This patch adds 4 flags: 1) O_DENYREAD that doesn't permit read access, 2) O_DENYWRITE that doesn't permit write access, 3) O_DENYDELETE that doesn't permit delete or rename, 4) O_DENYMAND that enables O_DENY* flags checks.
Network filesystems CIFS, SMB2.0, SMB3.0 and NFSv4 have such flags - this change can benefit cifs and nfs modules as well as Samba and NFS file servers. These flags are only take affect for opens with O_DENYMAND flags - there is no impact on native Linux opens.
Signed-off-by: Pavel Shilovsky piastry@etersoft.ru --- fs/fcntl.c | 5 +++-- include/uapi/asm-generic/fcntl.h | 14 ++++++++++++++ 2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/fs/fcntl.c b/fs/fcntl.c index 71a600a..d88a548 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -730,14 +730,15 @@ static int __init fcntl_init(void) * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY * is defined as O_NONBLOCK on some platforms and not on others. */ - BUILD_BUG_ON(19 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( + BUILD_BUG_ON(23 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( O_RDONLY | O_WRONLY | O_RDWR | O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC | O_APPEND | /* O_NONBLOCK | */ __O_SYNC | O_DSYNC | FASYNC | O_DIRECT | O_LARGEFILE | O_DIRECTORY | O_NOFOLLOW | O_NOATIME | O_CLOEXEC | - __FMODE_EXEC | O_PATH + __FMODE_EXEC | O_PATH | O_DENYREAD | + O_DENYWRITE | O_DENYDELETE | O_DENYMAND ));
fasync_cache = kmem_cache_create("fasync_cache", diff --git a/include/uapi/asm-generic/fcntl.h b/include/uapi/asm-generic/fcntl.h index a48937d..6e4e979 100644 --- a/include/uapi/asm-generic/fcntl.h +++ b/include/uapi/asm-generic/fcntl.h @@ -84,6 +84,20 @@ #define O_PATH 010000000 #endif
+#ifndef O_DENYREAD +#define O_DENYREAD 020000000 /* Do not permit read access */ +#endif +#ifndef O_DENYWRITE +#define O_DENYWRITE 040000000 /* Do not permit write access */ +#endif +/* FMODE_NONOTIFY 0100000000 */ +#ifndef O_DENYDELETE +#define O_DENYDELETE 0200000000 /* Do not permit delete or rename */ +#endif +#ifndef O_DENYMAND +#define O_DENYMAND 0400000000 /* Enable O_DENY flags checks */ +#endif + #ifndef O_NDELAY #define O_NDELAY O_NONBLOCK #endif