forked from mitra/lzfs
/
lzfs_vnops.c
1416 lines (1217 loc) · 31.7 KB
/
lzfs_vnops.c
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/*
* This file is part of the LZPL: Linux ZFS Posix Layer
*
* Copyright (c) 2010 Knowledge Quest Infotech Pvt. Ltd.
* Produced at Knowledge Quest Infotech Pvt. Ltd.
* Written by: Knowledge Quest Infotech Pvt. Ltd.
* zfs@kqinfotech.com
*
* This 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.
*
* This 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 this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <linux/fs.h>
#include <sys/vnode.h>
#include <spl-debug.h>
#include <sys/tsd_hashtable.h>
#include <linux/writeback.h>
#include <lzfs_snap.h>
#include <linux/fsync_compat.h>
#include <linux/xattr.h>
#include <lzfs_xattr.h>
#ifdef DEBUG_SUBSYSTEM
#undef DEBUG_SUBSYSTEM
#endif
#define DEBUG_SUBSYSTEM S_LZFS
static int checkname(char *name)
{
if (strlen(name) >= MAXNAMELEN) {
return ENAMETOOLONG;
} else {
return 0;
}
}
static int lzfs_vnop_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
{
struct inode *inode = dentry->d_inode;
vnode_t *vnode = NULL;
vattr_t vap;
const struct cred *cred = get_current_cred();
int err;
SENTRY;
vnode = LZFS_ITOV(inode);
err = zfs_getattr(vnode, &vap, 0, (struct cred *) cred, NULL);
if (err) {
put_cred(cred);
tsd_exit();
SEXIT;
return PTR_ERR(ERR_PTR(-err));
}
stat->dev = vap.va_rdev;
stat->rdev = vap.va_rdev;
stat->ino = inode->i_ino;
stat->mode = vap.va_mode;
stat->nlink = vap.va_nlink;
stat->gid = vap.va_gid;
stat->uid = vap.va_uid;
stat->atime = vap.va_atime;
stat->mtime = vap.va_mtime;
stat->ctime = vap.va_ctime;
stat->size = i_size_read(inode);
stat->blocks = vap.va_nblocks;
stat->blksize = (1 << inode->i_blkbits);
// stat->blksize = vap.va_blocksize;
//stat->blocks = stat->size >> inode->i_blkbits;
put_cred(cred);
tsd_exit();
SEXIT;
return 0;
}
static int
lzfs_vnop_create(struct inode *dir, struct dentry *dentry, int mode,
struct nameidata *nd)
{
vnode_t *vp;
vnode_t *dvp;
vattr_t *vap;
const struct cred *cred = get_current_cred();
int err, se_err;
SENTRY;
err = checkname((char *)dentry->d_name.name);
if(err)
return -ENAMETOOLONG;
vap = kmalloc(sizeof(vattr_t), GFP_KERNEL);
ASSERT(vap != NULL);
memset(vap, 0, sizeof(vap));
vap->va_type = IFTOVT(mode);
vap->va_mode = mode;
vap->va_mask = AT_TYPE|AT_MODE;
vap->va_uid = current_fsuid();
vap->va_gid = current_fsgid();
dvp = LZFS_ITOV(dir);
err = zfs_create(dvp, (char *)dentry->d_name.name, vap, 0, mode,
&vp, (struct cred *)cred, 0, NULL, NULL);
put_cred(cred);
kfree(vap);
if (err) {
tsd_exit();
SEXIT;
return PTR_ERR(ERR_PTR(-err));
}
d_instantiate(dentry, LZFS_VTOI(vp));
se_err = lzfs_init_security(dentry, dir);
if(se_err) {
tsd_exit();
SEXIT;
return se_err;
}
tsd_exit();
SEXIT;
return 0;
}
/* Read the directory. It uses the filldir function provided by Linux kernel.
*
*/
int
lzfs_vnop_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
vnode_t *vp;
int eof, err;
struct inode *inode = filp->f_path.dentry->d_inode;
SENTRY;
vp = LZFS_ITOV(inode);
err = zfs_readdir(vp, dirent, NULL, &eof, NULL, 0, filldir,
&filp->f_pos);
tsd_exit();
SEXIT;
if (err)
return PTR_ERR(ERR_PTR(-err));
return 0;
}
static struct dentry *
lzfs_vnop_lookup(struct inode * dir, struct dentry *dentry,
struct nameidata *nd)
{
vnode_t *vp;
vnode_t *dvp;
int err;
const struct cred *cred = get_current_cred();
SENTRY;
err = checkname((char *)dentry->d_name.name);
if(err)
return ((void * )-ENAMETOOLONG);
dvp = LZFS_ITOV(dir);
err = zfs_lookup(dvp, (char *)dentry->d_name.name, &vp, NULL, 0 , NULL,
(struct cred *) cred, NULL, NULL, NULL);
put_cred(cred);
tsd_exit();
SEXIT;
if (err) {
if (err == ENOENT)
return d_splice_alias(NULL, dentry);
else
return ERR_PTR(-err);
}
return d_splice_alias(LZFS_VTOI(vp), dentry);
}
#define ZFS_LINK_MAX UINT32_MAX
/* Add a hard link (new name) from dentry to inode pointed by old_dentry.
*/
static int
lzfs_vnop_link (struct dentry *old_dentry, struct inode * dir,
struct dentry *dentry)
{
vnode_t *tdvp;
vnode_t *svp;
struct inode *inode = old_dentry->d_inode;
char *name = (char *)dentry->d_name.name;
const struct cred *cred = get_current_cred();
int err;
SENTRY;
/* Linux Kernel enforces a limit on number of hardlinks to a file.
* struct kstat used in getattr uses unsigned int variable to store
* hardlink count. ZFS does not restrict the number of hardlinks,
* but we had to.
* */
if (inode->i_nlink >= ZFS_LINK_MAX)
return -EMLINK;
err = checkname(name) || checkname((char *)old_dentry->d_name.name);
if(err)
return -ENAMETOOLONG;
svp = LZFS_ITOV(inode);
tdvp = LZFS_ITOV(dir);
inode->i_ctime = CURRENT_TIME_SEC;
/* inode refernece counts are updated in zfs_inode_update
* inc_nlink(inode);
*/
atomic_inc(&inode->i_count);
err = zfs_link(tdvp, svp, name, (struct cred *)cred, NULL, 0);
put_cred(cred);
if (err) {
/* Decrement the link count and release the hold in error case.
*/
/* inode refernece counts are updated in zfs_inode_update
* drop_nlink(inode);
*/
iput(inode);
tsd_exit();
SEXIT;
return PTR_ERR(ERR_PTR(-err));
}
d_instantiate(dentry, LZFS_VTOI(svp));
tsd_exit();
SEXIT;
return 0;
}
static int
lzfs_vnop_unlink(struct inode *dir, struct dentry *dentry)
{
vnode_t *dvp;
const struct cred *cred = get_current_cred();
int err;
SENTRY;
dvp = LZFS_ITOV(dir);
err = zfs_remove(dvp, (char *)dentry->d_name.name,
(struct cred *)cred, NULL, 0);
put_cred(cred);
tsd_exit();
SEXIT;
if (err)
return PTR_ERR(ERR_PTR(-err));
/* inode refernece counts are updated in zfs_inode_update
* drop_nlink(inode);
*/
return 0;
}
static int
lzfs_vnop_symlink (struct inode *dir, struct dentry *dentry,
const char *symname)
{
vnode_t *dvp;
vnode_t *vp;
vattr_t *vap;
const struct cred *cred = get_current_cred();
int err, se_err;
SENTRY;
err = checkname((char *)dentry->d_name.name);
if(err)
return ENAMETOOLONG;
vap = kmalloc(sizeof(vattr_t), GFP_KERNEL);
ASSERT(vap != NULL);
memset(vap, 0, sizeof(vap));
dvp = LZFS_ITOV(dir);
vap->va_type = VLNK;
vap->va_mode = (S_IRWXU | S_IRWXG | S_IRWXO);
vap->va_mask = AT_TYPE|AT_MODE;
vap->va_uid = cred->uid;
vap->va_gid = cred->gid;
err = zfs_symlink(dvp, (char *)dentry->d_name.name, vap,
(char *)symname, (struct cred *)cred , NULL, 0, &vp);
kfree(vap);
put_cred(cred);
if (err) {
tsd_exit();
SEXIT;
return PTR_ERR(ERR_PTR(-err));
}
d_instantiate(dentry, LZFS_VTOI(vp));
se_err = lzfs_init_security(dentry, dir);
if(se_err) {
tsd_exit();
SEXIT;
return se_err;
}
tsd_exit();
SEXIT;
return 0;
}
static int
lzfs_vnop_mkdir(struct inode *dir, struct dentry *dentry, int mode)
{
vnode_t *vp;
vnode_t *dvp;
vattr_t *vap;
const struct cred *cred = get_current_cred();
int err, se_err;
SENTRY;
err = checkname((char *)dentry->d_name.name);
if(err)
return -ENAMETOOLONG;
vap = kmalloc(sizeof(vattr_t), GFP_KERNEL);
ASSERT(vap != NULL);
memset(vap, 0, sizeof(vap));
vap->va_type = VDIR;
vap->va_mode = mode;
vap->va_mask = AT_TYPE|AT_MODE;
vap->va_uid = current_fsuid();
vap->va_gid = current_fsgid();
dvp = LZFS_ITOV(dir);
err = zfs_mkdir(dvp, (char *)dentry->d_name.name, vap,
&vp, (struct cred *) cred, NULL, 0, NULL);
kfree(vap);
put_cred(cred);
if (err) {
tsd_exit();
SEXIT;
return PTR_ERR(ERR_PTR(-err));
}
d_instantiate(dentry, LZFS_VTOI(vp));
se_err = lzfs_init_security(dentry, dir);
if(se_err) {
tsd_exit();
SEXIT;
return se_err;
}
tsd_exit();
SEXIT;
return 0;
}
static int
lzfs_vnop_rmdir(struct inode * dir, struct dentry *dentry)
{
vnode_t *dvp;
const struct cred *cred = get_current_cred();
int err;
SENTRY;
dvp = LZFS_ITOV(dir);
err = zfs_rmdir(dvp, (char *)dentry->d_name.name, NULL,
(struct cred *) cred, NULL, 0);
put_cred(cred);
tsd_exit();
SEXIT;
if (err)
return PTR_ERR(ERR_PTR(-err));
return 0;
}
/*
* Create special node.
* This code is very similar to create, just passing rdev in the vap and
* calling zfs_create.
*/
static int
lzfs_vnop_mknod(struct inode * dir, struct dentry *dentry, int mode,
dev_t rdev)
{
vnode_t *vp;
vnode_t *dvp;
vattr_t *vap;
const struct cred *cred = get_current_cred();
int err, se_err;
SENTRY;
vap = kmalloc(sizeof(vattr_t), GFP_KERNEL);
ASSERT(vap != NULL);
memset(vap, 0, sizeof(vap));
vap->va_type = IFTOVT(mode);
vap->va_mode = mode;
vap->va_mask = AT_TYPE|AT_MODE;
vap->va_rdev = rdev;
vap->va_uid = current_fsuid();
vap->va_gid = current_fsgid();
/*
printk(KERN_ERR "vap->va_type is %x, vap.vamode is %x orig mode %x dev %u\n",
vap->va_type, vap->va_mode, mode, vap->va_rdev);
*/
dvp = LZFS_ITOV(dir);
err = zfs_create(dvp, (char *)dentry->d_name.name, vap, 0, mode,
&vp, (struct cred *)cred, 0, NULL, NULL);
put_cred(cred);
kfree(vap);
if (err) {
tsd_exit();
SEXIT;
return PTR_ERR(ERR_PTR(-err));
}
d_instantiate(dentry, LZFS_VTOI(vp));
se_err = lzfs_init_security(dentry, dir);
if(se_err) {
tsd_exit();
SEXIT;
return se_err;
}
tsd_exit();
SEXIT;
return 0;
}
static int
lzfs_vnop_rename (struct inode * old_dir, struct dentry * old_dentry,
struct inode * new_dir, struct dentry * new_dentry )
{
vnode_t *sdvp = LZFS_ITOV(old_dir);
vnode_t *tdvp = LZFS_ITOV(new_dir);
const struct cred *cred = get_current_cred();
int err;
SENTRY;
err = zfs_rename(sdvp, (char *)old_dentry->d_name.name, tdvp,
(char *) new_dentry->d_name.name, (struct cred *)cred,
NULL, 0);
put_cred(cred);
tsd_exit();
SEXIT;
if (err)
return PTR_ERR(ERR_PTR(-err));
return 0;
}
int
lzfs_vnop_setattr(struct dentry *dentry, struct iattr *iattr)
{
struct inode *inode = dentry->d_inode;
vnode_t *vp = LZFS_ITOV(inode);
vattr_t *vap;
int mask = iattr->ia_valid;
const struct cred *cred = get_current_cred();
int err;
SENTRY;
err = inode_change_ok(inode, iattr);
if(err)
return err;
vap = kmalloc(sizeof(vattr_t), GFP_KERNEL);
ASSERT(vap != NULL);
memset(vap, 0, sizeof(vap));
if (mask & ATTR_MODE) {
vap->va_mask |= AT_MODE;
vap->va_mode = iattr->ia_mode;
}
if (mask & ATTR_UID) {
vap->va_mask |= AT_UID;
vap->va_uid = iattr->ia_uid;
}
if (mask & ATTR_GID) {
vap->va_mask |= AT_GID;
vap->va_gid = iattr->ia_gid;
}
vap->va_type = IFTOVT(inode->i_mode);
vap->va_mask |= AT_TYPE;
if (mask & (ATTR_ATIME | ATTR_MTIME | ATTR_CTIME)) {
if (mask & ATTR_ATIME) {
vap->va_mask |= AT_ATIME;
vap->va_atime = iattr->ia_atime;
}
if (mask & ATTR_MTIME) {
vap->va_mask |= AT_MTIME;
vap->va_mtime = iattr->ia_mtime;
}
if (mask & ATTR_CTIME) {
vap->va_mask |= AT_CTIME;
vap->va_ctime = iattr->ia_ctime;
}
}
if (mask & ATTR_SIZE) {
/* truncate the inode, znode */
vap->va_mask |= AT_SIZE;
vap->va_size = iattr->ia_size;
err = vmtruncate(inode, iattr->ia_size);
if (err) {
kfree(vap);
put_cred(cred);
tsd_exit();
SEXIT;
return err;
}
}
err = zfs_setattr(vp, vap, 0, (struct cred *)cred, NULL);
kfree(vap);
put_cred(cred);
tsd_exit();
SEXIT;
if (err)
return PTR_ERR(ERR_PTR(-err));
return 0;
}
int
lzfs_vnop_permission(struct inode *inode, int mask)
{
return generic_permission(inode, mask, NULL);
}
static void lzfs_put_link(struct dentry *dentry, struct nameidata *nd, void *ptr)
{
char *buf = nd_get_link(nd);
if (!IS_ERR(buf)) {
/* Free the char* */
kfree(buf);
}
}
static void *lzfs_follow_link(struct dentry *dentry, struct nameidata *nd)
{
struct inode *inode = dentry->d_inode;
vnode_t *vp = LZFS_ITOV(inode);
const struct cred *cred = get_current_cred();
size_t len = i_size_read(inode);
char *buf = NULL;
struct iovec iov;
uio_t uio;
int err;
SENTRY;
if (NULL == (buf = kzalloc(len + 1, GFP_KERNEL))) {
put_cred(cred);
tsd_exit();
SEXIT;
return ERR_PTR(-ENOMEM);
}
bzero(&iov, sizeof(struct iovec));
iov.iov_base = buf;
iov.iov_len = len;
bzero(&uio, sizeof(uio_t));
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_resid = len;
uio.uio_segflg = UIO_SYSSPACE;
err = zfs_readlink(vp, &uio, (struct cred *)cred, NULL);
if (err) {
kfree(buf);
buf = ERR_PTR(-err);
} else
buf[len] = '\0';
nd_set_link(nd, buf);
put_cred(cred);
tsd_exit();
SEXIT;
return NULL;
}
#if 0
static int
lzfs_vnop_readlink(struct dentry *dentry, char __user *buf, int len)
{
struct iovec iov = { .iov_base = buf, .iov_len = len};
vnode_t *vp = LZFS_ITOV(dentry->d_inode);
const struct cred *cred = get_current_cred();
uio_t uio;
int err;
SENTRY;
uio.uio_iov = &iov;
uio.uio_iovcnt = 1;
uio.uio_resid = len;
uio.uio_segflg = UIO_SYSSPACE;
// printk("%s inode %ld\n", __FUNCTION__, dentry->d_inode->i_ino);
err = zfs_readlink(vp, &uio, (struct cred *)cred, NULL);
if (err)
return PTR_ERR(ERR_PTR(-err));
SEXIT;
/*
printk("%s err %d ret %d\n", __FUNCTION__, err,
(int)(len - uio.uio_resid));
*/
return ((int) (len - uio.uio_resid));
}
#endif
LZFS_VNOP_FSYNC_HANDLER(lzfs_vnop_fsync)
{
int err = 0;
vnode_t *vp = NULL;
const struct cred *cred = get_current_cred();
SENTRY;
vp = LZFS_ITOV(filep->f_path.dentry->d_inode);
err = zfs_fsync(vp, datasync, (struct cred *)cred, NULL);
put_cred(cred);
SEXIT;
return err;
}
/* XXX --> Internal function used by lzfs_vnop_readlink and lzfs_readpage
*
* Performs the read operation
*
* Explanation of parameters
* buf = buffer pointer to data
* len = length of the data
* pos = offest within file to wite
* segment = indicates whether buf pointer points to
* user space buffer or kernel buffer.
* */
static inline ssize_t lzfs_read(vnode_t *vp, const char *buf, ssize_t len,
loff_t pos, uio_seg_t segment)
{
int err;
struct iovec iov = {
.iov_base = (void *) buf,
.iov_len = len,
};
uio_t uio = {
.uio_iov = &iov,
.uio_iovcnt = 1,
.uio_loffset = (offset_t) pos,
.uio_resid = len,
.uio_segflg = segment,
};
const cred_t *cred = get_current_cred();
err = zfs_read(vp, &uio, 0, (cred_t *) cred, NULL);
put_cred(cred);
if (unlikely(err))
return -err;
return (len - uio.uio_resid);
}
int copy_data(read_descriptor_t *desc, struct page *page,
unsigned long offset, unsigned long size)
{
char *kaddr;
unsigned long left, count = desc->count;
if (size > count)
size = count;
kaddr = kmap(page);
left = copy_to_user(desc->arg.buf, kaddr + offset, size);
kunmap(page);
if (left) {
size -= left;
desc->error = -EFAULT;
}
desc->count = count - size;
desc->written += size;
desc->arg.buf += size;
return size;
}
ssize_t
lzfs_vnop_read (struct file *filep, char __user *buf, size_t len, loff_t *ppos)
{
vnode_t *vp = NULL;
loff_t isize;
ssize_t size;
/* PAGE CACHE SUPPORT VARIABLES */
struct address_space *mapping = filep->f_mapping;
struct inode *inode = mapping->host;
struct file_ra_state *ra = &filep->f_ra;
pgoff_t index;
pgoff_t last_index;
pgoff_t prev_index;
unsigned long offset; /* offset into pagecache page */
unsigned int prev_offset;
read_descriptor_t desc;
SENTRY;
vp = LZFS_ITOV(inode);
if (likely(!(vp->v_flag & VMMAPPED))) {
/* file is not memory mmapped, pass read directly to ZFS */
ssize_t rc;
rc = lzfs_read(vp, buf, len, *ppos, UIO_USERSPACE);
if (likely(rc > 0))
*ppos += rc;
tsd_exit();
SEXIT;
return rc;
}
desc.written = 0;
desc.arg.buf = buf;
desc.count = len;
desc.error = 0;
index = *ppos >> PAGE_CACHE_SHIFT;
prev_index = ra->prev_pos >> PAGE_CACHE_SHIFT;
prev_offset = ra->prev_pos & (PAGE_CACHE_SIZE - 1);
last_index = (*ppos + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
offset = *ppos & ~PAGE_CACHE_MASK;
while (1) {
struct page *page;
pgoff_t end_index;
unsigned long nr, ret;
#if 0
printk(KERN_INFO "desc.count=%ld, len=%ld, offset=%ld, pos=%lld\n",
desc.count, len, offset, *ppos);
#endif
if (!desc.count)
break;
BUG_ON(desc.written > len);
cond_resched();
page = find_get_page(mapping, index);
if (!page) {
/* NORMAL CASE: DATA IS NOT CACHED */
goto no_cached_page;
}
/* MMAPED DATA: DATA IS CACHED */
if (!PageUptodate(page)) {
/* WE ARE USING PAGE CACHE ONLY FOR MMAP, ONCE WE GET
* LOCKED PAGE IT HAS TO BE UPTODATE */
lock_page(page);
if (!page->mapping) {
/* truncate happened */
unlock_page(page);
page_cache_release(page);
continue;
}
if (!PageUptodate(page)) {
unlock_page(page);
BUG();
}
unlock_page(page);
}
isize = i_size_read(inode);
end_index = (isize - 1) >> PAGE_CACHE_SHIFT;
if (unlikely(!isize || index > end_index)) {
page_cache_release(page);
goto out;
}
/* nr is the maximum number of bytes to copy from this page */
nr = PAGE_CACHE_SIZE;
if (index == end_index) {
nr = ((isize - 1) & ~PAGE_CACHE_MASK) + 1;
if (nr <= offset) {
page_cache_release(page);
goto out;
}
}
nr = nr - offset;
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
mark_page_accessed(page);
prev_index = index;
ret = copy_data(&desc, page, offset, nr);
*ppos += ret;
offset += ret;
index += (offset >> PAGE_CACHE_SHIFT);
offset &= ~PAGE_CACHE_MASK;
prev_offset = offset;
page_cache_release(page);
#if 0
printk(KERN_ERR "%s: isize=%lld nr=%ld len=%ld offset=%ld desc.written=%ld desc.count=%ld pos=%lld.\n",
__FUNCTION__, isize, nr, len, offset, desc.written, desc.count, *ppos);
#endif
if (*ppos >= isize) {
ra->prev_pos = prev_index;
ra->prev_pos <<= PAGE_CACHE_SHIFT;
ra->prev_pos |= prev_offset;
goto out;
}
if (ret == nr && desc.count)
continue;
goto out;
no_cached_page:
isize = i_size_read(inode);
if (*ppos >= isize)
break;
size = PAGE_CACHE_SIZE;
if (desc.written + size > len)
size = len - desc.written;
if (offset + size > isize)
size = isize - desc.written;
ret = lzfs_read(vp, desc.arg.buf, size, *ppos, UIO_USERSPACE);
if (unlikely(ret < 0)) {
tsd_exit();
SEXIT;
return ret;
}
desc.count = desc.count - ret;
desc.written += ret;
desc.arg.buf += ret;
BUG_ON(desc.count < 0);
*ppos += ret;
index += (offset >> PAGE_CACHE_SHIFT);
offset = *ppos & ~PAGE_CACHE_MASK;
prev_offset = offset;
#if 0
printk(KERN_ERR "%s: isize=%lld size=%ld len=%ld offset=%ld written=%ld pos=%lld.\n",
__FUNCTION__, isize, size, len, offset, desc.written, *ppos);
#endif
if (!desc.count)
break; // goto out;
}
out:
// *ppos = ((loff_t)index << PAGE_CACHE_SHIFT) + offset;
zfs_file_accessed(vp);
tsd_exit();
SEXIT;
return ((ssize_t) (desc.written));
}
/* XXX --> Internal function used by lzfs_vnop_write and lzfs_writepage
*
* Performs the write operation
*
* Explanation of parameters
* file_flags = struct file *file->f_flags
* buf = buffer pointer to data
* len = length of the data
* pos = offest within file to wite
* segment = indicates whether buf pointer points to
* user space buffer or kernel buffer.
* */
static inline ssize_t lzfs_write(vnode_t *vp, unsigned int file_flags,
const char *buf, ssize_t len, loff_t pos, uio_seg_t segment)
{
int err;
struct iovec iov = {
.iov_base = (void *) buf,
.iov_len = len,
};
uio_t uio = {
.uio_iov = &iov,
.uio_resid = len,
.uio_iovcnt = 1,
.uio_loffset = (offset_t)(pos),
.uio_limit = MAXOFFSET_T,
.uio_segflg = segment,
};
const cred_t *cred = get_current_cred();
err = zfs_write(vp, &uio, file_flags, (cred_t *)cred, NULL);
put_cred(cred);
if (unlikely(err))
return -err;
return (len - uio.uio_resid);
}
ssize_t
lzfs_vnop_write (struct file *filep, const char __user *buf, size_t len,
loff_t *ppos)
{
vnode_t *vp = NULL;
ssize_t rc;
/* PAGE CACHE SUPPORT VARIABLES */
struct address_space *mapping = filep->f_mapping;
struct inode *inode = mapping->host;
pgoff_t index;
unsigned long written;
unsigned long offset;
const char *user_buf = buf;
loff_t pos_append;
SENTRY;
vp = LZFS_ITOV(inode);
rc = lzfs_write(vp, filep->f_flags, buf, len, *ppos, UIO_USERSPACE);
if (unlikely(rc < 0)) {
tsd_exit();
SEXIT;
return rc;
}
pos_append = *ppos;
*ppos += rc;
if (likely(!(vp->v_flag & VMMAPPED))) {
/* file is not memory mmapped, pass write directly to ZFS */
tsd_exit();
SEXIT;
return rc;
}
index = pos_append >> PAGE_CACHE_SHIFT;
offset = pos_append & ~PAGE_CACHE_MASK;
written = 0;
while (1) {
struct page *page = NULL;
char *page_buf;
ssize_t size;
ssize_t tmp;
if (written >= len)
break;
size = PAGE_CACHE_SIZE - offset;
if (written + size > len) {
size = len - written;
}
page = find_lock_page(mapping, index);
if (likely(!page)) {
#if 0
printk ("%s: Page not cached. ppos=%llu, pos_append=%llu, offset=%ld, "
"len=%ld, size=%ld\n", __FUNCTION__, *ppos, pos_append, offset,
len, size);
#endif
goto no_cached_page;
}
#if 0
printk ("%s: Page cached. ppos=%llu, pos_append=%llu, offset=%ld, len=%ld, "
"size=%ld\n", __FUNCTION__, *ppos, pos_append, offset, len, size);
#endif
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
pagefault_disable();
/* copy the data */
BUG_ON(!in_atomic());
page_buf = kmap_atomic(page, KM_USER0);
tmp = __copy_from_user_inatomic(page_buf + offset, user_buf, size);
kunmap_atomic(page_buf, KM_USER0);
pagefault_enable();
flush_dcache_page(page);
if (tmp) {