fs/jffs2/dir.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-)
Use fs_umode_to_dtype() instead of direct bit shifting when
setting directory entry type.
Signed-off-by: Adarsh Das <adarshdas950@gmail.com>
---
fs/jffs2/dir.c | 11 +++--------
1 file changed, 3 insertions(+), 8 deletions(-)
diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c
index dd91f725ded6..185cf76a061e 100644
--- a/fs/jffs2/dir.c
+++ b/fs/jffs2/dir.c
@@ -261,8 +261,7 @@ static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct de
if (d_is_dir(old_dentry))
return -EPERM;
- /* XXX: This is ugly */
- type = (d_inode(old_dentry)->i_mode & S_IFMT) >> 12;
+ type = fs_umode_to_dtype(d_inode(old_dentry)->i_mode);
if (!type) type = DT_REG;
now = JFFS2_NOW();
@@ -730,10 +729,7 @@ static int jffs2_mknod (struct mnt_idmap *idmap, struct inode *dir_i,
rd->ino = cpu_to_je32(inode->i_ino);
rd->mctime = cpu_to_je32(JFFS2_NOW());
rd->nsize = namelen;
-
- /* XXX: This is ugly. */
- rd->type = (mode & S_IFMT) >> 12;
-
+ rd->type = fs_umode_to_dtype(mode);
rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8));
rd->name_crc = cpu_to_je32(crc32(0, dentry->d_name.name, namelen));
@@ -811,8 +807,7 @@ static int jffs2_rename (struct mnt_idmap *idmap,
/* Make a hard link */
- /* XXX: This is ugly */
- type = (d_inode(old_dentry)->i_mode & S_IFMT) >> 12;
+ type = fs_umode_to_dtype(d_inode(old_dentry)->i_mode);
if (!type) type = DT_REG;
now = JFFS2_NOW();
--
2.53.0在 2026/2/6 19:51, Adarsh Das 写道: > Use fs_umode_to_dtype() instead of direct bit shifting when > setting directory entry type. > > Signed-off-by: Adarsh Das <adarshdas950@gmail.com> > --- > fs/jffs2/dir.c | 11 +++-------- > 1 file changed, 3 insertions(+), 8 deletions(-) > Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com> > diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c > index dd91f725ded6..185cf76a061e 100644 > --- a/fs/jffs2/dir.c > +++ b/fs/jffs2/dir.c > @@ -261,8 +261,7 @@ static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct de > if (d_is_dir(old_dentry)) > return -EPERM; > > - /* XXX: This is ugly */ > - type = (d_inode(old_dentry)->i_mode & S_IFMT) >> 12; > + type = fs_umode_to_dtype(d_inode(old_dentry)->i_mode); > if (!type) type = DT_REG; > > now = JFFS2_NOW(); > @@ -730,10 +729,7 @@ static int jffs2_mknod (struct mnt_idmap *idmap, struct inode *dir_i, > rd->ino = cpu_to_je32(inode->i_ino); > rd->mctime = cpu_to_je32(JFFS2_NOW()); > rd->nsize = namelen; > - > - /* XXX: This is ugly. */ > - rd->type = (mode & S_IFMT) >> 12; > - > + rd->type = fs_umode_to_dtype(mode); > rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8)); > rd->name_crc = cpu_to_je32(crc32(0, dentry->d_name.name, namelen)); > > @@ -811,8 +807,7 @@ static int jffs2_rename (struct mnt_idmap *idmap, > > /* Make a hard link */ > > - /* XXX: This is ugly */ > - type = (d_inode(old_dentry)->i_mode & S_IFMT) >> 12; > + type = fs_umode_to_dtype(d_inode(old_dentry)->i_mode); > if (!type) type = DT_REG; > > now = JFFS2_NOW(); >
在 2026/2/6 19:51, Adarsh Das 写道: > Use fs_umode_to_dtype() instead of direct bit shifting when > setting directory entry type. > > Signed-off-by: Adarsh Das <adarshdas950@gmail.com> > --- > fs/jffs2/dir.c | 11 +++-------- > 1 file changed, 3 insertions(+), 8 deletions(-) > > diff --git a/fs/jffs2/dir.c b/fs/jffs2/dir.c > index dd91f725ded6..185cf76a061e 100644 > --- a/fs/jffs2/dir.c > +++ b/fs/jffs2/dir.c > @@ -261,8 +261,7 @@ static int jffs2_link (struct dentry *old_dentry, struct inode *dir_i, struct de > if (d_is_dir(old_dentry)) > return -EPERM; > > - /* XXX: This is ugly */ > - type = (d_inode(old_dentry)->i_mode & S_IFMT) >> 12; > + type = fs_umode_to_dtype(d_inode(old_dentry)->i_mode); > if (!type) type = DT_REG; Hi Adarsh, The convertion result is wrong for jffs2_do_link. The i_mode of old_dentry is 'S_IFIFO', the jffs2 gets type DT_FIFO(1) and pass it to 'rd->type' by jffs2_do_link. However, after the patch applied, jffs2 gets type FT_FIFO(5), which will confuse other 'rd->type' accessing processes(eg. jffs2_scan_dirent_node[rd->type], jffs2_build_filesystem[fd->type]). > > now = JFFS2_NOW(); > @@ -730,10 +729,7 @@ static int jffs2_mknod (struct mnt_idmap *idmap, struct inode *dir_i, > rd->ino = cpu_to_je32(inode->i_ino); > rd->mctime = cpu_to_je32(JFFS2_NOW()); > rd->nsize = namelen; > - > - /* XXX: This is ugly. */ > - rd->type = (mode & S_IFMT) >> 12; > - > + rd->type = fs_umode_to_dtype(mode); > rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8)); > rd->name_crc = cpu_to_je32(crc32(0, dentry->d_name.name, namelen)); > > @@ -811,8 +807,7 @@ static int jffs2_rename (struct mnt_idmap *idmap, > > /* Make a hard link */ > > - /* XXX: This is ugly */ > - type = (d_inode(old_dentry)->i_mode & S_IFMT) >> 12; > + type = fs_umode_to_dtype(d_inode(old_dentry)->i_mode); > if (!type) type = DT_REG; > > now = JFFS2_NOW(); >
Hi Zhihao,
Thank you for taking the time to review my patch!
I'm trying to understand the issue you've identified. I looked at the
fs_umode_to_dtype() implementation in fs/fs_types.c:
unsigned char fs_umode_to_dtype(umode_t mode) {
return fs_ftype_to_dtype(fs_umode_to_ftype(mode));
}
From what I can see, it seems like the function does produce FT_FIFO (5)
as an intermediate value, but then converts it back before returning.
Here's what I think happens for S_IFIFO (0010000):
Old bit-shift code:
type = (mode & S_IFMT) >> 12
= (0010000 & 00170000) >> 12
= 0010000 >> 12
= 1 (DT_FIFO)
New fs_umode_to_dtype() code:
Step 1: fs_umode_to_ftype(0010000)
= fs_ftype_by_dtype[S_DT(0010000)]
= fs_ftype_by_dtype[1]
= FT_FIFO = 5
Step 2: fs_ftype_to_dtype(5)
= fs_dtype_by_ftype[5]
= DT_FIFO = 1
I'm not sure how FT_FIFO (5) would remain after the function returns, since
it seems to get converted back to DT_FIFO (1) in step 2.
If there's an issue with this approach, I can edit my patch and keep changes in only jffs2_mknod.
在 2026/2/7 15:39, Adarsh Das 写道:
> Hi Zhihao,
>
> Thank you for taking the time to review my patch!
>
> I'm trying to understand the issue you've identified. I looked at the
> fs_umode_to_dtype() implementation in fs/fs_types.c:
>
> unsigned char fs_umode_to_dtype(umode_t mode) {
> return fs_ftype_to_dtype(fs_umode_to_ftype(mode));
> }
>
>>From what I can see, it seems like the function does produce FT_FIFO (5)
> as an intermediate value, but then converts it back before returning.
> Here's what I think happens for S_IFIFO (0010000):
>
> Old bit-shift code:
> type = (mode & S_IFMT) >> 12
> = (0010000 & 00170000) >> 12
> = 0010000 >> 12
> = 1 (DT_FIFO)
>
> New fs_umode_to_dtype() code:
> Step 1: fs_umode_to_ftype(0010000)
> = fs_ftype_by_dtype[S_DT(0010000)]
> = fs_ftype_by_dtype[1]
> = FT_FIFO = 5
>
> Step 2: fs_ftype_to_dtype(5)
> = fs_dtype_by_ftype[5]
> = DT_FIFO = 1
>
Oh, that's fs_umode_to_dtype, sorry for the mistake, I saw it as
'fs_umode_to_ftype'.
> I'm not sure how FT_FIFO (5) would remain after the function returns, since
> it seems to get converted back to DT_FIFO (1) in step 2.
>
> If there's an issue with this approach, I can edit my patch and keep changes in only jffs2_mknod.
> .
>
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