[PATCH v4 1/2] readdir: split the core of getdents64(2) out into vfs_getdents()
From: Lennert Buytenhek <hidden>
Date: 2021-03-12 15:50:26
Also in:
linux-fsdevel
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
So that IORING_OP_GETDENTS may use it, split out the core of the
getdents64(2) syscall into a helper function, vfs_getdents().
vfs_getdents() calls into filesystems' ->iterate{,_shared}() which
expect serialization on struct file, which means that callers of
vfs_getdents() are responsible for either using fdget_pos() or
performing the equivalent serialization by hand.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Lennert Buytenhek <redacted>
---
fs/readdir.c | 25 +++++++++++++++++--------
include/linux/fs.h | 4 ++++
2 files changed, 21 insertions(+), 8 deletions(-)
diff --git a/fs/readdir.c b/fs/readdir.c
index 19434b3c982c..f52167c1eb61 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c@@ -348,10 +348,9 @@ static int filldir64(struct dir_context *ctx, const char *name, int namlen, return -EFAULT; } -SYSCALL_DEFINE3(getdents64, unsigned int, fd, - struct linux_dirent64 __user *, dirent, unsigned int, count) +int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent, + unsigned int count) { - struct fd f; struct getdents_callback64 buf = { .ctx.actor = filldir64, .count = count,
@@ -359,11 +358,7 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd, }; int error; - f = fdget_pos(fd); - if (!f.file) - return -EBADF; - - error = iterate_dir(f.file, &buf.ctx); + error = iterate_dir(file, &buf.ctx); if (error >= 0) error = buf.error; if (buf.prev_reclen) {
@@ -376,6 +371,20 @@ SYSCALL_DEFINE3(getdents64, unsigned int, fd, else error = count - buf.count; } + return error; +} + +SYSCALL_DEFINE3(getdents64, unsigned int, fd, + struct linux_dirent64 __user *, dirent, unsigned int, count) +{ + struct fd f; + int error; + + f = fdget_pos(fd); + if (!f.file) + return -EBADF; + + error = vfs_getdents(f.file, dirent, count); fdput_pos(f); return error; }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index ec8f3ddf4a6a..c03235883e18 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -3227,6 +3227,10 @@ extern const struct inode_operations simple_symlink_inode_operations; extern int iterate_dir(struct file *, struct dir_context *); +struct linux_dirent64; +int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent, + unsigned int count); + int vfs_fstatat(int dfd, const char __user *filename, struct kstat *stat, int flags); int vfs_fstat(int fd, struct kstat *stat);
--
2.29.2