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authorPavel Emelyanov <xemul@openvz.org>2007-09-11 15:24:01 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2007-09-26 10:54:40 -0700
commitcb67b06fd170b6b429f7ade84e2e1d428ae34548 (patch)
treeba6c69d8b612aa4d760d0d00a9e9b2751f2d8030
parent360a8cf493412bd03e5e24714f4d497d3f901926 (diff)
Leases can be hidden by flocks
commit 0e2f6db88a6900bc9db576d6b478b12ee60d61f7 in mainline. The inode->i_flock list contains the leases, flocks and posix locks in the specified order. However, the flocks are added in the head of this list thus hiding the leases from F_GETLEASE command, from time_out_leases() and other code that expects the leases to come first. The following example will demonstrate this: #define _GNU_SOURCE #include <unistd.h> #include <fcntl.h> #include <stdio.h> #include <sys/file.h> static void show_lease(int fd) { int res; res = fcntl(fd, F_GETLEASE); switch (res) { case F_RDLCK: printf("Read lease\n"); break; case F_WRLCK: printf("Write lease\n"); break; case F_UNLCK: printf("No leases\n"); break; default: printf("Some shit\n"); break; } } int main(int argc, char **argv) { int fd, res; fd = open(argv[1], O_RDONLY); if (fd == -1) { perror("Can't open file"); return 1; } res = fcntl(fd, F_SETLEASE, F_WRLCK); if (res == -1) { perror("Can't set lease"); return 1; } show_lease(fd); if (flock(fd, LOCK_SH) == -1) { perror("Can't flock shared"); return 1; } show_lease(fd); return 0; } The first call to show_lease() will show the write lease set, but the second will show no leases. Fix the flock adding so that the leases always stay in the head of this list. Found during making the flocks pid-namespaces aware. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: "J. Bruce Fields" <bfields@fieldses.org> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/locks.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/locks.c b/fs/locks.c
index 431a8b871fce..64286050a3b5 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -786,7 +786,7 @@ find_conflict:
if (request->fl_flags & FL_ACCESS)
goto out;
locks_copy_lock(new_fl, request);
- locks_insert_lock(&inode->i_flock, new_fl);
+ locks_insert_lock(before, new_fl);
new_fl = NULL;
error = 0;