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authorRoss Zwisler <ross.zwisler@linux.intel.com>2018-07-29 17:00:22 -0400
committerTheodore Ts'o <tytso@mit.edu>2018-07-29 17:00:22 -0400
commit430657b6be896db57d974375cc499ca212c7f01d (patch)
treeba4489c4000ac7946de998f9f6a5cd2a3834d283 /fs/ext4/inode.c
parentcdbf8897cb09b7baf2b8a7e78051a35a872b01d5 (diff)
downloadlinux-430657b6be896db57d974375cc499ca212c7f01d.tar.bz2
ext4: handle layout changes to pinned DAX mappings
Follow the lead of xfs_break_dax_layouts() and add synchronization between operations in ext4 which remove blocks from an inode (hole punch, truncate down, etc.) and pages which are pinned due to DAX DMA operations. Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Diffstat (limited to 'fs/ext4/inode.c')
-rw-r--r--fs/ext4/inode.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ba0de19fb1ad..60432498acfb 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4191,6 +4191,39 @@ int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
return 0;
}
+static void ext4_wait_dax_page(struct ext4_inode_info *ei, bool *did_unlock)
+{
+ *did_unlock = true;
+ up_write(&ei->i_mmap_sem);
+ schedule();
+ down_write(&ei->i_mmap_sem);
+}
+
+int ext4_break_layouts(struct inode *inode)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ struct page *page;
+ bool retry;
+ int error;
+
+ if (WARN_ON_ONCE(!rwsem_is_locked(&ei->i_mmap_sem)))
+ return -EINVAL;
+
+ do {
+ retry = false;
+ page = dax_layout_busy_page(inode->i_mapping);
+ if (!page)
+ return 0;
+
+ error = ___wait_var_event(&page->_refcount,
+ atomic_read(&page->_refcount) == 1,
+ TASK_INTERRUPTIBLE, 0, 0,
+ ext4_wait_dax_page(ei, &retry));
+ } while (error == 0 && retry);
+
+ return error;
+}
+
/*
* ext4_punch_hole: punches a hole in a file by releasing the blocks
* associated with the given offset and length
@@ -4264,6 +4297,11 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
* page cache.
*/
down_write(&EXT4_I(inode)->i_mmap_sem);
+
+ ret = ext4_break_layouts(inode);
+ if (ret)
+ goto out_dio;
+
first_block_offset = round_up(offset, sb->s_blocksize);
last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
@@ -5553,6 +5591,14 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
ext4_wait_for_tail_page_commit(inode);
}
down_write(&EXT4_I(inode)->i_mmap_sem);
+
+ rc = ext4_break_layouts(inode);
+ if (rc) {
+ up_write(&EXT4_I(inode)->i_mmap_sem);
+ error = rc;
+ goto err_out;
+ }
+
/*
* Truncate pagecache after we've waited for commit
* in data=journal mode to make pages freeable.