fs: simplify iget & friends
Merge get_new_inode/get_new_inode_fast into iget5_locked/iget_locked as those were the only callers. Remove the internal ifind/ifind_fast helpers - ifind_fast only had a single caller, and ifind had two callers wanting it to do different things. Also clean up the comments in this area to focus on information important to a developer trying to use it, instead of overloading them with implementation details. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Christoph Hellwig
Al Viro
parent
0f1b1fd86f
commit
0b2d0724e2
268
fs/inode.c
268
fs/inode.c
@ -931,20 +931,42 @@ void unlock_new_inode(struct inode *inode)
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}
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EXPORT_SYMBOL(unlock_new_inode);
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/*
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* This is called without the inode hash lock held.. Be careful.
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/**
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* iget5_locked - obtain an inode from a mounted file system
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* @sb: super block of file system
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* @hashval: hash value (usually inode number) to get
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* @test: callback used for comparisons between inodes
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* @set: callback used to initialize a new struct inode
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* @data: opaque data pointer to pass to @test and @set
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*
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* We no longer cache the sb_flags in i_flags - see fs.h
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* -- rmk@arm.uk.linux.org
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* Search for the inode specified by @hashval and @data in the inode cache,
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* and if present it is return it with an increased reference count. This is
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* a generalized version of iget_locked() for file systems where the inode
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* number is not sufficient for unique identification of an inode.
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*
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* If the inode is not in cache, allocate a new inode and return it locked,
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* hashed, and with the I_NEW flag set. The file system gets to fill it in
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* before unlocking it via unlock_new_inode().
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*
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* Note both @test and @set are called with the inode_hash_lock held, so can't
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* sleep.
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*/
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static struct inode *get_new_inode(struct super_block *sb,
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struct hlist_head *head,
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int (*test)(struct inode *, void *),
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int (*set)(struct inode *, void *),
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void *data)
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struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
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int (*test)(struct inode *, void *),
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int (*set)(struct inode *, void *), void *data)
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{
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struct hlist_head *head = inode_hashtable + hash(sb, hashval);
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struct inode *inode;
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spin_lock(&inode_hash_lock);
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inode = find_inode(sb, head, test, data);
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spin_unlock(&inode_hash_lock);
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if (inode) {
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wait_on_inode(inode);
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return inode;
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}
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inode = alloc_inode(sb);
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if (inode) {
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struct inode *old;
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@ -986,16 +1008,34 @@ static struct inode *get_new_inode(struct super_block *sb,
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destroy_inode(inode);
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return NULL;
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}
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EXPORT_SYMBOL(iget5_locked);
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/*
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* get_new_inode_fast is the fast path version of get_new_inode, see the
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* comment at iget_locked for details.
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/**
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* iget_locked - obtain an inode from a mounted file system
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* @sb: super block of file system
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* @ino: inode number to get
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*
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* Search for the inode specified by @ino in the inode cache and if present
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* return it with an increased reference count. This is for file systems
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* where the inode number is sufficient for unique identification of an inode.
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*
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* If the inode is not in cache, allocate a new inode and return it locked,
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* hashed, and with the I_NEW flag set. The file system gets to fill it in
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* before unlocking it via unlock_new_inode().
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*/
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static struct inode *get_new_inode_fast(struct super_block *sb,
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struct hlist_head *head, unsigned long ino)
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struct inode *iget_locked(struct super_block *sb, unsigned long ino)
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{
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struct hlist_head *head = inode_hashtable + hash(sb, ino);
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struct inode *inode;
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spin_lock(&inode_hash_lock);
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inode = find_inode_fast(sb, head, ino);
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spin_unlock(&inode_hash_lock);
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if (inode) {
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wait_on_inode(inode);
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return inode;
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}
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inode = alloc_inode(sb);
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if (inode) {
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struct inode *old;
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@ -1030,6 +1070,7 @@ static struct inode *get_new_inode_fast(struct super_block *sb,
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}
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return inode;
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}
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EXPORT_SYMBOL(iget_locked);
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/*
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* search the inode cache for a matching inode number.
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@ -1112,74 +1153,6 @@ struct inode *igrab(struct inode *inode)
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}
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EXPORT_SYMBOL(igrab);
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/**
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* ifind - internal function, you want ilookup5() or iget5().
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* @sb: super block of file system to search
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* @head: the head of the list to search
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* @test: callback used for comparisons between inodes
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* @data: opaque data pointer to pass to @test
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* @wait: if true wait for the inode to be unlocked, if false do not
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*
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* ifind() searches for the inode specified by @data in the inode
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* cache. This is a generalized version of ifind_fast() for file systems where
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* the inode number is not sufficient for unique identification of an inode.
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*
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* If the inode is in the cache, the inode is returned with an incremented
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* reference count.
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*
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* Otherwise NULL is returned.
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*
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* Note, @test is called with the inode_hash_lock held, so can't sleep.
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*/
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static struct inode *ifind(struct super_block *sb,
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struct hlist_head *head, int (*test)(struct inode *, void *),
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void *data, const int wait)
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{
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struct inode *inode;
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spin_lock(&inode_hash_lock);
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inode = find_inode(sb, head, test, data);
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if (inode) {
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spin_unlock(&inode_hash_lock);
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if (likely(wait))
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wait_on_inode(inode);
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return inode;
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}
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spin_unlock(&inode_hash_lock);
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return NULL;
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}
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/**
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* ifind_fast - internal function, you want ilookup() or iget().
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* @sb: super block of file system to search
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* @head: head of the list to search
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* @ino: inode number to search for
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*
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* ifind_fast() searches for the inode @ino in the inode cache. This is for
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* file systems where the inode number is sufficient for unique identification
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* of an inode.
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*
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* If the inode is in the cache, the inode is returned with an incremented
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* reference count.
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*
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* Otherwise NULL is returned.
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*/
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static struct inode *ifind_fast(struct super_block *sb,
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struct hlist_head *head, unsigned long ino)
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{
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struct inode *inode;
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spin_lock(&inode_hash_lock);
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inode = find_inode_fast(sb, head, ino);
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if (inode) {
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spin_unlock(&inode_hash_lock);
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wait_on_inode(inode);
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return inode;
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}
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spin_unlock(&inode_hash_lock);
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return NULL;
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}
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/**
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* ilookup5_nowait - search for an inode in the inode cache
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* @sb: super block of file system to search
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@ -1187,26 +1160,26 @@ static struct inode *ifind_fast(struct super_block *sb,
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* @test: callback used for comparisons between inodes
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* @data: opaque data pointer to pass to @test
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*
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* ilookup5() uses ifind() to search for the inode specified by @hashval and
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* @data in the inode cache. This is a generalized version of ilookup() for
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* file systems where the inode number is not sufficient for unique
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* identification of an inode.
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*
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* Search for the inode specified by @hashval and @data in the inode cache.
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* If the inode is in the cache, the inode is returned with an incremented
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* reference count. Note, the inode lock is not waited upon so you have to be
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* very careful what you do with the returned inode. You probably should be
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* using ilookup5() instead.
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* reference count.
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*
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* Otherwise NULL is returned.
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* Note: I_NEW is not waited upon so you have to be very careful what you do
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* with the returned inode. You probably should be using ilookup5() instead.
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*
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* Note, @test is called with the inode_hash_lock held, so can't sleep.
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* Note: @test is called with the inode_hash_lock held, so can't sleep.
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*/
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struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
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int (*test)(struct inode *, void *), void *data)
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{
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struct hlist_head *head = inode_hashtable + hash(sb, hashval);
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struct inode *inode;
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return ifind(sb, head, test, data, 0);
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spin_lock(&inode_hash_lock);
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inode = find_inode(sb, head, test, data);
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spin_unlock(&inode_hash_lock);
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return inode;
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}
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EXPORT_SYMBOL(ilookup5_nowait);
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@ -1217,24 +1190,24 @@ EXPORT_SYMBOL(ilookup5_nowait);
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* @test: callback used for comparisons between inodes
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* @data: opaque data pointer to pass to @test
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*
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* ilookup5() uses ifind() to search for the inode specified by @hashval and
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* @data in the inode cache. This is a generalized version of ilookup() for
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* file systems where the inode number is not sufficient for unique
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* identification of an inode.
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*
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* If the inode is in the cache, the inode lock is waited upon and the inode is
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* Search for the inode specified by @hashval and @data in the inode cache,
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* and if the inode is in the cache, return the inode with an incremented
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* reference count. Waits on I_NEW before returning the inode.
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* returned with an incremented reference count.
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*
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* Otherwise NULL is returned.
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* This is a generalized version of ilookup() for file systems where the
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* inode number is not sufficient for unique identification of an inode.
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*
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* Note, @test is called with the inode_hash_lock held, so can't sleep.
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* Note: @test is called with the inode_hash_lock held, so can't sleep.
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*/
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struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
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int (*test)(struct inode *, void *), void *data)
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{
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struct hlist_head *head = inode_hashtable + hash(sb, hashval);
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struct inode *inode = ilookup5_nowait(sb, hashval, test, data);
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return ifind(sb, head, test, data, 1);
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if (inode)
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wait_on_inode(inode);
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return inode;
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}
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EXPORT_SYMBOL(ilookup5);
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@ -1243,93 +1216,24 @@ EXPORT_SYMBOL(ilookup5);
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* @sb: super block of file system to search
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* @ino: inode number to search for
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*
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* ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
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* This is for file systems where the inode number is sufficient for unique
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* identification of an inode.
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*
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* If the inode is in the cache, the inode is returned with an incremented
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* reference count.
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*
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* Otherwise NULL is returned.
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* Search for the inode @ino in the inode cache, and if the inode is in the
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* cache, the inode is returned with an incremented reference count.
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*/
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struct inode *ilookup(struct super_block *sb, unsigned long ino)
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{
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struct hlist_head *head = inode_hashtable + hash(sb, ino);
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struct inode *inode;
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return ifind_fast(sb, head, ino);
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spin_lock(&inode_hash_lock);
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inode = find_inode_fast(sb, head, ino);
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spin_unlock(&inode_hash_lock);
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if (inode)
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wait_on_inode(inode);
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return inode;
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}
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EXPORT_SYMBOL(ilookup);
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/**
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* iget5_locked - obtain an inode from a mounted file system
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* @sb: super block of file system
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* @hashval: hash value (usually inode number) to get
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* @test: callback used for comparisons between inodes
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* @set: callback used to initialize a new struct inode
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* @data: opaque data pointer to pass to @test and @set
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*
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* iget5_locked() uses ifind() to search for the inode specified by @hashval
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* and @data in the inode cache and if present it is returned with an increased
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* reference count. This is a generalized version of iget_locked() for file
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* systems where the inode number is not sufficient for unique identification
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* of an inode.
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*
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* If the inode is not in cache, get_new_inode() is called to allocate a new
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* inode and this is returned locked, hashed, and with the I_NEW flag set. The
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* file system gets to fill it in before unlocking it via unlock_new_inode().
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*
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* Note both @test and @set are called with the inode_hash_lock held, so can't
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* sleep.
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*/
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struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
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int (*test)(struct inode *, void *),
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int (*set)(struct inode *, void *), void *data)
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{
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struct hlist_head *head = inode_hashtable + hash(sb, hashval);
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struct inode *inode;
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inode = ifind(sb, head, test, data, 1);
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if (inode)
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return inode;
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/*
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* get_new_inode() will do the right thing, re-trying the search
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* in case it had to block at any point.
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*/
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return get_new_inode(sb, head, test, set, data);
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}
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EXPORT_SYMBOL(iget5_locked);
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/**
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* iget_locked - obtain an inode from a mounted file system
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* @sb: super block of file system
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* @ino: inode number to get
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*
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* iget_locked() uses ifind_fast() to search for the inode specified by @ino in
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* the inode cache and if present it is returned with an increased reference
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* count. This is for file systems where the inode number is sufficient for
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* unique identification of an inode.
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*
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* If the inode is not in cache, get_new_inode_fast() is called to allocate a
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* new inode and this is returned locked, hashed, and with the I_NEW flag set.
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* The file system gets to fill it in before unlocking it via
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* unlock_new_inode().
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*/
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struct inode *iget_locked(struct super_block *sb, unsigned long ino)
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{
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struct hlist_head *head = inode_hashtable + hash(sb, ino);
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struct inode *inode;
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inode = ifind_fast(sb, head, ino);
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if (inode)
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return inode;
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/*
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* get_new_inode_fast() will do the right thing, re-trying the search
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* in case it had to block at any point.
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*/
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return get_new_inode_fast(sb, head, ino);
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}
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EXPORT_SYMBOL(iget_locked);
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int insert_inode_locked(struct inode *inode)
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{
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struct super_block *sb = inode->i_sb;
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