Return-Path: linux-nfs-owner@vger.kernel.org Received: from cantor2.suse.de ([195.135.220.15]:40933 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752200Ab2DPQOX (ORCPT ); Mon, 16 Apr 2012 12:14:23 -0400 From: Jan Kara To: Al Viro Cc: dchinner@redhat.com, LKML , linux-fsdevel@vger.kernel.org, Jan Kara , linux-nfs@vger.kernel.org, "J. Bruce Fields" Subject: [PATCH 12/27] nfsd: Push mnt_want_write() outside of i_mutex Date: Mon, 16 Apr 2012 18:13:50 +0200 Message-Id: <1334592845-22862-13-git-send-email-jack@suse.cz> In-Reply-To: <1334592845-22862-1-git-send-email-jack@suse.cz> References: <1334592845-22862-1-git-send-email-jack@suse.cz> Sender: linux-nfs-owner@vger.kernel.org List-ID: When mnt_want_write() starts to handle freezing it will get a full lock semantics requiring proper lock ordering. So push mnt_want_write() call consistently outside of i_mutex. CC: linux-nfs@vger.kernel.org CC: "J. Bruce Fields" Signed-off-by: Jan Kara --- fs/nfsd/nfs4recover.c | 9 +++-- fs/nfsd/nfsfh.c | 1 + fs/nfsd/nfsproc.c | 9 ++++- fs/nfsd/vfs.c | 79 ++++++++++++++++++++++--------------------- fs/nfsd/vfs.h | 11 +++++- include/linux/nfsd/nfsfh.h | 1 + 6 files changed, 64 insertions(+), 46 deletions(-) diff --git a/fs/nfsd/nfs4recover.c b/fs/nfsd/nfs4recover.c index 4767429..efa7574 100644 --- a/fs/nfsd/nfs4recover.c +++ b/fs/nfsd/nfs4recover.c @@ -154,6 +154,10 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) if (status < 0) return; + status = mnt_want_write_file(rec_file); + if (status) + return; + dir = rec_file->f_path.dentry; /* lock the parent */ mutex_lock(&dir->d_inode->i_mutex); @@ -173,11 +177,7 @@ nfsd4_create_clid_dir(struct nfs4_client *clp) * as well be forgiving and just succeed silently. */ goto out_put; - status = mnt_want_write_file(rec_file); - if (status) - goto out_put; status = vfs_mkdir(dir->d_inode, dentry, S_IRWXU); - mnt_drop_write_file(rec_file); out_put: dput(dentry); out_unlock: @@ -189,6 +189,7 @@ out_unlock: " (err %d); please check that %s exists" " and is writeable", status, user_recovery_dirname); + mnt_drop_write_file(rec_file); nfs4_reset_creds(original_cred); } diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c index 68454e7..8b93353 100644 --- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -635,6 +635,7 @@ fh_put(struct svc_fh *fhp) fhp->fh_post_saved = 0; #endif } + fh_drop_write(fhp); if (exp) { cache_put(&exp->h, &svc_export_cache); fhp->fh_export = NULL; diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index e15dc45..aad6d45 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -196,6 +196,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, struct dentry *dchild; int type, mode; __be32 nfserr; + int hosterr; dev_t rdev = 0, wanted = new_decode_dev(attr->ia_size); dprintk("nfsd: CREATE %s %.*s\n", @@ -214,6 +215,12 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, nfserr = nfserr_exist; if (isdotent(argp->name, argp->len)) goto done; + hosterr = fh_want_write(dirfhp); + if (hosterr) { + nfserr = nfserrno(hosterr); + goto done; + } + fh_lock_nested(dirfhp, I_MUTEX_PARENT); dchild = lookup_one_len(argp->name, dirfhp->fh_dentry, argp->len); if (IS_ERR(dchild)) { @@ -330,7 +337,7 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, out_unlock: /* We don't really need to unlock, as fh_put does it. */ fh_unlock(dirfhp); - + fh_drop_write(dirfhp); done: fh_put(dirfhp); return nfsd_return_dirop(nfserr, resp); diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 296d671..b8bb649 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1276,6 +1276,10 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, * If it has, the parent directory should already be locked. */ if (!resfhp->fh_dentry) { + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + /* called from nfsd_proc_mkdir, or possibly nfsd3_proc_create */ fh_lock_nested(fhp, I_MUTEX_PARENT); dchild = lookup_one_len(fname, dentry, flen); @@ -1319,14 +1323,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, goto out; } - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; - /* * Get the dir op function pointer. */ err = 0; + host_err = 0; switch (type) { case S_IFREG: host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL); @@ -1343,10 +1344,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, host_err = vfs_mknod(dirp, dchild, iap->ia_mode, rdev); break; } - if (host_err < 0) { - fh_drop_write(fhp); + if (host_err < 0) goto out_nfserr; - } err = nfsd_create_setattr(rqstp, resfhp, iap); @@ -1358,7 +1357,6 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, err2 = nfserrno(commit_metadata(fhp)); if (err2) err = err2; - fh_drop_write(fhp); /* * Update the file handle to get the new inode info. */ @@ -1417,6 +1415,11 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, err = nfserr_notdir; if (!dirp->i_op->lookup) goto out; + + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock_nested(fhp, I_MUTEX_PARENT); /* @@ -1449,9 +1452,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, v_atime = verifier[1]&0x7fffffff; } - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; if (dchild->d_inode) { err = 0; @@ -1522,7 +1522,6 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, if (!err) err = nfserrno(commit_metadata(fhp)); - fh_drop_write(fhp); /* * Update the filehandle to get the new inode info. */ @@ -1533,6 +1532,7 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, fh_unlock(fhp); if (dchild && !IS_ERR(dchild)) dput(dchild); + fh_drop_write(fhp); return err; out_nfserr: @@ -1613,6 +1613,11 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); if (err) goto out; + + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock(fhp); dentry = fhp->fh_dentry; dnew = lookup_one_len(fname, dentry, flen); @@ -1620,10 +1625,6 @@ nfsd_symlink(struct svc_rqst *rqstp, struct svc_fh *fhp, if (IS_ERR(dnew)) goto out_nfserr; - host_err = fh_want_write(fhp); - if (host_err) - goto out_nfserr; - if (unlikely(path[plen] != 0)) { char *path_alloced = kmalloc(plen+1, GFP_KERNEL); if (path_alloced == NULL) @@ -1683,6 +1684,12 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, if (isdotent(name, len)) goto out; + host_err = fh_want_write(tfhp); + if (host_err) { + err = nfserrno(host_err); + goto out; + } + fh_lock_nested(ffhp, I_MUTEX_PARENT); ddir = ffhp->fh_dentry; dirp = ddir->d_inode; @@ -1694,18 +1701,13 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, dold = tfhp->fh_dentry; - host_err = fh_want_write(tfhp); - if (host_err) { - err = nfserrno(host_err); - goto out_dput; - } err = nfserr_noent; if (!dold->d_inode) - goto out_drop_write; + goto out_dput; host_err = nfsd_break_lease(dold->d_inode); if (host_err) { err = nfserrno(host_err); - goto out_drop_write; + goto out_dput; } host_err = vfs_link(dold, dirp, dnew); if (!host_err) { @@ -1718,12 +1720,11 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp, else err = nfserrno(host_err); } -out_drop_write: - fh_drop_write(tfhp); out_dput: dput(dnew); out_unlock: fh_unlock(ffhp); + fh_drop_write(tfhp); out: return err; @@ -1766,6 +1767,12 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (!flen || isdotent(fname, flen) || !tlen || isdotent(tname, tlen)) goto out; + host_err = fh_want_write(ffhp); + if (host_err) { + err = nfserrno(host_err); + goto out; + } + /* cannot use fh_lock as we need deadlock protective ordering * so do it by hand */ trap = lock_rename(tdentry, fdentry); @@ -1796,17 +1803,14 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, host_err = -EXDEV; if (ffhp->fh_export->ex_path.mnt != tfhp->fh_export->ex_path.mnt) goto out_dput_new; - host_err = fh_want_write(ffhp); - if (host_err) - goto out_dput_new; host_err = nfsd_break_lease(odentry->d_inode); if (host_err) - goto out_drop_write; + goto out_dput_new; if (ndentry->d_inode) { host_err = nfsd_break_lease(ndentry->d_inode); if (host_err) - goto out_drop_write; + goto out_dput_new; } host_err = vfs_rename(fdir, odentry, tdir, ndentry); if (!host_err) { @@ -1814,8 +1818,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (!host_err) host_err = commit_metadata(ffhp); } -out_drop_write: - fh_drop_write(ffhp); out_dput_new: dput(ndentry); out_dput_old: @@ -1831,6 +1833,7 @@ out_drop_write: fill_post_wcc(tfhp); unlock_rename(tdentry, fdentry); ffhp->fh_locked = tfhp->fh_locked = 0; + fh_drop_write(ffhp); out: return err; @@ -1856,6 +1859,10 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (err) goto out; + host_err = fh_want_write(fhp); + if (host_err) + goto out_nfserr; + fh_lock_nested(fhp, I_MUTEX_PARENT); dentry = fhp->fh_dentry; dirp = dentry->d_inode; @@ -1874,21 +1881,15 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, if (!type) type = rdentry->d_inode->i_mode & S_IFMT; - host_err = fh_want_write(fhp); - if (host_err) - goto out_put; - host_err = nfsd_break_lease(rdentry->d_inode); if (host_err) - goto out_drop_write; + goto out_put; if (type != S_IFDIR) host_err = vfs_unlink(dirp, rdentry); else host_err = vfs_rmdir(dirp, rdentry); if (!host_err) host_err = commit_metadata(fhp); -out_drop_write: - fh_drop_write(fhp); out_put: dput(rdentry); diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h index ec0611b..359594c 100644 --- a/fs/nfsd/vfs.h +++ b/fs/nfsd/vfs.h @@ -110,12 +110,19 @@ int nfsd_set_posix_acl(struct svc_fh *, int, struct posix_acl *); static inline int fh_want_write(struct svc_fh *fh) { - return mnt_want_write(fh->fh_export->ex_path.mnt); + int ret = mnt_want_write(fh->fh_export->ex_path.mnt); + + if (!ret) + fh->fh_want_write = 1; + return ret; } static inline void fh_drop_write(struct svc_fh *fh) { - mnt_drop_write(fh->fh_export->ex_path.mnt); + if (fh->fh_want_write) { + fh->fh_want_write = 0; + mnt_drop_write(fh->fh_export->ex_path.mnt); + } } #endif /* LINUX_NFSD_VFS_H */ diff --git a/include/linux/nfsd/nfsfh.h b/include/linux/nfsd/nfsfh.h index ce4743a..fa63048 100644 --- a/include/linux/nfsd/nfsfh.h +++ b/include/linux/nfsd/nfsfh.h @@ -143,6 +143,7 @@ typedef struct svc_fh { int fh_maxsize; /* max size for fh_handle */ unsigned char fh_locked; /* inode locked by us */ + unsigned char fh_want_write; /* remount protection taken */ #ifdef CONFIG_NFSD_V3 unsigned char fh_post_saved; /* post-op attrs saved */ -- 1.7.1