fuse: implement NFS-like readdirplus support

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This patch implements readdirplus support in FUSE, similar to NFS.
The payload returned in the readdirplus call contains
'fuse_entry_out' structure thereby providing all the necessary inputs
for 'faking' a lookup() operation on the spot.

If the dentry and inode already existed (for e.g. in a re-run of ls -l)
then just the inode attributes timeout and dentry timeout are refreshed.

With a simple client->network->server implementation of a FUSE based
filesystem, the following performance observations were made:

Test: Performing a filesystem crawl over 20,000 files with

sh# time ls -lR /mnt

Without readdirplus:
Run 1: 18.1s
Run 2: 16.0s
Run 3: 16.2s

With readdirplus:
Run 1: 4.1s
Run 2: 3.8s
Run 3: 3.8s

The performance improvement is significant as it avoided 20,000 upcalls
calls (lookup). Cache consistency is no worse than what already is.

Signed-off-by: Anand V. Avati <avati@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>

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This commit is contained in:

Anand V. Avati 2012-08-19 08:53:23 -04:00 • committed by Miklos Szeredi

parent ff7532ca2c

commit 0b05b18381

5 changed files with 197 additions and 5 deletions

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19

fs/fuse/dev.c

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160

fs/fuse/dir.c

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6

fs/fuse/fuse_i.h

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5

fs/fuse/inode.c

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12

include/uapi/linux/fuse.h

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