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| author | Nick Piggin <npiggin@kernel.dk> | 2011-01-07 17:49:37 +1100 |
|---|---|---|
| committer | Nick Piggin <npiggin@kernel.dk> | 2011-01-07 17:50:22 +1100 |
| commit | 949854d02455080d20cd3e1db28a3a18daf7599d (patch) | |
| tree | 9b13a6f86c1d0b91e462a471e53b0e717036b18e /include | |
| 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 'include')
| -rw-r--r-- | include/linux/dcache.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h index bda5ec0b077d..c963ebada922 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -180,6 +180,7 @@ struct dentry_operations { #define DCACHE_FSNOTIFY_PARENT_WATCHED 0x0080 /* Parent inode is watched by some fsnotify listener */ #define DCACHE_CANT_MOUNT 0x0100 +#define DCACHE_GENOCIDE 0x0200 extern spinlock_t dcache_inode_lock; extern spinlock_t dcache_lock; |