// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/ext4/file.c
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card ([email protected])
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
*
* from
*
* linux/fs/minix/file.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* ext4 fs regular file handling primitives
*
* 64-bit file support on 64-bit platforms by Jakub Jelinek
* ([email protected])
*/
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/iomap.h>
#include <linux/mount.h>
#include <linux/path.h>
#include <linux/dax.h>
#include <linux/quotaops.h>
#include <linux/pagevec.h>
#include <linux/uio.h>
#include <linux/mman.h>
#include <linux/backing-dev.h>
#include "ext4.h"
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
#include "truncate.h"
/*
* Returns %true if the given DIO request should be attempted with DIO, or
* %false if it should fall back to buffered I/O.
*
* DIO isn't well specified; when it's unsupported (either due to the request
* being misaligned, or due to the file not supporting DIO at all), filesystems
* either fall back to buffered I/O or return EINVAL. For files that don't use
* any special features like encryption or verity, ext4 has traditionally
* returned EINVAL for misaligned DIO. iomap_dio_rw() uses this convention too.
* In this case, we should attempt the DIO, *not* fall back to buffered I/O.
*
* In contrast, in cases where DIO is unsupported due to ext4 features, ext4
* traditionally falls back to buffered I/O.
*
* This function implements the traditional ext4 behavior in all these cases.
*/
static bool ext4_should_use_dio(struct kiocb *iocb, struct iov_iter *iter)
{
struct inode *inode = file_inode(iocb->ki_filp);
u32 dio_align = ext4_dio_alignment(inode);
if (dio_align == 0)
return false;
if (dio_align == 1)
return true;
return IS_ALIGNED(iocb->ki_pos | iov_iter_alignment(iter), dio_align);
}
static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
ssize_t ret;
struct inode *inode = file_inode(iocb->ki_filp);
if (iocb->ki_flags & IOCB_NOWAIT) {
if (!inode_trylock_shared(inode))
return -EAGAIN;
} else {
inode_lock_shared(inode);
}
if (!ext4_should_use_dio(iocb, to)) {
inode_unlock_shared(inode);
/*
* Fallback to buffered I/O if the operation being performed on
* the inode is not supported by direct I/O. The IOCB_DIRECT
* flag needs to be cleared here in order to ensure that the
* direct I/O path within generic_file_read_iter() is not
* taken.
*/
iocb->ki_flags &= ~IOCB_DIRECT;
return generic_file_read_iter(iocb, to);
}
ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL, 0, NULL, 0);
inode_unlock_shared(inode);
file_accessed(iocb->ki_filp);
return ret;
}
#ifdef CONFIG_FS_DAX
static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;
if (iocb->ki_flags & IOCB_NOWAIT) {
if (!inode_trylock_shared(inode))
return -EAGAIN;
} else {
inode_lock_shared(inode);
}
/*
* Recheck under inode lock - at this point we are sure it cannot
* change anymore
*/
if (!IS_DAX(inode)) {
inode_unlock_shared(inode);
/* Fallback to buffered IO in case we cannot support DAX */
return generic_file_read_iter(iocb, to);
}
ret = dax_iomap_rw(iocb, to, &ext4_iomap_ops);
inode_unlock_shared(inode);
file_accessed(iocb->ki_filp);
return ret;
}
#endif
static ssize_t ext4_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct inode *inode = file_inode(iocb->ki_filp);
if (unlikely(ext4_forced_shutdown(inode->i_sb)))
return -EIO;
if (!iov_iter_count(to))
return 0; /* skip atime */
#ifdef CONFIG_FS_DAX
if (IS_DAX(inode))
return ext4_dax_read_iter(iocb, to);
#endif
if (iocb->ki_flags & IOCB_DIRECT)
return ext4_dio_read_iter(iocb, to);
return generic_file_read_iter(iocb, to);
}
static ssize_t ext4_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);
if (unlikely(ext4_forced_shutdown(inode->i_sb)))
return -EIO;
return filemap_splice_read(in, ppos, pipe, len, flags);
}
/*
* Called when an inode is released. Note that this is different
* from ext4_file_open: open gets called at every open, but release
* gets called only when /all/ the files are closed.
*/
static int ext4_release_file(struct inode *inode, struct file *filp)
{
if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
ext4_alloc_da_blocks(inode);
ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
}
/* if we are the last writer on the inode, drop the block reservation */
if ((filp->f_mode & FMODE_WRITE) &&
(atomic_read(&inode->i_writecount) == 1) &&
!EXT4_I(inode)->i_reserved_data_blocks) {
down_write(&EXT4_I(inode)->i_data_sem);
ext4_discard_preallocations(inode);
up_write(&EXT4_I(inode)->i_data_sem);
}
if (is_dx(inode) && filp->private_data)
ext4_htree_free_dir_info(filp->private_data);
return 0;
}
/*
* This tests whether the IO in question is block-aligned or not.
* Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
* are converted to written only after the IO is complete. Until they are
* mapped, these blocks appear as holes, so dio_zero_block() will assume that
* it needs to zero out portions of the start and/or end block. If 2 AIO
* threads are at work on the same unwritten block, they must be synchronized
* or one thread will zero the other's data, causing corruption.
*/
static bool
ext4_unaligned_io(struct inode *inode, struct iov_iter *from, loff_t pos)
{
struct super_block *sb = inode->i_sb;
unsigned long blockmask = sb->s_blocksize - 1;
if ((pos | iov_iter_alignment(from)) & blockmask)
return true;
return false;
}
static bool
ext4_extending_io(struct inode *inode, loff_t offset, size_t len)
{
if (offset + len > i_size_read(inode) ||
offset + len > EXT4_I(inode)->i_disksize)
return true;
return false;
}
/* Is IO overwriting allocated or initialized blocks? */
static bool ext4_overwrite_io(struct inode *inode,
loff_t pos, loff_t len, bool *unwritten)
{
struct ext4_map_blocks map;
unsigned int blkbits = inode->i_blkbits;
int err, blklen;
if (pos + len > i_size_read(inode))
return false;
map.m_lblk = pos >> blkbits;
map.m_len = EXT4_MAX_BLOCKS(len, pos, blkbits);
blklen = map.m_len;
err = ext4_map_blocks(NULL, inode, &map, 0);
if (err != blklen)
return false;
/*
* 'err==len' means that all of the blocks have been preallocated,
* regardless of whether they have been initialized or not. We need to
* check m_flags to distinguish the unwritten extents.
*/
*unwritten = !(map.m_flags & EXT4_MAP_MAPPED);
return true;
}
static ssize_t ext4_generic_write_checks(struct kiocb *iocb,
struct iov_iter *from)
{
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;
if (unlikely(IS_IMMUTABLE(inode)))
return -EPERM;
ret = generic_write_checks(iocb, from);
if (ret <= 0)
return ret;
/*
* If we have encountered a bitmap-format file, the size limit
* is smaller than s_maxbytes, which is for extent-mapped files.
*/
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
if (iocb->ki_pos >= sbi->s_bitmap_maxbytes)
return -EFBIG;
iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos);
}
return iov_iter_count(from);
}
static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from)
{
ssize_t ret, count;
count = ext4_generic_write_checks(iocb, from);
if (count <= 0)
return count;
ret = file_modified(iocb->ki_filp);
if (ret)
return ret;
return count;
}
static ssize_t ext4_buffered_write_iter(struct kiocb *iocb,
struct iov_iter *from)
{
ssize_t ret;
struct inode *inode = file_inode(iocb->ki_filp);
if (iocb->ki_flags & IOCB_NOWAIT)
return -EOPNOTSUPP;
inode_lock(inode);
ret = ext4_write_checks(iocb, from);
if (ret <= 0)
goto out;
ret = generic_perform_write(iocb, from);
out:
inode_unlock(inode);
if (unlikely(ret <= 0))
return ret;
return generic_write_sync(iocb, ret);
}
static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset,
ssize_t written, ssize_t count)
{
handle_t *handle;
lockdep_assert_held_write(&inode->i_rwsem);
handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle))
return PTR_ERR(handle);
if (ext4_update_inode_size(inode, offset + written)) {
int ret = ext4_mark_inode_dirty(handle, inode);
if (unlikely(ret)) {
ext4_journal_stop(handle);
return ret;
}
}
if ((written == count) && inode->i_nlink)
ext4_orphan_del(handle, inode);
ext4_journal_stop(handle);
return written;
}
/*
* Clean up the inode after DIO or DAX extending write has completed and the
* inode size has been updated using ext4_handle_inode_extension().
*/
static void ext4_inode_extension_cleanup(struct inode *inode, bool need_trunc)
{
lockdep_assert_held_write(&inode->i_rwsem);
if (need_trunc) {
ext4_truncate_failed_write(inode);
/*
* If the truncate operation failed early, then the inode may
* still be on the orphan list. In that case, we need to try
* remove the inode from the in-memory linked list.
*/
if (inode->i_nlink)
ext4_orphan_del(NULL, inode);
return;
}
/*
* If i_disksize got extended either due to writeback of delalloc
* blocks or extending truncate while the DIO was running we could fail
* to cleanup the orphan list in ext4_handle_inode_extension(). Do it
* now.
*/
if (!list_empty(&EXT4_I(inode)->i_orphan) && inode->i_nlink) {
handle_t *handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle)) {
/*
* The write has successfully completed. Not much to
* do with the error here so just cleanup the orphan
* list and hope for the best.
*/
ext4_orphan_del(NULL, inode);
return;
}
ext4_orphan_del(handle, inode);
ext4_journal_stop(handle);
}
}
static int ext4_dio_write_end_io(struct kiocb *iocb, ssize_t size,
int error, unsigned int flags)
{
loff_t pos = iocb->ki_pos;
struct inode *inode = file_inode(iocb->ki_filp);
if (!error && size && flags & IOMAP_DIO_UNWRITTEN)
error = ext4_convert_unwritten_extents(NULL, inode, pos, size);
if (error)
return error;
/*
* Note that EXT4_I(inode)->i_disksize can get extended up to
* inode->i_size while the I/O was running due to writeback of delalloc
* blocks. But the code in ext4_iomap_alloc() is careful to use
* zeroed/unwritten extents if this is possible; thus we won't leave
* uninitialized blocks in a file even if we didn't succeed in writing
* as much as we intended. Also we can race with truncate or write
* expanding the file so we have to be a bit careful here.
*/
if (pos + size <= READ_ONCE(EXT4_I(inode)->i_disksize) &&
pos + size <= i_size_read(inode))
return size;
return ext4_handle_inode_extension(inode, pos, size, size);
}
static const struct iomap_dio_ops ext4_dio_write_ops = {
.end_io = ext4_dio_write_end_io,
};
/*
* The intention here is to start with shared lock acquired then see if any
* condition requires an exclusive inode lock. If yes, then we restart the
* whole operation by releasing the shared lock and acquiring exclusive lock.
*
* - For unaligned_io we never take shared lock as it may cause data corruption
* when two unaligned IO tries to modify the same block e.g. while zeroing.
*
* - For extending writes case we don't take the shared lock, since it requires
* updating inode i_disksize and/or orphan handling with exclusive lock.
*
* - shared locking will only be true mostly with overwrites, including
* initialized blocks and unwritten blocks. For overwrite unwritten blocks
* we protect splitting extents by i_data_sem in ext4_inode_info, so we can
* also release exclusive i_rwsem lock.
*
* - Otherwise we will switch to exclusive i_rwsem lock.
*/
static ssize_t ext4_dio_write_checks(struct kiocb *iocb, struct iov_iter *from,
bool *ilock_shared, bool *extend,
bool *unwritten, int *dio_flags)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
loff_t offset;
size_t count;
ssize_t ret;
bool overwrite, unaligned_io;
restart:
ret = ext4_generic_write_checks(iocb, from);
if (ret <= 0)
goto out;
offset = iocb->ki_pos;
count = ret;
unaligned_io = ext4_unaligned_io(inode, from, offset);
*extend = ext4_extending_io(inode, offset, count);
overwrite = ext4_overwrite_io(inode, offset, count, unwritten);
/*
* Determine whether we need to upgrade to an exclusive lock. This is
* required to change security info in file_modified(), for extending
* I/O, any form of non-overwrite I/O, and unaligned I/O to unwritten
* extents (as partial block zeroing may be required).
*
* Note that unaligned writes are allowed under shared lock so long as
* they are pure overwrites. Otherwise, concurrent unaligned writes risk
* data corruption due to partial block zeroing in the dio layer, and so
* the I/O must occur exclusively.
*/
if (*ilock_shared &&
((!IS_NOSEC(inode) || *extend || !overwrite ||
(unaligned_io && *unwritten)))) {
if (iocb->ki_flags & IOCB_NOWAIT) {
ret = -EAGAIN;
goto out;
}
inode_unlock_shared(inode);
*ilock_shared = false;
inode_lock(inode);
goto restart;
}
/*
* Now that locking is settled, determine dio flags and exclusivity
* requirements. We don't use DIO_OVERWRITE_ONLY because we enforce
* behavior already. The inode lock is already held exclusive if the
* write is non-overwrite or extending, so drain all outstanding dio and
* set the force wait dio flag.
*/
if (!*ilock_shared && (unaligned_io || *extend)) {
if (iocb->ki_flags & IOCB_NOWAIT) {
ret = -EAGAIN;
goto out;
}
if (unaligned_io && (!overwrite || *unwritten))
inode_dio_wait(inode);
*dio_flags = IOMAP_DIO_FORCE_WAIT;
}
ret = file_modified(file);
if (ret < 0)
goto out;
return count;
out:
if (*ilock_shared)
inode_unlock_shared(inode);
else
inode_unlock(inode);
return ret;
}
static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
ssize_t ret;
handle_t *handle;
struct inode *inode = file_inode(iocb->ki_filp);
loff_t offset = iocb->ki_pos;
size_t count = iov_iter_count(from);
const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
bool extend = false, unwritten = false;
bool ilock_shared = true;
int dio_flags = 0;
/*
* Quick check here without any i_rwsem lock to see if it is extending
* IO. A more reliable check is done in ext4_dio_write_checks() with
* proper locking in place.
*/
if (offset + count > i_size_read(inode))
ilock_shared = false;
if (iocb->ki_flags & IOCB_NOWAIT) {
if (ilock_shared) {
if (!inode_trylock_shared(inode))
return -EAGAIN;
} else {
if (!inode_trylock(inode))
return -EAGAIN;
}
} else {
if (ilock_shared)
inode_lock_shared(inode);
else
inode_lock(inode);
}
/* Fallback to buffered I/O if the inode does not support direct I/O. */
if (!ext4_should_use_dio(iocb, from)) {
if (ilock_shared)
inode_unlock_shared(inode);
else
inode_unlock(inode);
return ext4_buffered_write_iter(iocb, from);
}
/*
* Prevent inline data from being created since we are going to allocate
* blocks for DIO. We know the inode does not currently have inline data
* because ext4_should_use_dio() checked for it, but we have to clear
* the state flag before the write checks because a lock cycle could
* introduce races with other writers.
*/
ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend,
&unwritten, &dio_flags);
if (ret <= 0)
return ret;
offset = iocb->ki_pos;
count = ret;
if (extend) {
handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out;
}
ret = ext4_orphan_add(handle, inode);
if (ret) {
ext4_journal_stop(handle);
goto out;
}
ext4_journal_stop(handle);
}
if (ilock_shared && !unwritten)
iomap_ops = &ext4_iomap_overwrite_ops;
ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
dio_flags, NULL, 0);
if (ret == -ENOTBLK)
ret = 0;
if (extend) {
/*
* We always perform extending DIO write synchronously so by
* now the IO is completed and ext4_handle_inode_extension()
* was called. Cleanup the inode in case of error or race with
* writeback of delalloc blocks.
*/
WARN_ON_ONCE(ret == -EIOCBQUEUED);
ext4_inode_extension_cleanup(inode, ret < 0);
}
out:
if (ilock_shared)
inode_unlock_shared(inode);
else
inode_unlock(inode);
if (ret >= 0 && iov_iter_count(from)) {
ssize_t err;
loff_t endbyte;
offset = iocb->ki_pos;
err = ext4_buffered_write_iter(iocb, from);
if (err < 0)
return err;
/*
* We need to ensure that the pages within the page cache for
* the range covered by this I/O are written to disk and
* invalidated. This is in attempt to preserve the expected
* direct I/O semantics in the case we fallback to buffered I/O
* to complete off the I/O request.
*/
ret += err;
endbyte = offset + err - 1;
err = filemap_write_and_wait_range(iocb->ki_filp->f_mapping,
offset, endbyte);
if (!err)
invalidate_mapping_pages(iocb->ki_filp->f_mapping,
offset >> PAGE_SHIFT,
endbyte >> PAGE_SHIFT);
}
return ret;
}
#ifdef CONFIG_FS_DAX
static ssize_t
ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
ssize_t ret;
size_t count;
loff_t offset;
handle_t *handle;
bool extend = false;
struct inode *inode = file_inode(iocb->ki_filp);
if (iocb->ki_flags & IOCB_NOWAIT) {
if (!inode_trylock(inode))
return -EAGAIN;
} else {
inode_lock(inode);
}
ret = ext4_write_checks(iocb, from);
if (ret <= 0)
goto out;
offset = iocb->ki_pos;
count = iov_iter_count(from);
if (offset + count > EXT4_I(inode)->i_disksize) {
handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle)) {
ret = PTR_ERR(handle);
goto out;
}
ret = ext4_orphan_add(handle, inode);
if (ret) {
ext4_journal_stop(handle);
goto out;
}
extend = true;
ext4_journal_stop(handle);
}
ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops);
if (extend) {
ret = ext4_handle_inode_extension(inode, offset, ret, count);
ext4_inode_extension_cleanup(inode, ret < (ssize_t)count);
}
out:
inode_unlock(inode);
if (ret > 0)
ret = generic_write_sync(iocb, ret);
return ret;
}
#endif
static ssize_t
ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct inode *inode = file_inode(iocb->ki_filp);
if (unlikely(ext4_forced_shutdown(inode->i_sb)))
return -EIO;
#ifdef CONFIG_FS_DAX
if (IS_DAX(inode))
return ext4_dax_write_iter(iocb, from);
#endif
if (iocb->ki_flags & IOCB_DIRECT)
return ext4_dio_write_iter(iocb, from);
else
return ext4_buffered_write_iter(iocb, from);
}
#ifdef CONFIG_FS_DAX
static vm_fault_t ext4_dax_huge_fault(struct vm_fault *vmf, unsigned int order)
{
int error = 0;
vm_fault_t result;
int retries = 0;
handle_t *handle = NULL;
struct inode *inode = file_inode(vmf->vma->vm_file);
struct super_block *sb = inode->i_sb;
/*
* We have to distinguish real writes from writes which will result in a
* COW page; COW writes should *not* poke the journal (the file will not
* be changed). Doing so would cause unintended failures when mounted
* read-only.
*
* We check for VM_SHARED rather than vmf->cow_page since the latter is
* unset for order != 0 (i.e. only in do_cow_fault); for
* other sizes, dax_iomap_fault will handle splitting / fallback so that
* we eventually come back with a COW page.
*/
bool write = (vmf->flags & FAULT_FLAG_WRITE) &&
(vmf->vma->vm_flags & VM_SHARED);
struct address_space *mapping = vmf->vma->vm_file->f_mapping;
pfn_t pfn;
if (write) {
sb_start_pagefault(sb);
file_update_time(vmf->vma->vm_file);
filemap_invalidate_lock_shared(mapping);
retry:
handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
EXT4_DATA_TRANS_BLOCKS(sb));
if (IS_ERR(handle)) {
filemap_invalidate_unlock_shared(mapping);
sb_end_pagefault(sb);
return VM_FAULT_SIGBUS;
}
} else {
filemap_invalidate_lock_shared(mapping);
}
result = dax_iomap_fault(vmf, order, &pfn, &error, &ext4_iomap_ops);
if (write) {
ext4_journal_stop(handle);
if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
ext4_should_retry_alloc(sb, &retries))
goto retry;
/* Handling synchronous page fault? */
if (result & VM_FAULT_NEEDDSYNC)
result = dax_finish_sync_fault(vmf, order, pfn);
filemap_invalidate_unlock_shared(mapping);
sb_end_pagefault(sb);
} else {
filemap_invalidate_unlock_shared(mapping);
}
return result;
}
static vm_fault_t ext4_dax_fault(struct vm_fault *vmf)
{
return ext4_dax_huge_fault(vmf, 0);
}
static const struct vm_operations_struct ext4_dax_vm_ops = {
.fault = ext4_dax_fault,
.huge_fault = ext4_dax_huge_fault,
.page_mkwrite = ext4_dax_fault,
.pfn_mkwrite = ext4_dax_fault,
};
#else
#define ext4_dax_vm_ops ext4_file_vm_ops
#endif
static const struct vm_operations_struct ext4_file_vm_ops = {
.fault = filemap_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = ext4_page_mkwrite,
};
static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
{
struct inode *inode = file->f_mapping->host;
struct dax_device *dax_dev = EXT4_SB(inode->i_sb)->s_daxdev;
if (unlikely(ext4_forced_shutdown(inode->i_sb)))
return -EIO;
/*
* 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, dax_dev))
return -EOPNOTSUPP;
file_accessed(file);
if (IS_DAX(file_inode(file))) {
vma->vm_ops = &ext4_dax_vm_ops;
vm_flags_set(vma, VM_HUGEPAGE);
} else {
vma->vm_ops = &ext4_file_vm_ops;
}
return 0;
}
static int ext4_sample_last_mounted(struct super_block *sb,
struct vfsmount *mnt)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct path path;
char buf[64], *cp;
handle_t *handle;
int err;
if (likely(ext4_test_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED)))
return 0;
if (sb_rdonly(sb) || !sb_start_intwrite_trylock(sb))
return 0;
ext4_set_mount_flag(sb, EXT4_MF_MNTDIR_SAMPLED);
/*
* Sample where the filesystem has been mounted and
* store it in the superblock for sysadmin convenience
* when trying to sort through large numbers of block
* devices or filesystem images.
*/
memset(buf, 0, sizeof(buf));
path.mnt = mnt;
path.dentry = mnt->mnt_root;
cp = d_path(&path, buf, sizeof(buf));
err = 0;
if (IS_ERR(cp))
goto out;
handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
err = PTR_ERR(handle);
if (IS_ERR(handle))
goto out;
BUFFER_TRACE(sbi->s_sbh, "get_write_access");
err = ext4_journal_get_write_access(handle, sb, sbi->s_sbh,
EXT4_JTR_NONE);
if (err)
goto out_journal;
lock_buffer(sbi->s_sbh);
strtomem_pad(sbi->s_es->s_last_mounted, cp, 0);
ext4_superblock_csum_set(sb);
unlock_buffer(sbi->s_sbh);
ext4_handle_dirty_metadata(handle, NULL, sbi->s_sbh);
out_journal:
ext4_journal_stop(handle);
out:
sb_end_intwrite(sb);
return err;
}
static int ext4_file_open(struct inode *inode, struct file *filp)
{
int ret;
if (unlikely(ext4_forced_shutdown(inode->i_sb)))
return -EIO;
ret = ext4_sample_last_mounted(inode->i_sb, filp->f_path.mnt);
if (ret)
return ret;
ret = fscrypt_file_open(inode, filp);
if (ret)
return ret;
ret = fsverity_file_open(inode, filp);
if (ret)
return ret;
/*
* Set up the jbd2_inode if we are opening the inode for
* writing and the journal is present
*/
if (filp->f_mode & FMODE_WRITE) {
ret = ext4_inode_attach_jinode(inode);
if (ret < 0)
return ret;
}
filp->f_mode |= FMODE_NOWAIT | FMODE_CAN_ODIRECT;
return dquot_file_open(inode, filp);
}
/*
* ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
* by calling generic_file_llseek_size() with the appropriate maxbytes
* value for each.
*/
loff_t ext4_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file->f_mapping->host;
loff_t maxbytes;
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
else
maxbytes = inode->i_sb->s_maxbytes;
switch (whence) {
default:
return generic_file_llseek_size(file, offset, whence,
maxbytes, i_size_read(inode));
case SEEK_HOLE:
inode_lock_shared(inode);
offset = iomap_seek_hole(inode, offset,
&ext4_iomap_report_ops);
inode_unlock_shared(inode);
break;
case SEEK_DATA:
inode_lock_shared(inode);
offset = iomap_seek_data(inode, offset,
&ext4_iomap_report_ops);
inode_unlock_shared(inode);
break;
}
if (offset < 0)
return offset;
return vfs_setpos(file, offset, maxbytes);
}
const struct file_operations ext4_file_operations = {
.llseek = ext4_llseek,
.read_iter = ext4_file_read_iter,
.write_iter = ext4_file_write_iter,
.iopoll = iocb_bio_iopoll,
.unlocked_ioctl = ext4_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = ext4_compat_ioctl,
#endif
.mmap = ext4_file_mmap,
.open = ext4_file_open,
.release = ext4_release_file,
.fsync = ext4_sync_file,
.get_unmapped_area = thp_get_unmapped_area,
.splice_read = ext4_file_splice_read,
.splice_write = iter_file_splice_write,
.fallocate = ext4_fallocate,
.fop_flags = FOP_MMAP_SYNC | FOP_BUFFER_RASYNC |
FOP_DIO_PARALLEL_WRITE,
};
const struct inode_operations ext4_file_inode_operations = {
.setattr = ext4_setattr,
.getattr = ext4_file_getattr,
.listxattr = ext4_listxattr,
.get_inode_acl = ext4_get_acl,
.set_acl = ext4_set_acl,
.fiemap = ext4_fiemap,
.fileattr_get = ext4_fileattr_get,
.fileattr_set = ext4_fileattr_set,
};
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