f2fs: expose main_blkaddr in sysfs
Expose in /sys/fs/f2fs/<blockdev>/main_blkaddr the block address where the
main area starts. This allows user mode programs to determine:
- That pinned files that are made exclusively of fully allocated 2MB
segments will never be unpinned by the file system.
- Where the main area starts. This is required by programs that want to
verify if a file is made exclusively of 2MB f2fs segments, the alignment
boundary for segments starts at this address. Testing for 2MB alignment
relative to the start of the device is incorrect, because for some
filesystems main_blkaddr is not at a 2MB boundary relative to the start
of the device.
The entry will be used when validating reliable pinning file feature proposed
by "f2fs: support aligned pinned file".
Signed-off-by: Ramon Pantin <pantin@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 7ab2b1b..aedeae1 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -31,6 +31,12 @@
Description:
Controls the issue rate of segment discard commands.
+What: /sys/fs/f2fs/<disk>/max_blkaddr
+Date: November 2019
+Contact: "Ramon Pantin" <pantin@google.com>
+Description:
+ Shows first block address of MAIN area.
+
What: /sys/fs/f2fs/<disk>/ipu_policy
Date: November 2013
Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index 29020af..3135b80 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -297,6 +297,9 @@
reclaim the prefree segments to free segments.
By default, 5% over total # of segments.
+ main_blkaddr This value gives the first block address of
+ MAIN area in the partition.
+
max_small_discards This parameter controls the number of discard
commands that consist small blocks less than 2MB.
The candidates to be discarded are cached until
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index f164959..70945ce 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -445,6 +445,7 @@ F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_idle, gc_mode);
F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_urgent, gc_mode);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments);
+F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, main_blkaddr, main_blkaddr);
F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, max_small_discards, max_discards);
F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, discard_granularity, discard_granularity);
F2FS_RW_ATTR(RESERVED_BLOCKS, f2fs_sb_info, reserved_blocks, reserved_blocks);
@@ -512,6 +513,7 @@ static struct attribute *f2fs_attrs[] = {
ATTR_LIST(gc_idle),
ATTR_LIST(gc_urgent),
ATTR_LIST(reclaim_segments),
+ ATTR_LIST(main_blkaddr),
ATTR_LIST(max_small_discards),
ATTR_LIST(discard_granularity),
ATTR_LIST(batched_trim_sections),