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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/fs/xfs/xfs_file.c

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36 KiB
C
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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_inode_item.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_ioctl.h"
#include "xfs_trace.h"
#include "xfs_log.h"
#include "xfs_icache.h"
#include "xfs_pnfs.h"
#include "xfs_iomap.h"
#include "xfs_reflink.h"
#include <linux/falloc.h>
#include <linux/backing-dev.h>
#include <linux/mman.h>
#include <linux/fadvise.h>
#include <linux/mount.h>
static const struct vm_operations_struct xfs_file_vm_ops;
/*
* Decide if the given file range is aligned to the size of the fundamental
* allocation unit for the file.
*/
static bool
xfs_is_falloc_aligned(
struct xfs_inode *ip,
loff_t pos,
long long int len)
{
struct xfs_mount *mp = ip->i_mount;
uint64_t mask;
if (XFS_IS_REALTIME_INODE(ip)) {
if (!is_power_of_2(mp->m_sb.sb_rextsize)) {
u64 rextbytes;
u32 mod;
rextbytes = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize);
div_u64_rem(pos, rextbytes, &mod);
if (mod)
return false;
div_u64_rem(len, rextbytes, &mod);
return mod == 0;
}
mask = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize) - 1;
} else {
mask = mp->m_sb.sb_blocksize - 1;
}
return !((pos | len) & mask);
}
int
xfs_update_prealloc_flags(
struct xfs_inode *ip,
enum xfs_prealloc_flags flags)
{
struct xfs_trans *tp;
int error;
error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_writeid,
0, 0, 0, &tp);
if (error)
return error;
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
if (!(flags & XFS_PREALLOC_INVISIBLE)) {
VFS_I(ip)->i_mode &= ~S_ISUID;
if (VFS_I(ip)->i_mode & S_IXGRP)
VFS_I(ip)->i_mode &= ~S_ISGID;
xfs_trans_ichgtime(tp, ip, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
}
if (flags & XFS_PREALLOC_SET)
ip->i_diflags |= XFS_DIFLAG_PREALLOC;
if (flags & XFS_PREALLOC_CLEAR)
ip->i_diflags &= ~XFS_DIFLAG_PREALLOC;
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
if (flags & XFS_PREALLOC_SYNC)
xfs_trans_set_sync(tp);
return xfs_trans_commit(tp);
}
/*
* Fsync operations on directories are much simpler than on regular files,
* as there is no file data to flush, and thus also no need for explicit
* cache flush operations, and there are no non-transaction metadata updates
* on directories either.
*/
STATIC int
xfs_dir_fsync(
struct file *file,
loff_t start,
loff_t end,
int datasync)
{
struct xfs_inode *ip = XFS_I(file->f_mapping->host);
trace_xfs_dir_fsync(ip);
return xfs_log_force_inode(ip);
}
static xfs_lsn_t
xfs_fsync_lsn(
struct xfs_inode *ip,
bool datasync)
{
if (!xfs_ipincount(ip))
return 0;
if (datasync && !(ip->i_itemp->ili_fsync_fields & ~XFS_ILOG_TIMESTAMP))
return 0;
return ip->i_itemp->ili_last_lsn;
}
/*
* All metadata updates are logged, which means that we just have to flush the
* log up to the latest LSN that touched the inode.
*
* If we have concurrent fsync/fdatasync() calls, we need them to all block on
* the log force before we clear the ili_fsync_fields field. This ensures that
* we don't get a racing sync operation that does not wait for the metadata to
* hit the journal before returning. If we race with clearing ili_fsync_fields,
* then all that will happen is the log force will do nothing as the lsn will
* already be on disk. We can't race with setting ili_fsync_fields because that
* is done under XFS_ILOCK_EXCL, and that can't happen because we hold the lock
* shared until after the ili_fsync_fields is cleared.
*/
static int
xfs_fsync_flush_log(
struct xfs_inode *ip,
bool datasync,
int *log_flushed)
{
int error = 0;
xfs_lsn_t lsn;
xfs_ilock(ip, XFS_ILOCK_SHARED);
lsn = xfs_fsync_lsn(ip, datasync);
if (lsn) {
error = xfs_log_force_lsn(ip->i_mount, lsn, XFS_LOG_SYNC,
log_flushed);
spin_lock(&ip->i_itemp->ili_lock);
ip->i_itemp->ili_fsync_fields = 0;
spin_unlock(&ip->i_itemp->ili_lock);
}
xfs_iunlock(ip, XFS_ILOCK_SHARED);
return error;
}
STATIC int
xfs_file_fsync(
struct file *file,
loff_t start,
loff_t end,
int datasync)
{
struct xfs_inode *ip = XFS_I(file->f_mapping->host);
struct xfs_mount *mp = ip->i_mount;
int error = 0;
int log_flushed = 0;
trace_xfs_file_fsync(ip);
error = file_write_and_wait_range(file, start, end);
if (error)
return error;
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
xfs_iflags_clear(ip, XFS_ITRUNCATED);
/*
* If we have an RT and/or log subvolume we need to make sure to flush
* the write cache the device used for file data first. This is to
* ensure newly written file data make it to disk before logging the new
* inode size in case of an extending write.
*/
if (XFS_IS_REALTIME_INODE(ip))
xfs_blkdev_issue_flush(mp->m_rtdev_targp);
else if (mp->m_logdev_targp != mp->m_ddev_targp)
xfs_blkdev_issue_flush(mp->m_ddev_targp);
/*
* Any inode that has dirty modifications in the log is pinned. The
* racy check here for a pinned inode while not catch modifications
* that happen concurrently to the fsync call, but fsync semantics
* only require to sync previously completed I/O.
*/
if (xfs_ipincount(ip))
error = xfs_fsync_flush_log(ip, datasync, &log_flushed);
/*
* If we only have a single device, and the log force about was
* a no-op we might have to flush the data device cache here.
* This can only happen for fdatasync/O_DSYNC if we were overwriting
* an already allocated file and thus do not have any metadata to
* commit.
*/
if (!log_flushed && !XFS_IS_REALTIME_INODE(ip) &&
mp->m_logdev_targp == mp->m_ddev_targp)
xfs_blkdev_issue_flush(mp->m_ddev_targp);
return error;
}
static int
xfs_ilock_iocb(
struct kiocb *iocb,
unsigned int lock_mode)
{
struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
if (iocb->ki_flags & IOCB_NOWAIT) {
if (!xfs_ilock_nowait(ip, lock_mode))
return -EAGAIN;
} else {
xfs_ilock(ip, lock_mode);
}
return 0;
}
STATIC ssize_t
xfs_file_dio_read(
struct kiocb *iocb,
struct iov_iter *to)
{
struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
ssize_t ret;
trace_xfs_file_direct_read(iocb, to);
if (!iov_iter_count(to))
return 0; /* skip atime */
file_accessed(iocb->ki_filp);
ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
if (ret)
return ret;
ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL, 0);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
return ret;
}
static noinline ssize_t
xfs_file_dax_read(
struct kiocb *iocb,
struct iov_iter *to)
{
struct xfs_inode *ip = XFS_I(iocb->ki_filp->f_mapping->host);
ssize_t ret = 0;
trace_xfs_file_dax_read(iocb, to);
if (!iov_iter_count(to))
return 0; /* skip atime */
ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
if (ret)
return ret;
ret = dax_iomap_rw(iocb, to, &xfs_read_iomap_ops);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
file_accessed(iocb->ki_filp);
return ret;
}
STATIC ssize_t
xfs_file_buffered_read(
struct kiocb *iocb,
struct iov_iter *to)
{
struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
ssize_t ret;
trace_xfs_file_buffered_read(iocb, to);
ret = xfs_ilock_iocb(iocb, XFS_IOLOCK_SHARED);
if (ret)
return ret;
ret = generic_file_read_iter(iocb, to);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
return ret;
}
STATIC ssize_t
xfs_file_read_iter(
struct kiocb *iocb,
struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct xfs_mount *mp = XFS_I(inode)->i_mount;
ssize_t ret = 0;
XFS_STATS_INC(mp, xs_read_calls);
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
if (IS_DAX(inode))
ret = xfs_file_dax_read(iocb, to);
else if (iocb->ki_flags & IOCB_DIRECT)
ret = xfs_file_dio_read(iocb, to);
else
ret = xfs_file_buffered_read(iocb, to);
if (ret > 0)
XFS_STATS_ADD(mp, xs_read_bytes, ret);
return ret;
}
/*
* Common pre-write limit and setup checks.
*
* Called with the iolocked held either shared and exclusive according to
* @iolock, and returns with it held. Might upgrade the iolock to exclusive
* if called for a direct write beyond i_size.
*/
STATIC ssize_t
xfs_file_write_checks(
struct kiocb *iocb,
struct iov_iter *from,
int *iolock)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct xfs_inode *ip = XFS_I(inode);
ssize_t error = 0;
size_t count = iov_iter_count(from);
bool drained_dio = false;
loff_t isize;
restart:
error = generic_write_checks(iocb, from);
if (error <= 0)
return error;
if (iocb->ki_flags & IOCB_NOWAIT) {
error = break_layout(inode, false);
if (error == -EWOULDBLOCK)
error = -EAGAIN;
} else {
error = xfs_break_layouts(inode, iolock, BREAK_WRITE);
}
if (error)
return error;
/*
* For changing security info in file_remove_privs() we need i_rwsem
* exclusively.
*/
if (*iolock == XFS_IOLOCK_SHARED && !IS_NOSEC(inode)) {
xfs_iunlock(ip, *iolock);
*iolock = XFS_IOLOCK_EXCL;
error = xfs_ilock_iocb(iocb, *iolock);
if (error) {
*iolock = 0;
return error;
}
goto restart;
}
/*
* If the offset is beyond the size of the file, we need to zero any
* blocks that fall between the existing EOF and the start of this
* write. If zeroing is needed and we are currently holding the
* iolock shared, we need to update it to exclusive which implies
* having to redo all checks before.
*
* We need to serialise against EOF updates that occur in IO
* completions here. We want to make sure that nobody is changing the
* size while we do this check until we have placed an IO barrier (i.e.
* hold the XFS_IOLOCK_EXCL) that prevents new IO from being dispatched.
* The spinlock effectively forms a memory barrier once we have the
* XFS_IOLOCK_EXCL so we are guaranteed to see the latest EOF value
* and hence be able to correctly determine if we need to run zeroing.
*/
spin_lock(&ip->i_flags_lock);
isize = i_size_read(inode);
if (iocb->ki_pos > isize) {
spin_unlock(&ip->i_flags_lock);
if (iocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
if (!drained_dio) {
if (*iolock == XFS_IOLOCK_SHARED) {
xfs_iunlock(ip, *iolock);
*iolock = XFS_IOLOCK_EXCL;
xfs_ilock(ip, *iolock);
iov_iter_reexpand(from, count);
}
/*
* We now have an IO submission barrier in place, but
* AIO can do EOF updates during IO completion and hence
* we now need to wait for all of them to drain. Non-AIO
* DIO will have drained before we are given the
* XFS_IOLOCK_EXCL, and so for most cases this wait is a
* no-op.
*/
inode_dio_wait(inode);
drained_dio = true;
goto restart;
}
trace_xfs_zero_eof(ip, isize, iocb->ki_pos - isize);
error = iomap_zero_range(inode, isize, iocb->ki_pos - isize,
NULL, &xfs_buffered_write_iomap_ops);
if (error)
return error;
} else
spin_unlock(&ip->i_flags_lock);
return file_modified(file);
}
static int
xfs_dio_write_end_io(
struct kiocb *iocb,
ssize_t size,
int error,
unsigned flags)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct xfs_inode *ip = XFS_I(inode);
loff_t offset = iocb->ki_pos;
unsigned int nofs_flag;
trace_xfs_end_io_direct_write(ip, offset, size);
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
return -EIO;
if (error)
return error;
if (!size)
return 0;
/*
* Capture amount written on completion as we can't reliably account
* for it on submission.
*/
XFS_STATS_ADD(ip->i_mount, xs_write_bytes, size);
/*
* We can allocate memory here while doing writeback on behalf of
* memory reclaim. To avoid memory allocation deadlocks set the
* task-wide nofs context for the following operations.
*/
nofs_flag = memalloc_nofs_save();
if (flags & IOMAP_DIO_COW) {
error = xfs_reflink_end_cow(ip, offset, size);
if (error)
goto out;
}
/*
* Unwritten conversion updates the in-core isize after extent
* conversion but before updating the on-disk size. Updating isize any
* earlier allows a racing dio read to find unwritten extents before
* they are converted.
*/
if (flags & IOMAP_DIO_UNWRITTEN) {
error = xfs_iomap_write_unwritten(ip, offset, size, true);
goto out;
}
/*
* We need to update the in-core inode size here so that we don't end up
* with the on-disk inode size being outside the in-core inode size. We
* have no other method of updating EOF for AIO, so always do it here
* if necessary.
*
* We need to lock the test/set EOF update as we can be racing with
* other IO completions here to update the EOF. Failing to serialise
* here can result in EOF moving backwards and Bad Things Happen when
* that occurs.
*/
spin_lock(&ip->i_flags_lock);
if (offset + size > i_size_read(inode)) {
i_size_write(inode, offset + size);
spin_unlock(&ip->i_flags_lock);
error = xfs_setfilesize(ip, offset, size);
} else {
spin_unlock(&ip->i_flags_lock);
}
out:
memalloc_nofs_restore(nofs_flag);
return error;
}
static const struct iomap_dio_ops xfs_dio_write_ops = {
.end_io = xfs_dio_write_end_io,
};
/*
* Handle block aligned direct I/O writes
*/
static noinline ssize_t
xfs_file_dio_write_aligned(
struct xfs_inode *ip,
struct kiocb *iocb,
struct iov_iter *from)
{
int iolock = XFS_IOLOCK_SHARED;
ssize_t ret;
ret = xfs_ilock_iocb(iocb, iolock);
if (ret)
return ret;
ret = xfs_file_write_checks(iocb, from, &iolock);
if (ret)
goto out_unlock;
/*
* We don't need to hold the IOLOCK exclusively across the IO, so demote
* the iolock back to shared if we had to take the exclusive lock in
* xfs_file_write_checks() for other reasons.
*/
if (iolock == XFS_IOLOCK_EXCL) {
xfs_ilock_demote(ip, XFS_IOLOCK_EXCL);
iolock = XFS_IOLOCK_SHARED;
}
trace_xfs_file_direct_write(iocb, from);
ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
&xfs_dio_write_ops, 0);
out_unlock:
if (iolock)
xfs_iunlock(ip, iolock);
return ret;
}
/*
* Handle block unaligned direct I/O writes
*
* In most cases direct I/O writes will be done holding IOLOCK_SHARED, allowing
* them to be done in parallel with reads and other direct I/O writes. However,
* if the I/O is not aligned to filesystem blocks, the direct I/O layer may need
* to do sub-block zeroing and that requires serialisation against other direct
* I/O to the same block. In this case we need to serialise the submission of
* the unaligned I/O so that we don't get racing block zeroing in the dio layer.
* In the case where sub-block zeroing is not required, we can do concurrent
* sub-block dios to the same block successfully.
*
* Optimistically submit the I/O using the shared lock first, but use the
* IOMAP_DIO_OVERWRITE_ONLY flag to tell the lower layers to return -EAGAIN
* if block allocation or partial block zeroing would be required. In that case
* we try again with the exclusive lock.
*/
static noinline ssize_t
xfs_file_dio_write_unaligned(
struct xfs_inode *ip,
struct kiocb *iocb,
struct iov_iter *from)
{
size_t isize = i_size_read(VFS_I(ip));
size_t count = iov_iter_count(from);
int iolock = XFS_IOLOCK_SHARED;
unsigned int flags = IOMAP_DIO_OVERWRITE_ONLY;
ssize_t ret;
/*
* Extending writes need exclusivity because of the sub-block zeroing
* that the DIO code always does for partial tail blocks beyond EOF, so
* don't even bother trying the fast path in this case.
*/
if (iocb->ki_pos > isize || iocb->ki_pos + count >= isize) {
retry_exclusive:
if (iocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
iolock = XFS_IOLOCK_EXCL;
flags = IOMAP_DIO_FORCE_WAIT;
}
ret = xfs_ilock_iocb(iocb, iolock);
if (ret)
return ret;
/*
* We can't properly handle unaligned direct I/O to reflink files yet,
* as we can't unshare a partial block.
*/
if (xfs_is_cow_inode(ip)) {
trace_xfs_reflink_bounce_dio_write(iocb, from);
ret = -ENOTBLK;
goto out_unlock;
}
ret = xfs_file_write_checks(iocb, from, &iolock);
if (ret)
goto out_unlock;
/*
* If we are doing exclusive unaligned I/O, this must be the only I/O
* in-flight. Otherwise we risk data corruption due to unwritten extent
* conversions from the AIO end_io handler. Wait for all other I/O to
* drain first.
*/
if (flags & IOMAP_DIO_FORCE_WAIT)
inode_dio_wait(VFS_I(ip));
trace_xfs_file_direct_write(iocb, from);
ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
&xfs_dio_write_ops, flags);
/*
* Retry unaligned I/O with exclusive blocking semantics if the DIO
* layer rejected it for mapping or locking reasons. If we are doing
* nonblocking user I/O, propagate the error.
*/
if (ret == -EAGAIN && !(iocb->ki_flags & IOCB_NOWAIT)) {
ASSERT(flags & IOMAP_DIO_OVERWRITE_ONLY);
xfs_iunlock(ip, iolock);
goto retry_exclusive;
}
out_unlock:
if (iolock)
xfs_iunlock(ip, iolock);
return ret;
}
static ssize_t
xfs_file_dio_write(
struct kiocb *iocb,
struct iov_iter *from)
{
struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
struct xfs_buftarg *target = xfs_inode_buftarg(ip);
size_t count = iov_iter_count(from);
/* direct I/O must be aligned to device logical sector size */
if ((iocb->ki_pos | count) & target->bt_logical_sectormask)
return -EINVAL;
if ((iocb->ki_pos | count) & ip->i_mount->m_blockmask)
return xfs_file_dio_write_unaligned(ip, iocb, from);
return xfs_file_dio_write_aligned(ip, iocb, from);
}
static noinline ssize_t
xfs_file_dax_write(
struct kiocb *iocb,
struct iov_iter *from)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
struct xfs_inode *ip = XFS_I(inode);
int iolock = XFS_IOLOCK_EXCL;
ssize_t ret, error = 0;
loff_t pos;
ret = xfs_ilock_iocb(iocb, iolock);
if (ret)
return ret;
ret = xfs_file_write_checks(iocb, from, &iolock);
if (ret)
goto out;
pos = iocb->ki_pos;
trace_xfs_file_dax_write(iocb, from);
ret = dax_iomap_rw(iocb, from, &xfs_direct_write_iomap_ops);
if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
i_size_write(inode, iocb->ki_pos);
error = xfs_setfilesize(ip, pos, ret);
}
out:
if (iolock)
xfs_iunlock(ip, iolock);
if (error)
return error;
if (ret > 0) {
XFS_STATS_ADD(ip->i_mount, xs_write_bytes, ret);
/* Handle various SYNC-type writes */
ret = generic_write_sync(iocb, ret);
}
return ret;
}
STATIC ssize_t
xfs_file_buffered_write(
struct kiocb *iocb,
struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
struct xfs_inode *ip = XFS_I(inode);
ssize_t ret;
bool cleared_space = false;
int iolock;
if (iocb->ki_flags & IOCB_NOWAIT)
return -EOPNOTSUPP;
write_retry:
iolock = XFS_IOLOCK_EXCL;
xfs_ilock(ip, iolock);
ret = xfs_file_write_checks(iocb, from, &iolock);
if (ret)
goto out;
/* We can write back this queue in page reclaim */
current->backing_dev_info = inode_to_bdi(inode);
trace_xfs_file_buffered_write(iocb, from);
ret = iomap_file_buffered_write(iocb, from,
&xfs_buffered_write_iomap_ops);
if (likely(ret >= 0))
iocb->ki_pos += ret;
/*
* If we hit a space limit, try to free up some lingering preallocated
* space before returning an error. In the case of ENOSPC, first try to
* write back all dirty inodes to free up some of the excess reserved
* metadata space. This reduces the chances that the eofblocks scan
* waits on dirty mappings. Since xfs_flush_inodes() is serialized, this
* also behaves as a filter to prevent too many eofblocks scans from
* running at the same time. Use a synchronous scan to increase the
* effectiveness of the scan.
*/
if (ret == -EDQUOT && !cleared_space) {
xfs_iunlock(ip, iolock);
xfs_blockgc_free_quota(ip, XFS_EOF_FLAGS_SYNC);
cleared_space = true;
goto write_retry;
} else if (ret == -ENOSPC && !cleared_space) {
struct xfs_eofblocks eofb = {0};
cleared_space = true;
xfs_flush_inodes(ip->i_mount);
xfs_iunlock(ip, iolock);
eofb.eof_flags = XFS_EOF_FLAGS_SYNC;
xfs_blockgc_free_space(ip->i_mount, &eofb);
goto write_retry;
}
current->backing_dev_info = NULL;
out:
if (iolock)
xfs_iunlock(ip, iolock);
if (ret > 0) {
XFS_STATS_ADD(ip->i_mount, xs_write_bytes, ret);
/* Handle various SYNC-type writes */
ret = generic_write_sync(iocb, ret);
}
return ret;
}
STATIC ssize_t
xfs_file_write_iter(
struct kiocb *iocb,
struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
struct xfs_inode *ip = XFS_I(inode);
ssize_t ret;
size_t ocount = iov_iter_count(from);
XFS_STATS_INC(ip->i_mount, xs_write_calls);
if (ocount == 0)
return 0;
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
return -EIO;
if (IS_DAX(inode))
return xfs_file_dax_write(iocb, from);
if (iocb->ki_flags & IOCB_DIRECT) {
/*
* Allow a directio write to fall back to a buffered
* write *only* in the case that we're doing a reflink
* CoW. In all other directio scenarios we do not
* allow an operation to fall back to buffered mode.
*/
ret = xfs_file_dio_write(iocb, from);
if (ret != -ENOTBLK)
return ret;
}
return xfs_file_buffered_write(iocb, from);
}
static void
xfs_wait_dax_page(
struct inode *inode)
{
struct xfs_inode *ip = XFS_I(inode);
xfs_iunlock(ip, XFS_MMAPLOCK_EXCL);
schedule();
xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
}
static int
xfs_break_dax_layouts(
struct inode *inode,
bool *retry)
{
struct page *page;
ASSERT(xfs_isilocked(XFS_I(inode), XFS_MMAPLOCK_EXCL));
page = dax_layout_busy_page(inode->i_mapping);
if (!page)
return 0;
*retry = true;
return ___wait_var_event(&page->_refcount,
atomic_read(&page->_refcount) == 1, TASK_INTERRUPTIBLE,
0, 0, xfs_wait_dax_page(inode));
}
int
xfs_break_layouts(
struct inode *inode,
uint *iolock,
enum layout_break_reason reason)
{
bool retry;
int error;
ASSERT(xfs_isilocked(XFS_I(inode), XFS_IOLOCK_SHARED|XFS_IOLOCK_EXCL));
do {
retry = false;
switch (reason) {
case BREAK_UNMAP:
error = xfs_break_dax_layouts(inode, &retry);
if (error || retry)
break;
/* fall through */
case BREAK_WRITE:
error = xfs_break_leased_layouts(inode, iolock, &retry);
break;
default:
WARN_ON_ONCE(1);
error = -EINVAL;
}
} while (error == 0 && retry);
return error;
}
#define XFS_FALLOC_FL_SUPPORTED \
(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | \
FALLOC_FL_INSERT_RANGE | FALLOC_FL_UNSHARE_RANGE)
STATIC long
xfs_file_fallocate(
struct file *file,
int mode,
loff_t offset,
loff_t len)
{
struct inode *inode = file_inode(file);
struct xfs_inode *ip = XFS_I(inode);
long error;
enum xfs_prealloc_flags flags = 0;
uint iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
loff_t new_size = 0;
bool do_file_insert = false;
if (!S_ISREG(inode->i_mode))
return -EINVAL;
if (mode & ~XFS_FALLOC_FL_SUPPORTED)
return -EOPNOTSUPP;
xfs_ilock(ip, iolock);
error = xfs_break_layouts(inode, &iolock, BREAK_UNMAP);
if (error)
goto out_unlock;
/*
* Must wait for all AIO to complete before we continue as AIO can
* change the file size on completion without holding any locks we
* currently hold. We must do this first because AIO can update both
* the on disk and in memory inode sizes, and the operations that follow
* require the in-memory size to be fully up-to-date.
*/
inode_dio_wait(inode);
/*
* Now AIO and DIO has drained we flush and (if necessary) invalidate
* the cached range over the first operation we are about to run.
*
* We care about zero and collapse here because they both run a hole
* punch over the range first. Because that can zero data, and the range
* of invalidation for the shift operations is much larger, we still do
* the required flush for collapse in xfs_prepare_shift().
*
* Insert has the same range requirements as collapse, and we extend the
* file first which can zero data. Hence insert has the same
* flush/invalidate requirements as collapse and so they are both
* handled at the right time by xfs_prepare_shift().
*/
if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE |
FALLOC_FL_COLLAPSE_RANGE)) {
error = xfs_flush_unmap_range(ip, offset, len);
if (error)
goto out_unlock;
}
if (mode & FALLOC_FL_PUNCH_HOLE) {
error = xfs_free_file_space(ip, offset, len);
if (error)
goto out_unlock;
} else if (mode & FALLOC_FL_COLLAPSE_RANGE) {
if (!xfs_is_falloc_aligned(ip, offset, len)) {
error = -EINVAL;
goto out_unlock;
}
/*
* There is no need to overlap collapse range with EOF,
* in which case it is effectively a truncate operation
*/
if (offset + len >= i_size_read(inode)) {
error = -EINVAL;
goto out_unlock;
}
new_size = i_size_read(inode) - len;
error = xfs_collapse_file_space(ip, offset, len);
if (error)
goto out_unlock;
} else if (mode & FALLOC_FL_INSERT_RANGE) {
loff_t isize = i_size_read(inode);
if (!xfs_is_falloc_aligned(ip, offset, len)) {
error = -EINVAL;
goto out_unlock;
}
/*
* New inode size must not exceed ->s_maxbytes, accounting for
* possible signed overflow.
*/
if (inode->i_sb->s_maxbytes - isize < len) {
error = -EFBIG;
goto out_unlock;
}
new_size = isize + len;
/* Offset should be less than i_size */
if (offset >= isize) {
error = -EINVAL;
goto out_unlock;
}
do_file_insert = true;
} else {
flags |= XFS_PREALLOC_SET;
if (!(mode & FALLOC_FL_KEEP_SIZE) &&
offset + len > i_size_read(inode)) {
new_size = offset + len;
error = inode_newsize_ok(inode, new_size);
if (error)
goto out_unlock;
}
if (mode & FALLOC_FL_ZERO_RANGE) {
/*
* Punch a hole and prealloc the range. We use a hole
* punch rather than unwritten extent conversion for two
* reasons:
*
* 1.) Hole punch handles partial block zeroing for us.
* 2.) If prealloc returns ENOSPC, the file range is
* still zero-valued by virtue of the hole punch.
*/
unsigned int blksize = i_blocksize(inode);
trace_xfs_zero_file_space(ip);
error = xfs_free_file_space(ip, offset, len);
if (error)
goto out_unlock;
len = round_up(offset + len, blksize) -
round_down(offset, blksize);
offset = round_down(offset, blksize);
} else if (mode & FALLOC_FL_UNSHARE_RANGE) {
error = xfs_reflink_unshare(ip, offset, len);
if (error)
goto out_unlock;
} else {
/*
* If always_cow mode we can't use preallocations and
* thus should not create them.
*/
if (xfs_is_always_cow_inode(ip)) {
error = -EOPNOTSUPP;
goto out_unlock;
}
}
if (!xfs_is_always_cow_inode(ip)) {
error = xfs_alloc_file_space(ip, offset, len,
XFS_BMAPI_PREALLOC);
if (error)
goto out_unlock;
}
}
if (file->f_flags & O_DSYNC)
flags |= XFS_PREALLOC_SYNC;
error = xfs_update_prealloc_flags(ip, flags);
if (error)
goto out_unlock;
/* Change file size if needed */
if (new_size) {
struct iattr iattr;
iattr.ia_valid = ATTR_SIZE;
iattr.ia_size = new_size;
error = xfs_vn_setattr_size(file_mnt_user_ns(file),
file_dentry(file), &iattr);
if (error)
goto out_unlock;
}
/*
* Perform hole insertion now that the file size has been
* updated so that if we crash during the operation we don't
* leave shifted extents past EOF and hence losing access to
* the data that is contained within them.
*/
if (do_file_insert)
error = xfs_insert_file_space(ip, offset, len);
out_unlock:
xfs_iunlock(ip, iolock);
return error;
}
STATIC int
xfs_file_fadvise(
struct file *file,
loff_t start,
loff_t end,
int advice)
{
struct xfs_inode *ip = XFS_I(file_inode(file));
int ret;
int lockflags = 0;
/*
* Operations creating pages in page cache need protection from hole
* punching and similar ops
*/
if (advice == POSIX_FADV_WILLNEED) {
lockflags = XFS_IOLOCK_SHARED;
xfs_ilock(ip, lockflags);
}
ret = generic_fadvise(file, start, end, advice);
if (lockflags)
xfs_iunlock(ip, lockflags);
return ret;
}
/* Does this file, inode, or mount want synchronous writes? */
static inline bool xfs_file_sync_writes(struct file *filp)
{
struct xfs_inode *ip = XFS_I(file_inode(filp));
if (ip->i_mount->m_flags & XFS_MOUNT_WSYNC)
return true;
if (filp->f_flags & (__O_SYNC | O_DSYNC))
return true;
if (IS_SYNC(file_inode(filp)))
return true;
return false;
}
STATIC loff_t
xfs_file_remap_range(
struct file *file_in,
loff_t pos_in,
struct file *file_out,
loff_t pos_out,
loff_t len,
unsigned int remap_flags)
{
struct inode *inode_in = file_inode(file_in);
struct xfs_inode *src = XFS_I(inode_in);
struct inode *inode_out = file_inode(file_out);
struct xfs_inode *dest = XFS_I(inode_out);
struct xfs_mount *mp = src->i_mount;
loff_t remapped = 0;
xfs_extlen_t cowextsize;
int ret;
if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY))
return -EINVAL;
if (!xfs_sb_version_hasreflink(&mp->m_sb))
return -EOPNOTSUPP;
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
/* Prepare and then clone file data. */
ret = xfs_reflink_remap_prep(file_in, pos_in, file_out, pos_out,
&len, remap_flags);
if (ret || len == 0)
return ret;
trace_xfs_reflink_remap_range(src, pos_in, len, dest, pos_out);
ret = xfs_reflink_remap_blocks(src, pos_in, dest, pos_out, len,
&remapped);
if (ret)
goto out_unlock;
/*
* Carry the cowextsize hint from src to dest if we're sharing the
* entire source file to the entire destination file, the source file
* has a cowextsize hint, and the destination file does not.
*/
cowextsize = 0;
if (pos_in == 0 && len == i_size_read(inode_in) &&
(src->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE) &&
pos_out == 0 && len >= i_size_read(inode_out) &&
!(dest->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE))
cowextsize = src->i_cowextsize;
ret = xfs_reflink_update_dest(dest, pos_out + len, cowextsize,
remap_flags);
if (ret)
goto out_unlock;
if (xfs_file_sync_writes(file_in) || xfs_file_sync_writes(file_out))
xfs_log_force_inode(dest);
out_unlock:
xfs_iunlock2_io_mmap(src, dest);
if (ret)
trace_xfs_reflink_remap_range_error(dest, ret, _RET_IP_);
return remapped > 0 ? remapped : ret;
}
STATIC int
xfs_file_open(
struct inode *inode,
struct file *file)
{
if (!(file->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
return -EFBIG;
if (XFS_FORCED_SHUTDOWN(XFS_M(inode->i_sb)))
return -EIO;
file->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC;
return 0;
}
STATIC int
xfs_dir_open(
struct inode *inode,
struct file *file)
{
struct xfs_inode *ip = XFS_I(inode);
int mode;
int error;
error = xfs_file_open(inode, file);
if (error)
return error;
/*
* If there are any blocks, read-ahead block 0 as we're almost
* certain to have the next operation be a read there.
*/
mode = xfs_ilock_data_map_shared(ip);
if (ip->i_df.if_nextents > 0)
error = xfs_dir3_data_readahead(ip, 0, 0);
xfs_iunlock(ip, mode);
return error;
}
STATIC int
xfs_file_release(
struct inode *inode,
struct file *filp)
{
return xfs_release(XFS_I(inode));
}
STATIC int
xfs_file_readdir(
struct file *file,
struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
xfs_inode_t *ip = XFS_I(inode);
size_t bufsize;
/*
* The Linux API doesn't pass down the total size of the buffer
* we read into down to the filesystem. With the filldir concept
* it's not needed for correct information, but the XFS dir2 leaf
* code wants an estimate of the buffer size to calculate it's
* readahead window and size the buffers used for mapping to
* physical blocks.
*
* Try to give it an estimate that's good enough, maybe at some
* point we can change the ->readdir prototype to include the
* buffer size. For now we use the current glibc buffer size.
*/
bufsize = (size_t)min_t(loff_t, XFS_READDIR_BUFSIZE, ip->i_disk_size);
return xfs_readdir(NULL, ip, ctx, bufsize);
}
STATIC loff_t
xfs_file_llseek(
struct file *file,
loff_t offset,
int whence)
{
struct inode *inode = file->f_mapping->host;
if (XFS_FORCED_SHUTDOWN(XFS_I(inode)->i_mount))
return -EIO;
switch (whence) {
default:
return generic_file_llseek(file, offset, whence);
case SEEK_HOLE:
offset = iomap_seek_hole(inode, offset, &xfs_seek_iomap_ops);
break;
case SEEK_DATA:
offset = iomap_seek_data(inode, offset, &xfs_seek_iomap_ops);
break;
}
if (offset < 0)
return offset;
return vfs_setpos(file, offset, inode->i_sb->s_maxbytes);
}
/*
* Locking for serialisation of IO during page faults. This results in a lock
* ordering of:
*
* mmap_lock (MM)
* sb_start_pagefault(vfs, freeze)
* i_mmaplock (XFS - truncate serialisation)
* page_lock (MM)
* i_lock (XFS - extent map serialisation)
*/
static vm_fault_t
__xfs_filemap_fault(
struct vm_fault *vmf,
enum page_entry_size pe_size,
bool write_fault)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
struct xfs_inode *ip = XFS_I(inode);
vm_fault_t ret;
trace_xfs_filemap_fault(ip, pe_size, write_fault);
if (write_fault) {
sb_start_pagefault(inode->i_sb);
file_update_time(vmf->vma->vm_file);
}
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
if (IS_DAX(inode)) {
pfn_t pfn;
ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL,
(write_fault && !vmf->cow_page) ?
&xfs_direct_write_iomap_ops :
&xfs_read_iomap_ops);
if (ret & VM_FAULT_NEEDDSYNC)
ret = dax_finish_sync_fault(vmf, pe_size, pfn);
} else {
if (write_fault)
ret = iomap_page_mkwrite(vmf,
&xfs_buffered_write_iomap_ops);
else
ret = filemap_fault(vmf);
}
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
if (write_fault)
sb_end_pagefault(inode->i_sb);
return ret;
}
static inline bool
xfs_is_write_fault(
struct vm_fault *vmf)
{
return (vmf->flags & FAULT_FLAG_WRITE) &&
(vmf->vma->vm_flags & VM_SHARED);
}
static vm_fault_t
xfs_filemap_fault(
struct vm_fault *vmf)
{
/* DAX can shortcut the normal fault path on write faults! */
return __xfs_filemap_fault(vmf, PE_SIZE_PTE,
IS_DAX(file_inode(vmf->vma->vm_file)) &&
xfs_is_write_fault(vmf));
}
static vm_fault_t
xfs_filemap_huge_fault(
struct vm_fault *vmf,
enum page_entry_size pe_size)
{
if (!IS_DAX(file_inode(vmf->vma->vm_file)))
return VM_FAULT_FALLBACK;
/* DAX can shortcut the normal fault path on write faults! */
return __xfs_filemap_fault(vmf, pe_size,
xfs_is_write_fault(vmf));
}
static vm_fault_t
xfs_filemap_page_mkwrite(
struct vm_fault *vmf)
{
return __xfs_filemap_fault(vmf, PE_SIZE_PTE, true);
}
/*
* pfn_mkwrite was originally intended to ensure we capture time stamp updates
* on write faults. In reality, it needs to serialise against truncate and
* prepare memory for writing so handle is as standard write fault.
*/
static vm_fault_t
xfs_filemap_pfn_mkwrite(
struct vm_fault *vmf)
{
return __xfs_filemap_fault(vmf, PE_SIZE_PTE, true);
}
static vm_fault_t
xfs_filemap_map_pages(
struct vm_fault *vmf,
pgoff_t start_pgoff,
pgoff_t end_pgoff)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
vm_fault_t ret;
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
ret = filemap_map_pages(vmf, start_pgoff, end_pgoff);
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
return ret;
}
static const struct vm_operations_struct xfs_file_vm_ops = {
.fault = xfs_filemap_fault,
.huge_fault = xfs_filemap_huge_fault,
.map_pages = xfs_filemap_map_pages,
.page_mkwrite = xfs_filemap_page_mkwrite,
.pfn_mkwrite = xfs_filemap_pfn_mkwrite,
};
STATIC int
xfs_file_mmap(
struct file *file,
struct vm_area_struct *vma)
{
struct inode *inode = file_inode(file);
struct xfs_buftarg *target = xfs_inode_buftarg(XFS_I(inode));
/*
* We don't support synchronous mappings for non-DAX files and
* for DAX files if underneath dax_device is not synchronous.
*/
if (!daxdev_mapping_supported(vma, target->bt_daxdev))
return -EOPNOTSUPP;
file_accessed(file);
vma->vm_ops = &xfs_file_vm_ops;
if (IS_DAX(inode))
vma->vm_flags |= VM_HUGEPAGE;
return 0;
}
const struct file_operations xfs_file_operations = {
.llseek = xfs_file_llseek,
.read_iter = xfs_file_read_iter,
.write_iter = xfs_file_write_iter,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
.iopoll = iomap_dio_iopoll,
.unlocked_ioctl = xfs_file_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = xfs_file_compat_ioctl,
#endif
.mmap = xfs_file_mmap,
.mmap_supported_flags = MAP_SYNC,
.open = xfs_file_open,
.release = xfs_file_release,
.fsync = xfs_file_fsync,
.get_unmapped_area = thp_get_unmapped_area,
.fallocate = xfs_file_fallocate,
.fadvise = xfs_file_fadvise,
.remap_file_range = xfs_file_remap_range,
};
const struct file_operations xfs_dir_file_operations = {
.open = xfs_dir_open,
.read = generic_read_dir,
.iterate_shared = xfs_file_readdir,
.llseek = generic_file_llseek,
.unlocked_ioctl = xfs_file_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = xfs_file_compat_ioctl,
#endif
.fsync = xfs_dir_fsync,
};
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