The patch titled
Subject: nilfs2: fix misuse of a semaphore in sysfs code
has been added to the -mm tree. Its filename is
nilfs2-fix-misuse-of-a-semaphore-in-sysfs-code.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/nilfs2-fix-misuse-of-a-semaphore-in-sysfs-code.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/nilfs2-fix-misuse-of-a-semaphore-in-sysfs-code.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
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------------------------------------------------------
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
Subject: nilfs2: fix misuse of a semaphore in sysfs code
Variables ns_seg_seq, ns_segnum, ns_nextnum, ns_pseg_offset, ns_cno,
ns_ctime, ns_nongc_ctime, and ns_ndirtyblks, are protected by
ns_segctor_sem, but ns_sem is wrongly used by the nilfs sysfs code
when reading these variables. This fixes the misuse and clarifies
which semaphore protects them in the comment of the_nilfs struct.
Link: http://lkml.kernel.org/r/1465825507-3407-2-git-send-email-konishi.ryusuke@xxxxxxxxxxxxx
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/sysfs.c | 44 ++++++++++++++++++++--------------------
fs/nilfs2/the_nilfs.h | 7 +-----
2 files changed, 24 insertions(+), 27 deletions(-)
diff -puN fs/nilfs2/sysfs.c~nilfs2-fix-misuse-of-a-semaphore-in-sysfs-code fs/nilfs2/sysfs.c
--- a/fs/nilfs2/sysfs.c~nilfs2-fix-misuse-of-a-semaphore-in-sysfs-code
+++ a/fs/nilfs2/sysfs.c
@@ -326,9 +326,9 @@ nilfs_checkpoints_next_checkpoint_show(s
{
__u64 cno;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
cno = nilfs->ns_cno;
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return snprintf(buf, PAGE_SIZE, "%llu\n", cno);
}
@@ -511,9 +511,9 @@ nilfs_segctor_current_seg_sequence_show(
{
u64 seg_seq;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
seg_seq = nilfs->ns_seg_seq;
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return snprintf(buf, PAGE_SIZE, "%llu\n", seg_seq);
}
@@ -525,9 +525,9 @@ nilfs_segctor_current_last_full_seg_show
{
__u64 segnum;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
segnum = nilfs->ns_segnum;
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return snprintf(buf, PAGE_SIZE, "%llu\n", segnum);
}
@@ -539,9 +539,9 @@ nilfs_segctor_next_full_seg_show(struct
{
__u64 nextnum;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
nextnum = nilfs->ns_nextnum;
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return snprintf(buf, PAGE_SIZE, "%llu\n", nextnum);
}
@@ -553,9 +553,9 @@ nilfs_segctor_next_pseg_offset_show(stru
{
unsigned long pseg_offset;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
pseg_offset = nilfs->ns_pseg_offset;
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return snprintf(buf, PAGE_SIZE, "%lu\n", pseg_offset);
}
@@ -567,9 +567,9 @@ nilfs_segctor_next_checkpoint_show(struc
{
__u64 cno;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
cno = nilfs->ns_cno;
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return snprintf(buf, PAGE_SIZE, "%llu\n", cno);
}
@@ -581,9 +581,9 @@ nilfs_segctor_last_seg_write_time_show(s
{
time_t ctime;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
ctime = nilfs->ns_ctime;
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return NILFS_SHOW_TIME(ctime, buf);
}
@@ -595,9 +595,9 @@ nilfs_segctor_last_seg_write_time_secs_s
{
time_t ctime;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
ctime = nilfs->ns_ctime;
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return snprintf(buf, PAGE_SIZE, "%llu\n", (unsigned long long)ctime);
}
@@ -609,9 +609,9 @@ nilfs_segctor_last_nongc_write_time_show
{
time_t nongc_ctime;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
nongc_ctime = nilfs->ns_nongc_ctime;
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return NILFS_SHOW_TIME(nongc_ctime, buf);
}
@@ -623,9 +623,9 @@ nilfs_segctor_last_nongc_write_time_secs
{
time_t nongc_ctime;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
nongc_ctime = nilfs->ns_nongc_ctime;
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return snprintf(buf, PAGE_SIZE, "%llu\n",
(unsigned long long)nongc_ctime);
@@ -638,9 +638,9 @@ nilfs_segctor_dirty_data_blocks_count_sh
{
u32 ndirtyblks;
- down_read(&nilfs->ns_sem);
+ down_read(&nilfs->ns_segctor_sem);
ndirtyblks = atomic_read(&nilfs->ns_ndirtyblks);
- up_read(&nilfs->ns_sem);
+ up_read(&nilfs->ns_segctor_sem);
return snprintf(buf, PAGE_SIZE, "%u\n", ndirtyblks);
}
diff -puN fs/nilfs2/the_nilfs.h~nilfs2-fix-misuse-of-a-semaphore-in-sysfs-code fs/nilfs2/the_nilfs.h
--- a/fs/nilfs2/the_nilfs.h~nilfs2-fix-misuse-of-a-semaphore-in-sysfs-code
+++ a/fs/nilfs2/the_nilfs.h
@@ -122,11 +122,8 @@ struct the_nilfs {
unsigned int ns_sb_update_freq;
/*
- * Following fields are dedicated to a writable FS-instance.
- * Except for the period seeking checkpoint, code outside the segment
- * constructor must lock a segment semaphore while accessing these
- * fields.
- * The writable FS-instance is sole during a lifetime of the_nilfs.
+ * The following fields are updated by a writable FS-instance.
+ * These fields are protected by ns_segctor_sem outside load_nilfs().
*/
u64 ns_seg_seq;
__u64 ns_segnum;
_
Patches currently in -mm which might be from konishi.ryusuke@xxxxxxxxxxxxx are
nilfs2-hide-function-name-argument-from-nilfs_error.patch
nilfs2-add-nilfs_msg-message-interface.patch
nilfs2-embed-a-back-pointer-to-super-block-instance-in-nilfs-object.patch
nilfs2-reduce-bare-use-of-printk-with-nilfs_msg.patch
nilfs2-replace-nilfs_warning-with-nilfs_msg.patch
nilfs2-emit-error-message-when-i-o-error-is-detected.patch
nilfs2-do-not-use-yield.patch
nilfs2-refactor-parser-of-snapshot-mount-option.patch
nilfs2-fix-misuse-of-a-semaphore-in-sysfs-code.patch
nilfs2-use-bit-macro.patch
nilfs2-move-ioctl-interface-and-disk-layout-to-uapi-separately.patch
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