From 7b08fc620109c2f66575e9ae884f45c37933ea18 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Tue, 24 Jul 2007 13:53:36 +0100 Subject: [PATCH] [GFS2] Fix an oops in glock dumping This fixes an oops which was occurring during glock dumping due to the seq file code not taking a reference to the glock. Also this fixes a memory leak which occurred in certain cases, in turn preventing the filesystem from unmounting. Signed-off-by: Steven Whitehouse --- fs/gfs2/glock.c | 73 ++++++++++++++++++++++++------------------------- 1 file changed, 35 insertions(+), 38 deletions(-) diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c index d403fd708075..e4bc8ae561aa 100644 --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -46,7 +46,6 @@ struct glock_iter { int hash; /* hash bucket index */ struct gfs2_sbd *sdp; /* incore superblock */ struct gfs2_glock *gl; /* current glock struct */ - struct hlist_head *hb_list; /* current hash bucket ptr */ struct seq_file *seq; /* sequence file for debugfs */ char string[512]; /* scratch space */ }; @@ -1990,47 +1989,38 @@ int __init gfs2_glock_init(void) static int gfs2_glock_iter_next(struct glock_iter *gi) { + struct gfs2_glock *gl; + read_lock(gl_lock_addr(gi->hash)); - while (1) { - if (!gi->hb_list) { /* If we don't have a hash bucket yet */ - gi->hb_list = &gl_hash_table[gi->hash].hb_list; - if (hlist_empty(gi->hb_list)) { - read_unlock(gl_lock_addr(gi->hash)); - gi->hash++; - read_lock(gl_lock_addr(gi->hash)); - gi->hb_list = NULL; - if (gi->hash >= GFS2_GL_HASH_SIZE) { - read_unlock(gl_lock_addr(gi->hash)); - return 1; - } - else - continue; - } - if (!hlist_empty(gi->hb_list)) { - gi->gl = list_entry(gi->hb_list->first, - struct gfs2_glock, - gl_list); - } - } else { - if (gi->gl->gl_list.next == NULL) { - read_unlock(gl_lock_addr(gi->hash)); - gi->hash++; - read_lock(gl_lock_addr(gi->hash)); - gi->hb_list = NULL; - continue; - } - gi->gl = list_entry(gi->gl->gl_list.next, - struct gfs2_glock, gl_list); - } + gl = gi->gl; + if (gl) { + gi->gl = hlist_entry(gl->gl_list.next, struct gfs2_glock, + gl_list); if (gi->gl) - break; + gfs2_glock_hold(gi->gl); } read_unlock(gl_lock_addr(gi->hash)); + if (gl) + gfs2_glock_put(gl); + + while(gi->gl == NULL) { + gi->hash++; + if (gi->hash >= GFS2_GL_HASH_SIZE) + return 1; + read_lock(gl_lock_addr(gi->hash)); + gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first, + struct gfs2_glock, gl_list); + if (gi->gl) + gfs2_glock_hold(gi->gl); + read_unlock(gl_lock_addr(gi->hash)); + } return 0; } static void gfs2_glock_iter_free(struct glock_iter *gi) { + if (gi->gl) + gfs2_glock_put(gi->gl); kfree(gi); } @@ -2044,12 +2034,17 @@ static struct glock_iter *gfs2_glock_iter_init(struct gfs2_sbd *sdp) gi->sdp = sdp; gi->hash = 0; - gi->gl = NULL; - gi->hb_list = NULL; gi->seq = NULL; memset(gi->string, 0, sizeof(gi->string)); - if (gfs2_glock_iter_next(gi)) { + read_lock(gl_lock_addr(gi->hash)); + gi->gl = hlist_entry(gl_hash_table[gi->hash].hb_list.first, + struct gfs2_glock, gl_list); + if (gi->gl) + gfs2_glock_hold(gi->gl); + read_unlock(gl_lock_addr(gi->hash)); + + if (!gi->gl && gfs2_glock_iter_next(gi)) { gfs2_glock_iter_free(gi); return NULL; } @@ -2066,7 +2061,7 @@ static void *gfs2_glock_seq_start(struct seq_file *file, loff_t *pos) if (!gi) return NULL; - while (n--) { + while(n--) { if (gfs2_glock_iter_next(gi)) { gfs2_glock_iter_free(gi); return NULL; @@ -2093,7 +2088,9 @@ static void *gfs2_glock_seq_next(struct seq_file *file, void *iter_ptr, static void gfs2_glock_seq_stop(struct seq_file *file, void *iter_ptr) { - /* nothing for now */ + struct glock_iter *gi = iter_ptr; + if (gi) + gfs2_glock_iter_free(gi); } static int gfs2_glock_seq_show(struct seq_file *file, void *iter_ptr) -- 2.34.1