![Alexander Viro](/assets/img/avatar_default.png)
Based on analysis and a patch from Russ Weight <rweight@us.ibm.com> There is a race condition that can occur if an inode is allocated and then released (using iput) during the ->fill_super functions. The race condition is between kswapd and mount. For most filesystems this can only happen in an error path when kswapd is running concurrently. For isofs, however, the error can occur in a more common code path (which is how the bug was found). The logic here is "we want final iput() to free inode *now* instead of letting it sit in cache if fs is going down or had not quite come up". The problem is with kswapd seeing such inodes in the middle of being killed and happily taking over. The clean solution would be to tell kswapd to leave those inodes alone and let our final iput deal with them. I.e. add a new flag (I_FORCED_FREEING), set it before write_inode_now() there and make prune_icache() leave those alone. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1367 lines
34 KiB
C
1367 lines
34 KiB
C
/*
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* linux/fs/inode.c
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*
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* (C) 1997 Linus Torvalds
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*/
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#include <linux/config.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/dcache.h>
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#include <linux/init.h>
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#include <linux/quotaops.h>
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#include <linux/slab.h>
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#include <linux/writeback.h>
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#include <linux/module.h>
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#include <linux/backing-dev.h>
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#include <linux/wait.h>
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#include <linux/hash.h>
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#include <linux/swap.h>
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#include <linux/security.h>
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#include <linux/pagemap.h>
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#include <linux/cdev.h>
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#include <linux/bootmem.h>
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/*
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* This is needed for the following functions:
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* - inode_has_buffers
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* - invalidate_inode_buffers
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* - invalidate_bdev
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*
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* FIXME: remove all knowledge of the buffer layer from this file
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*/
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#include <linux/buffer_head.h>
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/*
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* New inode.c implementation.
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*
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* This implementation has the basic premise of trying
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* to be extremely low-overhead and SMP-safe, yet be
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* simple enough to be "obviously correct".
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*
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* Famous last words.
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*/
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/* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
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/* #define INODE_PARANOIA 1 */
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/* #define INODE_DEBUG 1 */
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/*
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* Inode lookup is no longer as critical as it used to be:
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* most of the lookups are going to be through the dcache.
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*/
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#define I_HASHBITS i_hash_shift
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#define I_HASHMASK i_hash_mask
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static unsigned int i_hash_mask;
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static unsigned int i_hash_shift;
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/*
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* Each inode can be on two separate lists. One is
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* the hash list of the inode, used for lookups. The
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* other linked list is the "type" list:
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* "in_use" - valid inode, i_count > 0, i_nlink > 0
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* "dirty" - as "in_use" but also dirty
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* "unused" - valid inode, i_count = 0
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*
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* A "dirty" list is maintained for each super block,
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* allowing for low-overhead inode sync() operations.
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*/
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LIST_HEAD(inode_in_use);
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LIST_HEAD(inode_unused);
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static struct hlist_head *inode_hashtable;
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/*
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* A simple spinlock to protect the list manipulations.
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*
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* NOTE! You also have to own the lock if you change
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* the i_state of an inode while it is in use..
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*/
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DEFINE_SPINLOCK(inode_lock);
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/*
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* iprune_sem provides exclusion between the kswapd or try_to_free_pages
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* icache shrinking path, and the umount path. Without this exclusion,
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* by the time prune_icache calls iput for the inode whose pages it has
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* been invalidating, or by the time it calls clear_inode & destroy_inode
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* from its final dispose_list, the struct super_block they refer to
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* (for inode->i_sb->s_op) may already have been freed and reused.
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*/
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DECLARE_MUTEX(iprune_sem);
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/*
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* Statistics gathering..
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*/
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struct inodes_stat_t inodes_stat;
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static kmem_cache_t * inode_cachep;
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static struct inode *alloc_inode(struct super_block *sb)
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{
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static struct address_space_operations empty_aops;
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static struct inode_operations empty_iops;
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static struct file_operations empty_fops;
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struct inode *inode;
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if (sb->s_op->alloc_inode)
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inode = sb->s_op->alloc_inode(sb);
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else
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inode = (struct inode *) kmem_cache_alloc(inode_cachep, SLAB_KERNEL);
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if (inode) {
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struct address_space * const mapping = &inode->i_data;
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inode->i_sb = sb;
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inode->i_blkbits = sb->s_blocksize_bits;
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inode->i_flags = 0;
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atomic_set(&inode->i_count, 1);
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inode->i_op = &empty_iops;
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inode->i_fop = &empty_fops;
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inode->i_nlink = 1;
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atomic_set(&inode->i_writecount, 0);
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inode->i_size = 0;
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inode->i_blocks = 0;
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inode->i_bytes = 0;
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inode->i_generation = 0;
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#ifdef CONFIG_QUOTA
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memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
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#endif
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inode->i_pipe = NULL;
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inode->i_bdev = NULL;
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inode->i_cdev = NULL;
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inode->i_rdev = 0;
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inode->i_security = NULL;
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inode->dirtied_when = 0;
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if (security_inode_alloc(inode)) {
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if (inode->i_sb->s_op->destroy_inode)
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inode->i_sb->s_op->destroy_inode(inode);
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else
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kmem_cache_free(inode_cachep, (inode));
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return NULL;
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}
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mapping->a_ops = &empty_aops;
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mapping->host = inode;
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mapping->flags = 0;
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mapping_set_gfp_mask(mapping, GFP_HIGHUSER);
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mapping->assoc_mapping = NULL;
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mapping->backing_dev_info = &default_backing_dev_info;
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/*
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* If the block_device provides a backing_dev_info for client
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* inodes then use that. Otherwise the inode share the bdev's
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* backing_dev_info.
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*/
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if (sb->s_bdev) {
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struct backing_dev_info *bdi;
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bdi = sb->s_bdev->bd_inode_backing_dev_info;
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if (!bdi)
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bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
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mapping->backing_dev_info = bdi;
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}
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memset(&inode->u, 0, sizeof(inode->u));
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inode->i_mapping = mapping;
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}
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return inode;
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}
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void destroy_inode(struct inode *inode)
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{
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if (inode_has_buffers(inode))
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BUG();
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security_inode_free(inode);
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if (inode->i_sb->s_op->destroy_inode)
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inode->i_sb->s_op->destroy_inode(inode);
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else
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kmem_cache_free(inode_cachep, (inode));
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}
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/*
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* These are initializations that only need to be done
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* once, because the fields are idempotent across use
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* of the inode, so let the slab aware of that.
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*/
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void inode_init_once(struct inode *inode)
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{
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memset(inode, 0, sizeof(*inode));
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INIT_HLIST_NODE(&inode->i_hash);
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INIT_LIST_HEAD(&inode->i_dentry);
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INIT_LIST_HEAD(&inode->i_devices);
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sema_init(&inode->i_sem, 1);
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init_rwsem(&inode->i_alloc_sem);
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INIT_RADIX_TREE(&inode->i_data.page_tree, GFP_ATOMIC);
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rwlock_init(&inode->i_data.tree_lock);
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spin_lock_init(&inode->i_data.i_mmap_lock);
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INIT_LIST_HEAD(&inode->i_data.private_list);
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spin_lock_init(&inode->i_data.private_lock);
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INIT_RAW_PRIO_TREE_ROOT(&inode->i_data.i_mmap);
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INIT_LIST_HEAD(&inode->i_data.i_mmap_nonlinear);
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spin_lock_init(&inode->i_lock);
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i_size_ordered_init(inode);
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}
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EXPORT_SYMBOL(inode_init_once);
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static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
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{
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struct inode * inode = (struct inode *) foo;
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if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
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SLAB_CTOR_CONSTRUCTOR)
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inode_init_once(inode);
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}
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/*
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* inode_lock must be held
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*/
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void __iget(struct inode * inode)
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{
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if (atomic_read(&inode->i_count)) {
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atomic_inc(&inode->i_count);
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return;
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}
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atomic_inc(&inode->i_count);
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if (!(inode->i_state & (I_DIRTY|I_LOCK)))
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list_move(&inode->i_list, &inode_in_use);
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inodes_stat.nr_unused--;
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}
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/**
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* clear_inode - clear an inode
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* @inode: inode to clear
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*
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* This is called by the filesystem to tell us
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* that the inode is no longer useful. We just
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* terminate it with extreme prejudice.
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*/
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void clear_inode(struct inode *inode)
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{
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might_sleep();
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invalidate_inode_buffers(inode);
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if (inode->i_data.nrpages)
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BUG();
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if (!(inode->i_state & I_FREEING))
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BUG();
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if (inode->i_state & I_CLEAR)
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BUG();
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wait_on_inode(inode);
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DQUOT_DROP(inode);
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if (inode->i_sb && inode->i_sb->s_op->clear_inode)
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inode->i_sb->s_op->clear_inode(inode);
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if (inode->i_bdev)
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bd_forget(inode);
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if (inode->i_cdev)
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cd_forget(inode);
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inode->i_state = I_CLEAR;
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}
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EXPORT_SYMBOL(clear_inode);
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/*
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* dispose_list - dispose of the contents of a local list
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* @head: the head of the list to free
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*
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* Dispose-list gets a local list with local inodes in it, so it doesn't
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* need to worry about list corruption and SMP locks.
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*/
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static void dispose_list(struct list_head *head)
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{
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int nr_disposed = 0;
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while (!list_empty(head)) {
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struct inode *inode;
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inode = list_entry(head->next, struct inode, i_list);
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list_del(&inode->i_list);
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if (inode->i_data.nrpages)
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truncate_inode_pages(&inode->i_data, 0);
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clear_inode(inode);
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destroy_inode(inode);
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nr_disposed++;
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}
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spin_lock(&inode_lock);
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inodes_stat.nr_inodes -= nr_disposed;
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spin_unlock(&inode_lock);
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}
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/*
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* Invalidate all inodes for a device.
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*/
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static int invalidate_list(struct list_head *head, struct list_head *dispose)
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{
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struct list_head *next;
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int busy = 0, count = 0;
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next = head->next;
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for (;;) {
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struct list_head * tmp = next;
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struct inode * inode;
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/*
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* We can reschedule here without worrying about the list's
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* consistency because the per-sb list of inodes must not
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* change during umount anymore, and because iprune_sem keeps
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* shrink_icache_memory() away.
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*/
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cond_resched_lock(&inode_lock);
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next = next->next;
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if (tmp == head)
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break;
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inode = list_entry(tmp, struct inode, i_sb_list);
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invalidate_inode_buffers(inode);
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if (!atomic_read(&inode->i_count)) {
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hlist_del_init(&inode->i_hash);
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list_del(&inode->i_sb_list);
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list_move(&inode->i_list, dispose);
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inode->i_state |= I_FREEING;
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count++;
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continue;
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}
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busy = 1;
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}
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/* only unused inodes may be cached with i_count zero */
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inodes_stat.nr_unused -= count;
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return busy;
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}
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/**
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* invalidate_inodes - discard the inodes on a device
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* @sb: superblock
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*
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* Discard all of the inodes for a given superblock. If the discard
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* fails because there are busy inodes then a non zero value is returned.
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* If the discard is successful all the inodes have been discarded.
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*/
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int invalidate_inodes(struct super_block * sb)
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{
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int busy;
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LIST_HEAD(throw_away);
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down(&iprune_sem);
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spin_lock(&inode_lock);
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busy = invalidate_list(&sb->s_inodes, &throw_away);
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spin_unlock(&inode_lock);
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dispose_list(&throw_away);
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up(&iprune_sem);
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return busy;
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}
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EXPORT_SYMBOL(invalidate_inodes);
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int __invalidate_device(struct block_device *bdev)
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{
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struct super_block *sb = get_super(bdev);
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int res = 0;
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if (sb) {
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/*
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* no need to lock the super, get_super holds the
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* read semaphore so the filesystem cannot go away
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* under us (->put_super runs with the write lock
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* hold).
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*/
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shrink_dcache_sb(sb);
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res = invalidate_inodes(sb);
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drop_super(sb);
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}
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invalidate_bdev(bdev, 0);
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return res;
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}
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EXPORT_SYMBOL(__invalidate_device);
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static int can_unuse(struct inode *inode)
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{
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if (inode->i_state)
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return 0;
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if (inode_has_buffers(inode))
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return 0;
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if (atomic_read(&inode->i_count))
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return 0;
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if (inode->i_data.nrpages)
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return 0;
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return 1;
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}
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/*
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* Scan `goal' inodes on the unused list for freeable ones. They are moved to
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* a temporary list and then are freed outside inode_lock by dispose_list().
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*
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* Any inodes which are pinned purely because of attached pagecache have their
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* pagecache removed. We expect the final iput() on that inode to add it to
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* the front of the inode_unused list. So look for it there and if the
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* inode is still freeable, proceed. The right inode is found 99.9% of the
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* time in testing on a 4-way.
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*
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* If the inode has metadata buffers attached to mapping->private_list then
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* try to remove them.
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*/
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static void prune_icache(int nr_to_scan)
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{
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LIST_HEAD(freeable);
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int nr_pruned = 0;
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int nr_scanned;
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unsigned long reap = 0;
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down(&iprune_sem);
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spin_lock(&inode_lock);
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for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
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struct inode *inode;
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if (list_empty(&inode_unused))
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break;
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inode = list_entry(inode_unused.prev, struct inode, i_list);
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if (inode->i_state || atomic_read(&inode->i_count)) {
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list_move(&inode->i_list, &inode_unused);
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continue;
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}
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if (inode_has_buffers(inode) || inode->i_data.nrpages) {
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__iget(inode);
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spin_unlock(&inode_lock);
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if (remove_inode_buffers(inode))
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reap += invalidate_inode_pages(&inode->i_data);
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iput(inode);
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spin_lock(&inode_lock);
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if (inode != list_entry(inode_unused.next,
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struct inode, i_list))
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continue; /* wrong inode or list_empty */
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if (!can_unuse(inode))
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continue;
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}
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hlist_del_init(&inode->i_hash);
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list_del_init(&inode->i_sb_list);
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list_move(&inode->i_list, &freeable);
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inode->i_state |= I_FREEING;
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nr_pruned++;
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}
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inodes_stat.nr_unused -= nr_pruned;
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spin_unlock(&inode_lock);
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dispose_list(&freeable);
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up(&iprune_sem);
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if (current_is_kswapd())
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mod_page_state(kswapd_inodesteal, reap);
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else
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mod_page_state(pginodesteal, reap);
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}
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|
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/*
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* shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
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* "unused" means that no dentries are referring to the inodes: the files are
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* not open and the dcache references to those inodes have already been
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* reclaimed.
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*
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* This function is passed the number of inodes to scan, and it returns the
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* total number of remaining possibly-reclaimable inodes.
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*/
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static int shrink_icache_memory(int nr, unsigned int gfp_mask)
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{
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if (nr) {
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/*
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* Nasty deadlock avoidance. We may hold various FS locks,
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* and we don't want to recurse into the FS that called us
|
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* in clear_inode() and friends..
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*/
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if (!(gfp_mask & __GFP_FS))
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return -1;
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prune_icache(nr);
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}
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return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
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}
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|
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static void __wait_on_freeing_inode(struct inode *inode);
|
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/*
|
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* Called with the inode lock held.
|
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* NOTE: we are not increasing the inode-refcount, you must call __iget()
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* by hand after calling find_inode now! This simplifies iunique and won't
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* add any additional branch in the common code.
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*/
|
|
static struct inode * find_inode(struct super_block * sb, struct hlist_head *head, int (*test)(struct inode *, void *), void *data)
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{
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struct hlist_node *node;
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struct inode * inode = NULL;
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|
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repeat:
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hlist_for_each (node, head) {
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inode = hlist_entry(node, struct inode, i_hash);
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if (inode->i_sb != sb)
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continue;
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if (!test(inode, data))
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continue;
|
|
if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
|
|
__wait_on_freeing_inode(inode);
|
|
goto repeat;
|
|
}
|
|
break;
|
|
}
|
|
return node ? inode : NULL;
|
|
}
|
|
|
|
/*
|
|
* find_inode_fast is the fast path version of find_inode, see the comment at
|
|
* iget_locked for details.
|
|
*/
|
|
static struct inode * find_inode_fast(struct super_block * sb, struct hlist_head *head, unsigned long ino)
|
|
{
|
|
struct hlist_node *node;
|
|
struct inode * inode = NULL;
|
|
|
|
repeat:
|
|
hlist_for_each (node, head) {
|
|
inode = hlist_entry(node, struct inode, i_hash);
|
|
if (inode->i_ino != ino)
|
|
continue;
|
|
if (inode->i_sb != sb)
|
|
continue;
|
|
if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE)) {
|
|
__wait_on_freeing_inode(inode);
|
|
goto repeat;
|
|
}
|
|
break;
|
|
}
|
|
return node ? inode : NULL;
|
|
}
|
|
|
|
/**
|
|
* new_inode - obtain an inode
|
|
* @sb: superblock
|
|
*
|
|
* Allocates a new inode for given superblock.
|
|
*/
|
|
struct inode *new_inode(struct super_block *sb)
|
|
{
|
|
static unsigned long last_ino;
|
|
struct inode * inode;
|
|
|
|
spin_lock_prefetch(&inode_lock);
|
|
|
|
inode = alloc_inode(sb);
|
|
if (inode) {
|
|
spin_lock(&inode_lock);
|
|
inodes_stat.nr_inodes++;
|
|
list_add(&inode->i_list, &inode_in_use);
|
|
list_add(&inode->i_sb_list, &sb->s_inodes);
|
|
inode->i_ino = ++last_ino;
|
|
inode->i_state = 0;
|
|
spin_unlock(&inode_lock);
|
|
}
|
|
return inode;
|
|
}
|
|
|
|
EXPORT_SYMBOL(new_inode);
|
|
|
|
void unlock_new_inode(struct inode *inode)
|
|
{
|
|
/*
|
|
* This is special! We do not need the spinlock
|
|
* when clearing I_LOCK, because we're guaranteed
|
|
* that nobody else tries to do anything about the
|
|
* state of the inode when it is locked, as we
|
|
* just created it (so there can be no old holders
|
|
* that haven't tested I_LOCK).
|
|
*/
|
|
inode->i_state &= ~(I_LOCK|I_NEW);
|
|
wake_up_inode(inode);
|
|
}
|
|
|
|
EXPORT_SYMBOL(unlock_new_inode);
|
|
|
|
/*
|
|
* This is called without the inode lock held.. Be careful.
|
|
*
|
|
* We no longer cache the sb_flags in i_flags - see fs.h
|
|
* -- rmk@arm.uk.linux.org
|
|
*/
|
|
static struct inode * get_new_inode(struct super_block *sb, struct hlist_head *head, int (*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *data)
|
|
{
|
|
struct inode * inode;
|
|
|
|
inode = alloc_inode(sb);
|
|
if (inode) {
|
|
struct inode * old;
|
|
|
|
spin_lock(&inode_lock);
|
|
/* We released the lock, so.. */
|
|
old = find_inode(sb, head, test, data);
|
|
if (!old) {
|
|
if (set(inode, data))
|
|
goto set_failed;
|
|
|
|
inodes_stat.nr_inodes++;
|
|
list_add(&inode->i_list, &inode_in_use);
|
|
list_add(&inode->i_sb_list, &sb->s_inodes);
|
|
hlist_add_head(&inode->i_hash, head);
|
|
inode->i_state = I_LOCK|I_NEW;
|
|
spin_unlock(&inode_lock);
|
|
|
|
/* Return the locked inode with I_NEW set, the
|
|
* caller is responsible for filling in the contents
|
|
*/
|
|
return inode;
|
|
}
|
|
|
|
/*
|
|
* Uhhuh, somebody else created the same inode under
|
|
* us. Use the old inode instead of the one we just
|
|
* allocated.
|
|
*/
|
|
__iget(old);
|
|
spin_unlock(&inode_lock);
|
|
destroy_inode(inode);
|
|
inode = old;
|
|
wait_on_inode(inode);
|
|
}
|
|
return inode;
|
|
|
|
set_failed:
|
|
spin_unlock(&inode_lock);
|
|
destroy_inode(inode);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* get_new_inode_fast is the fast path version of get_new_inode, see the
|
|
* comment at iget_locked for details.
|
|
*/
|
|
static struct inode * get_new_inode_fast(struct super_block *sb, struct hlist_head *head, unsigned long ino)
|
|
{
|
|
struct inode * inode;
|
|
|
|
inode = alloc_inode(sb);
|
|
if (inode) {
|
|
struct inode * old;
|
|
|
|
spin_lock(&inode_lock);
|
|
/* We released the lock, so.. */
|
|
old = find_inode_fast(sb, head, ino);
|
|
if (!old) {
|
|
inode->i_ino = ino;
|
|
inodes_stat.nr_inodes++;
|
|
list_add(&inode->i_list, &inode_in_use);
|
|
list_add(&inode->i_sb_list, &sb->s_inodes);
|
|
hlist_add_head(&inode->i_hash, head);
|
|
inode->i_state = I_LOCK|I_NEW;
|
|
spin_unlock(&inode_lock);
|
|
|
|
/* Return the locked inode with I_NEW set, the
|
|
* caller is responsible for filling in the contents
|
|
*/
|
|
return inode;
|
|
}
|
|
|
|
/*
|
|
* Uhhuh, somebody else created the same inode under
|
|
* us. Use the old inode instead of the one we just
|
|
* allocated.
|
|
*/
|
|
__iget(old);
|
|
spin_unlock(&inode_lock);
|
|
destroy_inode(inode);
|
|
inode = old;
|
|
wait_on_inode(inode);
|
|
}
|
|
return inode;
|
|
}
|
|
|
|
static inline unsigned long hash(struct super_block *sb, unsigned long hashval)
|
|
{
|
|
unsigned long tmp;
|
|
|
|
tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
|
|
L1_CACHE_BYTES;
|
|
tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
|
|
return tmp & I_HASHMASK;
|
|
}
|
|
|
|
/**
|
|
* iunique - get a unique inode number
|
|
* @sb: superblock
|
|
* @max_reserved: highest reserved inode number
|
|
*
|
|
* Obtain an inode number that is unique on the system for a given
|
|
* superblock. This is used by file systems that have no natural
|
|
* permanent inode numbering system. An inode number is returned that
|
|
* is higher than the reserved limit but unique.
|
|
*
|
|
* BUGS:
|
|
* With a large number of inodes live on the file system this function
|
|
* currently becomes quite slow.
|
|
*/
|
|
ino_t iunique(struct super_block *sb, ino_t max_reserved)
|
|
{
|
|
static ino_t counter;
|
|
struct inode *inode;
|
|
struct hlist_head * head;
|
|
ino_t res;
|
|
spin_lock(&inode_lock);
|
|
retry:
|
|
if (counter > max_reserved) {
|
|
head = inode_hashtable + hash(sb,counter);
|
|
res = counter++;
|
|
inode = find_inode_fast(sb, head, res);
|
|
if (!inode) {
|
|
spin_unlock(&inode_lock);
|
|
return res;
|
|
}
|
|
} else {
|
|
counter = max_reserved + 1;
|
|
}
|
|
goto retry;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(iunique);
|
|
|
|
struct inode *igrab(struct inode *inode)
|
|
{
|
|
spin_lock(&inode_lock);
|
|
if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
|
|
__iget(inode);
|
|
else
|
|
/*
|
|
* Handle the case where s_op->clear_inode is not been
|
|
* called yet, and somebody is calling igrab
|
|
* while the inode is getting freed.
|
|
*/
|
|
inode = NULL;
|
|
spin_unlock(&inode_lock);
|
|
return inode;
|
|
}
|
|
|
|
EXPORT_SYMBOL(igrab);
|
|
|
|
/**
|
|
* ifind - internal function, you want ilookup5() or iget5().
|
|
* @sb: super block of file system to search
|
|
* @head: the head of the list to search
|
|
* @test: callback used for comparisons between inodes
|
|
* @data: opaque data pointer to pass to @test
|
|
*
|
|
* ifind() searches for the inode specified by @data in the inode
|
|
* cache. This is a generalized version of ifind_fast() for file systems where
|
|
* the inode number is not sufficient for unique identification of an inode.
|
|
*
|
|
* If the inode is in the cache, the inode is returned with an incremented
|
|
* reference count.
|
|
*
|
|
* Otherwise NULL is returned.
|
|
*
|
|
* Note, @test is called with the inode_lock held, so can't sleep.
|
|
*/
|
|
static inline struct inode *ifind(struct super_block *sb,
|
|
struct hlist_head *head, int (*test)(struct inode *, void *),
|
|
void *data)
|
|
{
|
|
struct inode *inode;
|
|
|
|
spin_lock(&inode_lock);
|
|
inode = find_inode(sb, head, test, data);
|
|
if (inode) {
|
|
__iget(inode);
|
|
spin_unlock(&inode_lock);
|
|
wait_on_inode(inode);
|
|
return inode;
|
|
}
|
|
spin_unlock(&inode_lock);
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* ifind_fast - internal function, you want ilookup() or iget().
|
|
* @sb: super block of file system to search
|
|
* @head: head of the list to search
|
|
* @ino: inode number to search for
|
|
*
|
|
* ifind_fast() searches for the inode @ino in the inode cache. This is for
|
|
* file systems where the inode number is sufficient for unique identification
|
|
* of an inode.
|
|
*
|
|
* If the inode is in the cache, the inode is returned with an incremented
|
|
* reference count.
|
|
*
|
|
* Otherwise NULL is returned.
|
|
*/
|
|
static inline struct inode *ifind_fast(struct super_block *sb,
|
|
struct hlist_head *head, unsigned long ino)
|
|
{
|
|
struct inode *inode;
|
|
|
|
spin_lock(&inode_lock);
|
|
inode = find_inode_fast(sb, head, ino);
|
|
if (inode) {
|
|
__iget(inode);
|
|
spin_unlock(&inode_lock);
|
|
wait_on_inode(inode);
|
|
return inode;
|
|
}
|
|
spin_unlock(&inode_lock);
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* ilookup5 - search for an inode in the inode cache
|
|
* @sb: super block of file system to search
|
|
* @hashval: hash value (usually inode number) to search for
|
|
* @test: callback used for comparisons between inodes
|
|
* @data: opaque data pointer to pass to @test
|
|
*
|
|
* ilookup5() uses ifind() to search for the inode specified by @hashval and
|
|
* @data in the inode cache. This is a generalized version of ilookup() for
|
|
* file systems where the inode number is not sufficient for unique
|
|
* identification of an inode.
|
|
*
|
|
* If the inode is in the cache, the inode is returned with an incremented
|
|
* reference count.
|
|
*
|
|
* Otherwise NULL is returned.
|
|
*
|
|
* Note, @test is called with the inode_lock held, so can't sleep.
|
|
*/
|
|
struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
|
|
int (*test)(struct inode *, void *), void *data)
|
|
{
|
|
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
|
|
|
|
return ifind(sb, head, test, data);
|
|
}
|
|
|
|
EXPORT_SYMBOL(ilookup5);
|
|
|
|
/**
|
|
* ilookup - search for an inode in the inode cache
|
|
* @sb: super block of file system to search
|
|
* @ino: inode number to search for
|
|
*
|
|
* ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
|
|
* This is for file systems where the inode number is sufficient for unique
|
|
* identification of an inode.
|
|
*
|
|
* If the inode is in the cache, the inode is returned with an incremented
|
|
* reference count.
|
|
*
|
|
* Otherwise NULL is returned.
|
|
*/
|
|
struct inode *ilookup(struct super_block *sb, unsigned long ino)
|
|
{
|
|
struct hlist_head *head = inode_hashtable + hash(sb, ino);
|
|
|
|
return ifind_fast(sb, head, ino);
|
|
}
|
|
|
|
EXPORT_SYMBOL(ilookup);
|
|
|
|
/**
|
|
* iget5_locked - obtain an inode from a mounted file system
|
|
* @sb: super block of file system
|
|
* @hashval: hash value (usually inode number) to get
|
|
* @test: callback used for comparisons between inodes
|
|
* @set: callback used to initialize a new struct inode
|
|
* @data: opaque data pointer to pass to @test and @set
|
|
*
|
|
* This is iget() without the read_inode() portion of get_new_inode().
|
|
*
|
|
* iget5_locked() uses ifind() to search for the inode specified by @hashval
|
|
* and @data in the inode cache and if present it is returned with an increased
|
|
* reference count. This is a generalized version of iget_locked() for file
|
|
* systems where the inode number is not sufficient for unique identification
|
|
* of an inode.
|
|
*
|
|
* If the inode is not in cache, get_new_inode() is called to allocate a new
|
|
* inode and this is returned locked, hashed, and with the I_NEW flag set. The
|
|
* file system gets to fill it in before unlocking it via unlock_new_inode().
|
|
*
|
|
* Note both @test and @set are called with the inode_lock held, so can't sleep.
|
|
*/
|
|
struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
|
|
int (*test)(struct inode *, void *),
|
|
int (*set)(struct inode *, void *), void *data)
|
|
{
|
|
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
|
|
struct inode *inode;
|
|
|
|
inode = ifind(sb, head, test, data);
|
|
if (inode)
|
|
return inode;
|
|
/*
|
|
* get_new_inode() will do the right thing, re-trying the search
|
|
* in case it had to block at any point.
|
|
*/
|
|
return get_new_inode(sb, head, test, set, data);
|
|
}
|
|
|
|
EXPORT_SYMBOL(iget5_locked);
|
|
|
|
/**
|
|
* iget_locked - obtain an inode from a mounted file system
|
|
* @sb: super block of file system
|
|
* @ino: inode number to get
|
|
*
|
|
* This is iget() without the read_inode() portion of get_new_inode_fast().
|
|
*
|
|
* iget_locked() uses ifind_fast() to search for the inode specified by @ino in
|
|
* the inode cache and if present it is returned with an increased reference
|
|
* count. This is for file systems where the inode number is sufficient for
|
|
* unique identification of an inode.
|
|
*
|
|
* If the inode is not in cache, get_new_inode_fast() is called to allocate a
|
|
* new inode and this is returned locked, hashed, and with the I_NEW flag set.
|
|
* The file system gets to fill it in before unlocking it via
|
|
* unlock_new_inode().
|
|
*/
|
|
struct inode *iget_locked(struct super_block *sb, unsigned long ino)
|
|
{
|
|
struct hlist_head *head = inode_hashtable + hash(sb, ino);
|
|
struct inode *inode;
|
|
|
|
inode = ifind_fast(sb, head, ino);
|
|
if (inode)
|
|
return inode;
|
|
/*
|
|
* get_new_inode_fast() will do the right thing, re-trying the search
|
|
* in case it had to block at any point.
|
|
*/
|
|
return get_new_inode_fast(sb, head, ino);
|
|
}
|
|
|
|
EXPORT_SYMBOL(iget_locked);
|
|
|
|
/**
|
|
* __insert_inode_hash - hash an inode
|
|
* @inode: unhashed inode
|
|
* @hashval: unsigned long value used to locate this object in the
|
|
* inode_hashtable.
|
|
*
|
|
* Add an inode to the inode hash for this superblock.
|
|
*/
|
|
void __insert_inode_hash(struct inode *inode, unsigned long hashval)
|
|
{
|
|
struct hlist_head *head = inode_hashtable + hash(inode->i_sb, hashval);
|
|
spin_lock(&inode_lock);
|
|
hlist_add_head(&inode->i_hash, head);
|
|
spin_unlock(&inode_lock);
|
|
}
|
|
|
|
EXPORT_SYMBOL(__insert_inode_hash);
|
|
|
|
/**
|
|
* remove_inode_hash - remove an inode from the hash
|
|
* @inode: inode to unhash
|
|
*
|
|
* Remove an inode from the superblock.
|
|
*/
|
|
void remove_inode_hash(struct inode *inode)
|
|
{
|
|
spin_lock(&inode_lock);
|
|
hlist_del_init(&inode->i_hash);
|
|
spin_unlock(&inode_lock);
|
|
}
|
|
|
|
EXPORT_SYMBOL(remove_inode_hash);
|
|
|
|
/*
|
|
* Tell the filesystem that this inode is no longer of any interest and should
|
|
* be completely destroyed.
|
|
*
|
|
* We leave the inode in the inode hash table until *after* the filesystem's
|
|
* ->delete_inode completes. This ensures that an iget (such as nfsd might
|
|
* instigate) will always find up-to-date information either in the hash or on
|
|
* disk.
|
|
*
|
|
* I_FREEING is set so that no-one will take a new reference to the inode while
|
|
* it is being deleted.
|
|
*/
|
|
void generic_delete_inode(struct inode *inode)
|
|
{
|
|
struct super_operations *op = inode->i_sb->s_op;
|
|
|
|
list_del_init(&inode->i_list);
|
|
list_del_init(&inode->i_sb_list);
|
|
inode->i_state|=I_FREEING;
|
|
inodes_stat.nr_inodes--;
|
|
spin_unlock(&inode_lock);
|
|
|
|
if (inode->i_data.nrpages)
|
|
truncate_inode_pages(&inode->i_data, 0);
|
|
|
|
security_inode_delete(inode);
|
|
|
|
if (op->delete_inode) {
|
|
void (*delete)(struct inode *) = op->delete_inode;
|
|
if (!is_bad_inode(inode))
|
|
DQUOT_INIT(inode);
|
|
/* s_op->delete_inode internally recalls clear_inode() */
|
|
delete(inode);
|
|
} else
|
|
clear_inode(inode);
|
|
spin_lock(&inode_lock);
|
|
hlist_del_init(&inode->i_hash);
|
|
spin_unlock(&inode_lock);
|
|
wake_up_inode(inode);
|
|
if (inode->i_state != I_CLEAR)
|
|
BUG();
|
|
destroy_inode(inode);
|
|
}
|
|
|
|
EXPORT_SYMBOL(generic_delete_inode);
|
|
|
|
static void generic_forget_inode(struct inode *inode)
|
|
{
|
|
struct super_block *sb = inode->i_sb;
|
|
|
|
if (!hlist_unhashed(&inode->i_hash)) {
|
|
if (!(inode->i_state & (I_DIRTY|I_LOCK)))
|
|
list_move(&inode->i_list, &inode_unused);
|
|
inodes_stat.nr_unused++;
|
|
if (!sb || (sb->s_flags & MS_ACTIVE)) {
|
|
spin_unlock(&inode_lock);
|
|
return;
|
|
}
|
|
inode->i_state |= I_WILL_FREE;
|
|
spin_unlock(&inode_lock);
|
|
write_inode_now(inode, 1);
|
|
spin_lock(&inode_lock);
|
|
inode->i_state &= ~I_WILL_FREE;
|
|
inodes_stat.nr_unused--;
|
|
hlist_del_init(&inode->i_hash);
|
|
}
|
|
list_del_init(&inode->i_list);
|
|
list_del_init(&inode->i_sb_list);
|
|
inode->i_state |= I_FREEING;
|
|
inodes_stat.nr_inodes--;
|
|
spin_unlock(&inode_lock);
|
|
if (inode->i_data.nrpages)
|
|
truncate_inode_pages(&inode->i_data, 0);
|
|
clear_inode(inode);
|
|
destroy_inode(inode);
|
|
}
|
|
|
|
/*
|
|
* Normal UNIX filesystem behaviour: delete the
|
|
* inode when the usage count drops to zero, and
|
|
* i_nlink is zero.
|
|
*/
|
|
static void generic_drop_inode(struct inode *inode)
|
|
{
|
|
if (!inode->i_nlink)
|
|
generic_delete_inode(inode);
|
|
else
|
|
generic_forget_inode(inode);
|
|
}
|
|
|
|
/*
|
|
* Called when we're dropping the last reference
|
|
* to an inode.
|
|
*
|
|
* Call the FS "drop()" function, defaulting to
|
|
* the legacy UNIX filesystem behaviour..
|
|
*
|
|
* NOTE! NOTE! NOTE! We're called with the inode lock
|
|
* held, and the drop function is supposed to release
|
|
* the lock!
|
|
*/
|
|
static inline void iput_final(struct inode *inode)
|
|
{
|
|
struct super_operations *op = inode->i_sb->s_op;
|
|
void (*drop)(struct inode *) = generic_drop_inode;
|
|
|
|
if (op && op->drop_inode)
|
|
drop = op->drop_inode;
|
|
drop(inode);
|
|
}
|
|
|
|
/**
|
|
* iput - put an inode
|
|
* @inode: inode to put
|
|
*
|
|
* Puts an inode, dropping its usage count. If the inode use count hits
|
|
* zero, the inode is then freed and may also be destroyed.
|
|
*
|
|
* Consequently, iput() can sleep.
|
|
*/
|
|
void iput(struct inode *inode)
|
|
{
|
|
if (inode) {
|
|
struct super_operations *op = inode->i_sb->s_op;
|
|
|
|
BUG_ON(inode->i_state == I_CLEAR);
|
|
|
|
if (op && op->put_inode)
|
|
op->put_inode(inode);
|
|
|
|
if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
|
|
iput_final(inode);
|
|
}
|
|
}
|
|
|
|
EXPORT_SYMBOL(iput);
|
|
|
|
/**
|
|
* bmap - find a block number in a file
|
|
* @inode: inode of file
|
|
* @block: block to find
|
|
*
|
|
* Returns the block number on the device holding the inode that
|
|
* is the disk block number for the block of the file requested.
|
|
* That is, asked for block 4 of inode 1 the function will return the
|
|
* disk block relative to the disk start that holds that block of the
|
|
* file.
|
|
*/
|
|
sector_t bmap(struct inode * inode, sector_t block)
|
|
{
|
|
sector_t res = 0;
|
|
if (inode->i_mapping->a_ops->bmap)
|
|
res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
|
|
return res;
|
|
}
|
|
|
|
EXPORT_SYMBOL(bmap);
|
|
|
|
/**
|
|
* update_atime - update the access time
|
|
* @inode: inode accessed
|
|
*
|
|
* Update the accessed time on an inode and mark it for writeback.
|
|
* This function automatically handles read only file systems and media,
|
|
* as well as the "noatime" flag and inode specific "noatime" markers.
|
|
*/
|
|
void update_atime(struct inode *inode)
|
|
{
|
|
struct timespec now;
|
|
|
|
if (IS_NOATIME(inode))
|
|
return;
|
|
if (IS_NODIRATIME(inode) && S_ISDIR(inode->i_mode))
|
|
return;
|
|
if (IS_RDONLY(inode))
|
|
return;
|
|
|
|
now = current_fs_time(inode->i_sb);
|
|
if (!timespec_equal(&inode->i_atime, &now)) {
|
|
inode->i_atime = now;
|
|
mark_inode_dirty_sync(inode);
|
|
} else {
|
|
if (!timespec_equal(&inode->i_atime, &now))
|
|
inode->i_atime = now;
|
|
}
|
|
}
|
|
|
|
EXPORT_SYMBOL(update_atime);
|
|
|
|
/**
|
|
* inode_update_time - update mtime and ctime time
|
|
* @inode: inode accessed
|
|
* @ctime_too: update ctime too
|
|
*
|
|
* Update the mtime time on an inode and mark it for writeback.
|
|
* When ctime_too is specified update the ctime too.
|
|
*/
|
|
|
|
void inode_update_time(struct inode *inode, int ctime_too)
|
|
{
|
|
struct timespec now;
|
|
int sync_it = 0;
|
|
|
|
if (IS_NOCMTIME(inode))
|
|
return;
|
|
if (IS_RDONLY(inode))
|
|
return;
|
|
|
|
now = current_fs_time(inode->i_sb);
|
|
if (!timespec_equal(&inode->i_mtime, &now))
|
|
sync_it = 1;
|
|
inode->i_mtime = now;
|
|
|
|
if (ctime_too) {
|
|
if (!timespec_equal(&inode->i_ctime, &now))
|
|
sync_it = 1;
|
|
inode->i_ctime = now;
|
|
}
|
|
if (sync_it)
|
|
mark_inode_dirty_sync(inode);
|
|
}
|
|
|
|
EXPORT_SYMBOL(inode_update_time);
|
|
|
|
int inode_needs_sync(struct inode *inode)
|
|
{
|
|
if (IS_SYNC(inode))
|
|
return 1;
|
|
if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(inode_needs_sync);
|
|
|
|
/*
|
|
* Quota functions that want to walk the inode lists..
|
|
*/
|
|
#ifdef CONFIG_QUOTA
|
|
|
|
/* Function back in dquot.c */
|
|
int remove_inode_dquot_ref(struct inode *, int, struct list_head *);
|
|
|
|
void remove_dquot_ref(struct super_block *sb, int type,
|
|
struct list_head *tofree_head)
|
|
{
|
|
struct inode *inode;
|
|
|
|
if (!sb->dq_op)
|
|
return; /* nothing to do */
|
|
spin_lock(&inode_lock); /* This lock is for inodes code */
|
|
|
|
/*
|
|
* We don't have to lock against quota code - test IS_QUOTAINIT is
|
|
* just for speedup...
|
|
*/
|
|
list_for_each_entry(inode, &sb->s_inodes, i_sb_list)
|
|
if (!IS_NOQUOTA(inode))
|
|
remove_inode_dquot_ref(inode, type, tofree_head);
|
|
|
|
spin_unlock(&inode_lock);
|
|
}
|
|
|
|
#endif
|
|
|
|
int inode_wait(void *word)
|
|
{
|
|
schedule();
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* If we try to find an inode in the inode hash while it is being deleted, we
|
|
* have to wait until the filesystem completes its deletion before reporting
|
|
* that it isn't found. This is because iget will immediately call
|
|
* ->read_inode, and we want to be sure that evidence of the deletion is found
|
|
* by ->read_inode.
|
|
* This is called with inode_lock held.
|
|
*/
|
|
static void __wait_on_freeing_inode(struct inode *inode)
|
|
{
|
|
wait_queue_head_t *wq;
|
|
DEFINE_WAIT_BIT(wait, &inode->i_state, __I_LOCK);
|
|
|
|
/*
|
|
* I_FREEING and I_CLEAR are cleared in process context under
|
|
* inode_lock, so we have to give the tasks who would clear them
|
|
* a chance to run and acquire inode_lock.
|
|
*/
|
|
if (!(inode->i_state & I_LOCK)) {
|
|
spin_unlock(&inode_lock);
|
|
yield();
|
|
spin_lock(&inode_lock);
|
|
return;
|
|
}
|
|
wq = bit_waitqueue(&inode->i_state, __I_LOCK);
|
|
prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
|
|
spin_unlock(&inode_lock);
|
|
schedule();
|
|
finish_wait(wq, &wait.wait);
|
|
spin_lock(&inode_lock);
|
|
}
|
|
|
|
void wake_up_inode(struct inode *inode)
|
|
{
|
|
/*
|
|
* Prevent speculative execution through spin_unlock(&inode_lock);
|
|
*/
|
|
smp_mb();
|
|
wake_up_bit(&inode->i_state, __I_LOCK);
|
|
}
|
|
|
|
static __initdata unsigned long ihash_entries;
|
|
static int __init set_ihash_entries(char *str)
|
|
{
|
|
if (!str)
|
|
return 0;
|
|
ihash_entries = simple_strtoul(str, &str, 0);
|
|
return 1;
|
|
}
|
|
__setup("ihash_entries=", set_ihash_entries);
|
|
|
|
/*
|
|
* Initialize the waitqueues and inode hash table.
|
|
*/
|
|
void __init inode_init_early(void)
|
|
{
|
|
int loop;
|
|
|
|
/* If hashes are distributed across NUMA nodes, defer
|
|
* hash allocation until vmalloc space is available.
|
|
*/
|
|
if (hashdist)
|
|
return;
|
|
|
|
inode_hashtable =
|
|
alloc_large_system_hash("Inode-cache",
|
|
sizeof(struct hlist_head),
|
|
ihash_entries,
|
|
14,
|
|
HASH_EARLY,
|
|
&i_hash_shift,
|
|
&i_hash_mask,
|
|
0);
|
|
|
|
for (loop = 0; loop < (1 << i_hash_shift); loop++)
|
|
INIT_HLIST_HEAD(&inode_hashtable[loop]);
|
|
}
|
|
|
|
void __init inode_init(unsigned long mempages)
|
|
{
|
|
int loop;
|
|
|
|
/* inode slab cache */
|
|
inode_cachep = kmem_cache_create("inode_cache", sizeof(struct inode),
|
|
0, SLAB_RECLAIM_ACCOUNT|SLAB_PANIC, init_once, NULL);
|
|
set_shrinker(DEFAULT_SEEKS, shrink_icache_memory);
|
|
|
|
/* Hash may have been set up in inode_init_early */
|
|
if (!hashdist)
|
|
return;
|
|
|
|
inode_hashtable =
|
|
alloc_large_system_hash("Inode-cache",
|
|
sizeof(struct hlist_head),
|
|
ihash_entries,
|
|
14,
|
|
0,
|
|
&i_hash_shift,
|
|
&i_hash_mask,
|
|
0);
|
|
|
|
for (loop = 0; loop < (1 << i_hash_shift); loop++)
|
|
INIT_HLIST_HEAD(&inode_hashtable[loop]);
|
|
}
|
|
|
|
void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
|
|
{
|
|
inode->i_mode = mode;
|
|
if (S_ISCHR(mode)) {
|
|
inode->i_fop = &def_chr_fops;
|
|
inode->i_rdev = rdev;
|
|
} else if (S_ISBLK(mode)) {
|
|
inode->i_fop = &def_blk_fops;
|
|
inode->i_rdev = rdev;
|
|
} else if (S_ISFIFO(mode))
|
|
inode->i_fop = &def_fifo_fops;
|
|
else if (S_ISSOCK(mode))
|
|
inode->i_fop = &bad_sock_fops;
|
|
else
|
|
printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o)\n",
|
|
mode);
|
|
}
|
|
EXPORT_SYMBOL(init_special_inode);
|