On Friday 04 July 2014 05:39 PM, Pranith Kumar Karampuri wrote:
On 07/04/2014 04:28 PM, Raghavendra Gowdappa wrote:
----- Original Message -----
From: "Pranith Kumar Karampuri" <pkara...@redhat.com>
To: "Gluster Devel" <gluster-devel@gluster.org>, "Anand Avati"
<av...@gluster.org>, "Brian Foster"
<bfos...@redhat.com>, "Raghavendra Gowdappa" <rgowd...@redhat.com>,
"Raghavendra Bhat" <rab...@redhat.com>
Sent: Friday, July 4, 2014 3:44:29 PM
Subject: regarding inode_link/unlink
hi,
I have a doubt about when a particular dentry_unset thus
inode_unref on parent dir happens on fuse-bridge in gluster.
When a file is looked up for the first time fuse_entry_cbk does
'inode_link' with parent-gfid/bname. Whenever an unlink/rmdir/(lookup
gives ENOENT) happens then corresponding inode unlink happens. The
question is, will the present set of operations lead to leaks:
1) Mount 'M0' creates a file 'a'
2) Mount 'M1' of same volume deletes file 'a'
M0 never touches 'a' anymore. When will inode_unlink happen for such
cases? Will it lead to memory leaks?
Kernel will eventually send forget (a) on M0 and that will cleanup
the dentries and inode. Its equivalent to a file being looked up and
never used again (deleting doesn't matter in this case).
Do you know the trigger points for that? When I do 'touch a' on the
mount point and leave the system like that, forget is not coming.
If I do unlink on the file then forget is coming.
Pranith
As per my understanding forgets can come in one of these below situations:
1) File/directory is removed
2) As per the above example where there are 2 mounts. In this case, say
one of the mounts removes the file/directory. The other client will get
forget if it tries to access the removed file/directory.
3) In glusterfs fuse client the lru limit for the inodes is infinity. If
the lru-limit is finite, then forgets can come once the lru-limit is
crossed.
4) When drop caches is done, the kernel will send forgets.
Please let me know if I have missed anything.
Regards,
Raghavendra Bhat
Pranith
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