From de01f484576d29b02fb2856387f29cfdf5ad4f19 Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Wed, 1 Sep 2021 10:09:55 +0800 Subject: [PATCH] ext4: prevent getting empty inode buffer In ext4_get_inode_loc(), we may skip IO and get an zero && uptodate inode buffer when the inode monopolize an inode block for performance reason. For most cases, ext4_mark_iloc_dirty() will fill the inode buffer to make it fine, but we could miss this call if something bad happened. Finally, __ext4_get_inode_loc_noinmem() may probably get an empty inode buffer and trigger ext4 error. For example, if we remove a nonexistent xattr on inode A, ext4_xattr_set_handle() will return ENODATA before invoking ext4_mark_iloc_dirty(), it will left an uptodate but zero buffer. We will get checksum error message in ext4_iget() when getting inode again. EXT4-fs error (device sda): ext4_lookup:1784: inode #131074: comm cat: iget: checksum invalid Even worse, if we allocate another inode B at the same inode block, it will corrupt the inode A on disk when write back inode B. So this patch initialize the inode buffer by filling the in-mem inode contents if we skip read I/O, ensure that the buffer is really uptodate. Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20210901020955.1657340-4-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o --- fs/ext4/inode.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index a46d5e022175..bfd3545f1e5d 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4380,12 +4380,12 @@ static int ext4_fill_raw_inode(struct inode *inode, struct ext4_inode *raw_inode /* * ext4_get_inode_loc returns with an extra refcount against the inode's - * underlying buffer_head on success. If 'in_mem' is true, we have all - * data in memory that is needed to recreate the on-disk version of this - * inode. + * underlying buffer_head on success. If we pass 'inode' and it does not + * have in-inode xattr, we have all inode data in memory that is needed + * to recreate the on-disk version of this inode. */ static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino, - struct ext4_iloc *iloc, int in_mem, + struct inode *inode, struct ext4_iloc *iloc, ext4_fsblk_t *ret_block) { struct ext4_group_desc *gdp; @@ -4431,7 +4431,7 @@ static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino, * is the only valid inode in the block, we need not read the * block. */ - if (in_mem) { + if (inode && !ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { struct buffer_head *bitmap_bh; int i, start; @@ -4459,8 +4459,13 @@ static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino, } brelse(bitmap_bh); if (i == start + inodes_per_block) { + struct ext4_inode *raw_inode = + (struct ext4_inode *) (bh->b_data + iloc->offset); + /* all other inodes are free, so skip I/O */ memset(bh->b_data, 0, bh->b_size); + if (!ext4_test_inode_state(inode, EXT4_STATE_NEW)) + ext4_fill_raw_inode(inode, raw_inode); set_buffer_uptodate(bh); unlock_buffer(bh); goto has_buffer; @@ -4521,7 +4526,7 @@ static int __ext4_get_inode_loc_noinmem(struct inode *inode, ext4_fsblk_t err_blk; int ret; - ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc, 0, + ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, NULL, iloc, &err_blk); if (ret == -EIO) @@ -4536,9 +4541,8 @@ int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc) ext4_fsblk_t err_blk; int ret; - /* We have all inode data except xattrs in memory here. */ - ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, iloc, - !ext4_test_inode_state(inode, EXT4_STATE_XATTR), &err_blk); + ret = __ext4_get_inode_loc(inode->i_sb, inode->i_ino, inode, iloc, + &err_blk); if (ret == -EIO) ext4_error_inode_block(inode, err_blk, EIO, @@ -4551,7 +4555,7 @@ int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc) int ext4_get_fc_inode_loc(struct super_block *sb, unsigned long ino, struct ext4_iloc *iloc) { - return __ext4_get_inode_loc(sb, ino, iloc, 0, NULL); + return __ext4_get_inode_loc(sb, ino, NULL, iloc, NULL); } static bool ext4_should_enable_dax(struct inode *inode) -- 2.11.0