To pleace an exclusive lock on a file, NFSv4 requires the file to be opened RW because of the emulation of flock() by fcntl(): http://www.spinics.net/lists/linux-nfs/msg18502.html So instead of O_RDONLY, open the file in O_RDWR if access() indicates it is possible (unless shared lock is requested). From: Michal Kubecek <mkubecek@xxxxxxx> Signed-off-by: Petr Uzel <petr.uzel@xxxxxxx> --- sys-utils/flock.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/sys-utils/flock.c b/sys-utils/flock.c index 7d321de..a500319 100644 --- a/sys-utils/flock.c +++ b/sys-utils/flock.c @@ -129,6 +129,7 @@ int main(int argc, char *argv[]) int have_timeout = 0; int type = LOCK_EX; int block = 0; + int open_accmode; int fd = -1; int opt, ix; int do_close = 0; @@ -211,9 +212,11 @@ int main(int argc, char *argv[]) } filename = argv[optind]; - fd = open(filename, O_RDONLY|O_NOCTTY|O_CREAT, 0666); + open_accmode = ((type == LOCK_SH || access(filename, R_OK|W_OK) < 0) ? + O_RDONLY : O_RDWR); + fd = open(filename, open_accmode|O_NOCTTY|O_CREAT, 0666); /* Linux doesn't like O_CREAT on a directory, even though it should be a - no-op */ + no-op; POSIX doesn't allow O_RDWR or O_WRONLY */ if (fd < 0 && errno == EISDIR) fd = open(filename, O_RDONLY|O_NOCTTY); -- 1.7.3.4 Petr -- Petr Uzel IRC: ptr_uzl @ freenode
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