From: Chris Mason In order for filesystems to detect asynchronous ordered write failures for buffers sent via submit_bh, they need a bit they can test for in the buffer head. This adds BH_Eopnotsupp and the related buffer operations end_buffer_write_sync is changed to avoid a printk for BH_Eoptnotsupp related failures, since the FS is responsible for a retry. sync_dirty_buffer is changed to test for BH_Eopnotsupp and return -EOPNOTSUPP to the caller Some of this came from Jens Axboe Signed-off-by: Andrew Morton --- 25-akpm/fs/buffer.c | 10 ++++++++-- 25-akpm/include/linux/buffer_head.h | 2 ++ 2 files changed, 10 insertions(+), 2 deletions(-) diff -puN fs/buffer.c~add-bh_eopnotsupp-for-testing fs/buffer.c --- 25/fs/buffer.c~add-bh_eopnotsupp-for-testing 2004-07-11 14:26:06.849610544 -0700 +++ 25-akpm/fs/buffer.c 2004-07-11 14:26:06.856609480 -0700 @@ -213,7 +213,7 @@ void end_buffer_write_sync(struct buffer if (uptodate) { set_buffer_uptodate(bh); } else { - if (printk_ratelimit()) { + if (!buffer_eopnotsupp(bh) && printk_ratelimit()) { buffer_io_error(bh); printk(KERN_WARNING "lost page write due to " "I/O error on %s\n", @@ -2756,8 +2756,10 @@ static int end_bio_bh_io_sync(struct bio if (bio->bi_size) return 1; - if (err == -EOPNOTSUPP) + if (err == -EOPNOTSUPP) { set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); + set_bit(BH_Eopnotsupp, &bh->b_state); + } bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags)); bio_put(bio); @@ -2882,6 +2884,10 @@ int sync_dirty_buffer(struct buffer_head bh->b_end_io = end_buffer_write_sync; ret = submit_bh(WRITE, bh); wait_on_buffer(bh); + if (buffer_eopnotsupp(bh)) { + clear_buffer_eopnotsupp(bh); + ret = -EOPNOTSUPP; + } if (!ret && !buffer_uptodate(bh)) ret = -EIO; } else { diff -puN include/linux/buffer_head.h~add-bh_eopnotsupp-for-testing include/linux/buffer_head.h --- 25/include/linux/buffer_head.h~add-bh_eopnotsupp-for-testing 2004-07-11 14:26:06.850610392 -0700 +++ 25-akpm/include/linux/buffer_head.h 2004-07-11 14:26:06.856609480 -0700 @@ -27,6 +27,7 @@ enum bh_state_bits { BH_Boundary, /* Block is followed by a discontiguity */ BH_Write_EIO, /* I/O error on write */ BH_Ordered, /* ordered write */ + BH_Eopnotsupp, /* operation not supported (barrier) */ BH_PrivateStart,/* not a state bit, but the first bit available * for private allocation by other entities @@ -113,6 +114,7 @@ BUFFER_FNS(Delay, delay) BUFFER_FNS(Boundary, boundary) BUFFER_FNS(Write_EIO, write_io_error) BUFFER_FNS(Ordered, ordered) +BUFFER_FNS(Eopnotsupp, eopnotsupp) #define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK) #define touch_buffer(bh) mark_page_accessed(bh->b_page) _