From: wengang wang Date: Tue, 10 Feb 2009 03:27:51 +0000 (+0800) Subject: nfsd(v2/v3): fix the failure of creation from HPUX client X-Git-Tag: firefly_0821_release~14758^2~69 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=4ac35c2f794503d3acda20d98e89cf63f6e94332;p=firefly-linux-kernel-4.4.55.git nfsd(v2/v3): fix the failure of creation from HPUX client sometimes HPUX nfs client sends a create request to linux nfs server(v2/v3). the dump of the request is like: obj_attributes mode: value follows set_it: value follows (1) mode: 00 uid: no value set_it: no value (0) gid: value follows set_it: value follows (1) gid: 8030 size: value follows set_it: value follows (1) size: 0 atime: don't change set_it: don't change (0) mtime: don't change set_it: don't change (0) note that mode is 00(havs no rwx privilege even for the owner) and it requires to set size to 0. as current nfsd(v2/v3) implementation, the server does mainly 2 steps: 1) creates the file in mode specified by calling vfs_create(). 2) sets attributes for the file by calling nfsd_setattr(). at step 2), it finally calls file system specific setattr() function which may fail when checking permission because changing size needs WRITE privilege but it has none since mode is 000. for this case, a new file created, we may simply ignore the request of setting size to 0, so that WRITE privilege is not needed and the open succeeds. Signed-off-by: Wengang Wang -- vfs.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) Signed-off-by: J. Bruce Fields --- diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 6e50aaa56ca2..0c076293155d 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1176,6 +1176,21 @@ nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp, return 0; } +/* HPUX client sometimes creates a file in mode 000, and sets size to 0. + * setting size to 0 may fail for some specific file systems by the permission + * checking which requires WRITE permission but the mode is 000. + * we ignore the resizing(to 0) on the just new created file, since the size is + * 0 after file created. + * + * call this only after vfs_create() is called. + * */ +static void +nfsd_check_ignore_resizing(struct iattr *iap) +{ + if ((iap->ia_valid & ATTR_SIZE) && (iap->ia_size == 0)) + iap->ia_valid &= ~ATTR_SIZE; +} + /* * Create a file (regular, directory, device, fifo); UNIX sockets * not yet implemented. @@ -1271,6 +1286,8 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, switch (type) { case S_IFREG: host_err = vfs_create(dirp, dchild, iap->ia_mode, NULL); + if (!host_err) + nfsd_check_ignore_resizing(iap); break; case S_IFDIR: host_err = vfs_mkdir(dirp, dchild, iap->ia_mode); @@ -1424,6 +1441,8 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp, /* setattr will sync the child (or not) */ } + nfsd_check_ignore_resizing(iap); + if (createmode == NFS3_CREATE_EXCLUSIVE) { /* Cram the verifier into atime/mtime */ iap->ia_valid = ATTR_MTIME|ATTR_ATIME