[PATCH] jffs2: bug fix of creating node when gc or find space
Brian Norris
computersforpeace at gmail.com
Thu Dec 10 18:58:20 PST 2015
+ David (JFFS2 "maintainer")
David,
Looks like there was a similar patch / bug report from Huawei about a
year ago, though this one has some modifications:
http://patchwork.ozlabs.org/patch/416301/
It's among the outstanding jffs2 patches from the last 2 years, after I
filtered out the noise:
http://patchwork.ozlabs.org/project/linux-mtd/list/?q=jffs2
They're mostly marked as delegated to you. What would you like to do
with them?
On Fri, Dec 11, 2015 at 09:36:55AM +0800, gaoyongliang at huawei.com wrote:
> From: gaoyongliang <gaoyongliang at huawei.com>
gayongliang,
It's standard practice to use your full name for patch submittions in
the 'From:' and 'Signed-off-by:' portions. See
Documentation/SubmittingPatches. While I can probably guess at the space
and capitalization of your name, it's probably best if you can do this
yourself.
>
> 1. create inode by insert_inode_locked, and return inode with I_NEW.
> 2. has writed the dnode successfully in the end of one block, then
> release the c->alloc_sem, but the dirent is not written yet.
> 3. the gc or jffs2_reserve_space which has got the c->alloc_sem may
> find the block which the dnode we just writed in, the dnode can't
> be gc because the dirent is not written and the state of inode is
> still I_NEW, we can only wait on inode without release c->alloc_sem.
> 4. we can't get the c->alloc_sem to write the dirent, so the inode
> state keep I_NEW forever.
> 5. this will cause deadlock, like ABBA deadlock.
>
> lockf2.test D c02dead8 0 11666 1 0x00000001
> locked:
> c90f9be8 &inode->i_mutex 0 [<c00bf158>] generic_file_aio_write+0x40/0xb0
> c2c54c44 &c->alloc_sem 1 [<bf056f9c>] jffs2_garbage_collect_pass+0x1c/0xf08 [jffs2]
> [<c02dead8>] (__schedule+0x458/0x604) from [<c0114090>] (inode_wait+0x8/0x10)
> [<c0114090>] (inode_wait+0x8/0x10) from [<c02dd050>] (__wait_on_bit+0x54/0xa0)
> [<c02dd050>] (__wait_on_bit+0x54/0xa0) from [<c02dd114>] (out_of_line_wait_on_bit+0x78/0x84)
> [<c02dd114>] (out_of_line_wait_on_bit+0x78/0x84) from [<c01157a0>] (iget_locked+0x90/0x1b0)
> [<c01157a0>] (iget_locked+0x90/0x1b0) from [<bf059fe8>] (jffs2_iget+0xc/0x344 [jffs2])
> [<bf059fe8>] (jffs2_iget+0xc/0x344 [jffs2]) from [<bf05a6fc>] (jffs2_gc_fetch_inode+0x104/0x158 [jffs2])
> [<bf05a6fc>] (jffs2_gc_fetch_inode+0x104/0x158 [jffs2]) from [<bf0577f0>] (jffs2_garbage_collect_pass+0x870/0xf08 [jffs2])
> [<bf0577f0>] (jffs2_garbage_collect_pass+0x870/0xf08 [jffs2]) from [<bf051248>] (jffs2_reserve_space+0x154/0x3b4 [jffs2])
> [<bf051248>] (jffs2_reserve_space+0x154/0x3b4 [jffs2]) from [<bf053eac>] (jffs2_write_inode_range+0x58/0x3ac [jffs2])
> [<bf053eac>] (jffs2_write_inode_range+0x58/0x3ac [jffs2]) from [<bf04ec20>] (jffs2_write_end+0x11c/0x224 [jffs2])
> [<bf04ec20>] (jffs2_write_end+0x11c/0x224 [jffs2]) from [<c00bdfa4>] (generic_file_buffered_write+0x160/0x23c)
> [<c00bdfa4>] (generic_file_buffered_write+0x160/0x23c) from [<c00bf0ac>] (__generic_file_aio_write+0x328/0x394)
> [<c00bf0ac>] (__generic_file_aio_write+0x328/0x394) from [<c00bf16c>] (generic_file_aio_write+0x54/0xb0)
> [<c00bf16c>] (generic_file_aio_write+0x54/0xb0) from [<c00fdc24>] (do_sync_write+0x74/0x98)
> [<c00fdc24>] (do_sync_write+0x74/0x98) from [<c00fe550>] (vfs_write+0xcc/0x174)
> [<c00fe550>] (vfs_write+0xcc/0x174) from [<c00fe8a8>] (SyS_write+0x38/0x64)
> [<c00fe8a8>] (SyS_write+0x38/0x64) from [<c000f0c0>] (ret_fast_syscall+0x0/0x58)
>
> Fixes: e72e6497e74811e01d72b4c1b7537b3aea3ee857
FWIW, this isn't the preferred style for 'Fixes:' lines. It's nice to
include the commit subject too, like:
Fixes: commit ("e72e6497e748 jffs2: Fix NFS race by using insert_inode_locked()")
> Cc: <stable at vger.kernel.org> # 3.10.y+
> Signed-off-by: gaoyongliang <gaoyongliang at huawei.com>
> ---
> fs/jffs2/dir.c | 25 +++++++++++++++++++++++++
> fs/jffs2/fs.c | 1 +
> fs/jffs2/gc.c | 11 +++++++++++
> fs/jffs2/jffs2_fs_sb.h | 1 +
> fs/jffs2/nodelist.h | 4 ++++
> fs/jffs2/super.c | 1 +
> fs/jffs2/write.c | 1 +
> 7 files changed, 44 insertions(+), 0 deletions(-)
This patch looks awfully similar to chenjie's patch, but it has a bit
different diffstat. Presumably there were reasons for the changes. Can
you include a changelog? (e.g., "changed foo becuase of bar")
No other comment from me on the patch.
Brian
>
> diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
> index d211b8e..808ec17 100644
> --- a/fs/jffs2/dir.c
> +++ b/fs/jffs2/dir.c
> @@ -195,7 +195,9 @@ static int jffs2_create(struct inode *dir_i, struct dentry *dentry,
> no chance of AB-BA deadlock involving its f->sem). */
> mutex_unlock(&f->sem);
>
> + mutex_lock(&c->create_sem);
> ret = jffs2_do_create(c, dir_f, f, ri, &dentry->d_name);
> + mutex_unlock(&c->create_sem);
> if (ret)
> goto fail;
>
> @@ -208,12 +210,14 @@ static int jffs2_create(struct inode *dir_i, struct dentry *dentry,
> f->inocache->pino_nlink, inode->i_mapping->nrpages);
>
> unlock_new_inode(inode);
> + f->inocache->state_new = INO_STATE_N_NEW;
> d_instantiate(dentry, inode);
> return 0;
>
> fail:
> iget_failed(inode);
> jffs2_free_raw_inode(ri);
> + f->inocache->state_new = INO_STATE_N_NEW;
> return ret;
> }
>
> @@ -304,11 +308,13 @@ static int jffs2_symlink (struct inode *dir_i, struct dentry *dentry, const char
> * Just the node will do for now, though
> */
> namelen = dentry->d_name.len;
> + mutex_lock(&c->create_sem);
> ret = jffs2_reserve_space(c, sizeof(*ri) + targetlen, &alloclen,
> ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
>
> if (ret) {
> jffs2_free_raw_inode(ri);
> + mutex_unlock(&c->create_sem);
> return ret;
> }
>
> @@ -317,6 +323,7 @@ static int jffs2_symlink (struct inode *dir_i, struct dentry *dentry, const char
> if (IS_ERR(inode)) {
> jffs2_free_raw_inode(ri);
> jffs2_complete_reservation(c);
> + mutex_unlock(&c->create_sem);
> return PTR_ERR(inode);
> }
>
> @@ -429,11 +436,15 @@ static int jffs2_symlink (struct inode *dir_i, struct dentry *dentry, const char
> jffs2_complete_reservation(c);
>
> unlock_new_inode(inode);
> + f->inocache->state_new = INO_STATE_N_NEW;
> + mutex_unlock(&c->create_sem);
> d_instantiate(dentry, inode);
> return 0;
>
> fail:
> iget_failed(inode);
> + f->inocache->state_new = INO_STATE_N_NEW;
> + mutex_unlock(&c->create_sem);
> return ret;
> }
>
> @@ -463,11 +474,13 @@ static int jffs2_mkdir (struct inode *dir_i, struct dentry *dentry, umode_t mode
> * Just the node will do for now, though
> */
> namelen = dentry->d_name.len;
> + mutex_lock(&c->create_sem);
> ret = jffs2_reserve_space(c, sizeof(*ri), &alloclen, ALLOC_NORMAL,
> JFFS2_SUMMARY_INODE_SIZE);
>
> if (ret) {
> jffs2_free_raw_inode(ri);
> + mutex_unlock(&c->create_sem);
> return ret;
> }
>
> @@ -476,6 +489,7 @@ static int jffs2_mkdir (struct inode *dir_i, struct dentry *dentry, umode_t mode
> if (IS_ERR(inode)) {
> jffs2_free_raw_inode(ri);
> jffs2_complete_reservation(c);
> + mutex_unlock(&c->create_sem);
> return PTR_ERR(inode);
> }
>
> @@ -574,11 +588,15 @@ static int jffs2_mkdir (struct inode *dir_i, struct dentry *dentry, umode_t mode
> jffs2_complete_reservation(c);
>
> unlock_new_inode(inode);
> + f->inocache->state_new = INO_STATE_N_NEW;
> + mutex_unlock(&c->create_sem);
> d_instantiate(dentry, inode);
> return 0;
>
> fail:
> iget_failed(inode);
> + f->inocache->state_new = INO_STATE_N_NEW;
> + mutex_unlock(&c->create_sem);
> return ret;
> }
>
> @@ -634,11 +652,13 @@ static int jffs2_mknod (struct inode *dir_i, struct dentry *dentry, umode_t mode
> * Just the node will do for now, though
> */
> namelen = dentry->d_name.len;
> + mutex_lock(&c->create_sem);
> ret = jffs2_reserve_space(c, sizeof(*ri) + devlen, &alloclen,
> ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
>
> if (ret) {
> jffs2_free_raw_inode(ri);
> + mutex_unlock(&c->create_sem);
> return ret;
> }
>
> @@ -647,6 +667,7 @@ static int jffs2_mknod (struct inode *dir_i, struct dentry *dentry, umode_t mode
> if (IS_ERR(inode)) {
> jffs2_free_raw_inode(ri);
> jffs2_complete_reservation(c);
> + mutex_unlock(&c->create_sem);
> return PTR_ERR(inode);
> }
> inode->i_op = &jffs2_file_inode_operations;
> @@ -746,11 +767,15 @@ static int jffs2_mknod (struct inode *dir_i, struct dentry *dentry, umode_t mode
> jffs2_complete_reservation(c);
>
> unlock_new_inode(inode);
> + f->inocache->state_new = INO_STATE_N_NEW;
> + mutex_unlock(&c->create_sem);
> d_instantiate(dentry, inode);
> return 0;
>
> fail:
> iget_failed(inode);
> + f->inocache->state_new = INO_STATE_N_NEW;
> + mutex_unlock(&c->create_sem);
> return ret;
> }
>
> diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
> index 2caf168..c98fd3c 100644
> --- a/fs/jffs2/fs.c
> +++ b/fs/jffs2/fs.c
> @@ -482,6 +482,7 @@ struct inode *jffs2_new_inode (struct inode *dir_i, umode_t mode, struct jffs2_r
> mutex_unlock(&f->sem);
> make_bad_inode(inode);
> iput(inode);
> + f->inocache->state_new = INO_STATE_N_NEW;
> return ERR_PTR(-EINVAL);
> }
>
> diff --git a/fs/jffs2/gc.c b/fs/jffs2/gc.c
> index 5a2dec2..51f2a4b 100644
> --- a/fs/jffs2/gc.c
> +++ b/fs/jffs2/gc.c
> @@ -333,6 +333,17 @@ int jffs2_garbage_collect_pass(struct jffs2_sb_info *c)
> __func__, jeb->offset, ref_offset(raw), ref_flags(raw),
> ic->ino);
>
> + /* create but not finished so find next block */
> + if (ic->state_new == INO_STATE_I_NEW) {
> + jffs2_dbg(1, "%s(): ino #%u in state new so find next block\n",
> + __func__, ic->ino);
> + c->gcblock = NULL;
> + list_add_tail(&jeb->list, &c->dirty_list);
> + mutex_unlock(&c->alloc_sem);
> + spin_unlock(&c->inocache_lock);
> + return 0;
> + }
> +
> /* Three possibilities:
> 1. Inode is already in-core. We must iget it and do proper
> updating to its fragtree, etc.
> diff --git a/fs/jffs2/jffs2_fs_sb.h b/fs/jffs2/jffs2_fs_sb.h
> index 046fee8..32193b7 100644
> --- a/fs/jffs2/jffs2_fs_sb.h
> +++ b/fs/jffs2/jffs2_fs_sb.h
> @@ -57,6 +57,7 @@ struct jffs2_sb_info {
> struct completion gc_thread_start; /* GC thread start completion */
> struct completion gc_thread_exit; /* GC thread exit completion port */
>
> + struct mutex create_sem; /* Used to protect write dnode and dirent in order */
> struct mutex alloc_sem; /* Used to protect all the following
> fields, and also to protect against
> out-of-order writing of nodes. And GC. */
> diff --git a/fs/jffs2/nodelist.h b/fs/jffs2/nodelist.h
> index fa35ff7..ec377e0 100644
> --- a/fs/jffs2/nodelist.h
> +++ b/fs/jffs2/nodelist.h
> @@ -180,6 +180,7 @@ struct jffs2_inode_cache {
> here; other inodes store nlink.
> Zero always means that it's
> completely unlinked. */
> + uint32_t state_new; /* create flag */
> };
>
> /* Inode states for 'state' above. We need the 'GC' state to prevent
> @@ -193,6 +194,9 @@ struct jffs2_inode_cache {
> #define INO_STATE_READING 5 /* In read_inode() */
> #define INO_STATE_CLEARING 6 /* In clear_inode() */
>
> +#define INO_STATE_N_NEW 0 /* Finish to create */
> +#define INO_STATE_I_NEW 1 /* Just create but not finish */
> +
> #define INO_FLAGS_XATTR_CHECKED 0x01 /* has no duplicate xattr_ref */
>
> #define RAWNODE_CLASS_INODE_CACHE 0
> diff --git a/fs/jffs2/super.c b/fs/jffs2/super.c
> index d86c5e3..99c5715 100644
> --- a/fs/jffs2/super.c
> +++ b/fs/jffs2/super.c
> @@ -292,6 +292,7 @@ static int jffs2_fill_super(struct super_block *sb, void *data, int silent)
>
> /* Initialize JFFS2 superblock locks, the further initialization will
> * be done later */
> + mutex_init(&c->create_sem);
> mutex_init(&c->alloc_sem);
> mutex_init(&c->erase_free_sem);
> init_waitqueue_head(&c->erase_wait);
> diff --git a/fs/jffs2/write.c b/fs/jffs2/write.c
> index b634de4..dc8242d 100644
> --- a/fs/jffs2/write.c
> +++ b/fs/jffs2/write.c
> @@ -36,6 +36,7 @@ int jffs2_do_new_inode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
> f->inocache->pino_nlink = 1; /* Will be overwritten shortly for directories */
> f->inocache->nodes = (struct jffs2_raw_node_ref *)f->inocache;
> f->inocache->state = INO_STATE_PRESENT;
> + f->inocache->state_new = INO_STATE_I_NEW;
>
> jffs2_add_ino_cache(c, f->inocache);
> jffs2_dbg(1, "%s(): Assigned ino# %d\n", __func__, f->inocache->ino);
> --
> 1.7.6
>
>
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