return retval;
}
+/*
+ * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
+ * we have to be careful as someone else may be manipulating b_state as well.
+ */
+static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
+{
+ unsigned long old_state;
+ unsigned long new_state;
+
+ flags &= EXT4_MAP_FLAGS;
+
+ /* Dummy buffer_head? Set non-atomically. */
+ if (!bh->b_page) {
+ bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
+ return;
+ }
+ /*
+ * Someone else may be modifying b_state. Be careful! This is ugly but
+ * once we get rid of using bh as a container for mapping information
+ * to pass to / from get_block functions, this can go away.
+ */
+ do {
+ old_state = READ_ONCE(bh->b_state);
+ new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
+ } while (unlikely(
+ cmpxchg(&bh->b_state, old_state, new_state) != old_state));
+}
+
/* Maximum number of blocks we map for direct IO at once. */
#define DIO_MAX_BLOCKS 4096
ext4_io_end_t *io_end = ext4_inode_aio(inode);
map_bh(bh, inode->i_sb, map.m_pblk);
- bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
+ ext4_update_bh_state(bh, map.m_flags);
if (IS_DAX(inode) && buffer_unwritten(bh)) {
/*
* dgc: I suspect unwritten conversion on ext4+DAX is
return ret;
map_bh(bh, inode->i_sb, map.m_pblk);
- bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
+ ext4_update_bh_state(bh, map.m_flags);
if (buffer_unwritten(bh)) {
/* A delayed write to unwritten bh should be marked
return 0;
}
+/*
+ * We have to make sure i_disksize gets properly updated before we truncate
+ * page cache due to hole punching or zero range. Otherwise i_disksize update
+ * can get lost as it may have been postponed to submission of writeback but
+ * that will never happen after we truncate page cache.
+ */
+int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
+ loff_t len)
+{
+ handle_t *handle;
+ loff_t size = i_size_read(inode);
+
+ WARN_ON(!mutex_is_locked(&inode->i_mutex));
+ if (offset > size || offset + len < size)
+ return 0;
+
+ if (EXT4_I(inode)->i_disksize >= size)
+ return 0;
+
+ handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+ ext4_update_i_disksize(inode, size);
+ ext4_mark_inode_dirty(handle, inode);
+ ext4_journal_stop(handle);
+
+ return 0;
+}
+
/*
* ext4_punch_hole: punches a hole in a file by releaseing the blocks
* associated with the given offset and length
}
+ /* Wait all existing dio workers, newcomers will block on i_mutex */
+ ext4_inode_block_unlocked_dio(inode);
+ inode_dio_wait(inode);
+
+ /*
+ * Prevent page faults from reinstantiating pages we have released from
+ * page cache.
+ */
+ down_write(&EXT4_I(inode)->i_mmap_sem);
first_block_offset = round_up(offset, sb->s_blocksize);
last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
/* Now release the pages and zero block aligned part of pages*/
- if (last_block_offset > first_block_offset)
+ if (last_block_offset > first_block_offset) {
+ ret = ext4_update_disksize_before_punch(inode, offset, length);
+ if (ret)
+ goto out_dio;
truncate_pagecache_range(inode, first_block_offset,
last_block_offset);
-
- /* Wait all existing dio workers, newcomers will block on i_mutex */
- ext4_inode_block_unlocked_dio(inode);
- inode_dio_wait(inode);
+ }
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
credits = ext4_writepage_trans_blocks(inode);
if (IS_SYNC(inode))
ext4_handle_sync(handle);
- /* Now release the pages again to reduce race window */
- if (last_block_offset > first_block_offset)
- truncate_pagecache_range(inode, first_block_offset,
- last_block_offset);
-
inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
ext4_mark_inode_dirty(handle, inode);
out_stop:
ext4_journal_stop(handle);
out_dio:
+ up_write(&EXT4_I(inode)->i_mmap_sem);
ext4_inode_resume_unlocked_dio(inode);
out_mutex:
mutex_unlock(&inode->i_mutex);
} else
ext4_wait_for_tail_page_commit(inode);
}
+ down_write(&EXT4_I(inode)->i_mmap_sem);
/*
* Truncate pagecache after we've waited for commit
* in data=journal mode to make pages freeable.
truncate_pagecache(inode, inode->i_size);
if (shrink)
ext4_truncate(inode);
+ up_write(&EXT4_I(inode)->i_mmap_sem);
}
if (!rc) {
might_sleep();
trace_ext4_mark_inode_dirty(inode, _RET_IP_);
err = ext4_reserve_inode_write(handle, inode, &iloc);
+ if (err)
+ return err;
if (ext4_handle_valid(handle) &&
EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize &&
!ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND)) {
}
}
}
- if (!err)
- err = ext4_mark_iloc_dirty(handle, inode, &iloc);
- return err;
+ return ext4_mark_iloc_dirty(handle, inode, &iloc);
}
/*
sb_start_pagefault(inode->i_sb);
file_update_time(vma->vm_file);
+
+ down_read(&EXT4_I(inode)->i_mmap_sem);
/* Delalloc case is easy... */
if (test_opt(inode->i_sb, DELALLOC) &&
!ext4_should_journal_data(inode) &&
out_ret:
ret = block_page_mkwrite_return(ret);
out:
+ up_read(&EXT4_I(inode)->i_mmap_sem);
sb_end_pagefault(inode->i_sb);
return ret;
}
+
+int ext4_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct inode *inode = file_inode(vma->vm_file);
+ int err;
+
+ down_read(&EXT4_I(inode)->i_mmap_sem);
+ err = filemap_fault(vma, vmf);
+ up_read(&EXT4_I(inode)->i_mmap_sem);
+
+ return err;
+}
projects / firefly-linux-kernel-4.4.55.git / blobdiff