diff options
author | Miklos Szeredi <mszeredi@suse.cz> | 2011-06-01 10:57:14 +0200 |
---|---|---|
committer | John Rigby <john.rigby@linaro.org> | 2011-10-17 09:52:05 -0600 |
commit | 01ffe7197176812e6a472fbeb95c843a1e5974a2 (patch) | |
tree | 432be6b7c17b194f169adf740eb894c6d87745d1 /fs | |
parent | 51fc9de7e5e1d9e4f9ee4e7cb3db0961b5b6787a (diff) |
UBUNTU: ubuntu: overlayfs -- vfs: add i_op->open()
Add a new inode operation i_op->open(). This is for stacked
filesystems that want to return a struct file from a different
filesystem.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/open.c | 76 |
1 files changed, 50 insertions, 26 deletions
diff --git a/fs/open.c b/fs/open.c index 6b15af414b3..a540e7bb3a3 100644 --- a/fs/open.c +++ b/fs/open.c @@ -670,8 +670,7 @@ static inline int __get_file_write_access(struct inode *inode, return error; } -static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt, - struct file *f, +static struct file *__dentry_open(struct path *path, struct file *f, int (*open)(struct inode *, struct file *), const struct cred *cred) { @@ -679,15 +678,16 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt, struct inode *inode; int error; + path_get(path); f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; if (unlikely(f->f_flags & O_PATH)) f->f_mode = FMODE_PATH; - inode = dentry->d_inode; + inode = path->dentry->d_inode; if (f->f_mode & FMODE_WRITE) { - error = __get_file_write_access(inode, mnt); + error = __get_file_write_access(inode, path->mnt); if (error) goto cleanup_file; if (!special_file(inode->i_mode)) @@ -695,8 +695,7 @@ static struct file *__dentry_open(struct dentry *dentry, struct vfsmount *mnt, } f->f_mapping = inode->i_mapping; - f->f_path.dentry = dentry; - f->f_path.mnt = mnt; + f->f_path = *path; f->f_pos = 0; file_sb_list_add(f, inode->i_sb); @@ -749,7 +748,7 @@ cleanup_all: * here, so just reset the state. */ file_reset_write(f); - mnt_drop_write(mnt); + mnt_drop_write(path->mnt); } } file_sb_list_del(f); @@ -757,8 +756,7 @@ cleanup_all: f->f_path.mnt = NULL; cleanup_file: put_filp(f); - dput(dentry); - mntput(mnt); + path_put(path); return ERR_PTR(error); } @@ -784,14 +782,14 @@ cleanup_file: struct file *lookup_instantiate_filp(struct nameidata *nd, struct dentry *dentry, int (*open)(struct inode *, struct file *)) { + struct path path = { .dentry = dentry, .mnt = nd->path.mnt }; const struct cred *cred = current_cred(); if (IS_ERR(nd->intent.open.file)) goto out; if (IS_ERR(dentry)) goto out_err; - nd->intent.open.file = __dentry_open(dget(dentry), mntget(nd->path.mnt), - nd->intent.open.file, + nd->intent.open.file = __dentry_open(&path, nd->intent.open.file, open, cred); out: return nd->intent.open.file; @@ -820,10 +818,17 @@ struct file *nameidata_to_filp(struct nameidata *nd) /* Has the filesystem initialised the file for us? */ if (filp->f_path.dentry == NULL) { - path_get(&nd->path); - filp = __dentry_open(nd->path.dentry, nd->path.mnt, filp, - NULL, cred); + struct inode *inode = nd->path.dentry->d_inode; + + if (inode->i_op->open) { + int flags = filp->f_flags; + put_filp(filp); + filp = inode->i_op->open(nd->path.dentry, flags, cred); + } else { + filp = __dentry_open(&nd->path, filp, NULL, cred); + } } + return filp; } @@ -834,26 +839,45 @@ struct file *nameidata_to_filp(struct nameidata *nd) struct file *dentry_open(struct dentry *dentry, struct vfsmount *mnt, int flags, const struct cred *cred) { - int error; - struct file *f; - - validate_creds(cred); + struct path path = { .dentry = dentry, .mnt = mnt }; + struct file *ret; /* We must always pass in a valid mount pointer. */ BUG_ON(!mnt); - error = -ENFILE; + ret = vfs_open(&path, flags, cred); + path_put(&path); + + return ret; +} +EXPORT_SYMBOL(dentry_open); + +/** + * vfs_open - open the file at the given path + * @path: path to open + * @flags: open flags + * @cred: credentials to use + * + * Open the file. If successful, the returned file will have acquired + * an additional reference for path. + */ +struct file *vfs_open(struct path *path, int flags, const struct cred *cred) +{ + struct file *f; + struct inode *inode = path->dentry->d_inode; + + validate_creds(cred); + + if (inode->i_op->open) + return inode->i_op->open(path->dentry, flags, cred); f = get_empty_filp(); - if (f == NULL) { - dput(dentry); - mntput(mnt); - return ERR_PTR(error); - } + if (f == NULL) + return ERR_PTR(-ENFILE); f->f_flags = flags; - return __dentry_open(dentry, mnt, f, NULL, cred); + return __dentry_open(path, f, NULL, cred); } -EXPORT_SYMBOL(dentry_open); +EXPORT_SYMBOL(vfs_open); static void __put_unused_fd(struct files_struct *files, unsigned int fd) { |