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-rw-r--r--fs/xfs/libxfs/xfs_alloc.c68
-rw-r--r--fs/xfs/libxfs/xfs_alloc.h11
-rw-r--r--fs/xfs/xfs_extent_busy.c33
-rw-r--r--fs/xfs/xfs_extent_busy.h6
4 files changed, 88 insertions, 30 deletions
diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index 155ed3cce52c..530c7f7f3c2e 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -1556,6 +1556,8 @@ xfs_alloc_ag_vextent_near(
if (args->agbno > args->max_agbno)
args->agbno = args->max_agbno;
+ /* Retry once quickly if we find busy extents before blocking. */
+ alloc_flags |= XFS_ALLOC_FLAG_TRYFLUSH;
restart:
len = 0;
@@ -1611,9 +1613,20 @@ restart:
*/
if (!acur.len) {
if (acur.busy) {
+ /*
+ * Our only valid extents must have been busy. Flush and
+ * retry the allocation again. If we get an -EAGAIN
+ * error, we're being told that a deadlock was avoided
+ * and the current transaction needs committing before
+ * the allocation can be retried.
+ */
trace_xfs_alloc_near_busy(args);
- xfs_extent_busy_flush(args->mp, args->pag,
- acur.busy_gen, alloc_flags);
+ error = xfs_extent_busy_flush(args->tp, args->pag,
+ acur.busy_gen, alloc_flags);
+ if (error)
+ goto out;
+
+ alloc_flags &= ~XFS_ALLOC_FLAG_TRYFLUSH;
goto restart;
}
trace_xfs_alloc_size_neither(args);
@@ -1653,6 +1666,8 @@ xfs_alloc_ag_vextent_size(
int error;
int i;
+ /* Retry once quickly if we find busy extents before blocking. */
+ alloc_flags |= XFS_ALLOC_FLAG_TRYFLUSH;
restart:
/*
* Allocate and initialize a cursor for the by-size btree.
@@ -1710,19 +1725,25 @@ restart:
error = xfs_btree_increment(cnt_cur, 0, &i);
if (error)
goto error0;
- if (i == 0) {
- /*
- * Our only valid extents must have been busy.
- * Make it unbusy by forcing the log out and
- * retrying.
- */
- xfs_btree_del_cursor(cnt_cur,
- XFS_BTREE_NOERROR);
- trace_xfs_alloc_size_busy(args);
- xfs_extent_busy_flush(args->mp, args->pag,
- busy_gen, alloc_flags);
- goto restart;
- }
+ if (i)
+ continue;
+
+ /*
+ * Our only valid extents must have been busy. Flush and
+ * retry the allocation again. If we get an -EAGAIN
+ * error, we're being told that a deadlock was avoided
+ * and the current transaction needs committing before
+ * the allocation can be retried.
+ */
+ trace_xfs_alloc_size_busy(args);
+ error = xfs_extent_busy_flush(args->tp, args->pag,
+ busy_gen, alloc_flags);
+ if (error)
+ goto error0;
+
+ alloc_flags &= ~XFS_ALLOC_FLAG_TRYFLUSH;
+ xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
+ goto restart;
}
}
@@ -1802,10 +1823,21 @@ restart:
args->len = rlen;
if (rlen < args->minlen) {
if (busy) {
- xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
+ /*
+ * Our only valid extents must have been busy. Flush and
+ * retry the allocation again. If we get an -EAGAIN
+ * error, we're being told that a deadlock was avoided
+ * and the current transaction needs committing before
+ * the allocation can be retried.
+ */
trace_xfs_alloc_size_busy(args);
- xfs_extent_busy_flush(args->mp, args->pag, busy_gen,
- alloc_flags);
+ error = xfs_extent_busy_flush(args->tp, args->pag,
+ busy_gen, alloc_flags);
+ if (error)
+ goto error0;
+
+ alloc_flags &= ~XFS_ALLOC_FLAG_TRYFLUSH;
+ xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
goto restart;
}
goto out_nominleft;
diff --git a/fs/xfs/libxfs/xfs_alloc.h b/fs/xfs/libxfs/xfs_alloc.h
index 7a10714171ca..e544ee43fba6 100644
--- a/fs/xfs/libxfs/xfs_alloc.h
+++ b/fs/xfs/libxfs/xfs_alloc.h
@@ -19,11 +19,12 @@ unsigned int xfs_agfl_size(struct xfs_mount *mp);
/*
* Flags for xfs_alloc_fix_freelist.
*/
-#define XFS_ALLOC_FLAG_TRYLOCK 0x00000001 /* use trylock for buffer locking */
-#define XFS_ALLOC_FLAG_FREEING 0x00000002 /* indicate caller is freeing extents*/
-#define XFS_ALLOC_FLAG_NORMAP 0x00000004 /* don't modify the rmapbt */
-#define XFS_ALLOC_FLAG_NOSHRINK 0x00000008 /* don't shrink the freelist */
-#define XFS_ALLOC_FLAG_CHECK 0x00000010 /* test only, don't modify args */
+#define XFS_ALLOC_FLAG_TRYLOCK (1U << 0) /* use trylock for buffer locking */
+#define XFS_ALLOC_FLAG_FREEING (1U << 1) /* indicate caller is freeing extents*/
+#define XFS_ALLOC_FLAG_NORMAP (1U << 2) /* don't modify the rmapbt */
+#define XFS_ALLOC_FLAG_NOSHRINK (1U << 3) /* don't shrink the freelist */
+#define XFS_ALLOC_FLAG_CHECK (1U << 4) /* test only, don't modify args */
+#define XFS_ALLOC_FLAG_TRYFLUSH (1U << 5) /* don't wait in busy extent flush */
/*
* Argument structure for xfs_alloc routines.
diff --git a/fs/xfs/xfs_extent_busy.c b/fs/xfs/xfs_extent_busy.c
index 5f44936eae1c..7c2fdc71e42d 100644
--- a/fs/xfs/xfs_extent_busy.c
+++ b/fs/xfs/xfs_extent_busy.c
@@ -566,10 +566,21 @@ xfs_extent_busy_clear(
/*
* Flush out all busy extents for this AG.
+ *
+ * If the current transaction is holding busy extents, the caller may not want
+ * to wait for committed busy extents to resolve. If we are being told just to
+ * try a flush or progress has been made since we last skipped a busy extent,
+ * return immediately to allow the caller to try again.
+ *
+ * If we are freeing extents, we might actually be holding the only free extents
+ * in the transaction busy list and the log force won't resolve that situation.
+ * In this case, we must return -EAGAIN to avoid a deadlock by informing the
+ * caller it needs to commit the busy extents it holds before retrying the
+ * extent free operation.
*/
-void
+int
xfs_extent_busy_flush(
- struct xfs_mount *mp,
+ struct xfs_trans *tp,
struct xfs_perag *pag,
unsigned busy_gen,
uint32_t alloc_flags)
@@ -577,10 +588,23 @@ xfs_extent_busy_flush(
DEFINE_WAIT (wait);
int error;
- error = xfs_log_force(mp, XFS_LOG_SYNC);
+ error = xfs_log_force(tp->t_mountp, XFS_LOG_SYNC);
if (error)
- return;
+ return error;
+
+ /* Avoid deadlocks on uncommitted busy extents. */
+ if (!list_empty(&tp->t_busy)) {
+ if (alloc_flags & XFS_ALLOC_FLAG_TRYFLUSH)
+ return 0;
+
+ if (busy_gen != READ_ONCE(pag->pagb_gen))
+ return 0;
+
+ if (alloc_flags & XFS_ALLOC_FLAG_FREEING)
+ return -EAGAIN;
+ }
+ /* Wait for committed busy extents to resolve. */
do {
prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE);
if (busy_gen != READ_ONCE(pag->pagb_gen))
@@ -589,6 +613,7 @@ xfs_extent_busy_flush(
} while (1);
finish_wait(&pag->pagb_wait, &wait);
+ return 0;
}
void
diff --git a/fs/xfs/xfs_extent_busy.h b/fs/xfs/xfs_extent_busy.h
index 7a82c689bfa4..c37bf87e6781 100644
--- a/fs/xfs/xfs_extent_busy.h
+++ b/fs/xfs/xfs_extent_busy.h
@@ -51,9 +51,9 @@ bool
xfs_extent_busy_trim(struct xfs_alloc_arg *args, xfs_agblock_t *bno,
xfs_extlen_t *len, unsigned *busy_gen);
-void
-xfs_extent_busy_flush(struct xfs_mount *mp, struct xfs_perag *pag,
- unsigned busy_gen, uint32_t alloc_flags);
+int
+xfs_extent_busy_flush(struct xfs_trans *tp, struct xfs_perag *pag,
+ unsigned busy_gen, uint32_t alloc_flags);
void
xfs_extent_busy_wait_all(struct xfs_mount *mp);
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-07 10:59:09 +0000