| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * linux/fs/ext4/file.c |
| * |
| * Copyright (C) 1992, 1993, 1994, 1995 |
| * Remy Card (card@masi.ibp.fr) |
| * 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 |
| * (jj@sunsite.ms.mff.cuni.cz) |
| */ |
| |
| #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(EXT4_SB(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); |
| } |
| |
| /* |
| * 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, 0); |
| 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 and initialized blocks? */ |
| static bool ext4_overwrite_io(struct inode *inode, loff_t pos, loff_t len) |
| { |
| 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); |
| /* |
| * 'err==len' means that all of the blocks have been preallocated, |
| * regardless of whether they have been initialized or not. To exclude |
| * unwritten extents, we need to check m_flags. |
| */ |
| return err == blklen && (map.m_flags & EXT4_MAP_MAPPED); |
| } |
| |
| 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; |
| |
| current->backing_dev_info = inode_to_bdi(inode); |
| ret = generic_perform_write(iocb, from); |
| current->backing_dev_info = NULL; |
| |
| out: |
| inode_unlock(inode); |
| if (likely(ret > 0)) { |
| iocb->ki_pos += ret; |
| ret = generic_write_sync(iocb, ret); |
| } |
| |
| return ret; |
| } |
| |
| static ssize_t ext4_handle_inode_extension(struct inode *inode, loff_t offset, |
| 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 + count)) { |
| int ret = ext4_mark_inode_dirty(handle, inode); |
| if (unlikely(ret)) { |
| ext4_journal_stop(handle); |
| return ret; |
| } |
| } |
| |
| if (inode->i_nlink) |
| ext4_orphan_del(handle, inode); |
| ext4_journal_stop(handle); |
| |
| return count; |
| } |
| |
| /* |
| * 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, ssize_t count) |
| { |
| lockdep_assert_held_write(&inode->i_rwsem); |
| if (count < 0) { |
| 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); |
| } |
| |
| 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. 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) |
| { |
| struct file *file = iocb->ki_filp; |
| struct inode *inode = file_inode(file); |
| loff_t offset; |
| size_t count; |
| ssize_t ret; |
| |
| restart: |
| ret = ext4_generic_write_checks(iocb, from); |
| if (ret <= 0) |
| goto out; |
| |
| offset = iocb->ki_pos; |
| count = ret; |
| if (ext4_extending_io(inode, offset, count)) |
| *extend = true; |
| /* |
| * Determine whether the IO operation will overwrite allocated |
| * and initialized blocks. |
| * We need exclusive i_rwsem for changing security info |
| * in file_modified(). |
| */ |
| if (*ilock_shared && (!IS_NOSEC(inode) || *extend || |
| !ext4_overwrite_io(inode, offset, count))) { |
| if (iocb->ki_flags & IOCB_NOWAIT) { |
| ret = -EAGAIN; |
| goto out; |
| } |
| inode_unlock_shared(inode); |
| *ilock_shared = false; |
| inode_lock(inode); |
| goto restart; |
| } |
| |
| 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, unaligned_io = false; |
| bool ilock_shared = true; |
| |
| /* |
| * We initially start with shared inode lock unless it is |
| * unaligned IO which needs exclusive lock anyways. |
| */ |
| if (ext4_unaligned_io(inode, from, offset)) { |
| unaligned_io = true; |
| ilock_shared = false; |
| } |
| /* |
| * 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); |
| } |
| |
| ret = ext4_dio_write_checks(iocb, from, &ilock_shared, &extend); |
| if (ret <= 0) |
| return ret; |
| |
| /* if we're going to block and IOCB_NOWAIT is set, return -EAGAIN */ |
| if ((iocb->ki_flags & IOCB_NOWAIT) && (unaligned_io || extend)) { |
| ret = -EAGAIN; |
| goto out; |
| } |
| /* |
| * Make sure inline data cannot be created anymore since we are going |
| * to allocate blocks for DIO. We know the inode does not have any |
| * inline data now because ext4_dio_supported() checked for that. |
| */ |
| ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA); |
| |
| offset = iocb->ki_pos; |
| count = ret; |
| |
| /* |
| * Unaligned direct IO must be serialized among each other as zeroing |
| * of partial blocks of two competing unaligned IOs can result in data |
| * corruption. |
| * |
| * So we make sure we don't allow any unaligned IO in flight. |
| * For IOs where we need not wait (like unaligned non-AIO DIO), |
| * below inode_dio_wait() may anyway become a no-op, since we start |
| * with exclusive lock. |
| */ |
| if (unaligned_io) |
| inode_dio_wait(inode); |
| |
| 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) |
| iomap_ops = &ext4_iomap_overwrite_ops; |
| ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops, |
| (unaligned_io || extend) ? IOMAP_DIO_FORCE_WAIT : 0, |
| 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); |
| } |
| |
| 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); |
| ext4_inode_extension_cleanup(inode, ret); |
| } |
| 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(EXT4_SB(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, |
| enum page_entry_size pe_size) |
| { |
| 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 pe_size != PE_SIZE_PTE (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, pe_size, &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, pe_size, 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, PE_SIZE_PTE); |
| } |
| |
| 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 ext4_sb_info *sbi = EXT4_SB(inode->i_sb); |
| struct dax_device *dax_dev = sbi->s_daxdev; |
| |
| if (unlikely(ext4_forced_shutdown(sbi))) |
| 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); |
| strncpy(sbi->s_es->s_last_mounted, cp, |
| sizeof(sbi->s_es->s_last_mounted)); |
| 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(EXT4_SB(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_BUF_RASYNC; |
| 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, |
| .mmap_supported_flags = MAP_SYNC, |
| .open = ext4_file_open, |
| .release = ext4_release_file, |
| .fsync = ext4_sync_file, |
| .get_unmapped_area = thp_get_unmapped_area, |
| .splice_read = generic_file_splice_read, |
| .splice_write = iter_file_splice_write, |
| .fallocate = ext4_fallocate, |
| }; |
| |
| const struct inode_operations ext4_file_inode_operations = { |
| .setattr = ext4_setattr, |
| .getattr = ext4_file_getattr, |
| .listxattr = ext4_listxattr, |
| .get_acl = ext4_get_acl, |
| .set_acl = ext4_set_acl, |
| .fiemap = ext4_fiemap, |
| .fileattr_get = ext4_fileattr_get, |
| .fileattr_set = ext4_fileattr_set, |
| }; |
| |