[PATCH 3.2 072/185] nfsd: split up nfsd_setattr

Ben Hutchings
2013-12-29T02:28:00Z

From: Christoph Hellwig <hch@infradead.org>

commit 818e5a22e907fbae75e9c1fd78233baec9fa64b6 upstream.

Split out two helpers to make the code more readable and easier to verify
for correctness.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
[bwh: Backported to 3.2: s/umode_t/int/]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/nfsd/vfs.c | 144 ++++++++++++++++++++++++++++++++++------------------------
1 file changed, 84 insertions(+), 60 deletions(-)

--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -297,41 +297,12 @@ commit_metadata(struct svc_fh *fhp)
}

/*
- * Set various file attributes.
- * N.B. After this call fhp needs an fh_put
+ * Go over the attributes and take care of the small differences between
+ * NFS semantics and what Linux expects.
*/
-__be32
-nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
- int check_guard, time_t guardtime)
+static void
+nfsd_sanitize_attrs(struct inode *inode, struct iattr *iap)
{
- struct dentry *dentry;
- struct inode *inode;
- int accmode = NFSD_MAY_SATTR;
- int ftype = 0;
- __be32 err;
- int host_err;
- int size_change = 0;
-
- if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
- accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
- if (iap->ia_valid & ATTR_SIZE)
- ftype = S_IFREG;
-
- /* Get inode */
- err = fh_verify(rqstp, fhp, ftype, accmode);
- if (err)
- goto out;
-
- dentry = fhp->fh_dentry;
- inode = dentry->d_inode;
-
- /* Ignore any mode updates on symlinks */
- if (S_ISLNK(inode->i_mode))
- iap->ia_valid &= ~ATTR_MODE;
-
- if (!iap->ia_valid)
- goto out;
-
/*
* NFSv2 does not differentiate between "set-[ac]time-to-now"
* which only requires access, and "set-[ac]time-to-X" which
@@ -341,8 +312,7 @@ nfsd_setattr(struct svc_rqst *rqstp, str
* convert to "set to now" instead of "set to explicit time"
*
* We only call inode_change_ok as the last test as technically
- * it is not an interface that we should be using. It is only
- * valid if the filesystem does not define it's own i_op->setattr.
+ * it is not an interface that we should be using.
*/
#define BOTH_TIME_SET (ATTR_ATIME_SET | ATTR_MTIME_SET)
#define MAX_TOUCH_TIME_ERROR (30*60)
@@ -368,30 +338,6 @@ nfsd_setattr(struct svc_rqst *rqstp, str
iap->ia_valid &= ~BOTH_TIME_SET;
}
}
-
- /*
- * The size case is special.
- * It changes the file as well as the attributes.
- */
- if (iap->ia_valid & ATTR_SIZE) {
- if (iap->ia_size < inode->i_size) {
- err = nfsd_permission(rqstp, fhp->fh_export, dentry,
- NFSD_MAY_TRUNC|NFSD_MAY_OWNER_OVERRIDE);
- if (err)
- goto out;
- }
-
- host_err = get_write_access(inode);
- if (host_err)
- goto out_nfserr;
-
- size_change = 1;
- host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
- if (host_err) {
- put_write_access(inode);
- goto out_nfserr;
- }
- }

/* sanitize the mode change */
if (iap->ia_valid & ATTR_MODE) {
@@ -414,8 +360,86 @@ nfsd_setattr(struct svc_rqst *rqstp, str
iap->ia_valid |= (ATTR_KILL_SUID | ATTR_KILL_SGID);
}
}
+}
+
+static __be32
+nfsd_get_write_access(struct svc_rqst *rqstp, struct svc_fh *fhp,
+ struct iattr *iap)
+{
+ struct inode *inode = fhp->fh_dentry->d_inode;
+ int host_err;
+
+ if (iap->ia_size < inode->i_size) {
+ __be32 err;
+
+ err = nfsd_permission(rqstp, fhp->fh_export, fhp->fh_dentry,
+ NFSD_MAY_TRUNC | NFSD_MAY_OWNER_OVERRIDE);
+ if (err)
+ return err;
+ }
+
+ host_err = get_write_access(inode);
+ if (host_err)
+ goto out_nfserrno;
+
+ host_err = locks_verify_truncate(inode, NULL, iap->ia_size);
+ if (host_err)
+ goto out_put_write_access;
+ return 0;
+
+out_put_write_access:
+ put_write_access(inode);
+out_nfserrno:
+ return nfserrno(host_err);
+}
+
+/*
+ * Set various file attributes. After this call fhp needs an fh_put.
+ */
+__be32
+nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
+ int check_guard, time_t guardtime)
+{
+ struct dentry *dentry;
+ struct inode *inode;
+ int accmode = NFSD_MAY_SATTR;
+ int ftype = 0;
+ __be32 err;
+ int host_err;
+ int size_change = 0;
+
+ if (iap->ia_valid & (ATTR_ATIME | ATTR_MTIME | ATTR_SIZE))
+ accmode |= NFSD_MAY_WRITE|NFSD_MAY_OWNER_OVERRIDE;
+ if (iap->ia_valid & ATTR_SIZE)
+ ftype = S_IFREG;
+
+ /* Get inode */
+ err = fh_verify(rqstp, fhp, ftype, accmode);
+ if (err)
+ goto out;
+
+ dentry = fhp->fh_dentry;
+ inode = dentry->d_inode;
+
+ /* Ignore any mode updates on symlinks */
+ if (S_ISLNK(inode->i_mode))
+ iap->ia_valid &= ~ATTR_MODE;
+
+ if (!iap->ia_valid)
+ goto out;
+
+ nfsd_sanitize_attrs(inode, iap);

- /* Change the attributes. */
+ /*
+ * The size case is special, it changes the file in addition to the
+ * attributes.
+ */
+ if (iap->ia_valid & ATTR_SIZE) {
+ err = nfsd_get_write_access(rqstp, fhp, iap);
+ if (err)
+ goto out;
+ size_change = 1;
+ }

iap->ia_valid |= ATTR_CTIME;