From mboxrd@z Thu Jan 1 00:00:00 1970 From: Emanuele Giuseppe Esposito Date: Tue, 14 Apr 2020 14:43:00 +0200 Subject: [Ocfs2-devel] [PATCH 6/8] simplefs: add file creation functions In-Reply-To: <20200414124304.4470-1-eesposit@redhat.com> References: <20200414124304.4470-1-eesposit@redhat.com> Message-ID: <20200414124304.4470-7-eesposit@redhat.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-nfs@vger.kernel.org Cc: Song Liu , linux-usb@vger.kernel.org, bpf@vger.kernel.org, "Rafael J. Wysocki" , David Airlie , Heiko Carstens , Alexei Starovoitov , dri-devel@lists.freedesktop.org, "J. Bruce Fields" , Joseph Qi , Hugh Dickins , Paul Mackerras , John Johansen , linux-s390@vger.kernel.org, Christoph Hellwig , Andrew Donnellan , Emanuele Giuseppe Esposito , Matthew Garrett , linux-efi@vger.kernel.org, Arnd Bergmann , Daniel Borkmann , Christian Borntraeger , linux-rdma@vger.kernel.org, Michael Ellerman , Mark Fasheh , Anton Vorontsov , John Fastabend , James Morris , Ard Biesheuvel , Jason Gunthorpe , Doug Ledford , oprofile-list@lists.sf.net, Yonghong Song , Ian Kent , Andrii Nakryiko , Alexey Dobriyan , "Serge E. Hallyn" , netdev@vger.kernel.org, Robert Richter , Thomas Zimmermann , Vasily Gorbik , Tony Luck , Kees Cook , "James E.J. Bottomley" , autofs@vger.kernel.org, Uma Krishnan , linux-fsdevel@vger.kernel.org, "Manoj N. Kumar" , Alexander Viro , Jakub Kicinski , KP Singh , Trond Myklebust , "Matthew R. Ochs" , "David S. Miller" , Felipe Balbi , Mike Marciniszyn , Iurii Zaikin , linux-scsi@vger.kernel.org, "Martin K. Petersen" , linux-mm@kvack.org, Greg Kroah-Hartman , Dennis Dalessandro , Miklos Szeredi , linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Anna Schumaker , Luis Chamberlain , Chuck Lever , Jeremy Kerr , Colin Cross , Frederic Barrat , Paolo Bonzini , Andrew Morton , Mike Kravetz , linuxppc-dev@lists.ozlabs.org, Martin KaFai Lau , ocfs2-devel@oss.oracle.com, Joel Becker A bunch of code is duplicated between debugfs and tracefs, unify it to the simplefs library. The code is very similar, except that dentry and inode creation are unified into a single function (unlike start_creating in debugfs and tracefs, which only takes care of dentries). This adds an output parameter to the creation functions, but pushes all error recovery into fs/simplefs.c. Signed-off-by: Emanuele Giuseppe Esposito --- fs/simplefs.c | 150 +++++++++++++++++++++++++++++++++++++++ include/linux/simplefs.h | 19 +++++ 2 files changed, 169 insertions(+) diff --git a/fs/simplefs.c b/fs/simplefs.c index c59eb8d996be..3e48a288beb3 100644 --- a/fs/simplefs.c +++ b/fs/simplefs.c @@ -1,6 +1,8 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include #include +#include +#include static DEFINE_SPINLOCK(pin_fs_lock); @@ -42,3 +44,151 @@ struct inode *simple_alloc_anon_inode(struct simple_fs *fs) return alloc_anon_inode(fs->mount->mnt_sb); } EXPORT_SYMBOL(simple_alloc_anon_inode); + +static struct dentry *failed_creating(struct simple_fs *fs, struct dentry *dentry) +{ + inode_unlock(d_inode(dentry->d_parent)); + dput(dentry); + simple_release_fs(fs); + return ERR_PTR(-ENOMEM); +} + +struct dentry *simplefs_create_dentry(struct simple_fs *fs, struct file_system_type *type, + const char *name, struct dentry *parent, + struct inode **inode) +{ + struct dentry *dentry; + int error; + + pr_debug("creating file '%s'\n", name); + + if (IS_ERR(parent)) + return parent; + + error = simple_pin_fs(fs, type); + if (error) { + pr_err("Unable to pin filesystem for file '%s'\n", name); + return ERR_PTR(error); + } + + /* If the parent is not specified, we create it in the root. + * We need the root dentry to do this, which is in the super + * block. A pointer to that is in the struct vfsmount that we + * have around. + */ + if (!parent) + parent = fs->mount->mnt_root; + + inode_lock(d_inode(parent)); + dentry = lookup_one_len(name, parent, strlen(name)); + if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { + if (d_is_dir(dentry)) + pr_err("Directory '%s' with parent '%s' already present!\n", + name, parent->d_name.name); + else + pr_err("File '%s' in directory '%s' already present!\n", + name, parent->d_name.name); + dput(dentry); + dentry = ERR_PTR(-EEXIST); + } + + if (IS_ERR(dentry)) { + inode_unlock(d_inode(parent)); + simple_release_fs(fs); + } + + + if (IS_ERR(dentry)) + return dentry; + + *inode = simple_new_inode(fs->mount->mnt_sb); + if (unlikely(!(*inode))) { + pr_err("out of free inodes, can not create file '%s'\n", + name); + return failed_creating(fs, dentry); + } + + return dentry; +} +EXPORT_SYMBOL(simplefs_create_dentry); + +struct dentry *simplefs_create_file(struct simple_fs *fs, struct file_system_type *type, + const char *name, umode_t mode, + struct dentry *parent, void *data, + struct inode **inode) +{ + struct dentry *dentry; + + WARN_ON((mode & S_IFMT) && !S_ISREG(mode)); + mode |= S_IFREG; + + dentry = simplefs_create_dentry(fs, type, name, parent, inode); + + if (IS_ERR(dentry)) + return dentry; + + (*inode)->i_mode = mode; + (*inode)->i_private = data; + + return dentry; +} +EXPORT_SYMBOL(simplefs_create_file); + +struct dentry *simplefs_finish_dentry(struct dentry *dentry, struct inode *inode) +{ + d_instantiate(dentry, inode); + if (S_ISDIR(inode->i_mode)) { + inc_nlink(d_inode(dentry->d_parent)); + fsnotify_mkdir(d_inode(dentry->d_parent), dentry); + } else { + fsnotify_create(d_inode(dentry->d_parent), dentry); + } + inode_unlock(d_inode(dentry->d_parent)); + return dentry; +} +EXPORT_SYMBOL(simplefs_finish_dentry); + +struct dentry *simplefs_create_dir(struct simple_fs *fs, struct file_system_type *type, + const char *name, umode_t mode, struct dentry *parent, + struct inode **inode) +{ + struct dentry *dentry; + + WARN_ON((mode & S_IFMT) && !S_ISDIR(mode)); + mode |= S_IFDIR; + + dentry = simplefs_create_dentry(fs, type, name, parent, inode); + if (IS_ERR(dentry)) + return dentry; + + (*inode)->i_mode = mode; + (*inode)->i_op = &simple_dir_inode_operations; + (*inode)->i_fop = &simple_dir_operations; + + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inc_nlink(*inode); + return dentry; +} +EXPORT_SYMBOL(simplefs_create_dir); + +struct dentry *simplefs_create_symlink(struct simple_fs *fs, struct file_system_type *type, + const char *name, struct dentry *parent, + const char *target, struct inode **inode) +{ + struct dentry *dentry; + char *link = kstrdup(target, GFP_KERNEL); + if (!link) + return ERR_PTR(-ENOMEM); + + dentry = simplefs_create_dentry(fs, type, name, parent, inode); + if (IS_ERR(dentry)) { + kfree_link(link); + return dentry; + } + + (*inode)->i_mode = S_IFLNK | S_IRWXUGO; + (*inode)->i_link = link; + (*inode)->i_op = &simple_symlink_inode_operations; + return dentry; +} +EXPORT_SYMBOL(simplefs_create_symlink); diff --git a/include/linux/simplefs.h b/include/linux/simplefs.h index c62ab526414e..cc53eed0bc3d 100644 --- a/include/linux/simplefs.h +++ b/include/linux/simplefs.h @@ -14,4 +14,23 @@ extern void simple_release_fs(struct simple_fs *); extern struct inode *simple_alloc_anon_inode(struct simple_fs *fs); +extern struct dentry *simplefs_create_dentry(struct simple_fs *fs, + struct file_system_type *type, + const char *name, struct dentry *parent, + struct inode **inode); +struct dentry *simplefs_finish_dentry(struct dentry *dentry, struct inode *inode); + +extern struct dentry *simplefs_create_file(struct simple_fs *fs, + struct file_system_type *type, + const char *name, umode_t mode, + struct dentry *parent, void *data, + struct inode **inode); +extern struct dentry *simplefs_create_dir(struct simple_fs *fs, struct file_system_type *type, + const char *name, umode_t mode, struct dentry *parent, + struct inode **inode); +extern struct dentry *simplefs_create_symlink(struct simple_fs *fs, struct file_system_type *type, + const char *name, struct dentry *parent, + const char *target, struct inode **inode); + + #endif -- 2.25.2