diff options
author | Dave Chinner <dchinner@redhat.com> | 2012-10-08 12:56:11 +0200 |
---|---|---|
committer | Ben Myers <bpm@sgi.com> | 2012-10-17 20:42:25 +0200 |
commit | 33479e0542df066fb0b47df18780e93bfe6e0dc5 (patch) | |
tree | 24efe5cd35b6d80af165c0148d462fb61f50a456 /fs/xfs/xfs_icache.c | |
parent | xfs: move inode locking functions to xfs_inode.c (diff) | |
download | linux-33479e0542df066fb0b47df18780e93bfe6e0dc5.tar.xz linux-33479e0542df066fb0b47df18780e93bfe6e0dc5.zip |
xfs: remove xfs_iget.c
The inode cache functions remaining in xfs_iget.c can be moved to xfs_icache.c
along with the other inode cache functions. This removes all functionality from
xfs_iget.c, so the file can simply be removed.
This move results in various functions now only having the scope of a single
file (e.g. xfs_inode_free()), so clean up all the definitions and exported
prototypes in xfs_icache.[ch] and xfs_inode.h appropriately.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>
Diffstat (limited to 'fs/xfs/xfs_icache.c')
-rw-r--r-- | fs/xfs/xfs_icache.c | 421 |
1 files changed, 418 insertions, 3 deletions
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c index eba216f11d5e..9c8703b5cd72 100644 --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -41,6 +41,421 @@ #include <linux/kthread.h> #include <linux/freezer.h> +STATIC void __xfs_inode_clear_reclaim_tag(struct xfs_mount *mp, + struct xfs_perag *pag, struct xfs_inode *ip); + +/* + * Allocate and initialise an xfs_inode. + */ +STATIC struct xfs_inode * +xfs_inode_alloc( + struct xfs_mount *mp, + xfs_ino_t ino) +{ + struct xfs_inode *ip; + + /* + * if this didn't occur in transactions, we could use + * KM_MAYFAIL and return NULL here on ENOMEM. Set the + * code up to do this anyway. + */ + ip = kmem_zone_alloc(xfs_inode_zone, KM_SLEEP); + if (!ip) + return NULL; + if (inode_init_always(mp->m_super, VFS_I(ip))) { + kmem_zone_free(xfs_inode_zone, ip); + return NULL; + } + + ASSERT(atomic_read(&ip->i_pincount) == 0); + ASSERT(!spin_is_locked(&ip->i_flags_lock)); + ASSERT(!xfs_isiflocked(ip)); + ASSERT(ip->i_ino == 0); + + mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino); + + /* initialise the xfs inode */ + ip->i_ino = ino; + ip->i_mount = mp; + memset(&ip->i_imap, 0, sizeof(struct xfs_imap)); + ip->i_afp = NULL; + memset(&ip->i_df, 0, sizeof(xfs_ifork_t)); + ip->i_flags = 0; + ip->i_delayed_blks = 0; + memset(&ip->i_d, 0, sizeof(xfs_icdinode_t)); + + return ip; +} + +STATIC void +xfs_inode_free_callback( + struct rcu_head *head) +{ + struct inode *inode = container_of(head, struct inode, i_rcu); + struct xfs_inode *ip = XFS_I(inode); + + kmem_zone_free(xfs_inode_zone, ip); +} + +STATIC void +xfs_inode_free( + struct xfs_inode *ip) +{ + switch (ip->i_d.di_mode & S_IFMT) { + case S_IFREG: + case S_IFDIR: + case S_IFLNK: + xfs_idestroy_fork(ip, XFS_DATA_FORK); + break; + } + + if (ip->i_afp) + xfs_idestroy_fork(ip, XFS_ATTR_FORK); + + if (ip->i_itemp) { + ASSERT(!(ip->i_itemp->ili_item.li_flags & XFS_LI_IN_AIL)); + xfs_inode_item_destroy(ip); + ip->i_itemp = NULL; + } + + /* asserts to verify all state is correct here */ + ASSERT(atomic_read(&ip->i_pincount) == 0); + ASSERT(!spin_is_locked(&ip->i_flags_lock)); + ASSERT(!xfs_isiflocked(ip)); + + /* + * Because we use RCU freeing we need to ensure the inode always + * appears to be reclaimed with an invalid inode number when in the + * free state. The ip->i_flags_lock provides the barrier against lookup + * races. + */ + spin_lock(&ip->i_flags_lock); + ip->i_flags = XFS_IRECLAIM; + ip->i_ino = 0; + spin_unlock(&ip->i_flags_lock); + + call_rcu(&VFS_I(ip)->i_rcu, xfs_inode_free_callback); +} + +/* + * Check the validity of the inode we just found it the cache + */ +static int +xfs_iget_cache_hit( + struct xfs_perag *pag, + struct xfs_inode *ip, + xfs_ino_t ino, + int flags, + int lock_flags) __releases(RCU) +{ + struct inode *inode = VFS_I(ip); + struct xfs_mount *mp = ip->i_mount; + int error; + + /* + * check for re-use of an inode within an RCU grace period due to the + * radix tree nodes not being updated yet. We monitor for this by + * setting the inode number to zero before freeing the inode structure. + * If the inode has been reallocated and set up, then the inode number + * will not match, so check for that, too. + */ + spin_lock(&ip->i_flags_lock); + if (ip->i_ino != ino) { + trace_xfs_iget_skip(ip); + XFS_STATS_INC(xs_ig_frecycle); + error = EAGAIN; + goto out_error; + } + + + /* + * 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 + * before continuing. + * + * XXX(hch): eventually we should do something equivalent to + * wait_on_inode to wait for these flags to be cleared + * instead of polling for it. + */ + if (ip->i_flags & (XFS_INEW|XFS_IRECLAIM)) { + trace_xfs_iget_skip(ip); + XFS_STATS_INC(xs_ig_frecycle); + error = EAGAIN; + goto out_error; + } + + /* + * If lookup is racing with unlink return an error immediately. + */ + if (ip->i_d.di_mode == 0 && !(flags & XFS_IGET_CREATE)) { + error = ENOENT; + 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); + + /* + * 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(); + + error = -inode_init_always(mp->m_super, inode); + if (error) { + /* + * 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); + + ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM); + 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_inode_clear_reclaim_tag(mp, pag, ip); + inode->i_state = I_NEW; + + ASSERT(!rwsem_is_locked(&ip->i_iolock.mr_lock)); + mrlock_init(&ip->i_iolock, MRLOCK_BARRIER, "xfsio", ip->i_ino); + + spin_unlock(&ip->i_flags_lock); + spin_unlock(&pag->pag_ici_lock); + } else { + /* If the VFS inode is being torn down, pause and try again. */ + if (!igrab(inode)) { + trace_xfs_iget_skip(ip); + error = EAGAIN; + goto out_error; + } + + /* We've got a live one. */ + spin_unlock(&ip->i_flags_lock); + rcu_read_unlock(); + trace_xfs_iget_hit(ip); + } + + if (lock_flags != 0) + xfs_ilock(ip, lock_flags); + + xfs_iflags_clear(ip, XFS_ISTALE | XFS_IDONTCACHE); + XFS_STATS_INC(xs_ig_found); + + return 0; + +out_error: + spin_unlock(&ip->i_flags_lock); + rcu_read_unlock(); + return error; +} + + +static int +xfs_iget_cache_miss( + struct xfs_mount *mp, + struct xfs_perag *pag, + xfs_trans_t *tp, + xfs_ino_t ino, + struct xfs_inode **ipp, + int flags, + int lock_flags) +{ + struct xfs_inode *ip; + int error; + xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ino); + int iflags; + + ip = xfs_inode_alloc(mp, ino); + if (!ip) + return ENOMEM; + + error = xfs_iread(mp, tp, ip, flags); + if (error) + goto out_destroy; + + trace_xfs_iget_miss(ip); + + if ((ip->i_d.di_mode == 0) && !(flags & XFS_IGET_CREATE)) { + error = ENOENT; + goto out_destroy; + } + + /* + * Preload the radix tree so we can insert safely under the + * write spinlock. Note that we cannot sleep inside the preload + * region. Since we can be called from transaction context, don't + * recurse into the file system. + */ + if (radix_tree_preload(GFP_NOFS)) { + error = EAGAIN; + goto out_destroy; + } + + /* + * Because the inode hasn't been added to the radix-tree yet it can't + * be found by another thread, so we can do the non-sleeping lock here. + */ + if (lock_flags) { + if (!xfs_ilock_nowait(ip, lock_flags)) + BUG(); + } + + /* + * These values must be set before inserting the inode into the radix + * tree as the moment it is inserted a concurrent lookup (allowed by the + * RCU locking mechanism) can find it and that lookup must see that this + * is an inode currently under construction (i.e. that XFS_INEW is set). + * The ip->i_flags_lock that protects the XFS_INEW flag forms the + * memory barrier that ensures this detection works correctly at lookup + * time. + */ + iflags = XFS_INEW; + if (flags & XFS_IGET_DONTCACHE) + iflags |= XFS_IDONTCACHE; + ip->i_udquot = ip->i_gdquot = NULL; + xfs_iflags_set(ip, iflags); + + /* insert the new inode */ + spin_lock(&pag->pag_ici_lock); + error = radix_tree_insert(&pag->pag_ici_root, agino, ip); + if (unlikely(error)) { + WARN_ON(error != -EEXIST); + XFS_STATS_INC(xs_ig_dup); + error = EAGAIN; + goto out_preload_end; + } + spin_unlock(&pag->pag_ici_lock); + radix_tree_preload_end(); + + *ipp = ip; + return 0; + +out_preload_end: + spin_unlock(&pag->pag_ici_lock); + radix_tree_preload_end(); + if (lock_flags) + xfs_iunlock(ip, lock_flags); +out_destroy: + __destroy_inode(VFS_I(ip)); + xfs_inode_free(ip); + return error; +} + +/* + * Look up an inode by number in the given file system. + * The inode is looked up in the cache held in each AG. + * If the inode is found in the cache, initialise the vfs inode + * if necessary. + * + * If it is not in core, read it in from the file system's device, + * add it to the cache and initialise the vfs inode. + * + * The inode is locked according to the value of the lock_flags parameter. + * This flag parameter indicates how and if the inode's IO lock and inode lock + * should be taken. + * + * mp -- the mount point structure for the current file system. It points + * to the inode hash table. + * tp -- a pointer to the current transaction if there is one. This is + * simply passed through to the xfs_iread() call. + * ino -- the number of the inode desired. This is the unique identifier + * within the file system for the inode being requested. + * lock_flags -- flags indicating how to lock the inode. See the comment + * for xfs_ilock() for a list of valid values. + */ +int +xfs_iget( + xfs_mount_t *mp, + xfs_trans_t *tp, + xfs_ino_t ino, + uint flags, + uint lock_flags, + xfs_inode_t **ipp) +{ + xfs_inode_t *ip; + int error; + xfs_perag_t *pag; + xfs_agino_t agino; + + /* + * xfs_reclaim_inode() uses the ILOCK to ensure an inode + * doesn't get freed while it's being referenced during a + * radix tree traversal here. It assumes this function + * aqcuires only the ILOCK (and therefore it has no need to + * involve the IOLOCK in this synchronization). + */ + ASSERT((lock_flags & (XFS_IOLOCK_EXCL | XFS_IOLOCK_SHARED)) == 0); + + /* reject inode numbers outside existing AGs */ + if (!ino || XFS_INO_TO_AGNO(mp, ino) >= mp->m_sb.sb_agcount) + return EINVAL; + + /* get the perag structure and ensure that it's inode capable */ + pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino)); + agino = XFS_INO_TO_AGINO(mp, ino); + +again: + error = 0; + rcu_read_lock(); + ip = radix_tree_lookup(&pag->pag_ici_root, agino); + + if (ip) { + error = xfs_iget_cache_hit(pag, ip, ino, flags, lock_flags); + if (error) + goto out_error_or_again; + } else { + rcu_read_unlock(); + XFS_STATS_INC(xs_ig_missed); + + error = xfs_iget_cache_miss(mp, pag, tp, ino, &ip, + flags, lock_flags); + if (error) + goto out_error_or_again; + } + xfs_perag_put(pag); + + *ipp = ip; + + /* + * If we have a real type for an on-disk inode, we can set ops(&unlock) + * now. If it's a new inode being created, xfs_ialloc will handle it. + */ + if (xfs_iflags_test(ip, XFS_INEW) && ip->i_d.di_mode != 0) + xfs_setup_inode(ip); + return 0; + +out_error_or_again: + if (error == EAGAIN) { + delay(1); + goto again; + } + xfs_perag_put(pag); + return error; +} + /* * The inode lookup is done in batches to keep the amount of lock traffic and * radix tree lookups to a minimum. The batch size is a trade off between @@ -253,7 +668,7 @@ xfs_reclaim_worker( xfs_reclaim_work_queue(mp); } -void +static void __xfs_inode_set_reclaim_tag( struct xfs_perag *pag, struct xfs_inode *ip) @@ -319,7 +734,7 @@ __xfs_inode_clear_reclaim( } } -void +STATIC void __xfs_inode_clear_reclaim_tag( xfs_mount_t *mp, xfs_perag_t *pag, @@ -542,7 +957,7 @@ out: * then a shut down during filesystem unmount reclaim walk leak all the * unreclaimed inodes. */ -int +STATIC int xfs_reclaim_inodes_ag( struct xfs_mount *mp, int flags, |