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authorChristoph Hellwig <hch@lst.de>2005-06-23 03:09:49 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-23 12:45:26 -0400
commitc663e5d80ebec426916ad2aa5400c7ec99aa572e (patch)
tree463dd4600525e536ed00579fa30bab9708c53824 /fs/namei.c
parent70f09f1fdf38cd7fca39913978d18cf998ab2c80 (diff)
[PATCH] add some comments to lookup_create()
In a duplicate of lookup_create in the af_unix code Al commented what's going on nicely, so let's bring that over to lookup_create before the copy is going away (I'll send a patch soon) Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c20
1 files changed, 18 insertions, 2 deletions
diff --git a/fs/namei.c b/fs/namei.c
index a7f7f44119b3..fa8df81ce8ca 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1577,19 +1577,35 @@ do_link:
1577 * 1577 *
1578 * Simple function to lookup and return a dentry and create it 1578 * Simple function to lookup and return a dentry and create it
1579 * if it doesn't exist. Is SMP-safe. 1579 * if it doesn't exist. Is SMP-safe.
1580 *
1581 * Returns with nd->dentry->d_inode->i_sem locked.
1580 */ 1582 */
1581struct dentry *lookup_create(struct nameidata *nd, int is_dir) 1583struct dentry *lookup_create(struct nameidata *nd, int is_dir)
1582{ 1584{
1583 struct dentry *dentry; 1585 struct dentry *dentry = ERR_PTR(-EEXIST);
1584 1586
1585 down(&nd->dentry->d_inode->i_sem); 1587 down(&nd->dentry->d_inode->i_sem);
1586 dentry = ERR_PTR(-EEXIST); 1588 /*
1589 * Yucky last component or no last component at all?
1590 * (foo/., foo/.., /////)
1591 */
1587 if (nd->last_type != LAST_NORM) 1592 if (nd->last_type != LAST_NORM)
1588 goto fail; 1593 goto fail;
1589 nd->flags &= ~LOOKUP_PARENT; 1594 nd->flags &= ~LOOKUP_PARENT;
1595
1596 /*
1597 * Do the final lookup.
1598 */
1590 dentry = lookup_hash(&nd->last, nd->dentry); 1599 dentry = lookup_hash(&nd->last, nd->dentry);
1591 if (IS_ERR(dentry)) 1600 if (IS_ERR(dentry))
1592 goto fail; 1601 goto fail;
1602
1603 /*
1604 * Special case - lookup gave negative, but... we had foo/bar/
1605 * From the vfs_mknod() POV we just have a negative dentry -
1606 * all is fine. Let's be bastards - you had / on the end, you've
1607 * been asking for (non-existent) directory. -ENOENT for you.
1608 */
1593 if (!is_dir && nd->last.name[nd->last.len] && !dentry->d_inode) 1609 if (!is_dir && nd->last.name[nd->last.len] && !dentry->d_inode)
1594 goto enoent; 1610 goto enoent;
1595 return dentry; 1611 return dentry;