On Sun 24-04-11 17:13:18, Manish Katiyar wrote:
> Update low level ext4 journal routines to pass an extra parameter
> to journal allocation routines to specify whether transaction allocation
> can fail or not. With this patch ext4_journal_start() can fail due to
> ENOMEM. Added a new interface ext4_journal_start_tryhard() which isn't
> supposed to fail and keep retrying till the allocation succeeds.
As I wrote in a comment in the comment to the first patch, first just
make ext4_journal_start_sb() and similar functions pass false as a part of
the first patch.
Then it would be better to create a new function that passes true - the
name does not really matter since it will be removed later in the series
but it will help the review process. You can call it
ext4_journal_start_sb_enomem() or whatever. This way we keep backward
compatibility because currently all call sites really expect the retry
behavior. Then in the patch you can switch safe call sites to use _enomem
variant and at the end of the series as a separate patch you just do
renaming - ext4_journal_start_sb() becomes ext4_journal_start_sb_tryhard()
and ext4_journal_start_sb_enomem() becomes ext4_journal_start_sb().
Honza
> Signed-off-by: Manish Katiyar <mkatiyar@xxxxxxxxx>
> ---
> fs/ext4/ext4_jbd2.h | 8 +++++++-
> fs/ext4/super.c | 15 +++++++++++++--
> 2 files changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
> index d0f5353..ee6385c 100644
> --- a/fs/ext4/ext4_jbd2.h
> +++ b/fs/ext4/ext4_jbd2.h
> @@ -162,6 +162,7 @@ int __ext4_handle_dirty_super(const char *where,
> unsigned int line,
> __ext4_handle_dirty_super(__func__, __LINE__, (handle), (sb))
>
> handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks);
> +handle_t *ext4_journal_start_sb_tryhard(struct super_block *sb, int nblocks);
> int __ext4_journal_stop(const char *where, unsigned int line,
> handle_t *handle);
>
> #define EXT4_NOJOURNAL_MAX_REF_COUNT ((unsigned long) 4096)
> @@ -207,6 +208,11 @@ static inline handle_t *ext4_journal_start(struct
> inode *inode, int nblocks)
> return ext4_journal_start_sb(inode->i_sb, nblocks);
> }
>
> +static inline handle_t *ext4_journal_start_tryhard(struct inode
> *inode, int nblocks)
> +{
> + return ext4_journal_start_sb_tryhard(inode->i_sb, nblocks);
> +}
> +
> #define ext4_journal_stop(handle) \
> __ext4_journal_stop(__func__, __LINE__, (handle))
>
> @@ -225,7 +231,7 @@ static inline int ext4_journal_extend(handle_t
> *handle, int nblocks)
> static inline int ext4_journal_restart(handle_t *handle, int nblocks)
> {
> if (ext4_handle_valid(handle))
> - return jbd2_journal_restart(handle, nblocks);
> + return jbd2_journal_restart(handle, nblocks, false);
> return 0;
> }
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 8553dfb..03eac6a 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -247,7 +247,8 @@ static void ext4_put_nojournal(handle_t *handle)
> * ext4 prevents a new handle from being started by s_frozen, which
> * is in an upper layer.
> */
> -handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
> +static handle_t *__ext4_journal_start_sb(struct super_block *sb,
> + int nblocks, bool errok)
> {
> journal_t *journal;
> handle_t *handle;
> @@ -279,7 +280,17 @@ handle_t *ext4_journal_start_sb(struct
> super_block *sb, int nblocks)
> ext4_abort(sb, "Detected aborted journal");
> return ERR_PTR(-EROFS);
> }
> - return jbd2_journal_start(journal, nblocks);
> + return jbd2_journal_start(journal, nblocks, errok);
> +}
> +
> +handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
> +{
> + return __ext4_journal_start_sb(sb, nblocks, true);
> +}
> +
> +handle_t *ext4_journal_start_sb_tryhard(struct super_block *sb, int nblocks)
> +{
> + return __ext4_journal_start_sb(sb, nblocks, false);
> }
>
> /*
> --
> 1.7.1
>
> --
> Thanks -
> Manish
> From 365d29cd8d5b139e332965a536dd380e656bbd15 Mon Sep 17 00:00:00 2001
> From: Manish Katiyar <mkatiyar@xxxxxxxxx>
> Date: Sun, 24 Apr 2011 16:49:48 -0700
> Subject: [PATCH 2/5] Update low level ext4 journal routines to pass an extra paramter
> to journal allocation routines to specify whether transaction allocation
> can fail or not. With this patch ext4_journal_start() can fail due to
> ENOMEM. Added a new interface ext4_journal_start_tryhard() which isn't
> supposed to fail and keep retrying till the allocation succeeds.
>
>
> Signed-off-by: Manish Katiyar <mkatiyar@xxxxxxxxx>
> ---
> fs/ext4/ext4_jbd2.h | 8 +++++++-
> fs/ext4/super.c | 15 +++++++++++++--
> 2 files changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
> index d0f5353..ee6385c 100644
> --- a/fs/ext4/ext4_jbd2.h
> +++ b/fs/ext4/ext4_jbd2.h
> @@ -162,6 +162,7 @@ int __ext4_handle_dirty_super(const char *where, unsigned int line,
> __ext4_handle_dirty_super(__func__, __LINE__, (handle), (sb))
>
> handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks);
> +handle_t *ext4_journal_start_sb_tryhard(struct super_block *sb, int nblocks);
> int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle);
>
> #define EXT4_NOJOURNAL_MAX_REF_COUNT ((unsigned long) 4096)
> @@ -207,6 +208,11 @@ static inline handle_t *ext4_journal_start(struct inode *inode, int nblocks)
> return ext4_journal_start_sb(inode->i_sb, nblocks);
> }
>
> +static inline handle_t *ext4_journal_start_tryhard(struct inode *inode, int nblocks)
> +{
> + return ext4_journal_start_sb_tryhard(inode->i_sb, nblocks);
> +}
> +
> #define ext4_journal_stop(handle) \
> __ext4_journal_stop(__func__, __LINE__, (handle))
>
> @@ -225,7 +231,7 @@ static inline int ext4_journal_extend(handle_t *handle, int nblocks)
> static inline int ext4_journal_restart(handle_t *handle, int nblocks)
> {
> if (ext4_handle_valid(handle))
> - return jbd2_journal_restart(handle, nblocks);
> + return jbd2_journal_restart(handle, nblocks, false);
> return 0;
> }
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 8553dfb..03eac6a 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -247,7 +247,8 @@ static void ext4_put_nojournal(handle_t *handle)
> * ext4 prevents a new handle from being started by s_frozen, which
> * is in an upper layer.
> */
> -handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
> +static handle_t *__ext4_journal_start_sb(struct super_block *sb,
> + int nblocks, bool errok)
> {
> journal_t *journal;
> handle_t *handle;
> @@ -279,7 +280,17 @@ handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
> ext4_abort(sb, "Detected aborted journal");
> return ERR_PTR(-EROFS);
> }
> - return jbd2_journal_start(journal, nblocks);
> + return jbd2_journal_start(journal, nblocks, errok);
> +}
> +
> +handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks)
> +{
> + return __ext4_journal_start_sb(sb, nblocks, true);
> +}
> +
> +handle_t *ext4_journal_start_sb_tryhard(struct super_block *sb, int nblocks)
> +{
> + return __ext4_journal_start_sb(sb, nblocks, false);
> }
>
> /*
> --
> 1.7.1
>
--
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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