[RFC v2 3/4] ext4: Add support for generic FS events

Beata Michalska
2015-04-27T11:58:25Z

Add support for generic FS events including threshold
notifications, ENOSPC and remount as read-only warnings,
along with generic internal warnings/errors.

Signed-off-by: Beata Michalska <b.michalska@samsung.com>
---
fs/ext4/balloc.c | 10 ++++++++--
fs/ext4/ext4.h | 1 +
fs/ext4/inode.c | 2 +-
fs/ext4/mballoc.c | 6 +++++-
fs/ext4/resize.c | 1 +
fs/ext4/super.c | 39 +++++++++++++++++++++++++++++++++++++++
6 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index e95b27a..a48450f 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -569,6 +569,7 @@ int ext4_claim_free_clusters(struct ext4_sb_info *sbi,
{
if (ext4_has_free_clusters(sbi, nclusters, flags)) {
percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters);
+ fs_event_alloc_space(sbi->s_sb, EXT4_C2B(sbi, nclusters));
return 0;
} else
return -ENOSPC;
@@ -590,9 +591,10 @@ int ext4_should_retry_alloc(struct super_block *sb, int *retries)
{
if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) ||
(*retries)++ > 3 ||
- !EXT4_SB(sb)->s_journal)
+ !EXT4_SB(sb)->s_journal) {
+ fs_event_notify(sb, FS_WARN_ENOSPC);
return 0;
-
+ }
jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);

return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
@@ -637,6 +639,10 @@ ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
dquot_alloc_block_nofail(inode,
EXT4_C2B(EXT4_SB(inode->i_sb), ar.len));
}
+
+ if (*errp == -ENOSPC)
+ fs_event_notify(inode->i_sb, FS_WARN_ENOSPC_META);
+
return ret;
}

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 163afe2..7d75ff9 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2542,6 +2542,7 @@ void ext4_mark_group_corrupted(struct ext4_sb_info *sbi,
if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
percpu_counter_sub(&sbi->s_freeclusters_counter, grp->bb_free);
set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
+ fs_event_alloc_space(sbi->s_sb, EXT4_C2B(sbi, grp->bb_free));
}

/*
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5cb9a21..2a7af0f 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1238,7 +1238,7 @@ static void ext4_da_release_space(struct inode *inode, int to_free)
percpu_counter_sub(&sbi->s_dirtyclusters_counter, to_free);

spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
-
+ fs_event_free_space(sbi->s_sb, to_free);
dquot_release_reservation_block(inode, EXT4_C2B(sbi, to_free));
}

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 24a4b6d..c2df6f0 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4511,6 +4511,9 @@ out:
kmem_cache_free(ext4_ac_cachep, ac);
if (inquota && ar->len < inquota)
dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
+ if (reserv_clstrs && ar->len < reserv_clstrs)
+ fs_event_free_space(sbi->s_sb,
+ EXT4_C2B(sbi, reserv_clstrs - ar->len));
if (!ar->len) {
if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0)
/* release all the reserved blocks if non delalloc */
@@ -4848,7 +4851,7 @@ do_more:
if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
percpu_counter_add(&sbi->s_freeclusters_counter, count_clusters);
-
+ fs_event_free_space(sb, EXT4_C2B(sbi, count_clusters));
ext4_mb_unload_buddy(&e4b);

/* We dirtied the bitmap block */
@@ -4982,6 +4985,7 @@ int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
ext4_unlock_group(sb, block_group);
percpu_counter_add(&sbi->s_freeclusters_counter,
EXT4_NUM_B2C(sbi, blocks_freed));
+ fs_event_free_space(sb, blocks_freed);

if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 8a8ec62..dbf08d6 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1378,6 +1378,7 @@ static void ext4_update_super(struct super_block *sb,
EXT4_NUM_B2C(sbi, free_blocks));
percpu_counter_add(&sbi->s_freeinodes_counter,
EXT4_INODES_PER_GROUP(sb) * flex_gd->count);
+ fs_event_free_space(sb, free_blocks - reserved_blocks);

ext4_debug("free blocks count %llu",
percpu_counter_read(&sbi->s_freeclusters_counter));
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index e061e66..108b667 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -585,6 +585,8 @@ void __ext4_abort(struct super_block *sb, const char *function,
if (EXT4_SB(sb)->s_journal)
jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
save_error_info(sb, function, line);
+ fs_event_notify(sb, FS_ERR_REMOUNT_RO);
+
}
if (test_opt(sb, ERRORS_PANIC))
panic("EXT4-fs panic from previous error\n");
@@ -1083,6 +1085,12 @@ static const struct quotactl_ops ext4_qctl_operations = {
};
#endif

+static void ext4_trace_query(struct super_block *sb, u64 *ncount);
+
+static const struct fs_trace_operations ext4_trace_ops = {
+ .query = ext4_trace_query,
+};
+
static const struct super_operations ext4_sops = {
.alloc_inode = ext4_alloc_inode,
.destroy_inode = ext4_destroy_inode,
@@ -3398,11 +3406,20 @@ static int ext4_reserve_clusters(struct ext4_sb_info *sbi, ext4_fsblk_t count)
{
ext4_fsblk_t clusters = ext4_blocks_count(sbi->s_es) >>
sbi->s_cluster_bits;
+ ext4_fsblk_t current_resv;

if (count >= clusters)
return -EINVAL;

+ current_resv = atomic64_read(&sbi->s_resv_clusters);
atomic64_set(&sbi->s_resv_clusters, count);
+
+ if (count > current_resv)
+ fs_event_alloc_space(sbi->s_sb,
+ EXT4_C2B(sbi, count - current_resv));
+ else
+ fs_event_free_space(sbi->s_sb,
+ EXT4_C2B(sbi, current_resv - count));
return 0;
}

@@ -3966,6 +3983,9 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
sb->s_qcop = &ext4_qctl_operations;
sb->s_quota_types = QTYPE_MASK_USR | QTYPE_MASK_GRP;
#endif
+ sb->s_etrace.ops = &ext4_trace_ops;
+ sb->s_etrace.events_cap_mask = FS_EVENTS_ALL;
+
memcpy(sb->s_uuid, es->s_uuid, sizeof(es->s_uuid));

INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
@@ -5438,6 +5458,25 @@ out:

#endif

+static void ext4_trace_query(struct super_block *sb, u64 *ncount)
+{
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ struct ext4_super_block *es = sbi->s_es;
+ ext4_fsblk_t rsv_blocks;
+ ext4_fsblk_t nblocks;
+
+ nblocks = percpu_counter_sum_positive(&sbi->s_freeclusters_counter) -
+ percpu_counter_sum_positive(&sbi->s_dirtyclusters_counter);
+ nblocks = EXT4_C2B(sbi, nblocks);
+ rsv_blocks = ext4_r_blocks_count(es) +
+ EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters));
+ if (nblocks < rsv_blocks)
+ nblocks = 0;
+ else
+ nblocks -= rsv_blocks;
+ *ncount = nblocks;
+}
+
static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data)
{
--
1.7.9.5