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| author | Abhijith Das <adas@redhat.com> | 2007-09-13 23:35:27 -0500 |
|---|---|---|
| committer | Steven Whitehouse <swhiteho@redhat.com> | 2007-10-10 08:56:14 +0100 |
| commit | b4c20166dcfca106f0f416bfce200099ed76ab18 (patch) | |
| tree | 474e8c3bda161953202793c0801ab00a5b5433de /fs/gfs2/ops_file.c | |
| parent | 1ad38c437fa33f85ba4b6a85ea8c5478ee72d5bd (diff) | |
| download | linux-b4c20166dcfca106f0f416bfce200099ed76ab18.tar.bz2 | |
[GFS2] flocks from same process trip kernel BUG at fs/gfs2/glock.c:1118!
This patch adds a new flag to the gfs2_holder structure GL_FLOCK.
It is set on holders of glocks representing flocks. This flag is
checked in add_to_queue() and a process is permitted to queue more
than one holder onto a glock if it is set. This solves the issue
of a process not being able to do multiple flocks on the same file.
Through a single descriptor, a process can now promote and demote
flocks. Through multiple descriptors a process can now queue
multiple flocks on the same file. There's still the problem of
a process deadlocking itself (because gfs2 blocking locks are not
interruptible) by queueing incompatible deadlock.
Signed-off-by: Abhijith Das <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs/gfs2/ops_file.c')
| -rw-r--r-- | fs/gfs2/ops_file.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/fs/gfs2/ops_file.c b/fs/gfs2/ops_file.c index 94d76ace0b95..46a9e10ff17b 100644 --- a/fs/gfs2/ops_file.c +++ b/fs/gfs2/ops_file.c @@ -571,7 +571,8 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl) int error = 0; state = (fl->fl_type == F_WRLCK) ? LM_ST_EXCLUSIVE : LM_ST_SHARED; - flags = (IS_SETLKW(cmd) ? 0 : LM_FLAG_TRY) | GL_EXACT | GL_NOCACHE; + flags = (IS_SETLKW(cmd) ? 0 : LM_FLAG_TRY) | GL_EXACT | GL_NOCACHE + | GL_FLOCK; mutex_lock(&fp->f_fl_mutex); @@ -579,21 +580,19 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl) if (gl) { if (fl_gh->gh_state == state) goto out; - gfs2_glock_hold(gl); flock_lock_file_wait(file, &(struct file_lock){.fl_type = F_UNLCK}); - gfs2_glock_dq_uninit(fl_gh); + gfs2_glock_dq_wait(fl_gh); + gfs2_holder_reinit(state, flags, fl_gh); } else { error = gfs2_glock_get(GFS2_SB(&ip->i_inode), ip->i_no_addr, &gfs2_flock_glops, CREATE, &gl); if (error) goto out; + gfs2_holder_init(gl, state, flags, fl_gh); + gfs2_glock_put(gl); } - - gfs2_holder_init(gl, state, flags, fl_gh); - gfs2_glock_put(gl); - error = gfs2_glock_nq(fl_gh); if (error) { gfs2_holder_uninit(fl_gh); |