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  1. 25 Mar, 2011 4 commits
    • Dave Chinner's avatar
      fs: remove inode_lock from iput_final and prune_icache · f283c86a
      Dave Chinner authored 
      Now that inode state changes are protected by the inode->i_lock and
the inode LRU manipulations by the inode_lru_lock, we can remove the
inode_lock from prune_icache and the initial part of iput_final().

instead of using the inode_lock to protect the inode during
iput_final, use the inode->i_lock instead. This protects the inode
against new references being taken while we change the inode state
to I_FREEING, as well as preventing prune_icache from grabbing the
inode while we are manipulating it. Hence we no longer need the
inode_lock in iput_final prior to setting I_FREEING on the inode.

For prune_icache, we no longer need the inode_lock to protect the
LRU list, and the inodes themselves are protected against freeing
races by the inode->i_lock. Hence we can lift the inode_lock from
prune_icache as well.
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      f283c86a
    • Dave Chinner's avatar
      fs: Lock the inode LRU list separately · 02afc410
      Dave Chinner authored 
      Introduce the inode_lru_lock to protect the inode_lru list. This
lock is nested inside the inode->i_lock to allow the inode to be
added to the LRU list in iput_final without needing to deal with
lock inversions. This keeps iput_final() clean and neat.

Further, where marking the inode I_FREEING and removing it from the
LRU, move the LRU list manipulation within the inode->i_lock to keep
the list manipulation consistent with iput_final. This also means
that most of the open coded LRU list removal + unused inode
accounting can now use the inode_lru_list_del() wrappers which
cleans the code up further.

However, this locking change means what the LRU traversal in
prune_icache() inverts this lock ordering and needs to use trylock
semantics on the inode->i_lock to avoid deadlocking. In these cases,
if we fail to lock the inode we move it to the back of the LRU to
prevent spinning on it.
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      02afc410
    • Dave Chinner's avatar
      fs: factor inode disposal · b2b2af8e
      Dave Chinner authored 
      We have a couple of places that dispose of inodes. factor the
disposal into evict() to isolate this code and make it simpler to
peel away the inode_lock from the code.

While doing this, change the logic flow in iput_final() to separate
the different cases that need to be handled to make the transitions
the inode goes through more obvious.
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      b2b2af8e
    • Dave Chinner's avatar
      fs: protect inode->i_state with inode->i_lock · 250df6ed
      Dave Chinner authored 
      Protect inode state transitions and validity checks with the
inode->i_lock. This enables us to make inode state transitions
independently of the inode_lock and is the first step to peeling
away the inode_lock from the code.

This requires that __iget() is done atomically with i_state checks
during list traversals so that we don't race with another thread
marking the inode I_FREEING between the state check and grabbing the
reference.

Also remove the unlock_new_inode() memory barrier optimisation
required to avoid taking the inode_lock when clearing I_NEW.
Simplify the code by simply taking the inode->i_lock around the
state change and wakeup. Because the wakeup is no longer tricky,
remove the wake_up_inode() function and open code the wakeup where
necessary.
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
      250df6ed
  3. 24 Mar, 2011 36 commits
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