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ext4: avoid running out of journal credits when appending to an inline file

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commit 8bc1379b82b8e809eef77a9fedbb75c6c297be19 upstream.

Use a separate journal transaction if it turns out that we need to
convert an inline file to use an data block.  Otherwise we could end
up failing due to not having journal credits.

This addresses CVE-2018-10883.

https://bugzilla.kernel.org/show_bug.cgi?id=200071

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
[fengc@google.com: 4.4 backport: adjust context]
Signed-off-by: Chenbo Feng <fengc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Change-Id: I75f040b4276587a6a234a6a53fd1d3d70be6ae09
(cherry picked from commit d49dc6f1d53479bca01900540a89639eea8b154e)
This commit is contained in:
Theodore Ts'o 2018-06-16 23:41:59 -04:00 • committed by codeworkx
parent 56c5b91e06
commit 092ca04237
3 changed files with 3 additions and 56 deletions
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3
fs/ext4/ext4.h
View file

@ -3069,9 +3069,6 @@ extern struct buffer_head *ext4_get_first_inline_block(struct inode *inode,
extern int ext4_inline_data_fiemap(struct inode *inode,
struct fiemap_extent_info *fieinfo,
int *has_inline, __u64 start, __u64 len);
extern int ext4_try_to_evict_inline_data(handle_t *handle,
struct inode *inode,
int needed);
extern void ext4_inline_data_truncate(struct inode *inode, int *has_inline);
extern int ext4_convert_inline_data(struct inode *inode);

38
fs/ext4/inline.c
View file

@ -902,11 +902,11 @@ retry_journal:
flags |= AOP_FLAG_NOFS;
if (ret == -ENOSPC) {
ext4_journal_stop(handle);
ret = ext4_da_convert_inline_data_to_extent(mapping,
inode,
flags,
fsdata);
ext4_journal_stop(handle);
if (ret == -ENOSPC &&
ext4_should_retry_alloc(inode->i_sb, &retries))
goto retry_journal;
@ -1877,42 +1877,6 @@ out:
return (error < 0 ? error : 0);
}
/*
* Called during xattr set, and if we can sparse space 'needed',
* just create the extent tree evict the data to the outer block.
*
* We use jbd2 instead of page cache to move data to the 1st block
* so that the whole transaction can be committed as a whole and
* the data isn't lost because of the delayed page cache write.
*/
int ext4_try_to_evict_inline_data(handle_t *handle,
struct inode *inode,
int needed)
{
int error;
struct ext4_xattr_entry *entry;
struct ext4_inode *raw_inode;
struct ext4_iloc iloc;
error = ext4_get_inode_loc(inode, &iloc);
if (error)
return error;
raw_inode = ext4_raw_inode(&iloc);
entry = (struct ext4_xattr_entry *)((void *)raw_inode +
EXT4_I(inode)->i_inline_off);
if (EXT4_XATTR_LEN(entry->e_name_len) +
EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size)) < needed) {
error = -ENOSPC;
goto out;
}
error = ext4_convert_inline_data_nolock(handle, inode, &iloc);
out:
brelse(iloc.bh);
return error;
}
void ext4_inline_data_truncate(struct inode *inode, int *has_inline)
{
handle_t *handle;

18
fs/ext4/xattr.c
View file

@ -1068,22 +1068,8 @@ int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode,
if (EXT4_I(inode)->i_extra_isize == 0)
return -ENOSPC;
error = ext4_xattr_set_entry(i, s, inode);
if (error) {
if (error == -ENOSPC &&
ext4_has_inline_data(inode)) {
error = ext4_try_to_evict_inline_data(handle, inode,
EXT4_XATTR_LEN(strlen(i->name) +
EXT4_XATTR_SIZE(i->value_len)));
if (error)
return error;
error = ext4_xattr_ibody_find(inode, i, is);
if (error)
return error;
error = ext4_xattr_set_entry(i, s, inode);
}
if (error)
return error;
}
if (error)
return error;
header = IHDR(inode, ext4_raw_inode(&is->iloc));
if (!IS_LAST_ENTRY(s->first)) {
header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);