From 12064f3a794e67c81d2bae15606f03f436630e88 Mon Sep 17 00:00:00 2001 From: Daniel Rosenberg Date: Fri, 6 Jul 2018 16:24:27 -0700 Subject: [PATCH] ANDROID: sdcardfs: Add option to drop unused dentries This adds the nocache mount option, which will cause sdcardfs to always drop dentries that are not in use, preventing cached entries from holding on to lower dentries, which could cause strange behavior when bypassing the sdcardfs layer and directly changing the lower fs. Change-Id: I70268584a20b989ae8cfdd278a2e4fa1605217fb Signed-off-by: Daniel Rosenberg --- fs/sdcardfs/dentry.c | 7 +++++++ fs/sdcardfs/main.c | 6 ++++++ fs/sdcardfs/sdcardfs.h | 1 + fs/sdcardfs/super.c | 2 ++ 4 files changed, 16 insertions(+) diff --git a/fs/sdcardfs/dentry.c b/fs/sdcardfs/dentry.c index 776d549b397b..cb573f1efbfc 100644 --- a/fs/sdcardfs/dentry.c +++ b/fs/sdcardfs/dentry.c @@ -123,6 +123,12 @@ out: return err; } +/* 1 = delete, 0 = cache */ +static int sdcardfs_d_delete(const struct dentry *d) +{ + return SDCARDFS_SB(d->d_sb)->options.nocache ? 1 : 0; +} + static void sdcardfs_d_release(struct dentry *dentry) { if (!dentry || !dentry->d_fsdata) @@ -181,6 +187,7 @@ static void sdcardfs_canonical_path(const struct path *path, const struct dentry_operations sdcardfs_ci_dops = { .d_revalidate = sdcardfs_d_revalidate, + .d_delete = sdcardfs_d_delete, .d_release = sdcardfs_d_release, .d_hash = sdcardfs_hash_ci, .d_compare = sdcardfs_cmp_ci, diff --git a/fs/sdcardfs/main.c b/fs/sdcardfs/main.c index 27ec726e7a46..ba52af8644cc 100644 --- a/fs/sdcardfs/main.c +++ b/fs/sdcardfs/main.c @@ -34,6 +34,7 @@ enum { Opt_reserved_mb, Opt_gid_derivation, Opt_default_normal, + Opt_nocache, Opt_err, }; @@ -48,6 +49,7 @@ static const match_table_t sdcardfs_tokens = { {Opt_gid_derivation, "derive_gid"}, {Opt_default_normal, "default_normal"}, {Opt_reserved_mb, "reserved_mb=%u"}, + {Opt_nocache, "nocache"}, {Opt_err, NULL} }; @@ -71,6 +73,7 @@ static int parse_options(struct super_block *sb, char *options, int silent, /* by default, gid derivation is off */ opts->gid_derivation = false; opts->default_normal = false; + opts->nocache = false; *debug = 0; @@ -128,6 +131,9 @@ static int parse_options(struct super_block *sb, char *options, int silent, case Opt_default_normal: opts->default_normal = true; break; + case Opt_nocache: + opts->nocache = true; + break; /* unknown option */ default: if (!silent) diff --git a/fs/sdcardfs/sdcardfs.h b/fs/sdcardfs/sdcardfs.h index ec2290a16d3c..c2a16a023f2c 100644 --- a/fs/sdcardfs/sdcardfs.h +++ b/fs/sdcardfs/sdcardfs.h @@ -198,6 +198,7 @@ struct sdcardfs_mount_options { bool gid_derivation; bool default_normal; unsigned int reserved_mb; + bool nocache; }; struct sdcardfs_vfsmount_options { diff --git a/fs/sdcardfs/super.c b/fs/sdcardfs/super.c index cffcdb11cb8a..140696ed3ed3 100644 --- a/fs/sdcardfs/super.c +++ b/fs/sdcardfs/super.c @@ -311,6 +311,8 @@ static int sdcardfs_show_options(struct vfsmount *mnt, struct seq_file *m, seq_puts(m, ",default_normal"); if (opts->reserved_mb != 0) seq_printf(m, ",reserved=%uMB", opts->reserved_mb); + if (opts->nocache) + seq_printf(m, ",nocache"); return 0; }; -- 2.20.1