2002-10-01 08:30:04

by Anton Altaparmakov

[permalink] [raw]
Subject: [RESEND][BK-PATCH-2/2] Introduce ilookup() for searching for inodes in icache

And here is the second patch which switches iget_locked() to use the new
helpers and it adds some documentation.

No functionality changed at all.

Best regards,

Anton
--
Anton Altaparmakov <aia21 at cantab.net> (replace at with @)
Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net
WWW: http://linux-ntfs.sf.net/, http://www-stu.christs.cam.ac.uk/~aia21/

===================================================================

This will update the following files:

fs/inode.c | 87 +++++++++++++++++++++++++++++++++++--------------------------
1 files changed, 50 insertions(+), 37 deletions(-)

through these ChangeSets:

<[email protected]> (02/09/18 1.536.35.9)
Cleanup: Convert fs/inode.c::iget_locked() and iget5_locked() to use
the new ifind_fast() and ifind() helpers, respectively.


diff -Nru a/fs/inode.c b/fs/inode.c
--- a/fs/inode.c Tue Oct 1 09:22:43 2002
+++ b/fs/inode.c Tue Oct 1 09:22:43 2002
@@ -535,7 +535,7 @@
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.
@@ -812,65 +812,78 @@
}
EXPORT_SYMBOL(ilookup);

-/*
- * This is iget without the read_inode portion of get_new_inode
- * the filesystem gets back a new locked and hashed inode and gets
- * to fill it in before unlocking it via unlock_new_inode().
+/**
+ * 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 inode *iget5_locked(struct super_block *sb, unsigned long hashval,
+ int (*test)(struct inode *, void *),
+ int (*set)(struct inode *, void *), void *data)
{
- struct list_head * head = inode_hashtable + hash(sb, hashval);
- struct inode * inode;
+ struct list_head *head = inode_hashtable + hash(sb, hashval);
+ 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);
+ inode = ifind(sb, head, test, data);
+ if (inode)
return inode;
- }
- spin_unlock(&inode_lock);
-
/*
* 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);

-/*
- * Because most filesystems are based on 32-bit unique inode numbers some
- * functions are duplicated to keep iget_locked as a fast path. We can avoid
- * unnecessary pointer dereferences and function calls for this specific
- * case. The duplicated functions (find_inode_fast and get_new_inode_fast)
- * have the same pre- and post-conditions as their original counterparts.
+/**
+ * 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 list_head * head = inode_hashtable + hash(sb, ino);
- struct inode * inode;
+ struct list_head *head = inode_hashtable + hash(sb, 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);
+ inode = ifind_fast(sb, head, ino);
+ if (inode)
return inode;
- }
- spin_unlock(&inode_lock);
-
/*
* 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(iget5_locked);
EXPORT_SYMBOL(iget_locked);
-EXPORT_SYMBOL(unlock_new_inode);

/**
* __insert_inode_hash - hash an inode

===================================================================

This BitKeeper patch contains the following changesets:
1.536.35.9
## Wrapped with gzip_uu ##


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