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authorJoern Engel <joern@logfs.org>2010-05-07 19:38:40 +0200
committerJoern Engel <joern@logfs.org>2010-05-07 19:38:40 +0200
commit6f485b41875dbf5160c1990322469c1f65f77b28 (patch)
tree9912cee9517b57c2cb3c0318861f2a9eeb4139b2 /fs/logfs/gc.c
parentccf31c10f125ab5233c8517f91d4b3bd0bd60936 (diff)
logfs: handle powerfail on NAND flash
The write buffer may not have been written and may no longer be written due to an interrupted write in the affected page. Signed-off-by: Joern Engel <joern@logfs.org>
Diffstat (limited to 'fs/logfs/gc.c')
-rw-r--r--fs/logfs/gc.c49
1 files changed, 21 insertions, 28 deletions
diff --git a/fs/logfs/gc.c b/fs/logfs/gc.c
index 76c242fbe1b0..caa4419285dc 100644
--- a/fs/logfs/gc.c
+++ b/fs/logfs/gc.c
@@ -122,7 +122,7 @@ static void logfs_cleanse_block(struct super_block *sb, u64 ofs, u64 ino,
logfs_safe_iput(inode, cookie);
}
-static u32 logfs_gc_segment(struct super_block *sb, u32 segno, u8 dist)
+static u32 logfs_gc_segment(struct super_block *sb, u32 segno)
{
struct logfs_super *super = logfs_super(sb);
struct logfs_segment_header sh;
@@ -401,7 +401,7 @@ static int __logfs_gc_once(struct super_block *sb, struct gc_candidate *cand)
segno, (u64)segno << super->s_segshift,
dist, no_free_segments(sb), valid,
super->s_free_bytes);
- cleaned = logfs_gc_segment(sb, segno, dist);
+ cleaned = logfs_gc_segment(sb, segno);
log_gc("GC segment #%02x complete - now %x valid\n", segno,
valid - cleaned);
BUG_ON(cleaned != valid);
@@ -632,38 +632,31 @@ static int check_area(struct super_block *sb, int i)
{
struct logfs_super *super = logfs_super(sb);
struct logfs_area *area = super->s_area[i];
- struct logfs_object_header oh;
+ gc_level_t gc_level;
+ u32 cleaned, valid, ec;
u32 segno = area->a_segno;
- u32 ofs = area->a_used_bytes;
- __be32 crc;
- int err;
+ u64 ofs = dev_ofs(sb, area->a_segno, area->a_written_bytes);
if (!area->a_is_open)
return 0;
- for (ofs = area->a_used_bytes;
- ofs <= super->s_segsize - sizeof(oh);
- ofs += (u32)be16_to_cpu(oh.len) + sizeof(oh)) {
- err = wbuf_read(sb, dev_ofs(sb, segno, ofs), sizeof(oh), &oh);
- if (err)
- return err;
-
- if (!memchr_inv(&oh, 0xff, sizeof(oh)))
- break;
+ if (super->s_devops->can_write_buf(sb, ofs) == 0)
+ return 0;
- crc = logfs_crc32(&oh, sizeof(oh) - 4, 4);
- if (crc != oh.crc) {
- printk(KERN_INFO "interrupted header at %llx\n",
- dev_ofs(sb, segno, ofs));
- return 0;
- }
- }
- if (ofs != area->a_used_bytes) {
- printk(KERN_INFO "%x bytes unaccounted data found at %llx\n",
- ofs - area->a_used_bytes,
- dev_ofs(sb, segno, area->a_used_bytes));
- area->a_used_bytes = ofs;
- }
+ printk(KERN_INFO"LogFS: Possibly incomplete write at %llx\n", ofs);
+ /*
+ * The device cannot write back the write buffer. Most likely the
+ * wbuf was already written out and the system crashed at some point
+ * before the journal commit happened. In that case we wouldn't have
+ * to do anything. But if the crash happened before the wbuf was
+ * written out correctly, we must GC this segment. So assume the
+ * worst and always do the GC run.
+ */
+ area->a_is_open = 0;
+ valid = logfs_valid_bytes(sb, segno, &ec, &gc_level);
+ cleaned = logfs_gc_segment(sb, segno);
+ if (cleaned != valid)
+ return -EIO;
return 0;
}