| Message ID | 20220401034409.256770-1-chenxiaosong2@huawei.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | nfs: handle writeback errors correctly | expand |
在 2022/4/1 11:44, ChenXiaoSong 写道: > v1: > cover letter: (nfs: check writeback errors correctly) > > v2: > - return more nuanced writeback errors in nfs_file_write(). > - return writeback error in close()->flush() without consumed it. > - fix: nfs_file_write() will always call nfs_wb_all() even if there is no > new writeback error. > > > ChenXiaoSong (3): > NFS: return more nuanced writeback errors in nfs_file_write() > NFS: nfs{,4}_file_flush() return correct writeback errors > Revert "nfs: nfs_file_write() should check for writeback errors" > > fs/nfs/file.c | 23 ++++++++++------------- > fs/nfs/nfs4file.c | 8 ++++---- > fs/nfs/write.c | 5 +---- > 3 files changed, 15 insertions(+), 21 deletions(-) > It is not a good idea to modify error sequence mechanism, as the `lib/errseq.c` described: 22 * Note that there is a risk of collisions if new errors are being recorded 23 * frequently, since we have so few bits to use as a counter. 24 * 25 * To mitigate this, one bit is used as a flag to tell whether the value has 26 * been sampled since a new value was recorded. That allows us to avoid bumping 27 * the counter if no one has sampled it since the last time an error was 28 * recorded. So, if we want to report nuanced writeback error, it is better to detect wb error from filemap_check_errors(), and then return -(file->f_mapping->wb_err & MAX_ERRNO) to userspace without consume it. nfs_mapping_set_error mapping_set_error __filemap_set_wb_err // record error sequence errseq_set set_bit(..., &mapping->flags) // record address_space flag // it is not used to be reported, just used to detect error = filemap_check_errors // -ENOSPC or -EIO test_and_clear_bit(..., &mapping->flags) // error bit cleared // now we try to return nuanced writeback error if (error) return filemap_check_wb_err(file->f_mapping, 0); return -(file->f_mapping->wb_err & MAX_ERRNO)
ping ... 在 2022/4/1 15:03, chenxiaosong (A) 写道: > 在 2022/4/1 11:44, ChenXiaoSong 写道: >> v1: >> cover letter: (nfs: check writeback errors correctly) >> >> v2: >> - return more nuanced writeback errors in nfs_file_write(). >> - return writeback error in close()->flush() without consumed it. >> - fix: nfs_file_write() will always call nfs_wb_all() even if there is no >> new writeback error. >> >> >> ChenXiaoSong (3): >> NFS: return more nuanced writeback errors in nfs_file_write() >> NFS: nfs{,4}_file_flush() return correct writeback errors >> Revert "nfs: nfs_file_write() should check for writeback errors" >> >> fs/nfs/file.c | 23 ++++++++++------------- >> fs/nfs/nfs4file.c | 8 ++++---- >> fs/nfs/write.c | 5 +---- >> 3 files changed, 15 insertions(+), 21 deletions(-) >> > > It is not a good idea to modify error sequence mechanism, as the > `lib/errseq.c` described: > > 22 * Note that there is a risk of collisions if new errors are > being recorded > 23 * frequently, since we have so few bits to use as a counter. > 24 * > 25 * To mitigate this, one bit is used as a flag to tell whether > the value has > 26 * been sampled since a new value was recorded. That allows us > to avoid bumping > 27 * the counter if no one has sampled it since the last time an > error was > 28 * recorded. > > > So, if we want to report nuanced writeback error, it is better to detect > wb error from filemap_check_errors(), and then return > -(file->f_mapping->wb_err & MAX_ERRNO) to userspace without consume it. > > nfs_mapping_set_error > mapping_set_error > __filemap_set_wb_err // record error sequence > errseq_set > set_bit(..., &mapping->flags) // record address_space flag > > // it is not used to be reported, just used to detect > error = filemap_check_errors // -ENOSPC or -EIO > test_and_clear_bit(..., &mapping->flags) // error bit cleared > > // now we try to return nuanced writeback error > if (error) > return filemap_check_wb_err(file->f_mapping, 0); > return -(file->f_mapping->wb_err & MAX_ERRNO) >
v1: cover letter: (nfs: check writeback errors correctly) v2: - return more nuanced writeback errors in nfs_file_write(). - return writeback error in close()->flush() without consumed it. - fix: nfs_file_write() will always call nfs_wb_all() even if there is no new writeback error. ChenXiaoSong (3): NFS: return more nuanced writeback errors in nfs_file_write() NFS: nfs{,4}_file_flush() return correct writeback errors Revert "nfs: nfs_file_write() should check for writeback errors" fs/nfs/file.c | 23 ++++++++++------------- fs/nfs/nfs4file.c | 8 ++++---- fs/nfs/write.c | 5 +---- 3 files changed, 15 insertions(+), 21 deletions(-)