Messages in this thread Patch in this message | | | Subject | Re: [patch] Real-Time Preemption, -VP-2.6.9-rc4-mm1-U3 | From | OGAWA Hirofumi <> | Date | Mon, 18 Oct 2004 00:32:17 +0900 |
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Dominik Karall <dominik.karall@gmx.net> writes:
> i could reproduce it now, but only once. it appeared when i started an avi > movie from my fat32 partition. mplayer stopped at buffering 2% and does not > play the movie. i tried to start mplayer again and reproduce it, but the bug > does not appear again. mplayer only stopped at 2% buffering and does nothing > more. it seems like the file couldn't be read clearly now from the fat32 > partition, as it does not work with xine and others too. > here is the bug i get now: > > ------------[ cut here ]------------ > kernel BUG at fs/fat/cache.c:150!
Probably this BUG_ON() was wrong. Does this bug occur only by the specific file?
If so, please do "filefrag -v filename" against that file.
Then, can you try the attached patch? This patch removes the BUG_ON(), and instead adds printk() for debugging. When the bug occured, it prints the current cache.
Thanks. -- OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> ---
fs/fat/cache.c | 26 +++++++++++++++++++++++++- 1 files changed, 25 insertions(+), 1 deletion(-)
diff -puN fs/fat/cache.c~fat-debug fs/fat/cache.c --- linux-2.6.9-final-a/fs/fat/cache.c~fat-debug 2004-10-17 23:45:27.000000000 +0900 +++ linux-2.6.9-final-a-hirofumi/fs/fat/cache.c 2004-10-18 00:26:44.000000000 +0900 @@ -134,6 +134,30 @@ static struct fat_cache *fat_cache_merge return NULL; } +static void fat_cache_check(struct inode *inode, struct fat_cache_id *new) +{ + struct fat_cache *p; + + if (new->id == FAT_CACHE_VALID) { + list_for_each_entry(p, &MSDOS_I(inode)->cache_lru, cache_list) { + /* Find the same part as "new" in cluster-chain. */ + if (p->fcluster == new->fcluster) { + BUG_ON(p->dcluster != new->dcluster); + goto dump_cache; + } + } + } + return; + +dump_cache: + printk("%s: id %u, contig %d, fclus %d, dclus %d\n", __FUNCTION__, + new->id, new->nr_contig, new->fcluster, new->dcluster); + list_for_each_entry(p, &MSDOS_I(inode)->cache_lru, cache_list) { + printk("contig %d, fclus %d, dclus %d\n", + p->nr_contig, p->fcluster, p->dcluster); + } +} + static void fat_cache_add(struct inode *inode, struct fat_cache_id *new) { struct fat_cache *cache, *tmp; @@ -146,8 +170,8 @@ static void fat_cache_add(struct inode * new->id != MSDOS_I(inode)->cache_valid_id) goto out; /* this cache was invalidated */ + fat_cache_check(inode, new); cache = fat_cache_merge(inode, new); - BUG_ON(new->id == FAT_CACHE_VALID && cache != NULL); if (cache == NULL) { if (MSDOS_I(inode)->nr_caches < fat_max_cache(inode)) { MSDOS_I(inode)->nr_caches++; _ | |