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Commit | Line | Data |
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00e5a55c BS |
1 | From: Jan Kara <jack@suse.cz> |
2 | Date: Mon, 12 Jan 2009 23:20:31 +0100 | |
3 | Subject: [PATCH] ocfs2: Push out dropping of dentry lock to ocfs2_wq | |
4 | Patch-mainline: 2.6.29 | |
5 | ||
6 | Dropping of last reference to dentry lock is a complicated operation involving | |
7 | dropping of reference to inode. This can get complicated and quota code in | |
8 | particular needs to obtain some quota locks which leads to potential deadlock. | |
9 | Thus we defer dropping of inode reference to ocfs2_wq. | |
10 | ||
11 | Signed-off-by: Jan Kara <jack@suse.cz> | |
12 | Signed-off-by: Mark Fasheh <mfasheh@suse.com> | |
13 | --- | |
14 | fs/ocfs2/dcache.c | 42 +++++++++++++++++++++++++++++++++++++++--- | |
15 | fs/ocfs2/dcache.h | 9 ++++++++- | |
16 | fs/ocfs2/ocfs2.h | 6 ++++++ | |
17 | fs/ocfs2/super.c | 3 +++ | |
18 | 4 files changed, 56 insertions(+), 4 deletions(-) | |
19 | ||
20 | --- a/fs/ocfs2/dcache.c | |
21 | +++ b/fs/ocfs2/dcache.c | |
22 | @@ -38,6 +38,7 @@ | |
23 | #include "dlmglue.h" | |
24 | #include "file.h" | |
25 | #include "inode.h" | |
26 | +#include "super.h" | |
27 | ||
28 | ||
29 | static int ocfs2_dentry_revalidate(struct dentry *dentry, | |
30 | @@ -294,6 +295,34 @@ out_attach: | |
31 | return ret; | |
32 | } | |
33 | ||
34 | +static DEFINE_SPINLOCK(dentry_list_lock); | |
35 | + | |
36 | +/* We limit the number of dentry locks to drop in one go. We have | |
37 | + * this limit so that we don't starve other users of ocfs2_wq. */ | |
38 | +#define DL_INODE_DROP_COUNT 64 | |
39 | + | |
40 | +/* Drop inode references from dentry locks */ | |
41 | +void ocfs2_drop_dl_inodes(struct work_struct *work) | |
42 | +{ | |
43 | + struct ocfs2_super *osb = container_of(work, struct ocfs2_super, | |
44 | + dentry_lock_work); | |
45 | + struct ocfs2_dentry_lock *dl; | |
46 | + int drop_count = DL_INODE_DROP_COUNT; | |
47 | + | |
48 | + spin_lock(&dentry_list_lock); | |
49 | + while (osb->dentry_lock_list && drop_count--) { | |
50 | + dl = osb->dentry_lock_list; | |
51 | + osb->dentry_lock_list = dl->dl_next; | |
52 | + spin_unlock(&dentry_list_lock); | |
53 | + iput(dl->dl_inode); | |
54 | + kfree(dl); | |
55 | + spin_lock(&dentry_list_lock); | |
56 | + } | |
57 | + if (osb->dentry_lock_list) | |
58 | + queue_work(ocfs2_wq, &osb->dentry_lock_work); | |
59 | + spin_unlock(&dentry_list_lock); | |
60 | +} | |
61 | + | |
62 | /* | |
63 | * ocfs2_dentry_iput() and friends. | |
64 | * | |
65 | @@ -318,16 +347,23 @@ out_attach: | |
66 | static void ocfs2_drop_dentry_lock(struct ocfs2_super *osb, | |
67 | struct ocfs2_dentry_lock *dl) | |
68 | { | |
69 | - iput(dl->dl_inode); | |
70 | ocfs2_simple_drop_lockres(osb, &dl->dl_lockres); | |
71 | ocfs2_lock_res_free(&dl->dl_lockres); | |
72 | - kfree(dl); | |
73 | + | |
74 | + /* We leave dropping of inode reference to ocfs2_wq as that can | |
75 | + * possibly lead to inode deletion which gets tricky */ | |
76 | + spin_lock(&dentry_list_lock); | |
77 | + if (!osb->dentry_lock_list) | |
78 | + queue_work(ocfs2_wq, &osb->dentry_lock_work); | |
79 | + dl->dl_next = osb->dentry_lock_list; | |
80 | + osb->dentry_lock_list = dl; | |
81 | + spin_unlock(&dentry_list_lock); | |
82 | } | |
83 | ||
84 | void ocfs2_dentry_lock_put(struct ocfs2_super *osb, | |
85 | struct ocfs2_dentry_lock *dl) | |
86 | { | |
87 | - int unlock = 0; | |
88 | + int unlock; | |
89 | ||
90 | BUG_ON(dl->dl_count == 0); | |
91 | ||
92 | --- a/fs/ocfs2/dcache.h | |
93 | +++ b/fs/ocfs2/dcache.h | |
94 | @@ -29,8 +29,13 @@ | |
95 | extern struct dentry_operations ocfs2_dentry_ops; | |
96 | ||
97 | struct ocfs2_dentry_lock { | |
98 | + /* Use count of dentry lock */ | |
99 | unsigned int dl_count; | |
100 | - u64 dl_parent_blkno; | |
101 | + union { | |
102 | + /* Linked list of dentry locks to release */ | |
103 | + struct ocfs2_dentry_lock *dl_next; | |
104 | + u64 dl_parent_blkno; | |
105 | + }; | |
106 | ||
107 | /* | |
108 | * The ocfs2_dentry_lock keeps an inode reference until | |
109 | @@ -47,6 +52,8 @@ int ocfs2_dentry_attach_lock(struct dent | |
110 | void ocfs2_dentry_lock_put(struct ocfs2_super *osb, | |
111 | struct ocfs2_dentry_lock *dl); | |
112 | ||
113 | +void ocfs2_drop_dl_inodes(struct work_struct *work); | |
114 | + | |
115 | struct dentry *ocfs2_find_local_alias(struct inode *inode, u64 parent_blkno, | |
116 | int skip_unhashed); | |
117 | ||
118 | --- a/fs/ocfs2/ocfs2.h | |
119 | +++ b/fs/ocfs2/ocfs2.h | |
120 | @@ -210,6 +210,7 @@ struct ocfs2_journal; | |
121 | struct ocfs2_slot_info; | |
122 | struct ocfs2_recovery_map; | |
123 | struct ocfs2_quota_recovery; | |
124 | +struct ocfs2_dentry_lock; | |
125 | struct ocfs2_super | |
126 | { | |
127 | struct task_struct *commit_task; | |
128 | @@ -325,6 +326,11 @@ struct ocfs2_super | |
129 | struct list_head blocked_lock_list; | |
130 | unsigned long blocked_lock_count; | |
131 | ||
132 | + /* List of dentry locks to release. Anyone can add locks to | |
133 | + * the list, ocfs2_wq processes the list */ | |
134 | + struct ocfs2_dentry_lock *dentry_lock_list; | |
135 | + struct work_struct dentry_lock_work; | |
136 | + | |
137 | wait_queue_head_t osb_mount_event; | |
138 | ||
139 | /* Truncate log info */ | |
140 | --- a/fs/ocfs2/super.c | |
141 | +++ b/fs/ocfs2/super.c | |
142 | @@ -1888,6 +1888,9 @@ static int ocfs2_initialize_super(struct | |
143 | INIT_WORK(&journal->j_recovery_work, ocfs2_complete_recovery); | |
144 | journal->j_state = OCFS2_JOURNAL_FREE; | |
145 | ||
146 | + INIT_WORK(&osb->dentry_lock_work, ocfs2_drop_dl_inodes); | |
147 | + osb->dentry_lock_list = NULL; | |
148 | + | |
149 | /* get some pseudo constants for clustersize bits */ | |
150 | osb->s_clustersize_bits = | |
151 | le32_to_cpu(di->id2.i_super.s_clustersize_bits); |