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authorAmir Goldstein <amir73il@gmail.com>2020-07-16 11:42:17 +0300
committerJan Kara <jack@suse.cz>2020-07-27 22:23:37 +0300
commitf454fa610a69b93e7ed4de739e736f988d95c2d2 (patch)
tree699289ff1b9413920896a3a7fd76f34c183a8528 /fs/notify/fanotify/fanotify.c
parent6ba8d7107f27c1bde60a80bc5def027979af3e8e (diff)
downloadlinux-f454fa610a69b93e7ed4de739e736f988d95c2d2.tar.xz
fanotify: use struct fanotify_info to parcel the variable size buffer
An fanotify event name is always recorded relative to a dir fh. Encapsulate the name_len member of fanotify_name_event in a new struct fanotify_info, which describes the parceling of the variable size buffer of an fanotify_name_event. The dir_fh member of fanotify_name_event is renamed to _dir_fh and is not accessed directly, but via the fanotify_info_dir_fh() accessor. Although the dir_fh len information is already available in struct fanotify_fh, we store it also in dif_fh_totlen member of fanotify_info, including the size of fanotify_fh header, so we know the offset of the name in the buffer without looking inside the dir_fh. We also add a file_fh_totlen member to allow packing another file handle in the variable size buffer after the dir_fh and before the name. We are going to use that space to store the child fid. Link: https://lore.kernel.org/r/20200716084230.30611-10-amir73il@gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify/fanotify/fanotify.c')
-rw-r--r--fs/notify/fanotify/fanotify.c66
1 files changed, 50 insertions, 16 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index b8c04a6f04c5..31fd41e91575 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -49,22 +49,44 @@ static bool fanotify_fid_event_equal(struct fanotify_fid_event *ffe1,
fanotify_fh_equal(&ffe1->object_fh, &ffe2->object_fh);
}
+static bool fanotify_info_equal(struct fanotify_info *info1,
+ struct fanotify_info *info2)
+{
+ if (info1->dir_fh_totlen != info2->dir_fh_totlen ||
+ info1->file_fh_totlen != info2->file_fh_totlen ||
+ info1->name_len != info2->name_len)
+ return false;
+
+ if (info1->dir_fh_totlen &&
+ !fanotify_fh_equal(fanotify_info_dir_fh(info1),
+ fanotify_info_dir_fh(info2)))
+ return false;
+
+ if (info1->file_fh_totlen &&
+ !fanotify_fh_equal(fanotify_info_file_fh(info1),
+ fanotify_info_file_fh(info2)))
+ return false;
+
+ return !info1->name_len ||
+ !memcmp(fanotify_info_name(info1), fanotify_info_name(info2),
+ info1->name_len);
+}
+
static bool fanotify_name_event_equal(struct fanotify_name_event *fne1,
struct fanotify_name_event *fne2)
{
- /* Do not merge name events without dir fh */
- if (!fne1->dir_fh.len)
- return false;
+ struct fanotify_info *info1 = &fne1->info;
+ struct fanotify_info *info2 = &fne2->info;
- if (fne1->name_len != fne2->name_len ||
- !fanotify_fh_equal(&fne1->dir_fh, &fne2->dir_fh))
+ /* Do not merge name events without dir fh */
+ if (!info1->dir_fh_totlen)
return false;
- return !memcmp(fne1->name, fne2->name, fne1->name_len);
+ return fanotify_info_equal(info1, info2);
}
static bool fanotify_should_merge(struct fsnotify_event *old_fsn,
- struct fsnotify_event *new_fsn)
+ struct fsnotify_event *new_fsn)
{
struct fanotify_event *old, *new;
@@ -276,8 +298,14 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
return test_mask & user_mask;
}
-static void fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
- gfp_t gfp)
+/*
+ * Encode fanotify_fh.
+ *
+ * Return total size of encoded fh including fanotify_fh header.
+ * Return 0 on failure to encode.
+ */
+static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
+ gfp_t gfp)
{
int dwords, type, bytes = 0;
char *ext_buf = NULL;
@@ -287,7 +315,7 @@ static void fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
fh->type = FILEID_ROOT;
fh->len = 0;
if (!inode)
- return;
+ return 0;
dwords = 0;
err = -ENOENT;
@@ -315,7 +343,7 @@ static void fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
fh->type = type;
fh->len = bytes;
- return;
+ return FANOTIFY_FH_HDR_LEN + bytes;
out_err:
pr_warn_ratelimited("fanotify: failed to encode fid (type=%d, len=%d, err=%i)\n",
@@ -325,6 +353,7 @@ out_err:
/* Report the event without a file identifier on encode error */
fh->type = FILEID_INVALID;
fh->len = 0;
+ return 0;
}
/*
@@ -401,6 +430,8 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *id,
gfp_t gfp)
{
struct fanotify_name_event *fne;
+ struct fanotify_info *info;
+ struct fanotify_fh *dfh;
fne = kmalloc(sizeof(*fne) + file_name->len + 1, gfp);
if (!fne)
@@ -408,9 +439,11 @@ static struct fanotify_event *fanotify_alloc_name_event(struct inode *id,
fne->fae.type = FANOTIFY_EVENT_TYPE_FID_NAME;
fne->fsid = *fsid;
- fanotify_encode_fh(&fne->dir_fh, id, gfp);
- fne->name_len = file_name->len;
- strcpy(fne->name, file_name->name);
+ info = &fne->info;
+ fanotify_info_init(info);
+ dfh = fanotify_info_dir_fh(info);
+ info->dir_fh_totlen = fanotify_encode_fh(dfh, id, gfp);
+ fanotify_info_copy_name(info, file_name);
return &fne->fae;
}
@@ -626,9 +659,10 @@ static void fanotify_free_fid_event(struct fanotify_event *event)
static void fanotify_free_name_event(struct fanotify_event *event)
{
struct fanotify_name_event *fne = FANOTIFY_NE(event);
+ struct fanotify_fh *dfh = fanotify_info_dir_fh(&fne->info);
- if (fanotify_fh_has_ext_buf(&fne->dir_fh))
- kfree(fanotify_fh_ext_buf(&fne->dir_fh));
+ if (fanotify_fh_has_ext_buf(dfh))
+ kfree(fanotify_fh_ext_buf(dfh));
kfree(fne);
}