// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2020-2024 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <[email protected]>
*/
#include "xfs.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_defer.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_quota.h"
#include "xfs_bmap_util.h"
#include "xfs_reflink.h"
#include "xfs_trace.h"
#include "xfs_exchrange.h"
#include "xfs_exchmaps.h"
#include "xfs_sb.h"
#include "xfs_icache.h"
#include "xfs_log.h"
#include "xfs_rtbitmap.h"
#include <linux/fsnotify.h>
/* Lock (and optionally join) two inodes for a file range exchange. */
void
xfs_exchrange_ilock(
struct xfs_trans *tp,
struct xfs_inode *ip1,
struct xfs_inode *ip2)
{
if (ip1 != ip2)
xfs_lock_two_inodes(ip1, XFS_ILOCK_EXCL,
ip2, XFS_ILOCK_EXCL);
else
xfs_ilock(ip1, XFS_ILOCK_EXCL);
if (tp) {
xfs_trans_ijoin(tp, ip1, 0);
if (ip2 != ip1)
xfs_trans_ijoin(tp, ip2, 0);
}
}
/* Unlock two inodes after a file range exchange operation. */
void
xfs_exchrange_iunlock(
struct xfs_inode *ip1,
struct xfs_inode *ip2)
{
if (ip2 != ip1)
xfs_iunlock(ip2, XFS_ILOCK_EXCL);
xfs_iunlock(ip1, XFS_ILOCK_EXCL);
}
/*
* Estimate the resource requirements to exchange file contents between the two
* files. The caller is required to hold the IOLOCK and the MMAPLOCK and to
* have flushed both inodes' pagecache and active direct-ios.
*/
int
xfs_exchrange_estimate(
struct xfs_exchmaps_req *req)
{
int error;
xfs_exchrange_ilock(NULL, req->ip1, req->ip2);
error = xfs_exchmaps_estimate(req);
xfs_exchrange_iunlock(req->ip1, req->ip2);
return error;
}
/*
* Check that file2's metadata agree with the snapshot that we took for the
* range commit request.
*
* This should be called after the filesystem has locked /all/ inode metadata
* against modification.
*/
STATIC int
xfs_exchrange_check_freshness(
const struct xfs_exchrange *fxr,
struct xfs_inode *ip2)
{
struct inode *inode2 = VFS_I(ip2);
struct timespec64 ctime = inode_get_ctime(inode2);
struct timespec64 mtime = inode_get_mtime(inode2);
trace_xfs_exchrange_freshness(fxr, ip2);
/* Check that file2 hasn't otherwise been modified. */
if (fxr->file2_ino != ip2->i_ino ||
fxr->file2_gen != inode2->i_generation ||
!timespec64_equal(&fxr->file2_ctime, &ctime) ||
!timespec64_equal(&fxr->file2_mtime, &mtime))
return -EBUSY;
return 0;
}
#define QRETRY_IP1 (0x1)
#define QRETRY_IP2 (0x2)
/*
* Obtain a quota reservation to make sure we don't hit EDQUOT. We can skip
* this if quota enforcement is disabled or if both inodes' dquots are the
* same. The qretry structure must be initialized to zeroes before the first
* call to this function.
*/
STATIC int
xfs_exchrange_reserve_quota(
struct xfs_trans *tp,
const struct xfs_exchmaps_req *req,
unsigned int *qretry)
{
int64_t ddelta, rdelta;
int ip1_error = 0;
int error;
/*
* Don't bother with a quota reservation if we're not enforcing them
* or the two inodes have the same dquots.
*/
if (!XFS_IS_QUOTA_ON(tp->t_mountp) || req->ip1 == req->ip2 ||
(req->ip1->i_udquot == req->ip2->i_udquot &&
req->ip1->i_gdquot == req->ip2->i_gdquot &&
req->ip1->i_pdquot == req->ip2->i_pdquot))
return 0;
*qretry = 0;
/*
* For each file, compute the net gain in the number of regular blocks
* that will be mapped into that file and reserve that much quota. The
* quota counts must be able to absorb at least that much space.
*/
ddelta = req->ip2_bcount - req->ip1_bcount;
rdelta = req->ip2_rtbcount - req->ip1_rtbcount;
if (ddelta > 0 || rdelta > 0) {
error = xfs_trans_reserve_quota_nblks(tp, req->ip1,
ddelta > 0 ? ddelta : 0,
rdelta > 0 ? rdelta : 0,
false);
if (error == -EDQUOT || error == -ENOSPC) {
/*
* Save this error and see what happens if we try to
* reserve quota for ip2. Then report both.
*/
*qretry |= QRETRY_IP1;
ip1_error = error;
error = 0;
}
if (error)
return error;
}
if (ddelta < 0 || rdelta < 0) {
error = xfs_trans_reserve_quota_nblks(tp, req->ip2,
ddelta < 0 ? -ddelta : 0,
rdelta < 0 ? -rdelta : 0,
false);
if (error == -EDQUOT || error == -ENOSPC)
*qretry |= QRETRY_IP2;
if (error)
return error;
}
if (ip1_error)
return ip1_error;
/*
* For each file, forcibly reserve the gross gain in mapped blocks so
* that we don't trip over any quota block reservation assertions.
* We must reserve the gross gain because the quota code subtracts from
* bcount the number of blocks that we unmap; it does not add that
* quantity back to the quota block reservation.
*/
error = xfs_trans_reserve_quota_nblks(tp, req->ip1, req->ip1_bcount,
req->ip1_rtbcount, true);
if (error)
return error;
return xfs_trans_reserve_quota_nblks(tp, req->ip2, req->ip2_bcount,
req->ip2_rtbcount, true);
}
/* Exchange the mappings (and hence the contents) of two files' forks. */
STATIC int
xfs_exchrange_mappings(
const struct xfs_exchrange *fxr,
struct xfs_inode *ip1,
struct xfs_inode *ip2)
{
struct xfs_mount *mp = ip1->i_mount;
struct xfs_exchmaps_req req = {
.ip1 = ip1,
.ip2 = ip2,
.startoff1 = XFS_B_TO_FSBT(mp, fxr->file1_offset),
.startoff2 = XFS_B_TO_FSBT(mp, fxr->file2_offset),
.blockcount = XFS_B_TO_FSB(mp, fxr->length),
};
struct xfs_trans *tp;
unsigned int qretry;
bool retried = false;
int error;
trace_xfs_exchrange_mappings(fxr, ip1, ip2);
if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF)
req.flags |= XFS_EXCHMAPS_SET_SIZES;
if (fxr->flags & XFS_EXCHANGE_RANGE_FILE1_WRITTEN)
req.flags |= XFS_EXCHMAPS_INO1_WRITTEN;
/*
* Round the request length up to the nearest file allocation unit.
* The prep function already checked that the request offsets and
* length in @fxr are safe to round up.
*/
if (xfs_inode_has_bigrtalloc(ip2))
req.blockcount = xfs_rtb_roundup_rtx(mp, req.blockcount);
error = xfs_exchrange_estimate(&req);
if (error)
return error;
retry:
/* Allocate the transaction, lock the inodes, and join them. */
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, req.resblks, 0,
XFS_TRANS_RES_FDBLKS, &tp);
if (error)
return error;
xfs_exchrange_ilock(tp, ip1, ip2);
trace_xfs_exchrange_before(ip2, 2);
trace_xfs_exchrange_before(ip1, 1);
error = xfs_exchmaps_check_forks(mp, &req);
if (error)
goto out_trans_cancel;
/*
* Reserve ourselves some quota if any of them are in enforcing mode.
* In theory we only need enough to satisfy the change in the number
* of blocks between the two ranges being remapped.
*/
error = xfs_exchrange_reserve_quota(tp, &req, &qretry);
if ((error == -EDQUOT || error == -ENOSPC) && !retried) {
xfs_trans_cancel(tp);
xfs_exchrange_iunlock(ip1, ip2);
if (qretry & QRETRY_IP1)
xfs_blockgc_free_quota(ip1, 0);
if (qretry & QRETRY_IP2)
xfs_blockgc_free_quota(ip2, 0);
retried = true;
goto retry;
}
if (error)
goto out_trans_cancel;
/* If we got this far on a dry run, all parameters are ok. */
if (fxr->flags & XFS_EXCHANGE_RANGE_DRY_RUN)
goto out_trans_cancel;
/* Update the mtime and ctime of both files. */
if (fxr->flags & __XFS_EXCHANGE_RANGE_UPD_CMTIME1)
xfs_trans_ichgtime(tp, ip1, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
if (fxr->flags & __XFS_EXCHANGE_RANGE_UPD_CMTIME2)
xfs_trans_ichgtime(tp, ip2, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
xfs_exchange_mappings(tp, &req);
/*
* Force the log to persist metadata updates if the caller or the
* administrator requires this. The generic prep function already
* flushed the relevant parts of the page cache.
*/
if (xfs_has_wsync(mp) || (fxr->flags & XFS_EXCHANGE_RANGE_DSYNC))
xfs_trans_set_sync(tp);
error = xfs_trans_commit(tp);
trace_xfs_exchrange_after(ip2, 2);
trace_xfs_exchrange_after(ip1, 1);
if (error)
goto out_unlock;
/*
* If the caller wanted us to exchange the contents of two complete
* files of unequal length, exchange the incore sizes now. This should
* be safe because we flushed both files' page caches, exchanged all
* the mappings, and updated the ondisk sizes.
*/
if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) {
loff_t temp;
temp = i_size_read(VFS_I(ip2));
i_size_write(VFS_I(ip2), i_size_read(VFS_I(ip1)));
i_size_write(VFS_I(ip1), temp);
}
out_unlock:
xfs_exchrange_iunlock(ip1, ip2);
return error;
out_trans_cancel:
xfs_trans_cancel(tp);
goto out_unlock;
}
/*
* Generic code for exchanging ranges of two files via XFS_IOC_EXCHANGE_RANGE.
* This part deals with struct file objects and byte ranges and does not deal
* with XFS-specific data structures such as xfs_inodes and block ranges. This
* separation may some day facilitate porting to another filesystem.
*
* The goal is to exchange fxr.length bytes starting at fxr.file1_offset in
* file1 with the same number of bytes starting at fxr.file2_offset in file2.
* Implementations must call xfs_exchange_range_prep to prepare the two
* files prior to taking locks; and they must update the inode change and mod
* times of both files as part of the metadata update. The timestamp update
* and freshness checks must be done atomically as part of the data exchange
* operation to ensure correctness of the freshness check.
* xfs_exchange_range_finish must be called after the operation completes
* successfully but before locks are dropped.
*/
/* Verify that we have security clearance to perform this operation. */
static int
xfs_exchange_range_verify_area(
struct xfs_exchrange *fxr)
{
int ret;
ret = remap_verify_area(fxr->file1, fxr->file1_offset, fxr->length,
true);
if (ret)
return ret;
return remap_verify_area(fxr->file2, fxr->file2_offset, fxr->length,
true);
}
/*
* Performs necessary checks before doing a range exchange, having stabilized
* mutable inode attributes via i_rwsem.
*/
static inline int
xfs_exchange_range_checks(
struct xfs_exchrange *fxr,
unsigned int alloc_unit)
{
struct inode *inode1 = file_inode(fxr->file1);
struct inode *inode2 = file_inode(fxr->file2);
uint64_t allocmask = alloc_unit - 1;
int64_t test_len;
uint64_t blen;
loff_t size1, size2, tmp;
int error;
/* Don't touch certain kinds of inodes */
if (IS_IMMUTABLE(inode1) || IS_IMMUTABLE(inode2))
return -EPERM;
if (IS_SWAPFILE(inode1) || IS_SWAPFILE(inode2))
return -ETXTBSY;
size1 = i_size_read(inode1);
size2 = i_size_read(inode2);
/* Ranges cannot start after EOF. */
if (fxr->file1_offset > size1 || fxr->file2_offset > size2)
return -EINVAL;
/*
* If the caller said to exchange to EOF, we set the length of the
* request large enough to cover everything to the end of both files.
*/
if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) {
fxr->length = max_t(int64_t, size1 - fxr->file1_offset,
size2 - fxr->file2_offset);
error = xfs_exchange_range_verify_area(fxr);
if (error)
return error;
}
/*
* The start of both ranges must be aligned to the file allocation
* unit.
*/
if (!IS_ALIGNED(fxr->file1_offset, alloc_unit) ||
!IS_ALIGNED(fxr->file2_offset, alloc_unit))
return -EINVAL;
/* Ensure offsets don't wrap. */
if (check_add_overflow(fxr->file1_offset, fxr->length, &tmp) ||
check_add_overflow(fxr->file2_offset, fxr->length, &tmp))
return -EINVAL;
/*
* We require both ranges to end within EOF, unless we're exchanging
* to EOF.
*/
if (!(fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) &&
(fxr->file1_offset + fxr->length > size1 ||
fxr->file2_offset + fxr->length > size2))
return -EINVAL;
/*
* Make sure we don't hit any file size limits. If we hit any size
* limits such that test_length was adjusted, we abort the whole
* operation.
*/
test_len = fxr->length;
error = generic_write_check_limits(fxr->file2, fxr->file2_offset,
&test_len);
if (error)
return error;
error = generic_write_check_limits(fxr->file1, fxr->file1_offset,
&test_len);
if (error)
return error;
if (test_len != fxr->length)
return -EINVAL;
/*
* If the user wanted us to exchange up to the infile's EOF, round up
* to the next allocation unit boundary for this check. Do the same
* for the outfile.
*
* Otherwise, reject the range length if it's not aligned to an
* allocation unit.
*/
if (fxr->file1_offset + fxr->length == size1)
blen = ALIGN(size1, alloc_unit) - fxr->file1_offset;
else if (fxr->file2_offset + fxr->length == size2)
blen = ALIGN(size2, alloc_unit) - fxr->file2_offset;
else if (!IS_ALIGNED(fxr->length, alloc_unit))
return -EINVAL;
else
blen = fxr->length;
/* Don't allow overlapped exchanges within the same file. */
if (inode1 == inode2 &&
fxr->file2_offset + blen > fxr->file1_offset &&
fxr->file1_offset + blen > fxr->file2_offset)
return -EINVAL;
/*
* Ensure that we don't exchange a partial EOF block into the middle of
* another file.
*/
if ((fxr->length & allocmask) == 0)
return 0;
blen = fxr->length;
if (fxr->file2_offset + blen < size2)
blen &= ~allocmask;
if (fxr->file1_offset + blen < size1)
blen &= ~allocmask;
return blen == fxr->length ? 0 : -EINVAL;
}
/*
* Check that the two inodes are eligible for range exchanges, the ranges make
* sense, and then flush all dirty data. Caller must ensure that the inodes
* have been locked against any other modifications.
*/
static inline int
xfs_exchange_range_prep(
struct xfs_exchrange *fxr,
unsigned int alloc_unit)
{
struct inode *inode1 = file_inode(fxr->file1);
struct inode *inode2 = file_inode(fxr->file2);
bool same_inode = (inode1 == inode2);
int error;
/* Check that we don't violate system file offset limits. */
error = xfs_exchange_range_checks(fxr, alloc_unit);
if (error || fxr->length == 0)
return error;
/* Wait for the completion of any pending IOs on both files */
inode_dio_wait(inode1);
if (!same_inode)
inode_dio_wait(inode2);
error = filemap_write_and_wait_range(inode1->i_mapping,
fxr->file1_offset,
fxr->file1_offset + fxr->length - 1);
if (error)
return error;
error = filemap_write_and_wait_range(inode2->i_mapping,
fxr->file2_offset,
fxr->file2_offset + fxr->length - 1);
if (error)
return error;
/*
* If the files or inodes involved require synchronous writes, amend
* the request to force the filesystem to flush all data and metadata
* to disk after the operation completes.
*/
if (((fxr->file1->f_flags | fxr->file2->f_flags) & O_SYNC) ||
IS_SYNC(inode1) || IS_SYNC(inode2))
fxr->flags |= XFS_EXCHANGE_RANGE_DSYNC;
return 0;
}
/*
* Finish a range exchange operation, if it was successful. Caller must ensure
* that the inodes are still locked against any other modifications.
*/
static inline int
xfs_exchange_range_finish(
struct xfs_exchrange *fxr)
{
int error;
error = file_remove_privs(fxr->file1);
if (error)
return error;
if (file_inode(fxr->file1) == file_inode(fxr->file2))
return 0;
return file_remove_privs(fxr->file2);
}
/*
* Check the alignment of an exchange request when the allocation unit size
* isn't a power of two. The generic file-level helpers use (fast)
* bitmask-based alignment checks, but here we have to use slow long division.
*/
static int
xfs_exchrange_check_rtalign(
const struct xfs_exchrange *fxr,
struct xfs_inode *ip1,
struct xfs_inode *ip2,
unsigned int alloc_unit)
{
uint64_t length = fxr->length;
uint64_t blen;
loff_t size1, size2;
size1 = i_size_read(VFS_I(ip1));
size2 = i_size_read(VFS_I(ip2));
/* The start of both ranges must be aligned to a rt extent. */
if (!isaligned_64(fxr->file1_offset, alloc_unit) ||
!isaligned_64(fxr->file2_offset, alloc_unit))
return -EINVAL;
if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF)
length = max_t(int64_t, size1 - fxr->file1_offset,
size2 - fxr->file2_offset);
/*
* If the user wanted us to exchange up to the infile's EOF, round up
* to the next rt extent boundary for this check. Do the same for the
* outfile.
*
* Otherwise, reject the range length if it's not rt extent aligned.
* We already confirmed the starting offsets' rt extent block
* alignment.
*/
if (fxr->file1_offset + length == size1)
blen = roundup_64(size1, alloc_unit) - fxr->file1_offset;
else if (fxr->file2_offset + length == size2)
blen = roundup_64(size2, alloc_unit) - fxr->file2_offset;
else if (!isaligned_64(length, alloc_unit))
return -EINVAL;
else
blen = length;
/* Don't allow overlapped exchanges within the same file. */
if (ip1 == ip2 &&
fxr->file2_offset + blen > fxr->file1_offset &&
fxr->file1_offset + blen > fxr->file2_offset)
return -EINVAL;
/*
* Ensure that we don't exchange a partial EOF rt extent into the
* middle of another file.
*/
if (isaligned_64(length, alloc_unit))
return 0;
blen = length;
if (fxr->file2_offset + length < size2)
blen = rounddown_64(blen, alloc_unit);
if (fxr->file1_offset + blen < size1)
blen = rounddown_64(blen, alloc_unit);
return blen == length ? 0 : -EINVAL;
}
/* Prepare two files to have their data exchanged. */
STATIC int
xfs_exchrange_prep(
struct xfs_exchrange *fxr,
struct xfs_inode *ip1,
struct xfs_inode *ip2)
{
struct xfs_mount *mp = ip2->i_mount;
unsigned int alloc_unit = xfs_inode_alloc_unitsize(ip2);
int error;
trace_xfs_exchrange_prep(fxr, ip1, ip2);
/* Verify both files are either real-time or non-realtime */
if (XFS_IS_REALTIME_INODE(ip1) != XFS_IS_REALTIME_INODE(ip2))
return -EINVAL;
/* Check non-power of two alignment issues, if necessary. */
if (!is_power_of_2(alloc_unit)) {
error = xfs_exchrange_check_rtalign(fxr, ip1, ip2, alloc_unit);
if (error)
return error;
/*
* Do the generic file-level checks with the regular block
* alignment.
*/
alloc_unit = mp->m_sb.sb_blocksize;
}
error = xfs_exchange_range_prep(fxr, alloc_unit);
if (error || fxr->length == 0)
return error;
if (fxr->flags & __XFS_EXCHANGE_RANGE_CHECK_FRESH2) {
error = xfs_exchrange_check_freshness(fxr, ip2);
if (error)
return error;
}
/* Attach dquots to both inodes before changing block maps. */
error = xfs_qm_dqattach(ip2);
if (error)
return error;
error = xfs_qm_dqattach(ip1);
if (error)
return error;
trace_xfs_exchrange_flush(fxr, ip1, ip2);
/* Flush the relevant ranges of both files. */
error = xfs_flush_unmap_range(ip2, fxr->file2_offset, fxr->length);
if (error)
return error;
error = xfs_flush_unmap_range(ip1, fxr->file1_offset, fxr->length);
if (error)
return error;
/*
* Cancel CoW fork preallocations for the ranges of both files. The
* prep function should have flushed all the dirty data, so the only
* CoW mappings remaining should be speculative.
*/
if (xfs_inode_has_cow_data(ip1)) {
error = xfs_reflink_cancel_cow_range(ip1, fxr->file1_offset,
fxr->length, true);
if (error)
return error;
}
if (xfs_inode_has_cow_data(ip2)) {
error = xfs_reflink_cancel_cow_range(ip2, fxr->file2_offset,
fxr->length, true);
if (error)
return error;
}
return 0;
}
/*
* Exchange contents of files. This is the binding between the generic
* file-level concepts and the XFS inode-specific implementation.
*/
STATIC int
xfs_exchrange_contents(
struct xfs_exchrange *fxr)
{
struct inode *inode1 = file_inode(fxr->file1);
struct inode *inode2 = file_inode(fxr->file2);
struct xfs_inode *ip1 = XFS_I(inode1);
struct xfs_inode *ip2 = XFS_I(inode2);
struct xfs_mount *mp = ip1->i_mount;
int error;
if (!xfs_has_exchange_range(mp))
return -EOPNOTSUPP;
if (fxr->flags & ~(XFS_EXCHANGE_RANGE_ALL_FLAGS |
XFS_EXCHANGE_RANGE_PRIV_FLAGS))
return -EINVAL;
if (xfs_is_shutdown(mp))
return -EIO;
/* Lock both files against IO */
error = xfs_ilock2_io_mmap(ip1, ip2);
if (error)
goto out_err;
/* Prepare and then exchange file contents. */
error = xfs_exchrange_prep(fxr, ip1, ip2);
if (error)
goto out_unlock;
error = xfs_exchrange_mappings(fxr, ip1, ip2);
if (error)
goto out_unlock;
/*
* Finish the exchange by removing special file privileges like any
* other file write would do. This may involve turning on support for
* logged xattrs if either file has security capabilities.
*/
error = xfs_exchange_range_finish(fxr);
if (error)
goto out_unlock;
out_unlock:
xfs_iunlock2_io_mmap(ip1, ip2);
out_err:
if (error)
trace_xfs_exchrange_error(ip2, error, _RET_IP_);
return error;
}
/* Exchange parts of two files. */
static int
xfs_exchange_range(
struct xfs_exchrange *fxr)
{
struct inode *inode1 = file_inode(fxr->file1);
struct inode *inode2 = file_inode(fxr->file2);
int ret;
BUILD_BUG_ON(XFS_EXCHANGE_RANGE_ALL_FLAGS &
XFS_EXCHANGE_RANGE_PRIV_FLAGS);
/* Both files must be on the same mount/filesystem. */
if (fxr->file1->f_path.mnt != fxr->file2->f_path.mnt)
return -EXDEV;
if (fxr->flags & ~(XFS_EXCHANGE_RANGE_ALL_FLAGS |
__XFS_EXCHANGE_RANGE_CHECK_FRESH2))
return -EINVAL;
/* Userspace requests only honored for regular files. */
if (S_ISDIR(inode1->i_mode) || S_ISDIR(inode2->i_mode))
return -EISDIR;
if (!S_ISREG(inode1->i_mode) || !S_ISREG(inode2->i_mode))
return -EINVAL;
/* Both files must be opened for read and write. */
if (!(fxr->file1->f_mode & FMODE_READ) ||
!(fxr->file1->f_mode & FMODE_WRITE) ||
!(fxr->file2->f_mode & FMODE_READ) ||
!(fxr->file2->f_mode & FMODE_WRITE))
return -EBADF;
/* Neither file can be opened append-only. */
if ((fxr->file1->f_flags & O_APPEND) ||
(fxr->file2->f_flags & O_APPEND))
return -EBADF;
/*
* If we're not exchanging to EOF, we can check the areas before
* stabilizing both files' i_size.
*/
if (!(fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF)) {
ret = xfs_exchange_range_verify_area(fxr);
if (ret)
return ret;
}
/* Update cmtime if the fd/inode don't forbid it. */
if (!(fxr->file1->f_mode & FMODE_NOCMTIME) && !IS_NOCMTIME(inode1))
fxr->flags |= __XFS_EXCHANGE_RANGE_UPD_CMTIME1;
if (!(fxr->file2->f_mode & FMODE_NOCMTIME) && !IS_NOCMTIME(inode2))
fxr->flags |= __XFS_EXCHANGE_RANGE_UPD_CMTIME2;
file_start_write(fxr->file2);
ret = xfs_exchrange_contents(fxr);
file_end_write(fxr->file2);
if (ret)
return ret;
fsnotify_modify(fxr->file1);
if (fxr->file2 != fxr->file1)
fsnotify_modify(fxr->file2);
return 0;
}
/* Collect exchange-range arguments from userspace. */
long
xfs_ioc_exchange_range(
struct file *file,
struct xfs_exchange_range __user *argp)
{
struct xfs_exchrange fxr = {
.file2 = file,
};
struct xfs_exchange_range args;
struct fd file1;
int error;
if (copy_from_user(&args, argp, sizeof(args)))
return -EFAULT;
if (memchr_inv(&args.pad, 0, sizeof(args.pad)))
return -EINVAL;
if (args.flags & ~XFS_EXCHANGE_RANGE_ALL_FLAGS)
return -EINVAL;
fxr.file1_offset = args.file1_offset;
fxr.file2_offset = args.file2_offset;
fxr.length = args.length;
fxr.flags = args.flags;
file1 = fdget(args.file1_fd);
if (!fd_file(file1))
return -EBADF;
fxr.file1 = fd_file(file1);
error = xfs_exchange_range(&fxr);
fdput(file1);
return error;
}
/* Opaque freshness blob for XFS_IOC_COMMIT_RANGE */
struct xfs_commit_range_fresh {
xfs_fsid_t fsid; /* m_fixedfsid */
__u64 file2_ino; /* inode number */
__s64 file2_mtime; /* modification time */
__s64 file2_ctime; /* change time */
__s32 file2_mtime_nsec; /* mod time, nsec */
__s32 file2_ctime_nsec; /* change time, nsec */
__u32 file2_gen; /* inode generation */
__u32 magic; /* zero */
};
#define XCR_FRESH_MAGIC 0x444F524B /* DORK */
/* Set up a commitrange operation by sampling file2's write-related attrs */
long
xfs_ioc_start_commit(
struct file *file,
struct xfs_commit_range __user *argp)
{
struct xfs_commit_range args = { };
struct timespec64 ts;
struct xfs_commit_range_fresh *kern_f;
struct xfs_commit_range_fresh __user *user_f;
struct inode *inode2 = file_inode(file);
struct xfs_inode *ip2 = XFS_I(inode2);
const unsigned int lockflags = XFS_IOLOCK_SHARED |
XFS_MMAPLOCK_SHARED |
XFS_ILOCK_SHARED;
BUILD_BUG_ON(sizeof(struct xfs_commit_range_fresh) !=
sizeof(args.file2_freshness));
kern_f = (struct xfs_commit_range_fresh *)&args.file2_freshness;
memcpy(&kern_f->fsid, ip2->i_mount->m_fixedfsid, sizeof(xfs_fsid_t));
xfs_ilock(ip2, lockflags);
ts = inode_get_ctime(inode2);
kern_f->file2_ctime = ts.tv_sec;
kern_f->file2_ctime_nsec = ts.tv_nsec;
ts = inode_get_mtime(inode2);
kern_f->file2_mtime = ts.tv_sec;
kern_f->file2_mtime_nsec = ts.tv_nsec;
kern_f->file2_ino = ip2->i_ino;
kern_f->file2_gen = inode2->i_generation;
kern_f->magic = XCR_FRESH_MAGIC;
xfs_iunlock(ip2, lockflags);
user_f = (struct xfs_commit_range_fresh __user *)&argp->file2_freshness;
if (copy_to_user(user_f, kern_f, sizeof(*kern_f)))
return -EFAULT;
return 0;
}
/*
* Exchange file1 and file2 contents if file2 has not been written since the
* start commit operation.
*/
long
xfs_ioc_commit_range(
struct file *file,
struct xfs_commit_range __user *argp)
{
struct xfs_exchrange fxr = {
.file2 = file,
};
struct xfs_commit_range args;
struct xfs_commit_range_fresh *kern_f;
struct xfs_inode *ip2 = XFS_I(file_inode(file));
struct xfs_mount *mp = ip2->i_mount;
struct fd file1;
int error;
kern_f = (struct xfs_commit_range_fresh *)&args.file2_freshness;
if (copy_from_user(&args, argp, sizeof(args)))
return -EFAULT;
if (args.flags & ~XFS_EXCHANGE_RANGE_ALL_FLAGS)
return -EINVAL;
if (kern_f->magic != XCR_FRESH_MAGIC)
return -EBUSY;
if (memcmp(&kern_f->fsid, mp->m_fixedfsid, sizeof(xfs_fsid_t)))
return -EBUSY;
fxr.file1_offset = args.file1_offset;
fxr.file2_offset = args.file2_offset;
fxr.length = args.length;
fxr.flags = args.flags | __XFS_EXCHANGE_RANGE_CHECK_FRESH2;
fxr.file2_ino = kern_f->file2_ino;
fxr.file2_gen = kern_f->file2_gen;
fxr.file2_mtime.tv_sec = kern_f->file2_mtime;
fxr.file2_mtime.tv_nsec = kern_f->file2_mtime_nsec;
fxr.file2_ctime.tv_sec = kern_f->file2_ctime;
fxr.file2_ctime.tv_nsec = kern_f->file2_ctime_nsec;
file1 = fdget(args.file1_fd);
if (fd_empty(file1))
return -EBADF;
fxr.file1 = fd_file(file1);
error = xfs_exchange_range(&fxr);
fdput(file1);
return error;
}
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