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ext4: cleanup pagecache before swap i_data 

While do swap, we should make sure there has no new dirty page since we
should swap i_data between two inode:
1.We should lock i_mmap_sem with write to avoid new pagecache from mmap
read/write;
2.Change filemap_flush to filemap_write_and_wait and move them to the
space protected by inode lock to avoid new pagecache from buffer read/write.

Signed-off-by: yangerkun <yangerkun@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
This commit is contained in:
yangerkun 2019-02-11 00:05:24 -05:00 committed by Theodore Ts'o
parent 67a11611e1
commit a46c68a318
1 changed files with 12 additions and 4 deletions
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16
fs/ext4/ioctl.c
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@ -121,9 +121,6 @@ static long swap_inode_boot_loader(struct super_block *sb,
return PTR_ERR(inode_bl);
ei_bl = EXT4_I(inode_bl);
filemap_flush(inode->i_mapping);
filemap_flush(inode_bl->i_mapping);
/* Protect orig inodes against a truncate and make sure,
* that only 1 swap_inode_boot_loader is running. */
lock_two_nondirectories(inode, inode_bl);
@ -141,6 +138,15 @@ static long swap_inode_boot_loader(struct super_block *sb,
goto journal_err_out;
}
down_write(&EXT4_I(inode)->i_mmap_sem);
err = filemap_write_and_wait(inode->i_mapping);
if (err)
goto err_out;
err = filemap_write_and_wait(inode_bl->i_mapping);
if (err)
goto err_out;
/* Wait for all existing dio workers */
inode_dio_wait(inode);
inode_dio_wait(inode_bl);
@ -151,7 +157,7 @@ static long swap_inode_boot_loader(struct super_block *sb,
handle = ext4_journal_start(inode_bl, EXT4_HT_MOVE_EXTENTS, 2);
if (IS_ERR(handle)) {
err = -EINVAL;
goto journal_err_out;
goto err_out;
}
/* Protect extent tree against block allocations via delalloc */
@ -208,6 +214,8 @@ static long swap_inode_boot_loader(struct super_block *sb,
ext4_journal_stop(handle);
ext4_double_up_write_data_sem(inode, inode_bl);
err_out:
up_write(&EXT4_I(inode)->i_mmap_sem);
journal_err_out:
unlock_two_nondirectories(inode, inode_bl);
iput(inode_bl);