| Message ID | 20240731022715.4044482-1-dongliang.cui@unisoc.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] exfat: check disk status during buffer write | expand |
2024년 7월 31일 (수) 오전 11:29, Dongliang Cui <dongliang.cui@unisoc.com>님이 작성: > > We found that when writing a large file through buffer write, if the > disk is inaccessible, exFAT does not return an error normally, which > leads to the writing process not stopping properly. > > To easily reproduce this issue, you can follow the steps below: > > 1. format a device to exFAT and then mount (with a full disk erase) > 2. dd if=/dev/zero of=/exfat_mount/test.img bs=1M count=8192 > 3. eject the device > > You may find that the dd process does not stop immediately and may > continue for a long time. > > The root cause of this issue is that during buffer write process, > exFAT does not need to access the disk to look up directory entries > or the FAT table (whereas FAT would do) every time data is written. > Instead, exFAT simply marks the buffer as dirty and returns, > delegating the writeback operation to the writeback process. > > If the disk cannot be accessed at this time, the error will only be > returned to the writeback process, and the original process will not > receive the error, so it cannot be returned to the user side. > > When the disk cannot be accessed normally, an error should be returned > to stop the writing process. > > Signed-off-by: Dongliang Cui <dongliang.cui@unisoc.com> > Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com> > --- > Changes in v3: > - Implement .shutdown to monitor disk status. > --- > fs/exfat/exfat_fs.h | 10 ++++++++++ > fs/exfat/inode.c | 3 +++ > fs/exfat/super.c | 11 +++++++++++ > 3 files changed, 24 insertions(+) > > diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h > index ecc5db952deb..c6cf36070aa3 100644 > --- a/fs/exfat/exfat_fs.h > +++ b/fs/exfat/exfat_fs.h > @@ -148,6 +148,9 @@ enum { > #define DIR_CACHE_SIZE \ > (DIV_ROUND_UP(EXFAT_DEN_TO_B(ES_MAX_ENTRY_NUM), SECTOR_SIZE) + 1) > > +/* Superblock flags */ > +#define EXFAT_FLAGS_SHUTDOWN 1 > + > struct exfat_dentry_namebuf { > char *lfn; > int lfnbuf_len; /* usually MAX_UNINAME_BUF_SIZE */ > @@ -267,6 +270,8 @@ struct exfat_sb_info { > unsigned int clu_srch_ptr; /* cluster search pointer */ > unsigned int used_clusters; /* number of used clusters */ > > + unsigned long s_exfat_flags; /* Exfat superblock flags */ > + > struct mutex s_lock; /* superblock lock */ > struct mutex bitmap_lock; /* bitmap lock */ > struct exfat_mount_options options; > @@ -338,6 +343,11 @@ static inline struct exfat_inode_info *EXFAT_I(struct inode *inode) > return container_of(inode, struct exfat_inode_info, vfs_inode); > } > > +static inline int exfat_forced_shutdown(struct super_block *sb) > +{ > + return test_bit(EXFAT_FLAGS_SHUTDOWN, &EXFAT_SB(sb)->s_exfat_flags); > +} > + > /* > * If ->i_mode can't hold 0222 (i.e. ATTR_RO), we use ->i_attrs to > * save ATTR_RO instead of ->i_mode. > diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c > index dd894e558c91..b1b814183494 100644 > --- a/fs/exfat/inode.c > +++ b/fs/exfat/inode.c > @@ -452,6 +452,9 @@ static int exfat_write_begin(struct file *file, struct address_space *mapping, > { > int ret; > > + if (unlikely(exfat_forced_shutdown(mapping->host->i_sb))) > + return -EIO; We need to add this to other write operations(exfat_create, unlink, mkdir, rmdir, rename, setattr, writepages) as well as exfat_write_begin(). Thanks.
Besides the additional checks for the shutdown flag already mentioned the subject is now incorrect I think, it should talk about implementing shutdown handling. In case you haven't done so yet, please also see if exfat now passes the various testcases in xfstests that exercise the shutdown path. Otherwise this looks reasonable to me, thanks for the work!
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index ecc5db952deb..c6cf36070aa3 100644 --- a/fs/exfat/exfat_fs.h +++ b/fs/exfat/exfat_fs.h @@ -148,6 +148,9 @@ enum { #define DIR_CACHE_SIZE \ (DIV_ROUND_UP(EXFAT_DEN_TO_B(ES_MAX_ENTRY_NUM), SECTOR_SIZE) + 1) +/* Superblock flags */ +#define EXFAT_FLAGS_SHUTDOWN 1 + struct exfat_dentry_namebuf { char *lfn; int lfnbuf_len; /* usually MAX_UNINAME_BUF_SIZE */ @@ -267,6 +270,8 @@ struct exfat_sb_info { unsigned int clu_srch_ptr; /* cluster search pointer */ unsigned int used_clusters; /* number of used clusters */ + unsigned long s_exfat_flags; /* Exfat superblock flags */ + struct mutex s_lock; /* superblock lock */ struct mutex bitmap_lock; /* bitmap lock */ struct exfat_mount_options options; @@ -338,6 +343,11 @@ static inline struct exfat_inode_info *EXFAT_I(struct inode *inode) return container_of(inode, struct exfat_inode_info, vfs_inode); } +static inline int exfat_forced_shutdown(struct super_block *sb) +{ + return test_bit(EXFAT_FLAGS_SHUTDOWN, &EXFAT_SB(sb)->s_exfat_flags); +} + /* * If ->i_mode can't hold 0222 (i.e. ATTR_RO), we use ->i_attrs to * save ATTR_RO instead of ->i_mode. diff --git a/fs/exfat/inode.c b/fs/exfat/inode.c index dd894e558c91..b1b814183494 100644 --- a/fs/exfat/inode.c +++ b/fs/exfat/inode.c @@ -452,6 +452,9 @@ static int exfat_write_begin(struct file *file, struct address_space *mapping, { int ret; + if (unlikely(exfat_forced_shutdown(mapping->host->i_sb))) + return -EIO; + *pagep = NULL; ret = block_write_begin(mapping, pos, len, pagep, exfat_get_block); diff --git a/fs/exfat/super.c b/fs/exfat/super.c index 323ecebe6f0e..9d7d9c4ba55a 100644 --- a/fs/exfat/super.c +++ b/fs/exfat/super.c @@ -167,6 +167,16 @@ static int exfat_show_options(struct seq_file *m, struct dentry *root) return 0; } +static void exfat_shutdown(struct super_block *sb) +{ + struct exfat_sb_info *sbi = EXFAT_SB(sb); + + if (exfat_forced_shutdown(sb)) + return; + + set_bit(EXFAT_FLAGS_SHUTDOWN, &sbi->s_exfat_flags); +} + static struct inode *exfat_alloc_inode(struct super_block *sb) { struct exfat_inode_info *ei; @@ -193,6 +203,7 @@ static const struct super_operations exfat_sops = { .sync_fs = exfat_sync_fs, .statfs = exfat_statfs, .show_options = exfat_show_options, + .shutdown = exfat_shutdown, }; enum {