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SubjectRe: [RFC][PATCH 4/8] file c/r: expose functions to query fs support
Dave Hansen [dave@linux.vnet.ibm.com] wrote:
|
| This pair of functions will check to see whether a given
| 'struct file' can be checkpointed. If it can't be, the
| "explain" function can also give a description why.
|
| Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
| ---
|
| linux-2.6.git-dave/checkpoint/ckpt_file.c | 46 ++++++++++++++++++++++++++
| linux-2.6.git-dave/include/linux/checkpoint.h | 18 ++++++++++
| 2 files changed, 64 insertions(+)
|
| diff -puN checkpoint/ckpt_file.c~cr-explain-unckpt-file checkpoint/ckpt_file.c
| --- linux-2.6.git/checkpoint/ckpt_file.c~cr-explain-unckpt-file 2009-02-27 12:07:38.000000000 -0800
| +++ linux-2.6.git-dave/checkpoint/ckpt_file.c 2009-02-27 12:07:38.000000000 -0800
| @@ -72,6 +72,52 @@ int cr_scan_fds(struct files_struct *fil
| return n;
| }
|
| +int fs_is_cr_able(struct file_system_type *fs_type)
| +{
| + if (fs_type->fs_flags & FS_CHECKPOINTABLE)
| + return 1;
| + /*
| + * We assume that all block-based filesystems that
| + * need devices work. This covers all of the
| + * "important" fs's by default like ext*. If this
| + * assumption becomes untrue, we may need a
| + * NOT_CHECKPOINTABLE flag in the future
| + */
| + if (fs_type->fs_flags & FS_REQUIRES_DEV)
| + return 1;
| + return 0;
| +}
| +
| +int cr_explain_file(struct file *file, char *explain, int left)
| +{
| + struct inode *inode = file->f_dentry->d_inode;
| + struct file_system_type *fs_type = inode->i_sb->s_type;
| +
| + if (!fs_is_cr_able(fs_type))
| + return snprintf(explain, left,
| + " (%s does not support checkpoint)",
| + fs_type->name);
| +
| + if (special_file(inode->i_mode))
| + return snprintf(explain, left, " (special file)");
| +
| + return 0;
| +}
| +
| +int cr_file_supported(struct file *file)
| +{
| + struct inode *inode = file->f_dentry->d_inode;
| + struct file_system_type *fs_type = inode->i_sb->s_type;
| +
| + if (fs_is_cr_able(fs_type))
| + return 0;

Should this be if (!fs_is_cr_able(fs_type)) ?

| +
| + if (special_file(inode->i_mode))
| + return 0;
| +
| + return 1;
| +}
| +
| /* cr_write_fd_data - dump the state of a given file pointer */
| static int cr_write_fd_data(struct cr_ctx *ctx, struct file *file, int parent)
| {
| diff -puN include/linux/checkpoint.h~cr-explain-unckpt-file include/linux/checkpoint.h
| --- linux-2.6.git/include/linux/checkpoint.h~cr-explain-unckpt-file 2009-02-27 12:07:38.000000000 -0800
| +++ linux-2.6.git-dave/include/linux/checkpoint.h 2009-02-27 12:07:38.000000000 -0800
| @@ -13,6 +13,8 @@
| #include <linux/path.h>
| #include <linux/fs.h>
|
| +#ifdef CONFIG_CHECKPOINT_RESTART
| +
| #define CR_VERSION 2
|
| struct cr_ctx {
| @@ -99,4 +101,20 @@ extern int cr_read_files(struct cr_ctx *
|
| #define pr_fmt(fmt) "[%d:c/r:%s] " fmt, task_pid_vnr(current), __func__
|
| +int cr_explain_file(struct file *file, char *explain, int left);
| +int cr_file_supported(struct file *file);
| +
| +#else /* !CONFIG_CHECKPOINT_RESTART */
| +
| +static inline int cr_explain_file(struct file *file, char *explain, int left)
| +{
| + return 0;
| +}
| +
| +int cr_file_supported(struct file *file)
| +{
| + return 0;
| +}
| +
| +#endif /* CONFIG_CHECKPOINT_RESTART */
| #endif /* _CHECKPOINT_CKPT_H_ */
| _
| --
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