Messages in this thread Patch in this message | | | Subject | [PATCH] Forward port of 2.4 fsync_buffers_list() fix. | From | Tim Wright <> | Date | 14 Oct 2002 17:01:20 -0700 |
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Hi, there was a bug in fysnc_buffers_list() in 2.4 (fixed in 2.4.19) that could cause the function to return without having written the current contents of all the buffers. Obviously, this could be bad for anybody relying on ordering using O_SYNC or fsync(). If an I/O was already in flight for a particular bh at the time of the call to fsync_buffers_list(), ll_rw_block() will not initiate a new I/O even though the contents may have changed. It is therefore necessary to wait before the call. Here's a patch against 2.5.42 that applies the same fix.
Regards,
Tim
--- linux-2.5.42/fs/buffer.c Mon Oct 14 16:38:53 2002 +++ linux/fs/buffer.c Mon Oct 14 16:51:54 2002 @@ -812,6 +812,13 @@ if (buffer_dirty(bh)) { get_bh(bh); spin_unlock(lock); + /* + * Ensure any pending I/O completes so that + * ll_rw_block() actually writes the current + * contents - it is a noop if I/O is still in + * flight on potentially older contents. + */ + wait_on_buffer(bh); ll_rw_block(WRITE, 1, &bh); brelse(bh); spin_lock(lock); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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