[Cluster-devel] [GFS2 PATCH 4/4] gfs2: read journal in large chunks to locate the head
Abhi Das
adas at redhat.com
Tue Oct 16 04:07:58 UTC 2018
Use bio(s) to read in the journal sequentially in large chunks and
locate the head of the journal.
Signed-off-by: Abhi Das <adas at redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba at redhat.com>
---
fs/gfs2/glops.c | 1 +
fs/gfs2/lops.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++++++-
fs/gfs2/lops.h | 2 +
fs/gfs2/ops_fstype.c | 1 +
fs/gfs2/recovery.c | 123 -------------------------------------
fs/gfs2/recovery.h | 2 -
fs/gfs2/super.c | 1 +
7 files changed, 171 insertions(+), 126 deletions(-)
diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index c63bee9..f79ef95 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -28,6 +28,7 @@
#include "util.h"
#include "trans.h"
#include "dir.h"
+#include "lops.h"
struct workqueue_struct *gfs2_freeze_wq;
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index 2295042..568b6cc 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -18,6 +18,7 @@
#include <linux/fs.h>
#include <linux/list_sort.h>
+#include "bmap.h"
#include "dir.h"
#include "gfs2.h"
#include "incore.h"
@@ -193,7 +194,6 @@ static void gfs2_end_log_write_bh(struct gfs2_sbd *sdp, struct bio_vec *bvec,
/**
* gfs2_end_log_write - end of i/o to the log
* @bio: The bio
- * @error: Status of i/o request
*
* Each bio_vec contains either data from the pagecache or data
* relating to the log itself. Here we iterate over the bio_vec
@@ -375,6 +375,171 @@ void gfs2_log_write_page(struct gfs2_sbd *sdp, struct page *page)
gfs2_log_bmap(sdp));
}
+/**
+ * gfs2_end_log_read - end I/O callback for reads from the log
+ * @bio: The bio
+ *
+ * Simply unlock the pages in the bio. The main thread will wait on them and
+ * process them in order as necessary.
+ */
+
+static void gfs2_end_log_read(struct bio *bio)
+{
+ struct gfs2_sbd *sdp = bio->bi_private;
+ struct page *page;
+ struct bio_vec *bvec;
+ int i;
+
+ if (bio->bi_status)
+ fs_err(sdp, "Error %d reading from journal\n", bio->bi_status);
+
+ bio_for_each_segment_all(bvec, bio, i)
+ unlock_page(bvec->bv_page);
+
+ bio_put(bio);
+}
+
+/**
+ * gfs2_jhead_pg_srch - Look for the journal head in a given page.
+ * @jd: The journal descriptor
+ * @page: The page to look in
+ *
+ * Returns: 1 if found, 0 otherwise.
+ */
+
+static bool gfs2_jhead_pg_srch(struct gfs2_jdesc *jd,
+ struct gfs2_log_header_host *head,
+ struct page *page)
+{
+ struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+ struct gfs2_log_header_host uninitialized_var(lh);
+ void *kaddr = kmap_atomic(page);
+ unsigned int offset;
+ bool ret = false;
+
+ for (offset = 0; offset < PAGE_SIZE; offset += sdp->sd_sb.sb_bsize) {
+ if (!__get_log_header(sdp, kaddr + offset, 0, &lh)) {
+ if (lh.lh_sequence > head->lh_sequence)
+ *head = lh;
+ else {
+ ret = true;
+ break;
+ }
+ }
+ }
+ kunmap_atomic(kaddr);
+ return ret;
+}
+
+/**
+ * gfs2_jhead_process_page - Search/cleanup a page
+ * @jd: The journal descriptor
+ * @index: Index of the page to look into
+ * @done: If set, perform only cleanup, else search and set if found.
+ *
+ * Find the page with 'index' in the journal's mapping. Search the page for
+ * the journal head if requested (cleanup == false). Release refs on the
+ * page so the page cache can reclaim it (put_page() twice). We grabbed a
+ * reference on this page two times, first when we did a find_or_create_page()
+ * to obtain the page to add it to the bio and second when we do a
+ * find_get_page() here to get the page to wait on while I/O on it is being
+ * completed.
+ * This function is also used to free up a page we might've grabbed but not
+ * used. Maybe we added it to a bio, but not submitted it for I/O. Or we
+ * submitted the I/O, but we already found the jhead so we only need to drop
+ * our references to the page.
+ */
+
+static void gfs2_jhead_process_page(struct gfs2_jdesc *jd, unsigned long index,
+ struct gfs2_log_header_host *head,
+ bool *done)
+{
+ struct page *page;
+
+ page = find_get_page(jd->jd_inode->i_mapping, index);
+ wait_on_page_locked(page);
+
+ if (!*done)
+ *done = gfs2_jhead_pg_srch(jd, head, page);
+
+ put_page(page); /* Once for find_get_page */
+ put_page(page); /* Once more for find_or_create_page */
+}
+
+/**
+ * gfs2_find_jhead - find the head of a log
+ * @jd: The journal descriptor
+ * @head: The log descriptor for the head of the log is returned here
+ *
+ * Do a search of a journal by reading it in large chunks using bios and find
+ * the valid log entry with the highest sequence number. (i.e. the log head)
+ *
+ * Returns: 0 on success, errno otherwise
+ */
+
+int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
+{
+ struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+ struct gfs2_journal_extent *je;
+ u32 block, read_idx = 0, submit_idx = 0, index = 0;
+ int shift = PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift;
+ int blocks_per_page = 1 << shift, sz, ret = 0;
+ struct bio *bio = NULL;
+ struct page *page;
+ bool done = false;
+
+ memset(head, 0, sizeof(*head));
+ if (list_empty(&jd->extent_list))
+ gfs2_map_journal_extents(sdp, jd);
+
+ list_for_each_entry(je, &jd->extent_list, list) {
+ for (block = 0; block < je->blocks; block += blocks_per_page) {
+ index = (je->lblock + block) >> shift;
+
+ page = find_or_create_page(jd->jd_inode->i_mapping,
+ index, GFP_NOFS);
+ if (!page) {
+ ret = -ENOMEM;
+ done = true;
+ goto out;
+ }
+
+ if (bio) {
+ sz = bio_add_page(bio, page, PAGE_SIZE, 0);
+ if (sz == PAGE_SIZE)
+ goto page_added;
+ submit_idx = index;
+ submit_bio(bio);
+ bio = NULL;
+ }
+
+ bio = gfs2_log_alloc_bio(sdp,
+ je->dblock + (index << shift),
+ gfs2_end_log_read);
+ bio_set_op_attrs(bio, REQ_OP_READ, 0);
+ sz = bio_add_page(bio, page, PAGE_SIZE, 0);
+ gfs2_assert_warn(sdp, sz == PAGE_SIZE);
+
+page_added:
+ if (submit_idx <= read_idx + BIO_MAX_PAGES) {
+ /* Keep at least one bio in flight */
+ continue;
+ }
+
+ gfs2_jhead_process_page(jd, read_idx++, head, &done);
+ if (done)
+ goto out; /* found */
+ }
+ }
+
+out:
+ if (bio)
+ submit_bio(bio);
+ while (read_idx <= index)
+ gfs2_jhead_process_page(jd, read_idx++, head, &done);
+ return ret;
+}
+
static struct page *gfs2_get_log_desc(struct gfs2_sbd *sdp, u32 ld_type,
u32 ld_length, u32 ld_data1)
{
diff --git a/fs/gfs2/lops.h b/fs/gfs2/lops.h
index 711c4d8..6a4714b 100644
--- a/fs/gfs2/lops.h
+++ b/fs/gfs2/lops.h
@@ -32,6 +32,8 @@ extern void gfs2_log_write(struct gfs2_sbd *sdp, struct page *page,
extern void gfs2_log_write_page(struct gfs2_sbd *sdp, struct page *page);
extern void gfs2_log_submit_bio(struct bio **biop, int op, int op_flags);
extern void gfs2_pin(struct gfs2_sbd *sdp, struct buffer_head *bh);
+extern int gfs2_find_jhead(struct gfs2_jdesc *jd,
+ struct gfs2_log_header_host *head);
static inline unsigned int buf_limit(struct gfs2_sbd *sdp)
{
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 4ec69d9..ae3ee51 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -41,6 +41,7 @@
#include "dir.h"
#include "meta_io.h"
#include "trace_gfs2.h"
+#include "lops.h"
#define DO 0
#define UNDO 1
diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c
index 2dac430..7389e44 100644
--- a/fs/gfs2/recovery.c
+++ b/fs/gfs2/recovery.c
@@ -182,129 +182,6 @@ static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,
}
/**
- * find_good_lh - find a good log header
- * @jd: the journal
- * @blk: the segment to start searching from
- * @lh: the log header to fill in
- * @forward: if true search forward in the log, else search backward
- *
- * Call get_log_header() to get a log header for a segment, but if the
- * segment is bad, either scan forward or backward until we find a good one.
- *
- * Returns: errno
- */
-
-static int find_good_lh(struct gfs2_jdesc *jd, unsigned int *blk,
- struct gfs2_log_header_host *head)
-{
- unsigned int orig_blk = *blk;
- int error;
-
- for (;;) {
- error = get_log_header(jd, *blk, head);
- if (error <= 0)
- return error;
-
- if (++*blk == jd->jd_blocks)
- *blk = 0;
-
- if (*blk == orig_blk) {
- gfs2_consist_inode(GFS2_I(jd->jd_inode));
- return -EIO;
- }
- }
-}
-
-/**
- * jhead_scan - make sure we've found the head of the log
- * @jd: the journal
- * @head: this is filled in with the log descriptor of the head
- *
- * At this point, seg and lh should be either the head of the log or just
- * before. Scan forward until we find the head.
- *
- * Returns: errno
- */
-
-static int jhead_scan(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
-{
- unsigned int blk = head->lh_blkno;
- struct gfs2_log_header_host lh;
- int error;
-
- for (;;) {
- if (++blk == jd->jd_blocks)
- blk = 0;
-
- error = get_log_header(jd, blk, &lh);
- if (error < 0)
- return error;
- if (error == 1)
- continue;
-
- if (lh.lh_sequence == head->lh_sequence) {
- gfs2_consist_inode(GFS2_I(jd->jd_inode));
- return -EIO;
- }
- if (lh.lh_sequence < head->lh_sequence)
- break;
-
- *head = lh;
- }
-
- return 0;
-}
-
-/**
- * gfs2_find_jhead - find the head of a log
- * @jd: the journal
- * @head: the log descriptor for the head of the log is returned here
- *
- * Do a binary search of a journal and find the valid log entry with the
- * highest sequence number. (i.e. the log head)
- *
- * Returns: errno
- */
-
-int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
-{
- struct gfs2_log_header_host lh_1, lh_m;
- u32 blk_1, blk_2, blk_m;
- int error;
-
- blk_1 = 0;
- blk_2 = jd->jd_blocks - 1;
-
- for (;;) {
- blk_m = (blk_1 + blk_2) / 2;
-
- error = find_good_lh(jd, &blk_1, &lh_1);
- if (error)
- return error;
-
- error = find_good_lh(jd, &blk_m, &lh_m);
- if (error)
- return error;
-
- if (blk_1 == blk_m || blk_m == blk_2)
- break;
-
- if (lh_1.lh_sequence <= lh_m.lh_sequence)
- blk_1 = blk_m;
- else
- blk_2 = blk_m;
- }
-
- error = jhead_scan(jd, &lh_1);
- if (error)
- return error;
-
- *head = lh_1;
-
- return error;
-}
-
-/**
* foreach_descriptor - go through the active part of the log
* @jd: the journal
* @start: the first log header in the active region
diff --git a/fs/gfs2/recovery.h b/fs/gfs2/recovery.h
index 943a67c..4d00a92 100644
--- a/fs/gfs2/recovery.h
+++ b/fs/gfs2/recovery.h
@@ -27,8 +27,6 @@ extern int gfs2_revoke_add(struct gfs2_jdesc *jd, u64 blkno, unsigned int where)
extern int gfs2_revoke_check(struct gfs2_jdesc *jd, u64 blkno, unsigned int where);
extern void gfs2_revoke_clean(struct gfs2_jdesc *jd);
-extern int gfs2_find_jhead(struct gfs2_jdesc *jd,
- struct gfs2_log_header_host *head);
extern int gfs2_recover_journal(struct gfs2_jdesc *gfs2_jd, bool wait);
extern void gfs2_recover_func(struct work_struct *work);
extern int __get_log_header(struct gfs2_sbd *sdp, const struct gfs2_log_header *lh,
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index a971862..ae38ba7 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -45,6 +45,7 @@
#include "util.h"
#include "sys.h"
#include "xattr.h"
+#include "lops.h"
#define args_neq(a1, a2, x) ((a1)->ar_##x != (a2)->ar_##x)
--
2.4.11
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