// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2014 Christoph Hellwig.
*/
#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_inode.h"
#include "xfs_trans.h"
#include "xfs_bmap.h"
#include "xfs_iomap.h"
#include "xfs_pnfs.h"
/*
* Ensure that we do not have any outstanding pNFS layouts that can be used by
* clients to directly read from or write to this inode. This must be called
* before every operation that can remove blocks from the extent map.
* Additionally we call it during the write operation, where aren't concerned
* about exposing unallocated blocks but just want to provide basic
* synchronization between a local writer and pNFS clients. mmap writes would
* also benefit from this sort of synchronization, but due to the tricky locking
* rules in the page fault path we don't bother.
*/
int
xfs_break_leased_layouts(
struct inode *inode,
uint *iolock,
bool *did_unlock)
{
struct xfs_inode *ip = XFS_I(inode);
int error;
while ((error = break_layout(inode, false)) == -EWOULDBLOCK) {
xfs_iunlock(ip, *iolock);
*did_unlock = true;
error = break_layout(inode, true);
*iolock &= ~XFS_IOLOCK_SHARED;
*iolock |= XFS_IOLOCK_EXCL;
xfs_ilock(ip, *iolock);
}
return error;
}
/*
* Get a unique ID including its location so that the client can identify
* the exported device.
*/
int
xfs_fs_get_uuid(
struct super_block *sb,
u8 *buf,
u32 *len,
u64 *offset)
{
struct xfs_mount *mp = XFS_M(sb);
xfs_notice_once(mp,
"Using experimental pNFS feature, use at your own risk!");
if (*len < sizeof(uuid_t))
return -EINVAL;
memcpy(buf, &mp->m_sb.sb_uuid, sizeof(uuid_t));
*len = sizeof(uuid_t);
*offset = offsetof(struct xfs_dsb, sb_uuid);
return 0;
}
/*
* We cannot use file based VFS helpers such as file_modified() to update
* inode state as we modify the data/metadata in the inode here. Hence we have
* to open code the timestamp updates and SUID/SGID stripping. We also need
* to set the inode prealloc flag to ensure that the extents we allocate are not
* removed if the inode is reclaimed from memory before xfs_fs_block_commit()
* is from the client to indicate that data has been written and the file size
* can be extended.
*/
static int
xfs_fs_map_update_inode(
struct xfs_inode *ip)
{
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);
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);
ip->i_diflags |= XFS_DIFLAG_PREALLOC;
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
return xfs_trans_commit(tp);
}
/*
* Get a layout for the pNFS client.
*/
int
xfs_fs_map_blocks(
struct inode *inode,
loff_t offset,
u64 length,
struct iomap *iomap,
bool write,
u32 *device_generation)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
struct xfs_bmbt_irec imap;
xfs_fileoff_t offset_fsb, end_fsb;
loff_t limit;
int bmapi_flags = XFS_BMAPI_ENTIRE;
int nimaps = 1;
uint lock_flags;
int error = 0;
u64 seq;
if (xfs_is_shutdown(mp))
return -EIO;
/*
* We can't export inodes residing on the realtime device. The realtime
* device doesn't have a UUID to identify it, so the client has no way
* to find it.
*/
if (XFS_IS_REALTIME_INODE(ip))
return -ENXIO;
/*
* The pNFS block layout spec actually supports reflink like
* functionality, but the Linux pNFS server doesn't implement it yet.
*/
if (xfs_is_reflink_inode(ip))
return -ENXIO;
/*
* Lock out any other I/O before we flush and invalidate the pagecache,
* and then hand out a layout to the remote system. This is very
* similar to direct I/O, except that the synchronization is much more
* complicated. See the comment near xfs_break_leased_layouts
* for a detailed explanation.
*/
xfs_ilock(ip, XFS_IOLOCK_EXCL);
error = -EINVAL;
limit = mp->m_super->s_maxbytes;
if (!write)
limit = max(limit, round_up(i_size_read(inode),
inode->i_sb->s_blocksize));
if (offset > limit)
goto out_unlock;
if (offset > limit - length)
length = limit - offset;
error = filemap_write_and_wait(inode->i_mapping);
if (error)
goto out_unlock;
error = invalidate_inode_pages2(inode->i_mapping);
if (WARN_ON_ONCE(error))
goto out_unlock;
end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + length);
offset_fsb = XFS_B_TO_FSBT(mp, offset);
lock_flags = xfs_ilock_data_map_shared(ip);
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
&imap, &nimaps, bmapi_flags);
seq = xfs_iomap_inode_sequence(ip, 0);
ASSERT(!nimaps || imap.br_startblock != DELAYSTARTBLOCK);
if (!error && write &&
(!nimaps || imap.br_startblock == HOLESTARTBLOCK)) {
if (offset + length > XFS_ISIZE(ip))
end_fsb = xfs_iomap_eof_align_last_fsb(ip, end_fsb);
else if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
end_fsb = min(end_fsb, imap.br_startoff +
imap.br_blockcount);
xfs_iunlock(ip, lock_flags);
error = xfs_iomap_write_direct(ip, offset_fsb,
end_fsb - offset_fsb, 0, &imap, &seq);
if (error)
goto out_unlock;
/*
* Ensure the next transaction is committed synchronously so
* that the blocks allocated and handed out to the client are
* guaranteed to be present even after a server crash.
*/
error = xfs_fs_map_update_inode(ip);
if (!error)
error = xfs_log_force_inode(ip);
if (error)
goto out_unlock;
} else {
xfs_iunlock(ip, lock_flags);
}
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
error = xfs_bmbt_to_iomap(ip, iomap, &imap, 0, 0, seq);
*device_generation = mp->m_generation;
return error;
out_unlock:
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
return error;
}
/*
* Ensure the size update falls into a valid allocated block.
*/
static int
xfs_pnfs_validate_isize(
struct xfs_inode *ip,
xfs_off_t isize)
{
struct xfs_bmbt_irec imap;
int nimaps = 1;
int error = 0;
xfs_ilock(ip, XFS_ILOCK_SHARED);
error = xfs_bmapi_read(ip, XFS_B_TO_FSBT(ip->i_mount, isize - 1), 1,
&imap, &nimaps, 0);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (error)
return error;
if (imap.br_startblock == HOLESTARTBLOCK ||
imap.br_startblock == DELAYSTARTBLOCK ||
imap.br_state == XFS_EXT_UNWRITTEN)
return -EIO;
return 0;
}
/*
* Make sure the blocks described by maps are stable on disk. This includes
* converting any unwritten extents, flushing the disk cache and updating the
* time stamps.
*
* Note that we rely on the caller to always send us a timestamp update so that
* we always commit a transaction here. If that stops being true we will have
* to manually flush the cache here similar to what the fsync code path does
* for datasyncs on files that have no dirty metadata.
*/
int
xfs_fs_commit_blocks(
struct inode *inode,
struct iomap *maps,
int nr_maps,
struct iattr *iattr)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
struct xfs_trans *tp;
bool update_isize = false;
int error, i;
loff_t size;
ASSERT(iattr->ia_valid & (ATTR_ATIME|ATTR_CTIME|ATTR_MTIME));
xfs_ilock(ip, XFS_IOLOCK_EXCL);
size = i_size_read(inode);
if ((iattr->ia_valid & ATTR_SIZE) && iattr->ia_size > size) {
update_isize = true;
size = iattr->ia_size;
}
for (i = 0; i < nr_maps; i++) {
u64 start, length, end;
start = maps[i].offset;
if (start > size)
continue;
end = start + maps[i].length;
if (end > size)
end = size;
length = end - start;
if (!length)
continue;
/*
* Make sure reads through the pagecache see the new data.
*/
error = invalidate_inode_pages2_range(inode->i_mapping,
start >> PAGE_SHIFT,
(end - 1) >> PAGE_SHIFT);
WARN_ON_ONCE(error);
error = xfs_iomap_write_unwritten(ip, start, length, false);
if (error)
goto out_drop_iolock;
}
if (update_isize) {
error = xfs_pnfs_validate_isize(ip, size);
if (error)
goto out_drop_iolock;
}
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
if (error)
goto out_drop_iolock;
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
ASSERT(!(iattr->ia_valid & (ATTR_UID | ATTR_GID)));
setattr_copy(&nop_mnt_idmap, inode, iattr);
if (update_isize) {
i_size_write(inode, iattr->ia_size);
ip->i_disk_size = iattr->ia_size;
}
xfs_trans_set_sync(tp);
error = xfs_trans_commit(tp);
out_drop_iolock:
xfs_iunlock(ip, XFS_IOLOCK_EXCL);
return error;
}
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