ while (!list_empty(dentries)) {
+ child = list_entry(dentries->next, struct dentry_list, list);
+ status = f(dir, child->dentry);
+ if (status)
+ goto out;
+ list_del(&child->list);
+ dput(child->dentry);
+ kfree(child);
+ }
+out:
+ while (!list_empty(dentries)) {
+ child = list_entry(dentries->next, struct dentry_list, list);
+ list_del(&child->list);
+ dput(child->dentry);
+ kfree(child);
+ }
+ nfs4_reset_user(uid, gid);
+ return status;
+}
+
+static int
+load_recdir(struct dentry *parent, struct dentry *child)
+{
+ if (child->d_name.len != HEXDIR_LEN - 1) {
+ printk("nfsd4: illegal name %s in recovery directory\n",
+ child->d_name.name);
+ /* Keep trying; maybe the others are OK: */
+ return nfs_ok;
+ }
+ nfs4_client_to_reclaim(child->d_name.name);
+ return nfs_ok;
+}
+
+int
+nfsd4_recdir_load(void) {
+ int status;
+
+ status = nfsd4_list_rec_dir(rec_dir.dentry, load_recdir);
+ if (status)
+ printk("nfsd4: failed loading clients from recovery"
+ " directory %s\n", rec_dir.dentry->d_name.name);
+ return status;
+}
+
+/*
+ * Hold reference to the recovery directory.
+ */
+
+void
+nfsd4_init_recdir(char *rec_dirname)
+{
+ uid_t uid = 0;
+ gid_t gid = 0;
+ int status;
+
+ printk("NFSD: Using %s as the NFSv4 state recovery directory\n",
+ rec_dirname);
+
+ BUG_ON(rec_dir_init);
+
+ nfs4_save_user(&uid, &gid);
+
+ status = path_lookup(rec_dirname, LOOKUP_FOLLOW, &rec_dir);
+ if (status == -ENOENT)
+ printk("NFSD: recovery directory %s doesn't exist\n",
+ rec_dirname);
+
+ if (!status)
+ rec_dir_init = 1;
+ nfs4_reset_user(uid, gid);
+}
+
+void
+nfsd4_shutdown_recdir(void)
+{
+ if (!rec_dir_init)
+ return;
+ rec_dir_init = 0;
+ path_release(&rec_dir);
+}