freebsd-dev/module/zfs/zpl_file.c
Michael Kjorling d1d7e2689d cstyle: Resolve C style issues
The vast majority of these changes are in Linux specific code.
They are the result of not having an automated style checker to
validate the code when it was originally written.  Others were
caused when the common code was slightly adjusted for Linux.

This patch contains no functional changes.  It only refreshes
the code to conform to style guide.

Everyone submitting patches for inclusion upstream should now
run 'make checkstyle' and resolve any warning prior to opening
a pull request.  The automated builders have been updated to
fail a build if when 'make checkstyle' detects an issue.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1821
2013-12-18 16:46:35 -08:00

582 lines
15 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2011, Lawrence Livermore National Security, LLC.
*/
#include <sys/dmu_objset.h>
#include <sys/zfs_vfsops.h>
#include <sys/zfs_vnops.h>
#include <sys/zfs_znode.h>
#include <sys/zpl.h>
static int
zpl_open(struct inode *ip, struct file *filp)
{
cred_t *cr = CRED();
int error;
error = generic_file_open(ip, filp);
if (error)
return (error);
crhold(cr);
error = -zfs_open(ip, filp->f_mode, filp->f_flags, cr);
crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
static int
zpl_release(struct inode *ip, struct file *filp)
{
cred_t *cr = CRED();
int error;
if (ITOZ(ip)->z_atime_dirty)
mark_inode_dirty(ip);
crhold(cr);
error = -zfs_close(ip, filp->f_flags, cr);
crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
static int
zpl_iterate(struct file *filp, struct dir_context *ctx)
{
struct dentry *dentry = filp->f_path.dentry;
cred_t *cr = CRED();
int error;
crhold(cr);
error = -zfs_readdir(dentry->d_inode, ctx, cr);
crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
#if !defined(HAVE_VFS_ITERATE)
static int
zpl_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
struct dir_context ctx = DIR_CONTEXT_INIT(dirent, filldir, filp->f_pos);
int error;
error = zpl_iterate(filp, &ctx);
filp->f_pos = ctx.pos;
return (error);
}
#endif /* HAVE_VFS_ITERATE */
#if defined(HAVE_FSYNC_WITH_DENTRY)
/*
* Linux 2.6.x - 2.6.34 API,
* Through 2.6.34 the nfsd kernel server would pass a NULL 'file struct *'
* to the fops->fsync() hook. For this reason, we must be careful not to
* use filp unconditionally.
*/
static int
zpl_fsync(struct file *filp, struct dentry *dentry, int datasync)
{
cred_t *cr = CRED();
int error;
crhold(cr);
error = -zfs_fsync(dentry->d_inode, datasync, cr);
crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
#elif defined(HAVE_FSYNC_WITHOUT_DENTRY)
/*
* Linux 2.6.35 - 3.0 API,
* As of 2.6.35 the dentry argument to the fops->fsync() hook was deemed
* redundant. The dentry is still accessible via filp->f_path.dentry,
* and we are guaranteed that filp will never be NULL.
*/
static int
zpl_fsync(struct file *filp, int datasync)
{
struct inode *inode = filp->f_mapping->host;
cred_t *cr = CRED();
int error;
crhold(cr);
error = -zfs_fsync(inode, datasync, cr);
crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
#elif defined(HAVE_FSYNC_RANGE)
/*
* Linux 3.1 - 3.x API,
* As of 3.1 the responsibility to call filemap_write_and_wait_range() has
* been pushed down in to the .fsync() vfs hook. Additionally, the i_mutex
* lock is no longer held by the caller, for zfs we don't require the lock
* to be held so we don't acquire it.
*/
static int
zpl_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
{
struct inode *inode = filp->f_mapping->host;
cred_t *cr = CRED();
int error;
error = filemap_write_and_wait_range(inode->i_mapping, start, end);
if (error)
return (error);
crhold(cr);
error = -zfs_fsync(inode, datasync, cr);
crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
#else
#error "Unsupported fops->fsync() implementation"
#endif
ssize_t
zpl_read_common(struct inode *ip, const char *buf, size_t len, loff_t pos,
uio_seg_t segment, int flags, cred_t *cr)
{
int error;
ssize_t read;
struct iovec iov;
uio_t uio;
iov.iov_base = (void *)buf;
iov.iov_len = len;
uio.uio_iov = &iov;
uio.uio_resid = len;
uio.uio_iovcnt = 1;
uio.uio_loffset = pos;
uio.uio_limit = MAXOFFSET_T;
uio.uio_segflg = segment;
error = -zfs_read(ip, &uio, flags, cr);
if (error < 0)
return (error);
read = len - uio.uio_resid;
task_io_account_read(read);
return (read);
}
static ssize_t
zpl_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
cred_t *cr = CRED();
ssize_t read;
crhold(cr);
read = zpl_read_common(filp->f_mapping->host, buf, len, *ppos,
UIO_USERSPACE, filp->f_flags, cr);
crfree(cr);
if (read < 0)
return (read);
*ppos += read;
return (read);
}
ssize_t
zpl_write_common(struct inode *ip, const char *buf, size_t len, loff_t pos,
uio_seg_t segment, int flags, cred_t *cr)
{
int error;
ssize_t wrote;
struct iovec iov;
uio_t uio;
iov.iov_base = (void *)buf;
iov.iov_len = len;
uio.uio_iov = &iov;
uio.uio_resid = len,
uio.uio_iovcnt = 1;
uio.uio_loffset = pos;
uio.uio_limit = MAXOFFSET_T;
uio.uio_segflg = segment;
error = -zfs_write(ip, &uio, flags, cr);
if (error < 0)
return (error);
wrote = len - uio.uio_resid;
task_io_account_write(wrote);
return (wrote);
}
static ssize_t
zpl_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
{
cred_t *cr = CRED();
ssize_t wrote;
crhold(cr);
wrote = zpl_write_common(filp->f_mapping->host, buf, len, *ppos,
UIO_USERSPACE, filp->f_flags, cr);
crfree(cr);
if (wrote < 0)
return (wrote);
*ppos += wrote;
return (wrote);
}
static loff_t
zpl_llseek(struct file *filp, loff_t offset, int whence)
{
#if defined(SEEK_HOLE) && defined(SEEK_DATA)
if (whence == SEEK_DATA || whence == SEEK_HOLE) {
struct inode *ip = filp->f_mapping->host;
loff_t maxbytes = ip->i_sb->s_maxbytes;
loff_t error;
spl_inode_lock(ip);
error = -zfs_holey(ip, whence, &offset);
if (error == 0)
error = lseek_execute(filp, ip, offset, maxbytes);
spl_inode_unlock(ip);
return (error);
}
#endif /* SEEK_HOLE && SEEK_DATA */
return (generic_file_llseek(filp, offset, whence));
}
/*
* It's worth taking a moment to describe how mmap is implemented
* for zfs because it differs considerably from other Linux filesystems.
* However, this issue is handled the same way under OpenSolaris.
*
* The issue is that by design zfs bypasses the Linux page cache and
* leaves all caching up to the ARC. This has been shown to work
* well for the common read(2)/write(2) case. However, mmap(2)
* is problem because it relies on being tightly integrated with the
* page cache. To handle this we cache mmap'ed files twice, once in
* the ARC and a second time in the page cache. The code is careful
* to keep both copies synchronized.
*
* When a file with an mmap'ed region is written to using write(2)
* both the data in the ARC and existing pages in the page cache
* are updated. For a read(2) data will be read first from the page
* cache then the ARC if needed. Neither a write(2) or read(2) will
* will ever result in new pages being added to the page cache.
*
* New pages are added to the page cache only via .readpage() which
* is called when the vfs needs to read a page off disk to back the
* virtual memory region. These pages may be modified without
* notifying the ARC and will be written out periodically via
* .writepage(). This will occur due to either a sync or the usual
* page aging behavior. Note because a read(2) of a mmap'ed file
* will always check the page cache first even when the ARC is out
* of date correct data will still be returned.
*
* While this implementation ensures correct behavior it does have
* have some drawbacks. The most obvious of which is that it
* increases the required memory footprint when access mmap'ed
* files. It also adds additional complexity to the code keeping
* both caches synchronized.
*
* Longer term it may be possible to cleanly resolve this wart by
* mapping page cache pages directly on to the ARC buffers. The
* Linux address space operations are flexible enough to allow
* selection of which pages back a particular index. The trick
* would be working out the details of which subsystem is in
* charge, the ARC, the page cache, or both. It may also prove
* helpful to move the ARC buffers to a scatter-gather lists
* rather than a vmalloc'ed region.
*/
static int
zpl_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct inode *ip = filp->f_mapping->host;
znode_t *zp = ITOZ(ip);
int error;
error = -zfs_map(ip, vma->vm_pgoff, (caddr_t *)vma->vm_start,
(size_t)(vma->vm_end - vma->vm_start), vma->vm_flags);
if (error)
return (error);
error = generic_file_mmap(filp, vma);
if (error)
return (error);
mutex_enter(&zp->z_lock);
zp->z_is_mapped = 1;
mutex_exit(&zp->z_lock);
return (error);
}
/*
* Populate a page with data for the Linux page cache. This function is
* only used to support mmap(2). There will be an identical copy of the
* data in the ARC which is kept up to date via .write() and .writepage().
*
* Current this function relies on zpl_read_common() and the O_DIRECT
* flag to read in a page. This works but the more correct way is to
* update zfs_fillpage() to be Linux friendly and use that interface.
*/
static int
zpl_readpage(struct file *filp, struct page *pp)
{
struct inode *ip;
struct page *pl[1];
int error = 0;
ASSERT(PageLocked(pp));
ip = pp->mapping->host;
pl[0] = pp;
error = -zfs_getpage(ip, pl, 1);
if (error) {
SetPageError(pp);
ClearPageUptodate(pp);
} else {
ClearPageError(pp);
SetPageUptodate(pp);
flush_dcache_page(pp);
}
unlock_page(pp);
return (error);
}
/*
* Populate a set of pages with data for the Linux page cache. This
* function will only be called for read ahead and never for demand
* paging. For simplicity, the code relies on read_cache_pages() to
* correctly lock each page for IO and call zpl_readpage().
*/
static int
zpl_readpages(struct file *filp, struct address_space *mapping,
struct list_head *pages, unsigned nr_pages)
{
return (read_cache_pages(mapping, pages,
(filler_t *)zpl_readpage, filp));
}
int
zpl_putpage(struct page *pp, struct writeback_control *wbc, void *data)
{
struct address_space *mapping = data;
ASSERT(PageLocked(pp));
ASSERT(!PageWriteback(pp));
ASSERT(!(current->flags & PF_NOFS));
/*
* Annotate this call path with a flag that indicates that it is
* unsafe to use KM_SLEEP during memory allocations due to the
* potential for a deadlock. KM_PUSHPAGE should be used instead.
*/
current->flags |= PF_NOFS;
(void) zfs_putpage(mapping->host, pp, wbc);
current->flags &= ~PF_NOFS;
return (0);
}
static int
zpl_writepages(struct address_space *mapping, struct writeback_control *wbc)
{
znode_t *zp = ITOZ(mapping->host);
zfs_sb_t *zsb = ITOZSB(mapping->host);
enum writeback_sync_modes sync_mode;
int result;
ZFS_ENTER(zsb);
if (zsb->z_os->os_sync == ZFS_SYNC_ALWAYS)
wbc->sync_mode = WB_SYNC_ALL;
ZFS_EXIT(zsb);
sync_mode = wbc->sync_mode;
/*
* We don't want to run write_cache_pages() in SYNC mode here, because
* that would make putpage() wait for a single page to be committed to
* disk every single time, resulting in atrocious performance. Instead
* we run it once in non-SYNC mode so that the ZIL gets all the data,
* and then we commit it all in one go.
*/
wbc->sync_mode = WB_SYNC_NONE;
result = write_cache_pages(mapping, wbc, zpl_putpage, mapping);
if (sync_mode != wbc->sync_mode) {
ZFS_ENTER(zsb);
ZFS_VERIFY_ZP(zp);
zil_commit(zsb->z_log, zp->z_id);
ZFS_EXIT(zsb);
/*
* We need to call write_cache_pages() again (we can't just
* return after the commit) because the previous call in
* non-SYNC mode does not guarantee that we got all the dirty
* pages (see the implementation of write_cache_pages() for
* details). That being said, this is a no-op in most cases.
*/
wbc->sync_mode = sync_mode;
result = write_cache_pages(mapping, wbc, zpl_putpage, mapping);
}
return (result);
}
/*
* Write out dirty pages to the ARC, this function is only required to
* support mmap(2). Mapped pages may be dirtied by memory operations
* which never call .write(). These dirty pages are kept in sync with
* the ARC buffers via this hook.
*/
static int
zpl_writepage(struct page *pp, struct writeback_control *wbc)
{
if (ITOZSB(pp->mapping->host)->z_os->os_sync == ZFS_SYNC_ALWAYS)
wbc->sync_mode = WB_SYNC_ALL;
return (zpl_putpage(pp, wbc, pp->mapping));
}
/*
* The only flag combination which matches the behavior of zfs_space()
* is FALLOC_FL_PUNCH_HOLE. This flag was introduced in the 2.6.38 kernel.
*/
long
zpl_fallocate_common(struct inode *ip, int mode, loff_t offset, loff_t len)
{
cred_t *cr = CRED();
int error = -EOPNOTSUPP;
if (mode & FALLOC_FL_KEEP_SIZE)
return (-EOPNOTSUPP);
crhold(cr);
#ifdef FALLOC_FL_PUNCH_HOLE
if (mode & FALLOC_FL_PUNCH_HOLE) {
flock64_t bf;
bf.l_type = F_WRLCK;
bf.l_whence = 0;
bf.l_start = offset;
bf.l_len = len;
bf.l_pid = 0;
error = -zfs_space(ip, F_FREESP, &bf, FWRITE, offset, cr);
}
#endif /* FALLOC_FL_PUNCH_HOLE */
crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
#ifdef HAVE_FILE_FALLOCATE
static long
zpl_fallocate(struct file *filp, int mode, loff_t offset, loff_t len)
{
return zpl_fallocate_common(filp->f_path.dentry->d_inode,
mode, offset, len);
}
#endif /* HAVE_FILE_FALLOCATE */
static long
zpl_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case ZFS_IOC_GETFLAGS:
case ZFS_IOC_SETFLAGS:
return (-EOPNOTSUPP);
default:
return (-ENOTTY);
}
}
#ifdef CONFIG_COMPAT
static long
zpl_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
return (zpl_ioctl(filp, cmd, arg));
}
#endif /* CONFIG_COMPAT */
const struct address_space_operations zpl_address_space_operations = {
.readpages = zpl_readpages,
.readpage = zpl_readpage,
.writepage = zpl_writepage,
.writepages = zpl_writepages,
};
const struct file_operations zpl_file_operations = {
.open = zpl_open,
.release = zpl_release,
.llseek = zpl_llseek,
.read = zpl_read,
.write = zpl_write,
.mmap = zpl_mmap,
.fsync = zpl_fsync,
#ifdef HAVE_FILE_FALLOCATE
.fallocate = zpl_fallocate,
#endif /* HAVE_FILE_FALLOCATE */
.unlocked_ioctl = zpl_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = zpl_compat_ioctl,
#endif
};
const struct file_operations zpl_dir_file_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
#ifdef HAVE_VFS_ITERATE
.iterate = zpl_iterate,
#else
.readdir = zpl_readdir,
#endif
.fsync = zpl_fsync,
.unlocked_ioctl = zpl_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = zpl_compat_ioctl,
#endif
};