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fsnotify: Update comments 

Add a comment that lifetime of a notification mark is protected by SRCU
and remove a comment about clearing of marks attached to the inode. It
is stale and more uptodate version is at fsnotify_destroy_marks() which
is the function handling this case.

Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2016-12-16 10:53:32 +01:00
parent 43471d15df
commit c1f33073ac
1 changed files with 1 additions and 12 deletions
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13
fs/notify/mark.c
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@ -51,7 +51,7 @@
*
* LIFETIME:
* Inode marks survive between when they are added to an inode and when their
* refcnt==0.
* refcnt==0. Marks are also protected by fsnotify_mark_srcu.
*
* The inode mark can be cleared for a number of different reasons including:
* - The inode is unlinked for the last time. (fsnotify_inode_remove)
@ -61,17 +61,6 @@
* - The fsnotify_group associated with the mark is going away and all such marks
* need to be cleaned up. (fsnotify_clear_marks_by_group)
*
* Worst case we are given an inode and need to clean up all the marks on that
* inode. We take i_lock and walk the i_fsnotify_marks safely. For each
* mark on the list we take a reference (so the mark can't disappear under us).
* We remove that mark form the inode's list of marks and we add this mark to a
* private list anchored on the stack using i_free_list; we walk i_free_list
* and before we destroy the mark we make sure that we dont race with a
* concurrent destroy_group by getting a ref to the marks group and taking the
* groups mutex.
* Very similarly for freeing by group, except we use free_g_list.
*
* This has the very interesting property of being able to run concurrently with
* any (or all) other directions.
*/