Return-Path: Received: from mail-pa0-f48.google.com ([209.85.220.48]:36301 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751132AbbEXPK5 (ORCPT ); Sun, 24 May 2015 11:10:57 -0400 Message-ID: <5561E9FA.4050808@gmail.com> Date: Sun, 24 May 2015 23:10:50 +0800 From: Kinglong Mee MIME-Version: 1.0 To: "J. Bruce Fields" , Al Viro , linux-fsdevel@vger.kernel.org, "linux-nfs@vger.kernel.org" , NeilBrown CC: Trond Myklebust , Steve Dickson , kinglongmee@gmail.com Subject: [PATCH 5/5] nfsd: allows user un-mounting filesystem where nfsd exports base on References: <5561E7E4.50604@gmail.com> In-Reply-To: <5561E7E4.50604@gmail.com> Content-Type: text/plain; charset=utf-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: If there are some mount points(not exported for nfs) under pseudo root, after client's operation of those entry under the root, anyone *can't* unmount those mount points until export cache expired. /nfs/xfs *(rw,insecure,no_subtree_check,no_root_squash) /nfs/pnfs *(rw,insecure,no_subtree_check,no_root_squash) total 0 drwxr-xr-x. 3 root root 84 Apr 21 22:27 pnfs drwxr-xr-x. 3 root root 84 Apr 21 22:27 test drwxr-xr-x. 2 root root 6 Apr 20 22:01 xfs Filesystem 1K-blocks Used Available Use% Mounted on ...... /dev/sdd 1038336 32944 1005392 4% /nfs/pnfs /dev/sdc 10475520 32928 10442592 1% /nfs/xfs /dev/sde 999320 1284 929224 1% /nfs/test /mnt/pnfs/: total 0 -rw-r--r--. 1 root root 0 Apr 21 22:23 attr drwxr-xr-x. 2 root root 6 Apr 21 22:19 tmp /mnt/xfs/: total 0 umount: /nfs/test/: target is busy (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1).) I don't think that's user expect, they want umount /nfs/test/. It's caused by exports cache of nfsd holds the reference of the path (here is /nfs/test/), so, it can't be umounted. v2, 1. Update exports according to the "allow_umount" option. Pin to vfsmnt default, change when updating. 2. Using kzalloc for all memory allocating without kmalloc. Signed-off-by: Kinglong Mee --- fs/nfsd/export.c | 52 ++++++++++++++++++++++++++++++++-------- fs/nfsd/export.h | 11 ++++++++- include/uapi/linux/nfsd/export.h | 3 ++- 3 files changed, 54 insertions(+), 12 deletions(-) diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c index f79521a..cc34b0b 100644 --- a/fs/nfsd/export.c +++ b/fs/nfsd/export.c @@ -43,9 +43,9 @@ static void expkey_put(struct kref *ref) if (test_bit(CACHE_VALID, &key->h.flags) && !test_bit(CACHE_NEGATIVE, &key->h.flags)) - path_put(&key->ek_path); + path_put_unpin(&key->ek_path, &key->ek_pin); auth_domain_put(key->ek_client); - kfree(key); + kfree_rcu(key, rcu_head); } static void expkey_request(struct cache_detail *cd, @@ -83,7 +83,7 @@ static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen) return -EINVAL; mesg[mlen-1] = 0; - buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + buf = kzalloc(PAGE_SIZE, GFP_KERNEL); err = -ENOMEM; if (!buf) goto out; @@ -120,6 +120,7 @@ static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen) goto out; key.ek_client = dom; + key.cd = cd; key.ek_fsidtype = fsidtype; memcpy(key.ek_fsid, buf, len); @@ -210,6 +211,13 @@ static inline void expkey_init(struct cache_head *cnew, new->ek_fsidtype = item->ek_fsidtype; memcpy(new->ek_fsid, item->ek_fsid, sizeof(new->ek_fsid)); + new->cd = item->cd; +} + +static void expkey_pin_kill(struct fs_pin *pin) +{ + struct svc_expkey *key = container_of(pin, struct svc_expkey, ek_pin); + cache_force_expire(key->cd, &key->h); } static inline void expkey_update(struct cache_head *cnew, @@ -218,13 +226,14 @@ static inline void expkey_update(struct cache_head *cnew, struct svc_expkey *new = container_of(cnew, struct svc_expkey, h); struct svc_expkey *item = container_of(citem, struct svc_expkey, h); + init_fs_pin(&new->ek_pin, expkey_pin_kill); new->ek_path = item->ek_path; - path_get(&item->ek_path); + path_get_pin(&new->ek_path, &new->ek_pin); } static struct cache_head *expkey_alloc(void) { - struct svc_expkey *i = kmalloc(sizeof(*i), GFP_KERNEL); + struct svc_expkey *i = kzalloc(sizeof(*i), GFP_KERNEL); if (i) return &i->h; else @@ -309,11 +318,16 @@ static void nfsd4_fslocs_free(struct nfsd4_fs_locations *fsloc) static void svc_export_put(struct kref *ref) { struct svc_export *exp = container_of(ref, struct svc_export, h.ref); - path_put(&exp->ex_path); + + if (EX_ALLOW_UMOUNT(exp)) + path_put_unpin(&exp->ex_path, &exp->ex_pin); + else + path_put(&exp->ex_path); + auth_domain_put(exp->ex_client); nfsd4_fslocs_free(&exp->ex_fslocs); kfree(exp->ex_uuid); - kfree(exp); + kfree_rcu(exp, rcu_head); } static void svc_export_request(struct cache_detail *cd, @@ -520,7 +534,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen) return -EINVAL; mesg[mlen-1] = 0; - buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + buf = kzalloc(PAGE_SIZE, GFP_KERNEL); if (!buf) return -ENOMEM; @@ -694,15 +708,23 @@ static int svc_export_match(struct cache_head *a, struct cache_head *b) path_equal(&orig->ex_path, &new->ex_path); } +static void export_pin_kill(struct fs_pin *pin) +{ + struct svc_export *exp = container_of(pin, struct svc_export, ex_pin); + cache_force_expire(exp->cd, &exp->h); +} + static void svc_export_init(struct cache_head *cnew, struct cache_head *citem) { struct svc_export *new = container_of(cnew, struct svc_export, h); struct svc_export *item = container_of(citem, struct svc_export, h); + init_fs_pin(&new->ex_pin, export_pin_kill); kref_get(&item->ex_client->ref); + new->ex_flags = NFSEXP_ALLOW_UMOUNT; new->ex_client = item->ex_client; new->ex_path = item->ex_path; - path_get(&item->ex_path); + path_get_pin(&new->ex_path, &new->ex_pin); new->ex_fslocs.locations = NULL; new->ex_fslocs.locations_count = 0; new->ex_fslocs.migrated = 0; @@ -717,6 +739,14 @@ static void export_update(struct cache_head *cnew, struct cache_head *citem) struct svc_export *item = container_of(citem, struct svc_export, h); int i; + if (!EX_ALLOW_UMOUNT(item)) { + path_get(&new->ex_path); + if (EX_ALLOW_UMOUNT(new)) + path_put_unpin(&new->ex_path, &new->ex_pin); + else + path_put(&new->ex_path); + } + new->ex_flags = item->ex_flags; new->ex_anon_uid = item->ex_anon_uid; new->ex_anon_gid = item->ex_anon_gid; @@ -740,7 +770,7 @@ static void export_update(struct cache_head *cnew, struct cache_head *citem) static struct cache_head *svc_export_alloc(void) { - struct svc_export *i = kmalloc(sizeof(*i), GFP_KERNEL); + struct svc_export *i = kzalloc(sizeof(*i), GFP_KERNEL); if (i) return &i->h; else @@ -811,6 +841,7 @@ exp_find_key(struct cache_detail *cd, struct auth_domain *clp, int fsid_type, key.ek_client = clp; key.ek_fsidtype = fsid_type; + key.cd = cd; memcpy(key.ek_fsid, fsidv, key_len(fsid_type)); ek = svc_expkey_lookup(cd, &key); @@ -1159,6 +1190,7 @@ static struct flags { { NFSEXP_NOAUTHNLM, {"insecure_locks", ""}}, { NFSEXP_V4ROOT, {"v4root", ""}}, { NFSEXP_PNFS, {"pnfs", ""}}, + { NFSEXP_ALLOW_UMOUNT, {"allow_umount", ""}}, { 0, {"", ""}} }; diff --git a/fs/nfsd/export.h b/fs/nfsd/export.h index 1f52bfc..1134875 100644 --- a/fs/nfsd/export.h +++ b/fs/nfsd/export.h @@ -4,6 +4,7 @@ #ifndef NFSD_EXPORT_H #define NFSD_EXPORT_H +#include #include #include @@ -46,6 +47,8 @@ struct exp_flavor_info { struct svc_export { struct cache_head h; + struct cache_detail *cd; + struct auth_domain * ex_client; int ex_flags; struct path ex_path; @@ -58,7 +61,9 @@ struct svc_export { struct exp_flavor_info ex_flavors[MAX_SECINFO_LIST]; enum pnfs_layouttype ex_layout_type; struct nfsd4_deviceid_map *ex_devid_map; - struct cache_detail *cd; + + struct fs_pin ex_pin; + struct rcu_head rcu_head; }; /* an "export key" (expkey) maps a filehandlefragement to an @@ -67,17 +72,21 @@ struct svc_export { */ struct svc_expkey { struct cache_head h; + struct cache_detail *cd; struct auth_domain * ek_client; int ek_fsidtype; u32 ek_fsid[6]; struct path ek_path; + struct fs_pin ek_pin; + struct rcu_head rcu_head; }; #define EX_ISSYNC(exp) (!((exp)->ex_flags & NFSEXP_ASYNC)) #define EX_NOHIDE(exp) ((exp)->ex_flags & NFSEXP_NOHIDE) #define EX_WGATHER(exp) ((exp)->ex_flags & NFSEXP_GATHERED_WRITES) +#define EX_ALLOW_UMOUNT(exp) ((exp)->ex_flags & NFSEXP_ALLOW_UMOUNT) int nfsexp_flags(struct svc_rqst *rqstp, struct svc_export *exp); __be32 check_nfsd_access(struct svc_export *exp, struct svc_rqst *rqstp); diff --git a/include/uapi/linux/nfsd/export.h b/include/uapi/linux/nfsd/export.h index 0df7bd5..61aa8bb 100644 --- a/include/uapi/linux/nfsd/export.h +++ b/include/uapi/linux/nfsd/export.h @@ -51,9 +51,10 @@ */ #define NFSEXP_V4ROOT 0x10000 #define NFSEXP_PNFS 0x20000 +#define NFSEXP_ALLOW_UMOUNT 0x40000 /* All flags that we claim to support. (Note we don't support NOACL.) */ -#define NFSEXP_ALLFLAGS 0x3FE7F +#define NFSEXP_ALLFLAGS 0x7FE7F /* The flags that may vary depending on security flavor: */ #define NFSEXP_SECINFO_FLAGS (NFSEXP_READONLY | NFSEXP_ROOTSQUASH \ -- 2.4.1