Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 3 Feb 2003 00:32:12 +0100 (CET) | From | Mikulas Patocka <> | Subject | 2.0, 2.2, 2.4, 2.5: fsync buffer race |
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Hi
there's a race condition in filesystem
let's have a two inodes that are placed in the same buffer.
call fsync on inode 1 it goes down to ext2_update_inode [update == 1] it calls ll_rw_block at the end ll_rw_block starts to write buffer ext2_update_inode waits on buffer
while the buffer is writing, another process calls fsync on inode 2 it goes again to ext2_update_inode it calls ll_rw_block ll_rw_block sees buffer locked and exits immediatelly ext2_update_inode waits for buffer the first write finished, ext2_update_inode exits and changes made by second proces to inode 2 ARE NOT WRITTEN TO DISK.
This bug causes that when you simultaneously fsync two inodes in the same buffer, only the first will be really written to disk.
Mikulas
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