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fs: Stop abusing find_inode_fast in iunique
Stop abusing find_inode_fast for iunique and opencode the inode hash walk. Introduce a new iunique_lock to protect the iunique counters once inode_lock is removed. Based on a patch originally from Nick Piggin. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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parent
4c51acbc66
commit
ad5e195ac9
1 changed files with 25 additions and 5 deletions
30
fs/inode.c
30
fs/inode.c
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@ -884,6 +884,27 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
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return inode;
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}
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/*
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* search the inode cache for a matching inode number.
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* If we find one, then the inode number we are trying to
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* allocate is not unique and so we should not use it.
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*
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* Returns 1 if the inode number is unique, 0 if it is not.
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*/
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static int test_inode_iunique(struct super_block *sb, unsigned long ino)
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{
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struct hlist_head *b = inode_hashtable + hash(sb, ino);
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struct hlist_node *node;
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struct inode *inode;
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hlist_for_each_entry(inode, node, b, i_hash) {
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if (inode->i_ino == ino && inode->i_sb == sb)
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return 0;
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}
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return 1;
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}
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/**
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* iunique - get a unique inode number
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* @sb: superblock
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@ -905,19 +926,18 @@ ino_t iunique(struct super_block *sb, ino_t max_reserved)
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* error if st_ino won't fit in target struct field. Use 32bit counter
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* here to attempt to avoid that.
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*/
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static DEFINE_SPINLOCK(iunique_lock);
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static unsigned int counter;
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struct inode *inode;
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struct hlist_head *head;
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ino_t res;
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spin_lock(&inode_lock);
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spin_lock(&iunique_lock);
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do {
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if (counter <= max_reserved)
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counter = max_reserved + 1;
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res = counter++;
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head = inode_hashtable + hash(sb, res);
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inode = find_inode_fast(sb, head, res);
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} while (inode != NULL);
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} while (!test_inode_iunique(sb, res));
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spin_unlock(&iunique_lock);
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spin_unlock(&inode_lock);
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return res;
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