mirrors/linux
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-02-14 05:34:49 -05:00
Code Issues Packages Projects Releases Wiki Activity

fuse: don't allow signals to interrupt getdents copying

Browse Source 
When getting the directory contents, the entries are first fetched to a
kernel buffer, then they are copied to userspace with dir_emit().  This
second phase is non-blocking as long as the userspace buffer is not paged
out, making it interruptible makes zero sense.

Overload d_type as flags, since it only uses 4 bits from 32.

Reviewed-by: Bernd Schubert <bschubert@ddn.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Miklos Szeredi
2025-04-16 10:53:58 +02:00
parent f3cb8bd908
commit c31f91c6af
3 changed files with 20 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
fs/fuse/readdir.c
View File

@@ -120,7 +120,7 @@ static bool fuse_emit(struct file *file, struct dir_context *ctx,
fuse_add_dirent_to_cache(file, dirent, ctx->pos);
return dir_emit(ctx, dirent->name, dirent->namelen, dirent->ino,
dirent->type);
dirent->type | FILLDIR_FLAG_NOINTR);
}
static int parse_dirfile(char *buf, size_t nbytes, struct file *file,
@@ -422,7 +422,7 @@ static enum fuse_parse_result fuse_parse_cache(struct fuse_file *ff,
if (ff->readdir.pos == ctx->pos) {
res = FOUND_SOME;
if (!dir_emit(ctx, dirent->name, dirent->namelen,
dirent->ino, dirent->type))
dirent->ino, dirent->type | FILLDIR_FLAG_NOINTR))
return FOUND_ALL;
ctx->pos = dirent->off;
}

18
fs/readdir.c
View File

@@ -266,6 +266,10 @@ static bool filldir(struct dir_context *ctx, const char *name, int namlen,
int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
sizeof(long));
int prev_reclen;
unsigned int flags = d_type;
BUILD_BUG_ON(FILLDIR_FLAG_NOINTR & S_DT_MASK);
d_type &= S_DT_MASK;
buf->error = verify_dirent_name(name, namlen);
if (unlikely(buf->error))
@@ -279,7 +283,7 @@ static bool filldir(struct dir_context *ctx, const char *name, int namlen,
return false;
}
prev_reclen = buf->prev_reclen;
if (prev_reclen && signal_pending(current))
if (!(flags & FILLDIR_FLAG_NOINTR) && prev_reclen && signal_pending(current))
return false;
dirent = buf->current_dir;
prev = (void __user *) dirent - prev_reclen;
@@ -351,6 +355,10 @@ static bool filldir64(struct dir_context *ctx, const char *name, int namlen,
int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
sizeof(u64));
int prev_reclen;
unsigned int flags = d_type;
BUILD_BUG_ON(FILLDIR_FLAG_NOINTR & S_DT_MASK);
d_type &= S_DT_MASK;
buf->error = verify_dirent_name(name, namlen);
if (unlikely(buf->error))
@@ -359,7 +367,7 @@ static bool filldir64(struct dir_context *ctx, const char *name, int namlen,
if (reclen > buf->count)
return false;
prev_reclen = buf->prev_reclen;
if (prev_reclen && signal_pending(current))
if (!(flags & FILLDIR_FLAG_NOINTR) && prev_reclen && signal_pending(current))
return false;
dirent = buf->current_dir;
prev = (void __user *)dirent - prev_reclen;
@@ -513,6 +521,10 @@ static bool compat_filldir(struct dir_context *ctx, const char *name, int namlen
int reclen = ALIGN(offsetof(struct compat_linux_dirent, d_name) +
namlen + 2, sizeof(compat_long_t));
int prev_reclen;
unsigned int flags = d_type;
BUILD_BUG_ON(FILLDIR_FLAG_NOINTR & S_DT_MASK);
d_type &= S_DT_MASK;
buf->error = verify_dirent_name(name, namlen);
if (unlikely(buf->error))
@@ -526,7 +538,7 @@ static bool compat_filldir(struct dir_context *ctx, const char *name, int namlen
return false;
}
prev_reclen = buf->prev_reclen;
if (prev_reclen && signal_pending(current))
if (!(flags & FILLDIR_FLAG_NOINTR) && prev_reclen && signal_pending(current))
return false;
dirent = buf->current_dir;
prev = (void __user *) dirent - prev_reclen;

3
include/linux/fs.h
View File

@@ -2073,6 +2073,9 @@ struct dir_context {
loff_t pos;
};
/* If OR-ed with d_type, pending signals are not checked */
#define FILLDIR_FLAG_NOINTR 0x1000
/*
* These flags let !MMU mmap() govern direct device mapping vs immediate
* copying more easily for MAP_PRIVATE, especially for ROM filesystems.