zfs-builds-mm/zfs-0.8.1/module/spl/spl-vnode.c

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2019-07-06 23:40:11 +02:00
/*
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://zfsonlinux.org/>.
*
* The SPL is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* The SPL is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with the SPL. If not, see <http://www.gnu.org/licenses/>.
*
* Solaris Porting Layer (SPL) Vnode Implementation.
*/
#include <sys/cred.h>
#include <sys/vnode.h>
#include <sys/kmem_cache.h>
#include <linux/falloc.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#ifdef HAVE_FDTABLE_HEADER
#include <linux/fdtable.h>
#endif
vnode_t *rootdir = (vnode_t *)0xabcd1234;
EXPORT_SYMBOL(rootdir);
static spl_kmem_cache_t *vn_cache;
static spl_kmem_cache_t *vn_file_cache;
static spinlock_t vn_file_lock;
static LIST_HEAD(vn_file_list);
static int
spl_filp_fallocate(struct file *fp, int mode, loff_t offset, loff_t len)
{
int error = -EOPNOTSUPP;
#ifdef HAVE_FILE_FALLOCATE
if (fp->f_op->fallocate)
error = fp->f_op->fallocate(fp, mode, offset, len);
#else
#ifdef HAVE_INODE_FALLOCATE
if (fp->f_dentry && fp->f_dentry->d_inode &&
fp->f_dentry->d_inode->i_op->fallocate)
error = fp->f_dentry->d_inode->i_op->fallocate(
fp->f_dentry->d_inode, mode, offset, len);
#endif /* HAVE_INODE_FALLOCATE */
#endif /* HAVE_FILE_FALLOCATE */
return (error);
}
static int
spl_filp_fsync(struct file *fp, int sync)
{
#ifdef HAVE_2ARGS_VFS_FSYNC
return (vfs_fsync(fp, sync));
#else
return (vfs_fsync(fp, (fp)->f_dentry, sync));
#endif /* HAVE_2ARGS_VFS_FSYNC */
}
static ssize_t
spl_kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos)
{
#if defined(HAVE_KERNEL_WRITE_PPOS)
return (kernel_write(file, buf, count, pos));
#else
mm_segment_t saved_fs;
ssize_t ret;
saved_fs = get_fs();
set_fs(KERNEL_DS);
ret = vfs_write(file, (__force const char __user *)buf, count, pos);
set_fs(saved_fs);
return (ret);
#endif
}
static ssize_t
spl_kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
{
#if defined(HAVE_KERNEL_READ_PPOS)
return (kernel_read(file, buf, count, pos));
#else
mm_segment_t saved_fs;
ssize_t ret;
saved_fs = get_fs();
set_fs(KERNEL_DS);
ret = vfs_read(file, (void __user *)buf, count, pos);
set_fs(saved_fs);
return (ret);
#endif
}
vtype_t
vn_mode_to_vtype(mode_t mode)
{
if (S_ISREG(mode))
return (VREG);
if (S_ISDIR(mode))
return (VDIR);
if (S_ISCHR(mode))
return (VCHR);
if (S_ISBLK(mode))
return (VBLK);
if (S_ISFIFO(mode))
return (VFIFO);
if (S_ISLNK(mode))
return (VLNK);
if (S_ISSOCK(mode))
return (VSOCK);
return (VNON);
} /* vn_mode_to_vtype() */
EXPORT_SYMBOL(vn_mode_to_vtype);
mode_t
vn_vtype_to_mode(vtype_t vtype)
{
if (vtype == VREG)
return (S_IFREG);
if (vtype == VDIR)
return (S_IFDIR);
if (vtype == VCHR)
return (S_IFCHR);
if (vtype == VBLK)
return (S_IFBLK);
if (vtype == VFIFO)
return (S_IFIFO);
if (vtype == VLNK)
return (S_IFLNK);
if (vtype == VSOCK)
return (S_IFSOCK);
return (VNON);
} /* vn_vtype_to_mode() */
EXPORT_SYMBOL(vn_vtype_to_mode);
vnode_t *
vn_alloc(int flag)
{
vnode_t *vp;
vp = kmem_cache_alloc(vn_cache, flag);
if (vp != NULL) {
vp->v_file = NULL;
vp->v_type = 0;
}
return (vp);
} /* vn_alloc() */
EXPORT_SYMBOL(vn_alloc);
void
vn_free(vnode_t *vp)
{
kmem_cache_free(vn_cache, vp);
} /* vn_free() */
EXPORT_SYMBOL(vn_free);
int
vn_open(const char *path, uio_seg_t seg, int flags, int mode, vnode_t **vpp,
int x1, void *x2)
{
struct file *fp;
struct kstat stat;
int rc, saved_umask = 0;
gfp_t saved_gfp;
vnode_t *vp;
ASSERT(flags & (FWRITE | FREAD));
ASSERT(seg == UIO_SYSSPACE);
ASSERT(vpp);
*vpp = NULL;
if (!(flags & FCREAT) && (flags & FWRITE))
flags |= FEXCL;
/*
* Note for filp_open() the two low bits must be remapped to mean:
* 01 - read-only -> 00 read-only
* 10 - write-only -> 01 write-only
* 11 - read-write -> 10 read-write
*/
flags--;
if (flags & FCREAT)
saved_umask = xchg(&current->fs->umask, 0);
fp = filp_open(path, flags, mode);
if (flags & FCREAT)
(void) xchg(&current->fs->umask, saved_umask);
if (IS_ERR(fp))
return (-PTR_ERR(fp));
#if defined(HAVE_4ARGS_VFS_GETATTR)
rc = vfs_getattr(&fp->f_path, &stat, STATX_TYPE, AT_STATX_SYNC_AS_STAT);
#elif defined(HAVE_2ARGS_VFS_GETATTR)
rc = vfs_getattr(&fp->f_path, &stat);
#else
rc = vfs_getattr(fp->f_path.mnt, fp->f_dentry, &stat);
#endif
if (rc) {
filp_close(fp, 0);
return (-rc);
}
vp = vn_alloc(KM_SLEEP);
if (!vp) {
filp_close(fp, 0);
return (ENOMEM);
}
saved_gfp = mapping_gfp_mask(fp->f_mapping);
mapping_set_gfp_mask(fp->f_mapping, saved_gfp & ~(__GFP_IO|__GFP_FS));
mutex_enter(&vp->v_lock);
vp->v_type = vn_mode_to_vtype(stat.mode);
vp->v_file = fp;
vp->v_gfp_mask = saved_gfp;
*vpp = vp;
mutex_exit(&vp->v_lock);
return (0);
} /* vn_open() */
EXPORT_SYMBOL(vn_open);
int
vn_openat(const char *path, uio_seg_t seg, int flags, int mode,
vnode_t **vpp, int x1, void *x2, vnode_t *vp, int fd)
{
char *realpath;
int len, rc;
ASSERT(vp == rootdir);
len = strlen(path) + 2;
realpath = kmalloc(len, kmem_flags_convert(KM_SLEEP));
if (!realpath)
return (ENOMEM);
(void) snprintf(realpath, len, "/%s", path);
rc = vn_open(realpath, seg, flags, mode, vpp, x1, x2);
kfree(realpath);
return (rc);
} /* vn_openat() */
EXPORT_SYMBOL(vn_openat);
int
vn_rdwr(uio_rw_t uio, vnode_t *vp, void *addr, ssize_t len, offset_t off,
uio_seg_t seg, int ioflag, rlim64_t x2, void *x3, ssize_t *residp)
{
struct file *fp = vp->v_file;
loff_t offset = off;
int rc;
ASSERT(uio == UIO_WRITE || uio == UIO_READ);
ASSERT(seg == UIO_SYSSPACE);
ASSERT((ioflag & ~FAPPEND) == 0);
if (ioflag & FAPPEND)
offset = fp->f_pos;
if (uio & UIO_WRITE)
rc = spl_kernel_write(fp, addr, len, &offset);
else
rc = spl_kernel_read(fp, addr, len, &offset);
fp->f_pos = offset;
if (rc < 0)
return (-rc);
if (residp) {
*residp = len - rc;
} else {
if (rc != len)
return (EIO);
}
return (0);
} /* vn_rdwr() */
EXPORT_SYMBOL(vn_rdwr);
int
vn_close(vnode_t *vp, int flags, int x1, int x2, void *x3, void *x4)
{
int rc;
ASSERT(vp);
ASSERT(vp->v_file);
mapping_set_gfp_mask(vp->v_file->f_mapping, vp->v_gfp_mask);
rc = filp_close(vp->v_file, 0);
vn_free(vp);
return (-rc);
} /* vn_close() */
EXPORT_SYMBOL(vn_close);
/*
* vn_seek() does not actually seek it only performs bounds checking on the
* proposed seek. We perform minimal checking and allow vn_rdwr() to catch
* anything more serious.
*/
int
vn_seek(vnode_t *vp, offset_t ooff, offset_t *noffp, void *ct)
{
return ((*noffp < 0 || *noffp > MAXOFFSET_T) ? EINVAL : 0);
}
EXPORT_SYMBOL(vn_seek);
int
vn_getattr(vnode_t *vp, vattr_t *vap, int flags, void *x3, void *x4)
{
struct file *fp;
struct kstat stat;
int rc;
ASSERT(vp);
ASSERT(vp->v_file);
ASSERT(vap);
fp = vp->v_file;
#if defined(HAVE_4ARGS_VFS_GETATTR)
rc = vfs_getattr(&fp->f_path, &stat, STATX_BASIC_STATS,
AT_STATX_SYNC_AS_STAT);
#elif defined(HAVE_2ARGS_VFS_GETATTR)
rc = vfs_getattr(&fp->f_path, &stat);
#else
rc = vfs_getattr(fp->f_path.mnt, fp->f_dentry, &stat);
#endif
if (rc)
return (-rc);
vap->va_type = vn_mode_to_vtype(stat.mode);
vap->va_mode = stat.mode;
vap->va_uid = KUID_TO_SUID(stat.uid);
vap->va_gid = KGID_TO_SGID(stat.gid);
vap->va_fsid = 0;
vap->va_nodeid = stat.ino;
vap->va_nlink = stat.nlink;
vap->va_size = stat.size;
vap->va_blksize = stat.blksize;
vap->va_atime = stat.atime;
vap->va_mtime = stat.mtime;
vap->va_ctime = stat.ctime;
vap->va_rdev = stat.rdev;
vap->va_nblocks = stat.blocks;
return (0);
}
EXPORT_SYMBOL(vn_getattr);
int
vn_fsync(vnode_t *vp, int flags, void *x3, void *x4)
{
int datasync = 0;
int error;
int fstrans;
ASSERT(vp);
ASSERT(vp->v_file);
if (flags & FDSYNC)
datasync = 1;
/*
* May enter XFS which generates a warning when PF_FSTRANS is set.
* To avoid this the flag is cleared over vfs_sync() and then reset.
*/
fstrans = __spl_pf_fstrans_check();
if (fstrans)
current->flags &= ~(__SPL_PF_FSTRANS);
error = -spl_filp_fsync(vp->v_file, datasync);
if (fstrans)
current->flags |= __SPL_PF_FSTRANS;
return (error);
} /* vn_fsync() */
EXPORT_SYMBOL(vn_fsync);
int vn_space(vnode_t *vp, int cmd, struct flock *bfp, int flag,
offset_t offset, void *x6, void *x7)
{
int error = EOPNOTSUPP;
#ifdef FALLOC_FL_PUNCH_HOLE
int fstrans;
#endif
if (cmd != F_FREESP || bfp->l_whence != SEEK_SET)
return (EOPNOTSUPP);
ASSERT(vp);
ASSERT(vp->v_file);
ASSERT(bfp->l_start >= 0 && bfp->l_len > 0);
#ifdef FALLOC_FL_PUNCH_HOLE
/*
* May enter XFS which generates a warning when PF_FSTRANS is set.
* To avoid this the flag is cleared over vfs_sync() and then reset.
*/
fstrans = __spl_pf_fstrans_check();
if (fstrans)
current->flags &= ~(__SPL_PF_FSTRANS);
/*
* When supported by the underlying file system preferentially
* use the fallocate() callback to preallocate the space.
*/
error = -spl_filp_fallocate(vp->v_file,
FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE,
bfp->l_start, bfp->l_len);
if (fstrans)
current->flags |= __SPL_PF_FSTRANS;
if (error == 0)
return (0);
#endif
#ifdef HAVE_INODE_TRUNCATE_RANGE
if (vp->v_file->f_dentry && vp->v_file->f_dentry->d_inode &&
vp->v_file->f_dentry->d_inode->i_op &&
vp->v_file->f_dentry->d_inode->i_op->truncate_range) {
off_t end = bfp->l_start + bfp->l_len;
/*
* Judging from the code in shmem_truncate_range(),
* it seems the kernel expects the end offset to be
* inclusive and aligned to the end of a page.
*/
if (end % PAGE_SIZE != 0) {
end &= ~(off_t)(PAGE_SIZE - 1);
if (end <= bfp->l_start)
return (0);
}
--end;
vp->v_file->f_dentry->d_inode->i_op->truncate_range(
vp->v_file->f_dentry->d_inode, bfp->l_start, end);
return (0);
}
#endif
return (error);
}
EXPORT_SYMBOL(vn_space);
/* Function must be called while holding the vn_file_lock */
static file_t *
file_find(int fd, struct task_struct *task)
{
file_t *fp;
list_for_each_entry(fp, &vn_file_list, f_list) {
if (fd == fp->f_fd && fp->f_task == task) {
ASSERT(atomic_read(&fp->f_ref) != 0);
return (fp);
}
}
return (NULL);
} /* file_find() */
file_t *
vn_getf(int fd)
{
struct kstat stat;
struct file *lfp;
file_t *fp;
vnode_t *vp;
int rc = 0;
if (fd < 0)
return (NULL);
/* Already open just take an extra reference */
spin_lock(&vn_file_lock);
fp = file_find(fd, current);
if (fp) {
lfp = fget(fd);
fput(fp->f_file);
/*
* areleasef() can cause us to see a stale reference when
* userspace has reused a file descriptor before areleasef()
* has run. fput() the stale reference and replace it. We
* retain the original reference count such that the concurrent
* areleasef() will decrement its reference and terminate.
*/
if (lfp != fp->f_file) {
fp->f_file = lfp;
fp->f_vnode->v_file = lfp;
}
atomic_inc(&fp->f_ref);
spin_unlock(&vn_file_lock);
return (fp);
}
spin_unlock(&vn_file_lock);
/* File was not yet opened create the object and setup */
fp = kmem_cache_alloc(vn_file_cache, KM_SLEEP);
if (fp == NULL)
goto out;
mutex_enter(&fp->f_lock);
fp->f_fd = fd;
fp->f_task = current;
fp->f_offset = 0;
atomic_inc(&fp->f_ref);
lfp = fget(fd);
if (lfp == NULL)
goto out_mutex;
vp = vn_alloc(KM_SLEEP);
if (vp == NULL)
goto out_fget;
#if defined(HAVE_4ARGS_VFS_GETATTR)
rc = vfs_getattr(&lfp->f_path, &stat, STATX_TYPE,
AT_STATX_SYNC_AS_STAT);
#elif defined(HAVE_2ARGS_VFS_GETATTR)
rc = vfs_getattr(&lfp->f_path, &stat);
#else
rc = vfs_getattr(lfp->f_path.mnt, lfp->f_dentry, &stat);
#endif
if (rc)
goto out_vnode;
mutex_enter(&vp->v_lock);
vp->v_type = vn_mode_to_vtype(stat.mode);
vp->v_file = lfp;
mutex_exit(&vp->v_lock);
fp->f_vnode = vp;
fp->f_file = lfp;
/* Put it on the tracking list */
spin_lock(&vn_file_lock);
list_add(&fp->f_list, &vn_file_list);
spin_unlock(&vn_file_lock);
mutex_exit(&fp->f_lock);
return (fp);
out_vnode:
vn_free(vp);
out_fget:
fput(lfp);
out_mutex:
mutex_exit(&fp->f_lock);
kmem_cache_free(vn_file_cache, fp);
out:
return (NULL);
} /* getf() */
EXPORT_SYMBOL(getf);
static void releasef_locked(file_t *fp)
{
ASSERT(fp->f_file);
ASSERT(fp->f_vnode);
/* Unlinked from list, no refs, safe to free outside mutex */
fput(fp->f_file);
vn_free(fp->f_vnode);
kmem_cache_free(vn_file_cache, fp);
}
void
vn_releasef(int fd)
{
areleasef(fd, P_FINFO(current));
}
EXPORT_SYMBOL(releasef);
void
vn_areleasef(int fd, uf_info_t *fip)
{
file_t *fp;
struct task_struct *task = (struct task_struct *)fip;
if (fd < 0)
return;
spin_lock(&vn_file_lock);
fp = file_find(fd, task);
if (fp) {
atomic_dec(&fp->f_ref);
if (atomic_read(&fp->f_ref) > 0) {
spin_unlock(&vn_file_lock);
return;
}
list_del(&fp->f_list);
releasef_locked(fp);
}
spin_unlock(&vn_file_lock);
} /* releasef() */
EXPORT_SYMBOL(areleasef);
static void
vn_set_fs_pwd(struct fs_struct *fs, struct path *path)
{
struct path old_pwd;
#ifdef HAVE_FS_STRUCT_SPINLOCK
spin_lock(&fs->lock);
old_pwd = fs->pwd;
fs->pwd = *path;
path_get(path);
spin_unlock(&fs->lock);
#else
write_lock(&fs->lock);
old_pwd = fs->pwd;
fs->pwd = *path;
path_get(path);
write_unlock(&fs->lock);
#endif /* HAVE_FS_STRUCT_SPINLOCK */
if (old_pwd.dentry)
path_put(&old_pwd);
}
int
vn_set_pwd(const char *filename)
{
struct path path;
mm_segment_t saved_fs;
int rc;
/*
* user_path_dir() and __user_walk() both expect 'filename' to be
* a user space address so we must briefly increase the data segment
* size to ensure strncpy_from_user() does not fail with -EFAULT.
*/
saved_fs = get_fs();
set_fs(KERNEL_DS);
rc = user_path_dir(filename, &path);
if (rc)
goto out;
rc = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);
if (rc)
goto dput_and_out;
vn_set_fs_pwd(current->fs, &path);
dput_and_out:
path_put(&path);
out:
set_fs(saved_fs);
return (-rc);
} /* vn_set_pwd() */
EXPORT_SYMBOL(vn_set_pwd);
static int
vn_cache_constructor(void *buf, void *cdrarg, int kmflags)
{
struct vnode *vp = buf;
mutex_init(&vp->v_lock, NULL, MUTEX_DEFAULT, NULL);
return (0);
} /* vn_cache_constructor() */
static void
vn_cache_destructor(void *buf, void *cdrarg)
{
struct vnode *vp = buf;
mutex_destroy(&vp->v_lock);
} /* vn_cache_destructor() */
static int
vn_file_cache_constructor(void *buf, void *cdrarg, int kmflags)
{
file_t *fp = buf;
atomic_set(&fp->f_ref, 0);
mutex_init(&fp->f_lock, NULL, MUTEX_DEFAULT, NULL);
INIT_LIST_HEAD(&fp->f_list);
return (0);
} /* vn_file_cache_constructor() */
static void
vn_file_cache_destructor(void *buf, void *cdrarg)
{
file_t *fp = buf;
mutex_destroy(&fp->f_lock);
} /* vn_file_cache_destructor() */
int
spl_vn_init(void)
{
spin_lock_init(&vn_file_lock);
vn_cache = kmem_cache_create("spl_vn_cache",
sizeof (struct vnode), 64, vn_cache_constructor,
vn_cache_destructor, NULL, NULL, NULL, 0);
vn_file_cache = kmem_cache_create("spl_vn_file_cache",
sizeof (file_t), 64, vn_file_cache_constructor,
vn_file_cache_destructor, NULL, NULL, NULL, 0);
return (0);
} /* spl_vn_init() */
void
spl_vn_fini(void)
{
file_t *fp, *next_fp;
int leaked = 0;
spin_lock(&vn_file_lock);
list_for_each_entry_safe(fp, next_fp, &vn_file_list, f_list) {
list_del(&fp->f_list);
releasef_locked(fp);
leaked++;
}
spin_unlock(&vn_file_lock);
if (leaked > 0)
printk(KERN_WARNING "WARNING: %d vnode files leaked\n", leaked);
kmem_cache_destroy(vn_file_cache);
kmem_cache_destroy(vn_cache);
} /* spl_vn_fini() */