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author | Nick Piggin <npiggin@kernel.dk> | 2011-01-07 17:49:37 +1100 |
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committer | Nick Piggin <npiggin@kernel.dk> | 2011-01-07 17:50:22 +1100 |
commit | 949854d02455080d20cd3e1db28a3a18daf7599d (patch) | |
tree | 9b13a6f86c1d0b91e462a471e53b0e717036b18e /fs/ncpfs | |
parent | 9abca36087288fe28de4749c71ca003d4b9e3ed0 (diff) | |
download | linux-949854d02455080d20cd3e1db28a3a18daf7599d.tar.bz2 |
fs: Use rename lock and RCU for multi-step operations
The remaining usages for dcache_lock is to allow atomic, multi-step read-side
operations over the directory tree by excluding modifications to the tree.
Also, to walk in the leaf->root direction in the tree where we don't have
a natural d_lock ordering.
This could be accomplished by taking every d_lock, but this would mean a
huge number of locks and actually gets very tricky.
Solve this instead by using the rename seqlock for multi-step read-side
operations, retry in case of a rename so we don't walk up the wrong parent.
Concurrent dentry insertions are not serialised against. Concurrent deletes
are tricky when walking up the directory: our parent might have been deleted
when dropping locks so also need to check and retry for that.
We can also use the rename lock in cases where livelock is a worry (and it
is introduced in subsequent patch).
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Diffstat (limited to 'fs/ncpfs')
0 files changed, 0 insertions, 0 deletions