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ANDROID: Incremental fs: Remove back links and crcs

Browse Source 
Bug: 166638631
Test: incfs_test passes
Signed-off-by: Paul Lawrence <paullawrence@google.com>
Change-Id: Ia6061f8985db85a66fce0f2f09e1305a21753dd6
This commit is contained in:
Paul Lawrence
2020-08-27 14:01:52 -07:00
parent 37436094c8
commit 63702b82a4
2 changed files with 0 additions and 43 deletions
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34
fs/incfs/format.c
View File

@@ -148,26 +148,6 @@ static int append_zeros(struct backing_file_context *bfc, size_t len)
return append_zeros_no_fallocate(bfc, file_size, len);
}
static u32 calc_md_crc(struct incfs_md_header *record)
{
u32 result = 0;
__le32 saved_crc = record->h_record_crc;
__le64 saved_md_offset = record->h_next_md_offset;
size_t record_size = min_t(size_t, le16_to_cpu(record->h_record_size),
INCFS_MAX_METADATA_RECORD_SIZE);
/* Zero fields which needs to be excluded from CRC calculation. */
record->h_record_crc = 0;
record->h_next_md_offset = 0;
result = crc32(0, record, record_size);
/* Restore excluded fields. */
record->h_record_crc = saved_crc;
record->h_next_md_offset = saved_md_offset;
return result;
}
/*
* Append a given metadata record to the backing file and update a previous
* record to add the new record the the metadata list.
@@ -191,9 +171,7 @@ static int append_md_to_backing_file(struct backing_file_context *bfc,
record_size = le16_to_cpu(record->h_record_size);
file_pos = incfs_get_end_offset(bfc->bc_file);
record->h_prev_md_offset = cpu_to_le64(bfc->bc_last_md_record_offset);
record->h_next_md_offset = 0;
record->h_record_crc = cpu_to_le32(calc_md_crc(record));
/* Write the metadata record to the end of the backing file */
record_offset = file_pos;
@@ -601,7 +579,6 @@ int incfs_read_next_metadata_record(struct backing_file_context *bfc,
ssize_t bytes_read = 0;
size_t md_record_size = 0;
loff_t next_record = 0;
loff_t prev_record = 0;
int res = 0;
struct incfs_md_header *md_hdr = NULL;
@@ -623,7 +600,6 @@ int incfs_read_next_metadata_record(struct backing_file_context *bfc,
md_hdr = &handler->md_buffer.md_header;
next_record = le64_to_cpu(md_hdr->h_next_md_offset);
prev_record = le64_to_cpu(md_hdr->h_prev_md_offset);
md_record_size = le16_to_cpu(md_hdr->h_record_size);
if (md_record_size > max_md_size) {
@@ -643,16 +619,6 @@ int incfs_read_next_metadata_record(struct backing_file_context *bfc,
return -EBADMSG;
}
if (prev_record != handler->md_prev_record_offset) {
pr_warn("incfs: Metadata chain has been corrupted.");
return -EBADMSG;
}
if (le32_to_cpu(md_hdr->h_record_crc) != calc_md_crc(md_hdr)) {
pr_warn("incfs: Metadata CRC mismatch.");
return -EBADMSG;
}
switch (md_hdr->h_md_entry_type) {
case INCFS_MD_NONE:
break;

9
fs/incfs/format.h
View File

@@ -135,18 +135,9 @@ struct incfs_md_header {
*/
__le16 h_record_size;
/*
* CRC32 of the metadata record.
* (e.g. inode, dir entry etc) not just this struct.
*/
__le32 h_record_crc;
/* Offset of the next metadata entry if any */
__le64 h_next_md_offset;
/* Offset of the previous metadata entry if any */
__le64 h_prev_md_offset;
} __packed;
/* Backing file header */