From b44061d0b914c11fb8f8a747c91d111973f56d76 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Wed, 20 Jul 2016 16:16:06 -0400 Subject: [PATCH] nfsd: reorganize nfsd_create There's some odd logic in nfsd_create() that allows it to be called with the parent directory either locked or unlocked. The only already-locked caller is NFSv2's nfsd_proc_create(). It's less confusing to split out the unlocked case into a separate function which the NFSv2 code can call directly. Also fix some comments while we're here. Signed-off-by: J. Bruce Fields --- fs/nfsd/nfsproc.c | 4 +- fs/nfsd/vfs.c | 109 ++++++++++++++++++++++++---------------------- fs/nfsd/vfs.h | 3 ++ 3 files changed, 61 insertions(+), 55 deletions(-) diff --git a/fs/nfsd/nfsproc.c b/fs/nfsd/nfsproc.c index 6722fe52ea15..e9214768cde9 100644 --- a/fs/nfsd/nfsproc.c +++ b/fs/nfsd/nfsproc.c @@ -359,8 +359,8 @@ nfsd_proc_create(struct svc_rqst *rqstp, struct nfsd_createargs *argp, nfserr = 0; if (!inode) { /* File doesn't exist. Create it and set attrs */ - nfserr = nfsd_create(rqstp, dirfhp, argp->name, argp->len, - attr, type, rdev, newfhp); + nfserr = nfsd_create_locked(rqstp, dirfhp, argp->name, + argp->len, attr, type, rdev, newfhp); } else if (type == S_IFREG) { dprintk("nfsd: existing %s, valid=%x, size=%ld\n", argp->name, attr->ia_valid, (long) attr->ia_size); diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index cf14e394a1b0..d21d0827cac4 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1135,16 +1135,9 @@ nfsd_check_ignore_resizing(struct iattr *iap) iap->ia_valid &= ~ATTR_SIZE; } -/* - * Create a file (regular, directory, device, fifo); UNIX sockets - * not yet implemented. - * If the response fh has been verified, the parent directory should - * already be locked. Note that the parent directory is left locked. - * - * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp - */ +/* The parent directory should already be locked: */ __be32 -nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, +nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp, char *fname, int flen, struct iattr *iap, int type, dev_t rdev, struct svc_fh *resfhp) { @@ -1154,50 +1147,15 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, __be32 err2; int host_err; - err = nfserr_exist; - if (isdotent(fname, flen)) - goto out; - - /* - * Even though it is a create, first let's see if we are even allowed - * to peek inside the parent - */ - err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); - if (err) - goto out; - dentry = fhp->fh_dentry; dirp = d_inode(dentry); - /* - * Check whether the response file handle has been verified yet. - * 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); - host_err = PTR_ERR(dchild); - if (IS_ERR(dchild)) - goto out_nfserr; - err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); - if (err) - goto out; - } else { - /* called from nfsd_proc_create */ - dchild = dget(resfhp->fh_dentry); - if (!fhp->fh_locked) { - /* not actually possible */ - printk(KERN_ERR - "nfsd_create: parent %pd2 not locked!\n", + dchild = dget(resfhp->fh_dentry); + if (!fhp->fh_locked) { + WARN_ONCE(1, "nfsd_create: parent %pd2 not locked!\n", dentry); - err = nfserr_io; - goto out; - } + err = nfserr_io; + goto out; } /* * Make sure the child dentry is still negative ... @@ -1225,9 +1183,6 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, goto out; } - /* - * Get the dir op function pointer. - */ err = 0; host_err = 0; switch (type) { @@ -1254,7 +1209,7 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, /* * nfsd_create_setattr already committed the child. Transactional * filesystems had a chance to commit changes for both parent and - * child * simultaneously making the following commit_metadata a + * child simultaneously making the following commit_metadata a * noop. */ err2 = nfserrno(commit_metadata(fhp)); @@ -1275,6 +1230,54 @@ out_nfserr: goto out; } +/* + * Create a filesystem object (regular, directory, special). + * Note that the parent directory is left locked. + * + * N.B. Every call to nfsd_create needs an fh_put for _both_ fhp and resfhp + */ +__be32 +nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, + char *fname, int flen, struct iattr *iap, + int type, dev_t rdev, struct svc_fh *resfhp) +{ + struct dentry *dentry, *dchild = NULL; + struct inode *dirp; + __be32 err; + int host_err; + + if (isdotent(fname, flen)) + return nfserr_exist; + + /* + * Even though it is a create, first let's see if we are even allowed + * to peek inside the parent + */ + err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); + if (err) + return err; + + dentry = fhp->fh_dentry; + dirp = d_inode(dentry); + + host_err = fh_want_write(fhp); + if (host_err) + return nfserrno(host_err); + + fh_lock_nested(fhp, I_MUTEX_PARENT); + dchild = lookup_one_len(fname, dentry, flen); + host_err = PTR_ERR(dchild); + if (IS_ERR(dchild)) + return nfserrno(host_err); + err = fh_compose(resfhp, fhp->fh_export, dchild, fhp); + if (err) { + dput(dchild); + return err; + } + return nfsd_create_locked(rqstp, fhp, fname, flen, iap, type, + rdev, resfhp); +} + #ifdef CONFIG_NFSD_V3 /* diff --git a/fs/nfsd/vfs.h b/fs/nfsd/vfs.h index 2d573ec057f8..3cbb1b33777b 100644 --- a/fs/nfsd/vfs.h +++ b/fs/nfsd/vfs.h @@ -59,6 +59,9 @@ __be32 nfsd4_vfs_fallocate(struct svc_rqst *, struct svc_fh *, __be32 nfsd4_clone_file_range(struct file *, u64, struct file *, u64, u64); #endif /* CONFIG_NFSD_V4 */ +__be32 nfsd_create_locked(struct svc_rqst *, struct svc_fh *, + char *name, int len, struct iattr *attrs, + int type, dev_t rdev, struct svc_fh *res); __be32 nfsd_create(struct svc_rqst *, struct svc_fh *, char *name, int len, struct iattr *attrs, int type, dev_t rdev, struct svc_fh *res); -- 2.20.1