diff options
| author | Bob Peterson <rpeterso@redhat.com> | 2014-08-20 18:44:45 +0200 |
|---|---|---|
| committer | Steven Whitehouse <swhiteho@redhat.com> | 2014-08-21 11:22:52 +0200 |
| commit | 2ddfbdd6848d496d8088b28992d257fd02e58c9d (patch) | |
| tree | 58ba5b778b6cb26bcafe52fb7034480a4c68af45 /fs | |
| parent | GFS2: Change maxlen variables to size_t (diff) | |
| download | linux-2ddfbdd6848d496d8088b28992d257fd02e58c9d.tar.xz linux-2ddfbdd6848d496d8088b28992d257fd02e58c9d.zip | |
GFS2: Request demote when a "try" flock fails
This patch changes the flock code so that it uses the TRY_1CB flag
instead of the TRY flag on the first attempt. That forces any holding
nodes to issue a dlm callback, which requests a demote of the glock.
Then, if the "try" failed, it sleeps a small amount of time for the
demote to occur. Then it tries again, for an increasing amount of time.
Subsequent attempts to gain the "try" lock don't use "_1CB" so that
only one callback is issued.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/gfs2/file.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index 26b3f952e6b1..7f4ed3daa38c 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -26,6 +26,7 @@ #include <linux/dlm.h> #include <linux/dlm_plock.h> #include <linux/aio.h> +#include <linux/delay.h> #include "gfs2.h" #include "incore.h" @@ -979,9 +980,10 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl) unsigned int state; int flags; int error = 0; + int sleeptime; state = (fl->fl_type == F_WRLCK) ? LM_ST_EXCLUSIVE : LM_ST_SHARED; - flags = (IS_SETLKW(cmd) ? 0 : LM_FLAG_TRY) | GL_EXACT; + flags = (IS_SETLKW(cmd) ? 0 : LM_FLAG_TRY_1CB) | GL_EXACT; mutex_lock(&fp->f_fl_mutex); @@ -1001,7 +1003,14 @@ static int do_flock(struct file *file, int cmd, struct file_lock *fl) gfs2_holder_init(gl, state, flags, fl_gh); gfs2_glock_put(gl); } - error = gfs2_glock_nq(fl_gh); + for (sleeptime = 1; sleeptime <= 4; sleeptime <<= 1) { + error = gfs2_glock_nq(fl_gh); + if (error != GLR_TRYFAILED) + break; + fl_gh->gh_flags = LM_FLAG_TRY | GL_EXACT; + fl_gh->gh_error = 0; + msleep(sleeptime); + } if (error) { gfs2_holder_uninit(fl_gh); if (error == GLR_TRYFAILED) @@ -1024,7 +1033,7 @@ static void do_unflock(struct file *file, struct file_lock *fl) mutex_lock(&fp->f_fl_mutex); flock_lock_file_wait(file, fl); if (fl_gh->gh_gl) { - gfs2_glock_dq_wait(fl_gh); + gfs2_glock_dq(fl_gh); gfs2_holder_uninit(fl_gh); } mutex_unlock(&fp->f_fl_mutex); |