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authorDamien Le Moal <damien.lemoal@wdc.com>2020-03-20 15:36:54 +0300
committerDamien Le Moal <damien.lemoal@wdc.com>2020-03-25 05:28:26 +0300
commitccf4ad7da0d9c30a962a116cb55bcd7d8c44b0fe (patch)
tree7dd69481e52106a8dceeaad3ee2157d34e640ce7 /Documentation
parent0dda2ddb7ded1395189e95d43106469687c07795 (diff)
downloadlinux-ccf4ad7da0d9c30a962a116cb55bcd7d8c44b0fe.tar.xz
zonfs: Fix handling of read-only zones
The write pointer of zones in the read-only consition is defined as invalid by the SCSI ZBC and ATA ZAC specifications. It is thus not possible to determine the correct size of a read-only zone file on mount. Fix this by handling read-only zones in the same manner as offline zones by disabling all accesses to the zone (read and write) and initializing the inode size of the read-only zone to 0). For zones found to be in the read-only condition at runtime, only disable write access to the zone and keep the size of the zone file to its last updated value to allow the user to recover previously written data. Also fix zonefs documentation file to reflect this change. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/zonefs.txt18
1 files changed, 13 insertions, 5 deletions
diff --git a/Documentation/filesystems/zonefs.txt b/Documentation/filesystems/zonefs.txt
index d54fa98ac158..78813c34ec47 100644
--- a/Documentation/filesystems/zonefs.txt
+++ b/Documentation/filesystems/zonefs.txt
@@ -258,11 +258,11 @@ conditions.
| option | condition | size read write read write |
+--------------+-----------+-----------------------------------------+
| | good | fixed yes no yes yes |
- | remount-ro | read-only | fixed yes no yes no |
+ | remount-ro | read-only | as is yes no yes no |
| (default) | offline | 0 no no no no |
+--------------+-----------+-----------------------------------------+
| | good | fixed yes no yes yes |
- | zone-ro | read-only | fixed yes no yes no |
+ | zone-ro | read-only | as is yes no yes no |
| | offline | 0 no no no no |
+--------------+-----------+-----------------------------------------+
| | good | 0 no no yes yes |
@@ -270,7 +270,7 @@ conditions.
| | offline | 0 no no no no |
+--------------+-----------+-----------------------------------------+
| | good | fixed yes yes yes yes |
- | repair | read-only | fixed yes no yes no |
+ | repair | read-only | as is yes no yes no |
| | offline | 0 no no no no |
+--------------+-----------+-----------------------------------------+
@@ -307,8 +307,16 @@ condition changes. The defined behaviors are as follow:
* zone-offline
* repair
-The I/O error actions defined for each behavior are detailed in the previous
-section.
+The run-time I/O error actions defined for each behavior are detailed in the
+previous section. Mount time I/O errors will cause the mount operation to fail.
+The handling of read-only zones also differs between mount-time and run-time.
+If a read-only zone is found at mount time, the zone is always treated in the
+same manner as offline zones, that is, all accesses are disabled and the zone
+file size set to 0. This is necessary as the write pointer of read-only zones
+is defined as invalib by the ZBC and ZAC standards, making it impossible to
+discover the amount of data that has been written to the zone. In the case of a
+read-only zone discovered at run-time, as indicated in the previous section.
+the size of the zone file is left unchanged from its last updated value.
Zonefs User Space Tools
=======================