remarkable-linux/fs
Pavel Emelyanov 0e2f6db88a Leases can be hidden by flocks
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>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-09-11 17:21:27 -07:00
..
9p 9p: remove deprecated v9fs_fid_lookup_remove() 2007-08-23 10:13:45 -05:00
adfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
affs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
afs afs: mntput called before dput 2007-09-11 17:21:19 -07:00
autofs
autofs4 autofs4: deadlock during create 2007-08-22 19:52:46 -07:00
befs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
bfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
cifs [CIFS] Check return code on failed alloc 2007-08-18 00:15:20 +00:00
coda coda: remove CODA_STORE/CODA_RELEASE upcalls 2007-07-21 17:49:14 -07:00
configfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
cramfs
debugfs debugfs: remove rmdir() non-empty complaint 2007-07-18 15:49:48 -07:00
devpts
dlm [DLM] fix basts for granted PR waiting CW 2007-08-14 10:31:02 +01:00
ecryptfs eCryptfs: fix possible fault in ecryptfs_sync_page 2007-08-31 01:42:23 -07:00
efs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
exportfs knfsd: exportfs: split out reconnecting a dentry from find_exported_dentry 2007-07-17 10:23:06 -07:00
ext2 fix inode_table test in ext234_check_descriptors 2007-07-26 11:35:17 -07:00
ext3 quota: fix infinite loop 2007-09-11 17:21:19 -07:00
ext4 quota: fix infinite loop 2007-09-11 17:21:19 -07:00
fat mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
freevxfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
fuse mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
gfs2 [GFS2] Revert remounting w/o acl option leaves acls enabled 2007-08-14 10:34:40 +01:00
hfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
hfsplus mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
hostfs
hpfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
hppfs
hugetlbfs hugepage: fix broken check for offset alignment in hugepage mappings 2007-08-31 01:42:23 -07:00
isofs isofs: mounting to regular file may succeed 2007-07-31 15:39:41 -07:00
jbd mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
jbd2 mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
jffs2 [JFFS2] fix write deadlock regression 2007-09-02 18:18:38 +01:00
jfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
lockd lockd and nfsd endianness annotation fixes 2007-07-26 11:11:56 -07:00
minix mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
msdos
ncpfs NCP: delete test of long-deceased CONFIG_NCPFS_DEBUGDENTRY 2007-07-31 15:39:41 -07:00
nfs NFS: Fix a write request leak in nfs_invalidate_page() 2007-09-01 10:14:54 -04:00
nfs_common
nfsd knfsd: Validate filehandle type in fsid_source 2007-09-10 18:57:47 -07:00
nls NLS: Remove obsolete Makefile entries 2007-07-16 09:05:52 -07:00
ntfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
ocfs2 ocfs2: set non-default s_time_gran during mount 2007-08-09 17:27:58 -07:00
openpromfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
partitions [PARTITION]: Sun/Solaris VTOC table corrections 2007-07-30 00:27:31 -07:00
proc Fix select on /proc files without ->poll 2007-09-11 17:21:20 -07:00
qnx4 mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
ramfs NOMMU: Fix SYSV IPC SHM 2007-07-31 15:39:36 -07:00
reiserfs quota: fix infinite loop 2007-09-11 17:21:19 -07:00
romfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
smbfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
sysfs sysfs: don't warn on removal of a nonexistent binary file 2007-08-22 14:35:36 -07:00
sysv mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
udf Fix possible NULL pointer dereference in udf_table_free_blocks() 2007-08-31 01:42:22 -07:00
ufs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
vfat
xfs [XFS] fix nasty quota hashtable allocation bug 2007-09-05 14:51:04 +10:00
aio.c
anon_inodes.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm 2007-07-17 11:50:26 -07:00
attr.c Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check 2007-07-17 12:00:03 -07:00
bad_inode.c
binfmt_aout.c
binfmt_elf.c revert "PIE randomization" 2007-07-21 17:49:14 -07:00
binfmt_elf_fdpic.c coredump masking: ELF-FDPIC: enable core dump filtering 2007-07-19 10:04:47 -07:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c mm: variable length argument support 2007-07-19 10:04:45 -07:00
binfmt_script.c mm: variable length argument support 2007-07-19 10:04:45 -07:00
binfmt_som.c
bio.c [BLOCK] Get rid of request_queue_t typedef 2007-07-24 09:28:11 +02:00
block_dev.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
buffer.c fix some conversion overflows 2007-07-20 08:44:19 -07:00
char_dev.c unregister_chrdev() return void 2007-07-19 10:04:43 -07:00
compat.c mm: variable length argument support 2007-07-19 10:04:45 -07:00
compat_ioctl.c [PATCH] remove duplicated ioctl entries in compat_ioctl.c 2007-08-06 15:06:03 -04:00
dcache.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
dcookies.c Remove fs.h from mm.h 2007-07-29 17:09:29 -07:00
direct-io.c dio: zero struct dio with kzalloc instead of manually 2007-08-20 22:50:25 -07:00
dnotify.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
dquot.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
drop_caches.c invalidate_mapping_pages(): add cond_resched 2007-07-16 09:05:36 -07:00
eventfd.c
eventpoll.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
exec.c exec: kill unsafe BUG_ON(sig->count) checks 2007-08-22 19:52:47 -07:00
fcntl.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
fifo.c
file.c
file_table.c
filesystems.c
fs-writeback.c
generic_acl.c Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check 2007-07-17 12:00:03 -07:00
inode.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
inotify.c
inotify_user.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
internal.h
ioctl.c drop obsolete sys_ioctl export 2007-07-16 09:05:48 -07:00
ioprio.c
Kconfig NFSD/SUNRPC: Fix the automatic selection of RPCSEC_GSS 2007-07-19 15:09:02 -04:00
Kconfig.binfmt
libfs.c
locks.c Leases can be hidden by flocks 2007-09-11 17:21:27 -07:00
Makefile
mbcache.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
mpage.c
namei.c fs: remove path_walk export 2007-07-19 10:04:45 -07:00
namespace.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
nfsctl.c nfsctl: use vfs_path_lookup 2007-07-19 10:04:45 -07:00
no-block.c
open.c VFS: fix a race in lease-breaking during truncate 2007-07-31 15:39:42 -07:00
pipe.c docbook: add pipes, other fixes 2007-07-27 08:08:51 +02:00
pnode.c
pnode.h
posix_acl.c
quota.c [IA64] Fix build failure in fs/quota.c 2007-07-27 15:40:13 -07:00
quota_v1.c
quota_v2.c
read_write.c
read_write.h
readdir.c
select.c Fix select on /proc files without ->poll 2007-09-11 17:21:20 -07:00
seq_file.c seq_file: more atomicity in traverse() 2007-07-16 09:05:45 -07:00
signalfd.c signalfd: make it group-wide, fix posix-timers scheduling 2007-08-22 19:52:46 -07:00
splice.c docbook: add pipes, other fixes 2007-07-27 08:08:51 +02:00
stack.c
stat.c
super.c hugetlbfs: handle empty options string 2007-07-16 09:05:46 -07:00
sync.c
timerfd.c make timerfd return a u64 and fix the __put_user 2007-07-26 11:35:17 -07:00
utimes.c Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check 2007-07-17 12:00:03 -07:00
xattr.c Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check 2007-07-17 12:00:03 -07:00
xattr_acl.c