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xfs: refactor the inode recycling code

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Hoist the code in xfs_iget_cache_hit that restores the VFS inode state
to an xfs_inode that was previously vfs-destroyed.  The next patch will
add a new set of state flags, so we need the helper to avoid
duplication.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This commit is contained in:
Darrick J. Wong 2021-06-18 11:57:05 -07:00
parent 956f6daa84
commit ff7bebeb91
2 changed files with 83 additions and 64 deletions
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143
fs/xfs/xfs_icache.c
View file

@ -355,14 +355,14 @@ xfs_reinit_inode(
struct xfs_mount *mp,
struct inode *inode)
{
int error;
uint32_t nlink = inode->i_nlink;
uint32_t generation = inode->i_generation;
uint64_t version = inode_peek_iversion(inode);
umode_t mode = inode->i_mode;
dev_t dev = inode->i_rdev;
kuid_t uid = inode->i_uid;
kgid_t gid = inode->i_gid;
int error;
uint32_t nlink = inode->i_nlink;
uint32_t generation = inode->i_generation;
uint64_t version = inode_peek_iversion(inode);
umode_t mode = inode->i_mode;
dev_t dev = inode->i_rdev;
kuid_t uid = inode->i_uid;
kgid_t gid = inode->i_gid;
error = inode_init_always(mp->m_super, inode);
@ -376,6 +376,74 @@ xfs_reinit_inode(
return error;
}
/*
* Carefully nudge an inode whose VFS state has been torn down back into a
* usable state. Drops the i_flags_lock and the rcu read lock.
*/
static int
xfs_iget_recycle(
struct xfs_perag *pag,
struct xfs_inode *ip) __releases(&ip->i_flags_lock)
{
struct xfs_mount *mp = ip->i_mount;
struct inode *inode = VFS_I(ip);
int error;
trace_xfs_iget_recycle(ip);
/*
* We need to make it look like the inode is being reclaimed to prevent
* the actual reclaim workers from stomping over us while we recycle
* the inode. We can't clear the radix tree tag yet as it requires
* pag_ici_lock to be held exclusive.
*/
ip->i_flags |= XFS_IRECLAIM;
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
ASSERT(!rwsem_is_locked(&inode->i_rwsem));
error = xfs_reinit_inode(mp, inode);
if (error) {
bool wake;
/*
* Re-initializing the inode failed, and we are in deep
* trouble. Try to re-add it to the reclaim list.
*/
rcu_read_lock();
spin_lock(&ip->i_flags_lock);
wake = !!__xfs_iflags_test(ip, XFS_INEW);
ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
if (wake)
wake_up_bit(&ip->i_flags, __XFS_INEW_BIT);
ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
trace_xfs_iget_recycle_fail(ip);
return error;
}
spin_lock(&pag->pag_ici_lock);
spin_lock(&ip->i_flags_lock);
/*
* Clear the per-lifetime state in the inode as we are now effectively
* a new inode and need to return to the initial state before reuse
* occurs.
*/
ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
ip->i_flags |= XFS_INEW;
xfs_perag_clear_inode_tag(pag, XFS_INO_TO_AGINO(mp, ip->i_ino),
XFS_ICI_RECLAIM_TAG);
inode->i_state = I_NEW;
spin_unlock(&ip->i_flags_lock);
spin_unlock(&pag->pag_ici_lock);
return 0;
}
/*
* If we are allocating a new inode, then check what was returned is
* actually a free, empty inode. If we are not allocating an inode,
@ -450,7 +518,7 @@ xfs_iget_cache_hit(
/*
* If we are racing with another cache hit that is currently
* instantiating this inode or currently recycling it out of
* reclaimabe state, wait for the initialisation to complete
* reclaimable state, wait for the initialisation to complete
* before continuing.
*
* XXX(hch): eventually we should do something equivalent to
@ -472,64 +540,16 @@ xfs_iget_cache_hit(
if (error)
goto out_error;
/*
* If IRECLAIMABLE is set, we've torn down the VFS inode already.
* Need to carefully get it back into useable state.
*/
if (ip->i_flags & XFS_IRECLAIMABLE) {
trace_xfs_iget_reclaim(ip);
if (flags & XFS_IGET_INCORE) {
error = -EAGAIN;
goto out_error;
}
/*
* We need to set XFS_IRECLAIM to prevent xfs_reclaim_inode
* from stomping over us while we recycle the inode. We can't
* clear the radix tree reclaimable tag yet as it requires
* pag_ici_lock to be held exclusive.
*/
ip->i_flags |= XFS_IRECLAIM;
spin_unlock(&ip->i_flags_lock);
rcu_read_unlock();
ASSERT(!rwsem_is_locked(&inode->i_rwsem));
error = xfs_reinit_inode(mp, inode);
if (error) {
bool wake;
/*
* Re-initializing the inode failed, and we are in deep
* trouble. Try to re-add it to the reclaim list.
*/
rcu_read_lock();
spin_lock(&ip->i_flags_lock);
wake = !!__xfs_iflags_test(ip, XFS_INEW);
ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
if (wake)
wake_up_bit(&ip->i_flags, __XFS_INEW_BIT);
ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
trace_xfs_iget_reclaim_fail(ip);
goto out_error;
}
spin_lock(&pag->pag_ici_lock);
spin_lock(&ip->i_flags_lock);
/*
* Clear the per-lifetime state in the inode as we are now
* effectively a new inode and need to return to the initial
* state before reuse occurs.
*/
ip->i_flags &= ~XFS_IRECLAIM_RESET_FLAGS;
ip->i_flags |= XFS_INEW;
xfs_perag_clear_inode_tag(pag,
XFS_INO_TO_AGINO(pag->pag_mount, ino),
XFS_ICI_RECLAIM_TAG);
inode->i_state = I_NEW;
spin_unlock(&ip->i_flags_lock);
spin_unlock(&pag->pag_ici_lock);
/* Drops i_flags_lock and RCU read lock. */
error = xfs_iget_recycle(pag, ip);
if (error)
return error;
} else {
/* If the VFS inode is being torn down, pause and try again. */
if (!igrab(inode)) {
@ -559,7 +579,6 @@ xfs_iget_cache_hit(
return error;
}
static int
xfs_iget_cache_miss(
struct xfs_mount *mp,

4
fs/xfs/xfs_trace.h
View file

@ -631,8 +631,8 @@ DEFINE_EVENT(xfs_inode_class, name, \
TP_PROTO(struct xfs_inode *ip), \
TP_ARGS(ip))
DEFINE_INODE_EVENT(xfs_iget_skip);
DEFINE_INODE_EVENT(xfs_iget_reclaim);
DEFINE_INODE_EVENT(xfs_iget_reclaim_fail);
DEFINE_INODE_EVENT(xfs_iget_recycle);
DEFINE_INODE_EVENT(xfs_iget_recycle_fail);
DEFINE_INODE_EVENT(xfs_iget_hit);
DEFINE_INODE_EVENT(xfs_iget_miss);