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ext4: remove unnecessary comments in ext4_orphan_add() 

The comment from Al Viro about possible race in the ext4_orphan_add() is
not justified. There is no race possible as we always have either i_mutex
locked, or the inode can not be referenced from outside hence the
J_ASSERS should not be hit from the reason described in comment.

This commit replaces it with notion that we are holding i_mutex so it
should not be possible for i_nlink to be changed while waiting for
s_orphan_lock.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Lukas Czerner 2011-07-11 18:47:04 -04:00 committed by Theodore Ts'o
parent caaf7a29d3
commit afb86178cb
1 changed files with 5 additions and 12 deletions
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17
fs/ext4/namei.c
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@ -1989,18 +1989,11 @@ int ext4_orphan_add(handle_t *handle, struct inode *inode)
if (!list_empty(&EXT4_I(inode)->i_orphan))
goto out_unlock;
/* Orphan handling is only valid for files with data blocks
* being truncated, or files being unlinked. */
/* @@@ FIXME: Observation from aviro:
* I think I can trigger J_ASSERT in ext4_orphan_add(). We block
* here (on s_orphan_lock), so race with ext4_link() which might bump
* ->i_nlink. For, say it, character device. Not a regular file,
* not a directory, not a symlink and ->i_nlink > 0.
*
* tytso, 4/25/2009: I'm not sure how that could happen;
* shouldn't the fs core protect us from these sort of
* unlink()/link() races?
/*
* Orphan handling is only valid for files with data blocks
* being truncated, or files being unlinked. Note that we either
* hold i_mutex, or the inode can not be referenced from outside,
* so i_nlink should not be bumped due to race
*/
J_ASSERT((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);