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authorSage Weil <sage@newdream.net>2012-01-10 09:12:55 -0800
committerSage Weil <sage@newdream.net>2012-01-12 11:00:40 -0800
commita40dc6cc2e121abcbd1b22583ef5447763df510c (patch)
tree1c747cfabf33c6c9ad56811fabd22285816fc27a /Documentation
parent46f72b349290d2bd7aecea38f02609d814332df6 (diff)
ceph: enable/disable dentry complete flags via mount option
Enable/disable use of the dentry dir 'complete' flag via a mount option. This lets the admin control whether ceph uses the dcache to satisfy negative lookups or readdir when it has the entire directory contents in its cache. This is purely a performance optimization; correctness is guaranteed whether it is enabled or not. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sage Weil <sage@newdream.net>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/ceph.txt18
1 files changed, 13 insertions, 5 deletions
diff --git a/Documentation/filesystems/ceph.txt b/Documentation/filesystems/ceph.txt
index 763d8ebbbeb..d6030aa3337 100644
--- a/Documentation/filesystems/ceph.txt
+++ b/Documentation/filesystems/ceph.txt
@@ -119,12 +119,20 @@ Mount Options
must rely on TCP's error correction to detect data corruption
in the data payload.
- noasyncreaddir
- Disable client's use its local cache to satisfy readdir
- requests. (This does not change correctness; the client uses
- cached metadata only when a lease or capability ensures it is
- valid.)
+ dcache
+ Use the dcache contents to perform negative lookups and
+ readdir when the client has the entire directory contents in
+ its cache. (This does not change correctness; the client uses
+ cached metadata only when a lease or capability ensures it is
+ valid.)
+
+ nodcache
+ Do not use the dcache as above. This avoids a significant amount of
+ complex code, sacrificing performance without affecting correctness,
+ and is useful for tracking down bugs.
+ noasyncreaddir
+ Do not use the dcache as above for readdir.
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