On Fri, Feb 21, 2020 at 08:15:30AM -0800, Darrick J. Wong wrote: > > I understand the part about skipping the verifiers. But how does ignoring > > EIO in this case fir the scheme? > > "Salvage" mode means that the caller wants an xfs_buf even if the > contents are invalid or missing due to EIO. This is useful for db and > repair because we can fill the buffer with fixed or new metadata and > write it back to disk. I thought the aim was to look at the buffer for the content even if said content fails the verifiers, for which it makes sense to me. > On a practical level this means I don't have to amend all callsites: > > err = libxfs_buf_read(...LIBXFS_READBUF_SALVAGE..., &bp); > if (err == -EIO) > err = libxfs_buf_get(..., &bp); > if (err) > goto barf; > > ...since EIO doesn't seem that much more special than EFSCORRUPTED. I actually prefer that, as it really documents what is going on. That being said if reading the block fails with EIO chances are writing will fail as well..
