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| author | Andreas Gruenbacher <agruenba@redhat.com> | 2022-04-27 00:31:06 +0300 |
|---|---|---|
| committer | Andreas Gruenbacher <agruenba@redhat.com> | 2022-05-24 22:29:14 +0300 |
| commit | 53bb540fd591f6fdd4cb5c9a785d9790ac33862d (patch) | |
| tree | 6fce7c67fcb582ed83cc46d26024ea563bce5f8e | |
| parent | b846f2d7e2d28ebfa112ac595bde2ef87693d8d9 (diff) | |
| download | linux-53bb540fd591f6fdd4cb5c9a785d9790ac33862d.tar.xz | |
gfs2: Explain some direct I/O oddities
Add some comments explaining the oddities of partial direct I/O reads
and writes.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
| -rw-r--r-- | fs/gfs2/file.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index 2556ae1f92ea..f1d2f4d74b89 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -840,6 +840,7 @@ retry: pagefault_enable(); if (ret <= 0 && ret != -EFAULT) goto out_unlock; + /* No increment (+=) because iomap_dio_rw returns a cumulative value. */ if (ret > 0) read = ret; @@ -854,6 +855,7 @@ out_unlock: gfs2_glock_dq(gh); out_uninit: gfs2_holder_uninit(gh); + /* User space doesn't expect partial success. */ if (ret < 0) return ret; return read; @@ -906,6 +908,7 @@ retry: if (ret != -EFAULT) goto out_unlock; } + /* No increment (+=) because iomap_dio_rw returns a cumulative value. */ if (ret > 0) written = ret; @@ -920,6 +923,7 @@ out_unlock: gfs2_glock_dq(gh); out_uninit: gfs2_holder_uninit(gh); + /* User space doesn't expect partial success. */ if (ret < 0) return ret; return written; |