From: NeilBrown 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 Signed-off-by: J. Bruce Fields Signed-off-by: Neil Brown Signed-off-by: Andrew Morton --- fs/nfsd/nfs4recover.c | 166 +++++++++++++++++++++++++++++++++++++++++++++ fs/nfsd/nfs4state.c | 18 ++++ include/linux/nfsd/state.h | 4 + 3 files changed, 186 insertions(+), 2 deletions(-) diff -puN fs/nfsd/nfs4recover.c~nfsd4-initialize-recovery-directory fs/nfsd/nfs4recover.c --- 25/fs/nfsd/nfs4recover.c~nfsd4-initialize-recovery-directory Thu Jun 2 16:25:37 2005 +++ 25-akpm/fs/nfsd/nfs4recover.c Thu Jun 2 16:25:37 2005 @@ -39,6 +39,9 @@ #include #include #include +#include +#include +#include #include #include #include @@ -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); +} diff -puN fs/nfsd/nfs4state.c~nfsd4-initialize-recovery-directory fs/nfsd/nfs4state.c --- 25/fs/nfsd/nfs4state.c~nfsd4-initialize-recovery-directory Thu Jun 2 16:25:37 2005 +++ 25-akpm/fs/nfsd/nfs4state.c Thu Jun 2 16:25:37 2005 @@ -71,6 +71,7 @@ static stateid_t onestateid; static struct nfs4_stateid * find_stateid(stateid_t *stid, int flags); static struct nfs4_delegation * find_delegation_stateid(struct inode *ino, stateid_t *stid); static void release_stateid_lockowners(struct nfs4_stateid *open_stp); +extern char recovery_dirname[]; /* Locking: * @@ -3091,8 +3092,8 @@ alloc_reclaim(void) /* * failure => all reset bets are off, nfserr_no_grace... */ -static int -nfs4_client_to_reclaim(char *name) +int +nfs4_client_to_reclaim(const char *name) { unsigned int strhashval; struct nfs4_client_reclaim *crp = NULL; @@ -3202,6 +3203,17 @@ nfs4_state_init(void) reclaim_str_hashtbl_size = 0; } +static void +nfsd4_load_reboot_recovery_data(void) +{ + int status; + + nfsd4_init_recdir(recovery_dirname); + status = nfsd4_recdir_load(); + if (status) + printk("NFSD: Failure reading reboot recovery data\n"); +} + /* initialization to perform when the nfsd service is started: */ static void @@ -3228,6 +3240,7 @@ nfs4_state_start(void) status = nfsd4_init_slabs(); if (status) return status; + nfsd4_load_reboot_recovery_data(); __nfs4_state_start(); nfs4_init = 1; return 0; @@ -3286,6 +3299,7 @@ __nfs4_state_shutdown(void) cancel_delayed_work(&laundromat_work); flush_workqueue(laundry_wq); destroy_workqueue(laundry_wq); + nfsd4_shutdown_recdir(); nfs4_init = 0; } diff -puN include/linux/nfsd/state.h~nfsd4-initialize-recovery-directory include/linux/nfsd/state.h --- 25/include/linux/nfsd/state.h~nfsd4-initialize-recovery-directory Thu Jun 2 16:25:37 2005 +++ 25-akpm/include/linux/nfsd/state.h Thu Jun 2 16:25:37 2005 @@ -278,6 +278,10 @@ extern void nfsd4_probe_callback(struct extern void nfsd4_cb_recall(struct nfs4_delegation *dp); extern void nfs4_put_delegation(struct nfs4_delegation *dp); extern int nfs4_make_rec_clidname(char *clidname, struct xdr_netobj *clname); +extern void nfsd4_init_recdir(char *recdir_name); +extern int nfsd4_recdir_load(void); +extern void nfsd4_shutdown_recdir(void); +extern int nfs4_client_to_reclaim(const char *name); static inline void nfs4_put_stateowner(struct nfs4_stateowner *so) _