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authorRoss Zwisler <ross.zwisler@linux.intel.com>2017-10-12 11:52:34 -0400
committerTheodore Ts'o <tytso@mit.edu>2017-10-12 11:52:34 -0400
commit559db4c6d784ceedc2a5418ced4d357cb843e221 (patch)
treebe6a1f50c715af12510c45a7632a445efa4c1cd6 /fs/ext4/inline.c
parent51e3ae81ec58e95f10a98ef3dd6d7bce5d8e35a2 (diff)
downloadlinux-stericsson-559db4c6d784ceedc2a5418ced4d357cb843e221.tar.gz
ext4: prevent data corruption with inline data + DAX
If an inode has inline data it is currently prevented from using DAX by a check in ext4_set_inode_flags(). When the inode grows inline data via ext4_create_inline_data() or removes its inline data via ext4_destroy_inline_data_nolock(), the value of S_DAX can change. Currently these changes are unsafe because we don't hold off page faults and I/O, write back dirty radix tree entries and invalidate all mappings. There are also issues with mm-level races when changing the value of S_DAX, as well as issues with the VM_MIXEDMAP flag: https://www.spinics.net/lists/linux-xfs/msg09859.html The unsafe transition of S_DAX can reliably cause data corruption, as shown by the following fstest: https://patchwork.kernel.org/patch/9948381/ Fix this issue by preventing the DAX mount option from being used on filesystems that were created to support inline data. Inline data is an option given to mkfs.ext4. 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> CC: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/inline.c')
-rw-r--r--fs/ext4/inline.c10
1 files changed, 0 insertions, 10 deletions
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index f0bbc8cb6555..1367553c43bb 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -303,11 +303,6 @@ static int ext4_create_inline_data(handle_t *handle,
EXT4_I(inode)->i_inline_size = len + EXT4_MIN_INLINE_DATA_SIZE;
ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
ext4_set_inode_flag(inode, EXT4_INODE_INLINE_DATA);
- /*
- * Propagate changes to inode->i_flags as well - e.g. S_DAX may
- * get cleared
- */
- ext4_set_inode_flags(inode);
get_bh(is.iloc.bh);
error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
@@ -452,11 +447,6 @@ static int ext4_destroy_inline_data_nolock(handle_t *handle,
}
}
ext4_clear_inode_flag(inode, EXT4_INODE_INLINE_DATA);
- /*
- * Propagate changes to inode->i_flags as well - e.g. S_DAX may
- * get set.
- */
- ext4_set_inode_flags(inode);
get_bh(is.iloc.bh);
error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);