// 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 "xfs_file.h"
#include <linux/dax.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.
*/
bool
xfs_is_falloc_aligned(
struct xfs_inode *ip,
loff_t pos,
long long int len)
{
unsigned int alloc_unit = xfs_inode_alloc_unitsize(ip);
if (!is_power_of_2(alloc_unit))
return isaligned_64(pos, alloc_unit) &&
isaligned_64(len, alloc_unit);
return !((pos | len) & (alloc_unit - 1));
}
/*
* 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_csn_t
xfs_fsync_seq(
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_commit_seq;
}
/*
* 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_csn_t seq;
xfs_ilock(ip, XFS_ILOCK_SHARED);
seq = xfs_fsync_seq(ip, datasync);
if (seq) {
error = xfs_log_force_seq(ip->i_mount, seq, 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, err2;
int log_flushed = 0;
trace_xfs_file_fsync(ip);
error = file_write_and_wait_range(file, start, end);
if (error)
return error;
if (xfs_is_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))
error = blkdev_issue_flush(mp->m_rtdev_targp->bt_bdev);
else if (mp->m_logdev_targp != mp->m_ddev_targp)
error = blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
/*
* Any inode that has dirty modifications in the log is pinned. The
* racy check here for a pinned inode will 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)) {
err2 = xfs_fsync_flush_log(ip, datasync, &log_flushed);
if (err2 && !error)
error = err2;
}
/*
* 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) {
err2 = blkdev_issue_flush(mp->m_ddev_targp->bt_bdev);
if (err2 && !error)
error = err2;
}
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 int
xfs_ilock_iocb_for_write(
struct kiocb *iocb,
unsigned int *lock_mode)
{
ssize_t ret;
struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
ret = xfs_ilock_iocb(iocb, *lock_mode);
if (ret)
return ret;
/*
* If a reflink remap is in progress we always need to take the iolock
* exclusively to wait for it to finish.
*/
if (*lock_mode == XFS_IOLOCK_SHARED &&
xfs_iflags_test(ip, XFS_IREMAPPING)) {
xfs_iunlock(ip, *lock_mode);
*lock_mode = XFS_IOLOCK_EXCL;
return xfs_ilock_iocb(iocb, *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, 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_is_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;
}
STATIC ssize_t
xfs_file_splice_read(
struct file *in,
loff_t *ppos,
struct pipe_inode_info *pipe,
size_t len,
unsigned int flags)
{
struct inode *inode = file_inode(in);
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
ssize_t ret = 0;
XFS_STATS_INC(mp, xs_read_calls);
if (xfs_is_shutdown(mp))
return -EIO;
trace_xfs_file_splice_read(ip, *ppos, len);
xfs_ilock(ip, XFS_IOLOCK_SHARED);
ret = filemap_splice_read(in, ppos, pipe, len, flags);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
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,
unsigned 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.
*
* We can do an unlocked check here safely as IO completion can only
* extend EOF. Truncate is locked out at this point, so the EOF can
* not move backwards, only forwards. Hence we only need to take the
* slow path and spin locks when we are at or beyond the current EOF.
*/
if (iocb->ki_pos <= i_size_read(inode))
goto out;
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 = xfs_zero_range(ip, isize, iocb->ki_pos - isize, NULL);
if (error)
return error;
} else
spin_unlock(&ip->i_flags_lock);
out:
return kiocb_modified(iocb);
}
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_is_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.
*
* As IO completion only ever extends EOF, we can do an unlocked check
* here to avoid taking the spinlock. If we land within the current EOF,
* then we do not need to do an extending update at all, and we don't
* need to take the lock to check this. If we race with an update moving
* EOF, then we'll either still be beyond EOF and need to take the lock,
* or we'll be within EOF and we don't need to take it at all.
*/
if (offset + size <= i_size_read(inode))
goto out;
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)
{
unsigned int iolock = XFS_IOLOCK_SHARED;
ssize_t ret;
ret = xfs_ilock_iocb_for_write(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, NULL, 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);
unsigned 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) {
if (iocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
retry_exclusive:
iolock = XFS_IOLOCK_EXCL;
flags = IOMAP_DIO_FORCE_WAIT;
}
ret = xfs_ilock_iocb_for_write(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, NULL, 0);
/*
* 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);
unsigned 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_dax_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 inode *inode = iocb->ki_filp->f_mapping->host;
struct xfs_inode *ip = XFS_I(inode);
ssize_t ret;
bool cleared_space = false;
unsigned int iolock;
write_retry:
iolock = XFS_IOLOCK_EXCL;
ret = xfs_ilock_iocb(iocb, iolock);
if (ret)
return ret;
ret = xfs_file_write_checks(iocb, from, &iolock);
if (ret)
goto out;
trace_xfs_file_buffered_write(iocb, from);
ret = iomap_file_buffered_write(iocb, from,
&xfs_buffered_write_iomap_ops, NULL);
/*
* 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_ICWALK_FLAG_SYNC);
cleared_space = true;
goto write_retry;
} else if (ret == -ENOSPC && !cleared_space) {
struct xfs_icwalk icw = {0};
cleared_space = true;
xfs_flush_inodes(ip->i_mount);
xfs_iunlock(ip, iolock);
icw.icw_flags = XFS_ICWALK_FLAG_SYNC;
xfs_blockgc_free_space(ip->i_mount, &icw);
goto write_retry;
}
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 inode *inode = iocb->ki_filp->f_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_is_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);
}
/* 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 (xfs_has_wsync(ip->i_mount))
return true;
if (filp->f_flags & (__O_SYNC | O_DSYNC))
return true;
if (IS_SYNC(file_inode(filp)))
return true;
return false;
}
static int
xfs_falloc_newsize(
struct file *file,
int mode,
loff_t offset,
loff_t len,
loff_t *new_size)
{
struct inode *inode = file_inode(file);
if ((mode & FALLOC_FL_KEEP_SIZE) || offset + len <= i_size_read(inode))
return 0;
*new_size = offset + len;
return inode_newsize_ok(inode, *new_size);
}
static int
xfs_falloc_setsize(
struct file *file,
loff_t new_size)
{
struct iattr iattr = {
.ia_valid = ATTR_SIZE,
.ia_size = new_size,
};
if (!new_size)
return 0;
return xfs_vn_setattr_size(file_mnt_idmap(file), file_dentry(file),
&iattr);
}
static int
xfs_falloc_collapse_range(
struct file *file,
loff_t offset,
loff_t len)
{
struct inode *inode = file_inode(file);
loff_t new_size = i_size_read(inode) - len;
int error;
if (!xfs_is_falloc_aligned(XFS_I(inode), offset, len))
return -EINVAL;
/*
* 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))
return -EINVAL;
error = xfs_collapse_file_space(XFS_I(inode), offset, len);
if (error)
return error;
return xfs_falloc_setsize(file, new_size);
}
static int
xfs_falloc_insert_range(
struct file *file,
loff_t offset,
loff_t len)
{
struct inode *inode = file_inode(file);
loff_t isize = i_size_read(inode);
int error;
if (!xfs_is_falloc_aligned(XFS_I(inode), offset, len))
return -EINVAL;
/*
* New inode size must not exceed ->s_maxbytes, accounting for
* possible signed overflow.
*/
if (inode->i_sb->s_maxbytes - isize < len)
return -EFBIG;
/* Offset should be less than i_size */
if (offset >= isize)
return -EINVAL;
error = xfs_falloc_setsize(file, isize + len);
if (error)
return error;
/*
* 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.
*/
return xfs_insert_file_space(XFS_I(inode), offset, len);
}
/*
* 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.
*/
static int
xfs_falloc_zero_range(
struct file *file,
int mode,
loff_t offset,
loff_t len)
{
struct inode *inode = file_inode(file);
unsigned int blksize = i_blocksize(inode);
loff_t new_size = 0;
int error;
trace_xfs_zero_file_space(XFS_I(inode));
error = xfs_falloc_newsize(file, mode, offset, len, &new_size);
if (error)
return error;
error = xfs_free_file_space(XFS_I(inode), offset, len);
if (error)
return error;
len = round_up(offset + len, blksize) - round_down(offset, blksize);
offset = round_down(offset, blksize);
error = xfs_alloc_file_space(XFS_I(inode), offset, len);
if (error)
return error;
return xfs_falloc_setsize(file, new_size);
}
static int
xfs_falloc_unshare_range(
struct file *file,
int mode,
loff_t offset,
loff_t len)
{
struct inode *inode = file_inode(file);
loff_t new_size = 0;
int error;
error = xfs_falloc_newsize(file, mode, offset, len, &new_size);
if (error)
return error;
error = xfs_reflink_unshare(XFS_I(inode), offset, len);
if (error)
return error;
error = xfs_alloc_file_space(XFS_I(inode), offset, len);
if (error)
return error;
return xfs_falloc_setsize(file, new_size);
}
static int
xfs_falloc_allocate_range(
struct file *file,
int mode,
loff_t offset,
loff_t len)
{
struct inode *inode = file_inode(file);
loff_t new_size = 0;
int error;
/*
* If always_cow mode we can't use preallocations and thus should not
* create them.
*/
if (xfs_is_always_cow_inode(XFS_I(inode)))
return -EOPNOTSUPP;
error = xfs_falloc_newsize(file, mode, offset, len, &new_size);
if (error)
return error;
error = xfs_alloc_file_space(XFS_I(inode), offset, len);
if (error)
return error;
return xfs_falloc_setsize(file, new_size);
}
#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;
uint iolock = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
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);
error = file_modified(file);
if (error)
goto out_unlock;
switch (mode & FALLOC_FL_MODE_MASK) {
case FALLOC_FL_PUNCH_HOLE:
error = xfs_free_file_space(ip, offset, len);
break;
case FALLOC_FL_COLLAPSE_RANGE:
error = xfs_falloc_collapse_range(file, offset, len);
break;
case FALLOC_FL_INSERT_RANGE:
error = xfs_falloc_insert_range(file, offset, len);
break;
case FALLOC_FL_ZERO_RANGE:
error = xfs_falloc_zero_range(file, mode, offset, len);
break;
case FALLOC_FL_UNSHARE_RANGE:
error = xfs_falloc_unshare_range(file, mode, offset, len);
break;
case FALLOC_FL_ALLOCATE_RANGE:
error = xfs_falloc_allocate_range(file, mode, offset, len);
break;
default:
error = -EOPNOTSUPP;
break;
}
if (!error && xfs_file_sync_writes(file))
error = xfs_log_force_inode(ip);
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;
}
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_has_reflink(mp))
return -EOPNOTSUPP;
if (xfs_is_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_remapping(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 (xfs_is_shutdown(XFS_M(inode->i_sb)))
return -EIO;
file->f_mode |= FMODE_NOWAIT | FMODE_CAN_ODIRECT;
return generic_file_open(inode, file);
}
STATIC int
xfs_dir_open(
struct inode *inode,
struct file *file)
{
struct xfs_inode *ip = XFS_I(inode);
unsigned int mode;
int error;
if (xfs_is_shutdown(ip->i_mount))
return -EIO;
error = generic_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;
}
/*
* Don't bother propagating errors. We're just doing cleanup, and the caller
* ignores the return value anyway.
*/
STATIC int
xfs_file_release(
struct inode *inode,
struct file *file)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
/*
* If this is a read-only mount or the file system has been shut down,
* don't generate I/O.
*/
if (xfs_is_readonly(mp) || xfs_is_shutdown(mp))
return 0;
/*
* If we previously truncated this file and removed old data in the
* process, we want to initiate "early" writeout on the last close.
* This is an attempt to combat the notorious NULL files problem which
* is particularly noticeable from a truncate down, buffered (re-)write
* (delalloc), followed by a crash. What we are effectively doing here
* is significantly reducing the time window where we'd otherwise be
* exposed to that problem.
*/
if (xfs_iflags_test_and_clear(ip, XFS_ITRUNCATED)) {
xfs_iflags_clear(ip, XFS_EOFBLOCKS_RELEASED);
if (ip->i_delayed_blks > 0)
filemap_flush(inode->i_mapping);
}
/*
* XFS aggressively preallocates post-EOF space to generate contiguous
* allocations for writers that append to the end of the file.
*
* To support workloads that close and reopen the file frequently, these
* preallocations usually persist after a close unless it is the first
* close for the inode. This is a tradeoff to generate tightly packed
* data layouts for unpacking tarballs or similar archives that write
* one file after another without going back to it while keeping the
* preallocation for files that have recurring open/write/close cycles.
*
* This heuristic is skipped for inodes with the append-only flag as
* that flag is rather pointless for inodes written only once.
*
* There is no point in freeing blocks here for open but unlinked files
* as they will be taken care of by the inactivation path soon.
*
* When releasing a read-only context, don't flush data or trim post-EOF
* blocks. This avoids open/read/close workloads from removing EOF
* blocks that other writers depend upon to reduce fragmentation.
*
* If we can't get the iolock just skip truncating the blocks past EOF
* because we could deadlock with the mmap_lock otherwise. We'll get
* another chance to drop them once the last reference to the inode is
* dropped, so we'll never leak blocks permanently.
*/
if (inode->i_nlink &&
(file->f_mode & FMODE_WRITE) &&
!(ip->i_diflags & XFS_DIFLAG_APPEND) &&
!xfs_iflags_test(ip, XFS_EOFBLOCKS_RELEASED) &&
xfs_ilock_nowait(ip, XFS_IOLOCK_EXCL)) {
if (xfs_can_free_eofblocks(ip) &&
!xfs_iflags_test_and_set(ip, XFS_EOFBLOCKS_RELEASED))
xfs_free_eofblocks(ip);
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
}
return 0;
}
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_is_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);
}
static inline vm_fault_t
xfs_dax_fault_locked(
struct vm_fault *vmf,
unsigned int order,
bool write_fault)
{
vm_fault_t ret;
pfn_t pfn;
if (!IS_ENABLED(CONFIG_FS_DAX)) {
ASSERT(0);
return VM_FAULT_SIGBUS;
}
ret = dax_iomap_fault(vmf, order, &pfn, NULL,
(write_fault && !vmf->cow_page) ?
&xfs_dax_write_iomap_ops :
&xfs_read_iomap_ops);
if (ret & VM_FAULT_NEEDDSYNC)
ret = dax_finish_sync_fault(vmf, order, pfn);
return ret;
}
static vm_fault_t
xfs_dax_read_fault(
struct vm_fault *vmf,
unsigned int order)
{
struct xfs_inode *ip = XFS_I(file_inode(vmf->vma->vm_file));
vm_fault_t ret;
xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
ret = xfs_dax_fault_locked(vmf, order, false);
xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
return ret;
}
static vm_fault_t
xfs_write_fault(
struct vm_fault *vmf,
unsigned int order)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
struct xfs_inode *ip = XFS_I(inode);
unsigned int lock_mode = XFS_MMAPLOCK_SHARED;
vm_fault_t ret;
sb_start_pagefault(inode->i_sb);
file_update_time(vmf->vma->vm_file);
/*
* Normally we only need the shared mmaplock, but if a reflink remap is
* in progress we take the exclusive lock to wait for the remap to
* finish before taking a write fault.
*/
xfs_ilock(ip, XFS_MMAPLOCK_SHARED);
if (xfs_iflags_test(ip, XFS_IREMAPPING)) {
xfs_iunlock(ip, XFS_MMAPLOCK_SHARED);
xfs_ilock(ip, XFS_MMAPLOCK_EXCL);
lock_mode = XFS_MMAPLOCK_EXCL;
}
if (IS_DAX(inode))
ret = xfs_dax_fault_locked(vmf, order, true);
else
ret = iomap_page_mkwrite(vmf, &xfs_page_mkwrite_iomap_ops);
xfs_iunlock(ip, lock_mode);
sb_end_pagefault(inode->i_sb);
return ret;
}
/*
* Locking for serialisation of IO during page faults. This results in a lock
* ordering of:
*
* mmap_lock (MM)
* sb_start_pagefault(vfs, freeze)
* invalidate_lock (vfs/XFS_MMAPLOCK - truncate serialisation)
* page_lock (MM)
* i_lock (XFS - extent map serialisation)
*/
static vm_fault_t
__xfs_filemap_fault(
struct vm_fault *vmf,
unsigned int order,
bool write_fault)
{
struct inode *inode = file_inode(vmf->vma->vm_file);
trace_xfs_filemap_fault(XFS_I(inode), order, write_fault);
if (write_fault)
return xfs_write_fault(vmf, order);
if (IS_DAX(inode))
return xfs_dax_read_fault(vmf, order);
return filemap_fault(vmf);
}
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, 0,
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,
unsigned int order)
{
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, order,
xfs_is_write_fault(vmf));
}
static vm_fault_t
xfs_filemap_page_mkwrite(
struct vm_fault *vmf)
{
return __xfs_filemap_fault(vmf, 0, 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, 0, true);
}
static const struct vm_operations_struct xfs_file_vm_ops = {
.fault = xfs_filemap_fault,
.huge_fault = xfs_filemap_huge_fault,
.map_pages = 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))
vm_flags_set(vma, 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 = xfs_file_splice_read,
.splice_write = iter_file_splice_write,
.iopoll = iocb_bio_iopoll,
.unlocked_ioctl = xfs_file_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = xfs_file_compat_ioctl,
#endif
.mmap = xfs_file_mmap,
.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,
.fop_flags = FOP_MMAP_SYNC | FOP_BUFFER_RASYNC |
FOP_BUFFER_WASYNC | FOP_DIO_PARALLEL_WRITE,
};
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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