diff options
| author | Alex Elder <elder@inktank.com> | 2013-03-30 15:09:59 -0500 |
|---|---|---|
| committer | Sage Weil <sage@inktank.com> | 2013-05-01 21:17:39 -0700 |
| commit | 5df521b1eecf276c4bae8ffb7945acef45530449 (patch) | |
| tree | b6a8434361e786d81b364aa202cc40628eb60b65 | |
| parent | 1190bf06a6b033384a65b5acdb1193d41cd257a6 (diff) | |
libceph: page offset must be less than page size
Currently ceph_msg_data_pages_advance() allows the page offset value
to be PAGE_SIZE, apparently assuming ceph_msg_data_pages_next() will
treat it as 0. But that doesn't happen, and the result led to a
helpful assertion failure.
Change ceph_msg_data_pages_advance() to truncate the offset to 0
before returning if it reaches PAGE_SIZE.
Make a few other minor adjustments in this area (comments and a
better assertion) while modifying it.
This resolves a second issue described in:
http://tracker.ceph.com/issues/4598
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
| -rw-r--r-- | net/ceph/messenger.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 24f3aba3480..198b9026288 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -766,8 +766,8 @@ static struct page *ceph_msg_data_bio_next(struct ceph_msg_data *data, *length = cursor->resid; else *length = (size_t) (bio_vec->bv_len - cursor->vector_offset); - BUG_ON(*length > PAGE_SIZE); BUG_ON(*length > cursor->resid); + BUG_ON(*page_offset + *length > PAGE_SIZE); return bio_vec->bv_page; } @@ -876,14 +876,13 @@ static bool ceph_msg_data_pages_advance(struct ceph_msg_data *data, /* Advance the cursor page offset */ cursor->resid -= bytes; - cursor->page_offset += bytes; - if (!bytes || cursor->page_offset & ~PAGE_MASK) + cursor->page_offset = (cursor->page_offset + bytes) & ~PAGE_MASK; + if (!bytes || cursor->page_offset) return false; /* more bytes to process in the current page */ - /* Move on to the next page */ + /* Move on to the next page; offset is already at 0 */ BUG_ON(cursor->page_index >= cursor->page_count); - cursor->page_offset = 0; cursor->page_index++; cursor->last_piece = cursor->resid <= PAGE_SIZE; @@ -934,8 +933,9 @@ static struct page *ceph_msg_data_pagelist_next(struct ceph_msg_data *data, BUG_ON(!cursor->page); BUG_ON(cursor->offset + cursor->resid != pagelist->length); + /* offset of first page in pagelist is always 0 */ *page_offset = cursor->offset & ~PAGE_MASK; - if (cursor->last_piece) /* pagelist offset is always 0 */ + if (cursor->last_piece) *length = cursor->resid; else *length = PAGE_SIZE - *page_offset; @@ -961,7 +961,7 @@ static bool ceph_msg_data_pagelist_advance(struct ceph_msg_data *data, cursor->resid -= bytes; cursor->offset += bytes; - /* pagelist offset is always 0 */ + /* offset of first page in pagelist is always 0 */ if (!bytes || cursor->offset & ~PAGE_MASK) return false; /* more bytes to process in the current page */ |