From a70e65df8812c52252fa07a2eb92a46451a4427f Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 15 Feb 2008 14:37:28 -0800 Subject: [PATCH] [PATCH] merge open_namei() and do_filp_open() open_namei() will, in the future, need to take mount write counts over its creation and truncation (via may_open()) operations. It needs to keep these write counts until any potential filp that is created gets __fput()'d. This gets complicated in the error handling and becomes very murky as to how far open_namei() actually got, and whether or not that mount write count was taken. That makes it a bad interface. All that the current do_filp_open() really does is allocate the nameidata on the stack, then call open_namei(). So, this merges those two functions and moves filp_open() over to namei.c so it can be close to its buddy: do_filp_open(). It also gets a kerneldoc comment in the process. Acked-by: Al Viro Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Dave Hansen Signed-off-by: Al Viro --- fs/namei.c | 100 ++++++++++++++++++++++++++------------------- fs/open.c | 19 --------- include/linux/fs.h | 3 +- 3 files changed, 59 insertions(+), 63 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index c70dbf72010..a1f8bbbd58e 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1725,17 +1725,13 @@ static inline int open_to_namei_flags(int flag) } /* - * open_namei() - * - * namei for open - this is in fact almost the whole open-routine. - * * Note that the low bits of "flag" aren't the same as in the open * system call. See open_to_namei_flags(). - * SMP-safe */ -int open_namei(int dfd, const char *pathname, int open_flag, - int mode, struct nameidata *nd) +struct file *do_filp_open(int dfd, const char *pathname, + int open_flag, int mode) { + struct nameidata nd; int acc_mode, error; struct path path; struct dentry *dir; @@ -1758,18 +1754,19 @@ int open_namei(int dfd, const char *pathname, int open_flag, */ if (!(flag & O_CREAT)) { error = path_lookup_open(dfd, pathname, lookup_flags(flag), - nd, flag); + &nd, flag); if (error) - return error; + return ERR_PTR(error); goto ok; } /* * Create - we need to know the parent. */ - error = path_lookup_create(dfd,pathname,LOOKUP_PARENT,nd,flag,mode); + error = path_lookup_create(dfd, pathname, LOOKUP_PARENT, + &nd, flag, mode); if (error) - return error; + return ERR_PTR(error); /* * We have the parent and last component. First of all, check @@ -1777,14 +1774,14 @@ int open_namei(int dfd, const char *pathname, int open_flag, * will not do. */ error = -EISDIR; - if (nd->last_type != LAST_NORM || nd->last.name[nd->last.len]) + if (nd.last_type != LAST_NORM || nd.last.name[nd.last.len]) goto exit; - dir = nd->path.dentry; - nd->flags &= ~LOOKUP_PARENT; + dir = nd.path.dentry; + nd.flags &= ~LOOKUP_PARENT; mutex_lock(&dir->d_inode->i_mutex); - path.dentry = lookup_hash(nd); - path.mnt = nd->path.mnt; + path.dentry = lookup_hash(&nd); + path.mnt = nd.path.mnt; do_last: error = PTR_ERR(path.dentry); @@ -1793,18 +1790,18 @@ do_last: goto exit; } - if (IS_ERR(nd->intent.open.file)) { + if (IS_ERR(nd.intent.open.file)) { mutex_unlock(&dir->d_inode->i_mutex); - error = PTR_ERR(nd->intent.open.file); + error = PTR_ERR(nd.intent.open.file); goto exit_dput; } /* Negative dentry, just create the file */ if (!path.dentry->d_inode) { - error = __open_namei_create(nd, &path, flag, mode); + error = __open_namei_create(&nd, &path, flag, mode); if (error) goto exit; - return 0; + return nameidata_to_filp(&nd, open_flag); } /* @@ -1829,23 +1826,23 @@ do_last: if (path.dentry->d_inode->i_op && path.dentry->d_inode->i_op->follow_link) goto do_link; - path_to_nameidata(&path, nd); + path_to_nameidata(&path, &nd); error = -EISDIR; if (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode)) goto exit; ok: - error = may_open(nd, acc_mode, flag); + error = may_open(&nd, acc_mode, flag); if (error) goto exit; - return 0; + return nameidata_to_filp(&nd, open_flag); exit_dput: - path_put_conditional(&path, nd); + path_put_conditional(&path, &nd); exit: - if (!IS_ERR(nd->intent.open.file)) - release_open_intent(nd); - path_put(&nd->path); - return error; + if (!IS_ERR(nd.intent.open.file)) + release_open_intent(&nd); + path_put(&nd.path); + return ERR_PTR(error); do_link: error = -ELOOP; @@ -1861,42 +1858,59 @@ do_link: * stored in nd->last.name and we will have to putname() it when we * are done. Procfs-like symlinks just set LAST_BIND. */ - nd->flags |= LOOKUP_PARENT; - error = security_inode_follow_link(path.dentry, nd); + nd.flags |= LOOKUP_PARENT; + error = security_inode_follow_link(path.dentry, &nd); if (error) goto exit_dput; - error = __do_follow_link(&path, nd); + error = __do_follow_link(&path, &nd); if (error) { /* Does someone understand code flow here? Or it is only * me so stupid? Anathema to whoever designed this non-sense * with "intent.open". */ - release_open_intent(nd); - return error; + release_open_intent(&nd); + return ERR_PTR(error); } - nd->flags &= ~LOOKUP_PARENT; - if (nd->last_type == LAST_BIND) + nd.flags &= ~LOOKUP_PARENT; + if (nd.last_type == LAST_BIND) goto ok; error = -EISDIR; - if (nd->last_type != LAST_NORM) + if (nd.last_type != LAST_NORM) goto exit; - if (nd->last.name[nd->last.len]) { - __putname(nd->last.name); + if (nd.last.name[nd.last.len]) { + __putname(nd.last.name); goto exit; } error = -ELOOP; if (count++==32) { - __putname(nd->last.name); + __putname(nd.last.name); goto exit; } - dir = nd->path.dentry; + dir = nd.path.dentry; mutex_lock(&dir->d_inode->i_mutex); - path.dentry = lookup_hash(nd); - path.mnt = nd->path.mnt; - __putname(nd->last.name); + path.dentry = lookup_hash(&nd); + path.mnt = nd.path.mnt; + __putname(nd.last.name); goto do_last; } +/** + * filp_open - open file and return file pointer + * + * @filename: path to open + * @flags: open flags as per the open(2) second argument + * @mode: mode for the new file if O_CREAT is set, else ignored + * + * This is the helper to open a file from kernelspace if you really + * have to. But in generally you should not do this, so please move + * along, nothing to see here.. + */ +struct file *filp_open(const char *filename, int flags, int mode) +{ + return do_filp_open(AT_FDCWD, filename, flags, mode); +} +EXPORT_SYMBOL(filp_open); + /** * lookup_create - lookup a dentry, creating it if it doesn't exist * @nd: nameidata info diff --git a/fs/open.c b/fs/open.c index 5ab3f3f079c..8111947905d 100644 --- a/fs/open.c +++ b/fs/open.c @@ -796,25 +796,6 @@ cleanup_file: return ERR_PTR(error); } -static struct file *do_filp_open(int dfd, const char *filename, int flags, - int mode) -{ - int error; - struct nameidata nd; - - error = open_namei(dfd, filename, flags, mode, &nd); - if (!error) - return nameidata_to_filp(&nd, flags); - - return ERR_PTR(error); -} - -struct file *filp_open(const char *filename, int flags, int mode) -{ - return do_filp_open(AT_FDCWD, filename, flags, mode); -} -EXPORT_SYMBOL(filp_open); - /** * lookup_instantiate_filp - instantiates the open intent filp * @nd: pointer to nameidata diff --git a/include/linux/fs.h b/include/linux/fs.h index b84b848431f..013b9c2b88e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1735,7 +1735,8 @@ extern struct file *create_read_pipe(struct file *f); extern struct file *create_write_pipe(void); extern void free_write_pipe(struct file *); -extern int open_namei(int dfd, const char *, int, int, struct nameidata *); +extern struct file *do_filp_open(int dfd, const char *pathname, + int open_flag, int mode); extern int may_open(struct nameidata *, int, int); extern int kernel_read(struct file *, unsigned long, char *, unsigned long);