Overlayfs and cachefiles use vfs_open_tmpfile() to open a tmpfile without accounting for nr_files. Rename this helper to kernel_tmpfile_open() to better reflect this helper is used for kernel internal users. cachefiles uses open_with_fake_path() without the need for a fake path only to use the noaccount feature of open_with_fake_path(). Fork open_with_fake_path() to kernel_file_open() which only does the noaccount feature and use it in cachefiles. Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> --- Christian, Per your request, here is an extra patch to decouple cachefiles from open_with_fake_path(). This patch comes before the backing_file patches [1]. There is a minor merge conflict with backing_file patches please see how I resolved it on my branch [2] - Note that the mention of 'cachefiles' was removed from the backing_file commit message and there is a slight rewording that you also requested s/open_backing_file/backing_file_open, to be consistent with kernel_file_open. I truely hope that this patch is not going to steer a bike shedding session over the names of the helpers. Note that all the inernal kernel files opened by cachefiles using the new kernel_*_open() helpers also have the S_KERNEL_FILE inode flag. Thanks, Amir. [1] https://lore.kernel.org/linux-fsdevel/20230614074907.1943007-1-amir73il@xxxxxxxxx/ [2] https://github.com/amir73il/linux/commits/ovl_fake_path fs/cachefiles/namei.c | 10 +++++----- fs/namei.c | 24 +++++++++++++----------- fs/open.c | 31 +++++++++++++++++++++++++++++++ fs/overlayfs/overlayfs.h | 5 +++-- include/linux/fs.h | 9 ++++++--- 5 files changed, 58 insertions(+), 21 deletions(-) diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index 82219a8f6084..499cf73f097b 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -451,9 +451,9 @@ struct file *cachefiles_create_tmpfile(struct cachefiles_object *object) ret = cachefiles_inject_write_error(); if (ret == 0) { - file = vfs_tmpfile_open(&nop_mnt_idmap, &parentpath, S_IFREG, - O_RDWR | O_LARGEFILE | O_DIRECT, - cache->cache_cred); + file = kernel_tmpfile_open(&nop_mnt_idmap, &parentpath, S_IFREG, + O_RDWR | O_LARGEFILE | O_DIRECT, + cache->cache_cred); ret = PTR_ERR_OR_ZERO(file); } if (ret) { @@ -560,8 +560,8 @@ static bool cachefiles_open_file(struct cachefiles_object *object, */ path.mnt = cache->mnt; path.dentry = dentry; - file = open_with_fake_path(&path, O_RDWR | O_LARGEFILE | O_DIRECT, - d_backing_inode(dentry), cache->cache_cred); + file = kernel_file_open(&path, O_RDWR | O_LARGEFILE | O_DIRECT, + d_backing_inode(dentry), cache->cache_cred); if (IS_ERR(file)) { trace_cachefiles_vfs_error(object, d_backing_inode(dentry), PTR_ERR(file), diff --git a/fs/namei.c b/fs/namei.c index e4fe0879ae55..36e335c39c44 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -3703,7 +3703,7 @@ static int vfs_tmpfile(struct mnt_idmap *idmap, } /** - * vfs_tmpfile_open - open a tmpfile for kernel internal use + * kernel_tmpfile_open - open a tmpfile for kernel internal use * @idmap: idmap of the mount the inode was found from * @parentpath: path of the base directory * @mode: mode of the new tmpfile @@ -3714,24 +3714,26 @@ static int vfs_tmpfile(struct mnt_idmap *idmap, * hence this is only for kernel internal use, and must not be installed into * file tables or such. */ -struct file *vfs_tmpfile_open(struct mnt_idmap *idmap, - const struct path *parentpath, - umode_t mode, int open_flag, const struct cred *cred) +struct file *kernel_tmpfile_open(struct mnt_idmap *idmap, + const struct path *parentpath, + umode_t mode, int open_flag, + const struct cred *cred) { struct file *file; int error; file = alloc_empty_file_noaccount(open_flag, cred); - if (!IS_ERR(file)) { - error = vfs_tmpfile(idmap, parentpath, file, mode); - if (error) { - fput(file); - file = ERR_PTR(error); - } + if (IS_ERR(file)) + return file; + + error = vfs_tmpfile(idmap, parentpath, file, mode); + if (error) { + fput(file); + file = ERR_PTR(error); } return file; } -EXPORT_SYMBOL(vfs_tmpfile_open); +EXPORT_SYMBOL(kernel_tmpfile_open); static int do_tmpfile(struct nameidata *nd, unsigned flags, const struct open_flags *op, diff --git a/fs/open.c b/fs/open.c index 005ca91a173b..c3491ecd9ae8 100644 --- a/fs/open.c +++ b/fs/open.c @@ -1121,6 +1121,37 @@ struct file *dentry_create(const struct path *path, int flags, umode_t mode, } EXPORT_SYMBOL(dentry_create); +/** + * kernel_file_open - open a file for kernel internal use + * @path: path of the file to open + * @flags: open flags + * @inode: the inode + * @cred: credentials for open + * + * Open a file that is not accounted in nr_files. + * This is only for kernel internal use, and must not be installed into + * file tables or such. + */ +struct file *kernel_file_open(const struct path *path, int flags, + struct inode *inode, const struct cred *cred) +{ + struct file *f; + int error; + + f = alloc_empty_file_noaccount(flags, cred); + if (IS_ERR(f)) + return f; + + f->f_path = *path; + error = do_dentry_open(f, inode, NULL); + if (error) { + fput(f); + f = ERR_PTR(error); + } + return f; +} +EXPORT_SYMBOL(kernel_file_open); + struct file *open_with_fake_path(const struct path *path, int flags, struct inode *inode, const struct cred *cred) { diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index fcac4e2c56ab..6129f0984cf7 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -329,8 +329,9 @@ static inline struct file *ovl_do_tmpfile(struct ovl_fs *ofs, struct dentry *dentry, umode_t mode) { struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = dentry }; - struct file *file = vfs_tmpfile_open(ovl_upper_mnt_idmap(ofs), &path, mode, - O_LARGEFILE | O_WRONLY, current_cred()); + struct file *file = kernel_tmpfile_open(ovl_upper_mnt_idmap(ofs), &path, + mode, O_LARGEFILE | O_WRONLY, + current_cred()); int err = PTR_ERR_OR_ZERO(file); pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); diff --git a/include/linux/fs.h b/include/linux/fs.h index 21a981680856..1f8486e773af 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1672,9 +1672,12 @@ static inline int vfs_whiteout(struct mnt_idmap *idmap, WHITEOUT_DEV); } -struct file *vfs_tmpfile_open(struct mnt_idmap *idmap, - const struct path *parentpath, - umode_t mode, int open_flag, const struct cred *cred); +struct file *kernel_tmpfile_open(struct mnt_idmap *idmap, + const struct path *parentpath, + umode_t mode, int open_flag, + const struct cred *cred); +struct file *kernel_file_open(const struct path *path, int flags, + struct inode *inode, const struct cred *cred); int vfs_mkobj(struct dentry *, umode_t, int (*f)(struct dentry *, umode_t, void *), -- 2.34.1
