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authorJan Kara <jack@suse.cz>2016-08-11 11:50:30 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-09-15 08:27:50 +0200
commitf2c06c7321aa080b18f36090cc1c3b2fa03a5cc8 (patch)
tree438098dbb356a5e1ede73752a852deaf86f5175d /fs
parentdfa0a22733804636fb8ac7963bd24e7ce6dbaa45 (diff)
ext4: fix xattr shifting when expanding inodes
commit d0141191a20289f8955c1e03dad08e42e6f71ca9 upstream. The code in ext4_expand_extra_isize_ea() treated new_extra_isize argument sometimes as the desired target i_extra_isize and sometimes as the amount by which we need to grow current i_extra_isize. These happen to coincide when i_extra_isize is 0 which used to be the common case and so nobody noticed this until recently when we added i_projid to the inode and so i_extra_isize now needs to grow from 28 to 32 bytes. The result of these bugs was that we sometimes unnecessarily decided to move xattrs out of inode even if there was enough space and we often ended up corrupting in-inode xattrs because arguments to ext4_xattr_shift_entries() were just wrong. This could demonstrate itself as BUG_ON in ext4_xattr_shift_entries() triggering. Fix the problem by introducing new isize_diff variable and use it where appropriate. Reported-by: Dave Chinner <david@fromorbit.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext4/xattr.c27
1 files changed, 14 insertions, 13 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 6b6b3e751f8c..bf3130e275ee 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1264,11 +1264,13 @@ int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
size_t min_offs, free;
int total_ino;
void *base, *start, *end;
- int extra_isize = 0, error = 0, tried_min_extra_isize = 0;
+ int error = 0, tried_min_extra_isize = 0;
int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize);
+ int isize_diff; /* How much do we need to grow i_extra_isize */
down_write(&EXT4_I(inode)->xattr_sem);
retry:
+ isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize;
if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) {
up_write(&EXT4_I(inode)->xattr_sem);
return 0;
@@ -1289,7 +1291,7 @@ retry:
total_ino = sizeof(struct ext4_xattr_ibody_header);
free = ext4_xattr_free_space(last, &min_offs, base, &total_ino);
- if (free >= new_extra_isize) {
+ if (free >= isize_diff) {
entry = IFIRST(header);
ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize
- new_extra_isize, (void *)raw_inode +
@@ -1321,7 +1323,7 @@ retry:
end = bh->b_data + bh->b_size;
min_offs = end - base;
free = ext4_xattr_free_space(first, &min_offs, base, NULL);
- if (free < new_extra_isize) {
+ if (free < isize_diff) {
if (!tried_min_extra_isize && s_min_extra_isize) {
tried_min_extra_isize++;
new_extra_isize = s_min_extra_isize;
@@ -1335,7 +1337,7 @@ retry:
free = inode->i_sb->s_blocksize;
}
- while (new_extra_isize > 0) {
+ while (isize_diff > 0) {
size_t offs, size, entry_size;
struct ext4_xattr_entry *small_entry = NULL;
struct ext4_xattr_info i = {
@@ -1366,7 +1368,7 @@ retry:
EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) +
EXT4_XATTR_LEN(last->e_name_len);
if (total_size <= free && total_size < min_total_size) {
- if (total_size < new_extra_isize) {
+ if (total_size < isize_diff) {
small_entry = last;
} else {
entry = last;
@@ -1423,20 +1425,19 @@ retry:
goto cleanup;
entry = IFIRST(header);
- if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize)
- shift_bytes = new_extra_isize;
+ if (entry_size + EXT4_XATTR_SIZE(size) >= isize_diff)
+ shift_bytes = isize_diff;
else
shift_bytes = entry_size + size;
/* Adjust the offsets and shift the remaining entries ahead */
- ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize -
- shift_bytes, (void *)raw_inode +
- EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes,
+ ext4_xattr_shift_entries(entry, -shift_bytes,
+ (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE +
+ EXT4_I(inode)->i_extra_isize + shift_bytes,
(void *)header, total_ino - entry_size,
inode->i_sb->s_blocksize);
- extra_isize += shift_bytes;
- new_extra_isize -= shift_bytes;
- EXT4_I(inode)->i_extra_isize = extra_isize;
+ isize_diff -= shift_bytes;
+ EXT4_I(inode)->i_extra_isize += shift_bytes;
i.name = b_entry_name;
i.value = buffer;