Messages in this thread | | | Date | Mon, 23 Mar 2020 02:50:36 +0100 | From | Ondřej Jirman <> | Subject | Re: [PATCH v3] f2fs: fix potential .flags overflow on 32bit architecture |
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Hello Chao Yu,
On Mon, Mar 23, 2020 at 09:25:19AM +0800, Chao Yu wrote: > [snip] > > +static inline void __set_inode_flag(struct inode *inode, int flag) > +{ > + test_and_set_bit(flag % BITS_PER_LONG, > + &F2FS_I(inode)->flags[BIT_WORD(flag)]);
This can simply be:
test_and_set_bit(flag, F2FS_I(inode)->flags);
all of these bitmap manipulation functions already will do the right thing to access the correct location in the flags array:
https://elixir.bootlin.com/linux/latest/source/include/asm-generic/bitops/atomic.h#L32
see BIT_MASK and BIT_WORD use in that function.
> +} > + > static inline void set_inode_flag(struct inode *inode, int flag) > { > - if (!test_bit(flag, &F2FS_I(inode)->flags)) > - set_bit(flag, &F2FS_I(inode)->flags); > + __set_inode_flag(inode, flag); > __mark_inode_dirty_flag(inode, flag, true); > } > > static inline int is_inode_flag_set(struct inode *inode, int flag) > { > - return test_bit(flag, &F2FS_I(inode)->flags); > + return test_bit(flag % BITS_PER_LONG, > + &F2FS_I(inode)->flags[BIT_WORD(flag)]);
ditto
> } > > static inline void clear_inode_flag(struct inode *inode, int flag) > { > - if (test_bit(flag, &F2FS_I(inode)->flags)) > - clear_bit(flag, &F2FS_I(inode)->flags); > + test_and_clear_bit(flag % BITS_PER_LONG, > + &F2FS_I(inode)->flags[BIT_WORD(flag)]);
ditto
I'm going to test the patch. It looks like that this was really the root cause of all those locking issues I was seeing on my 32-bit tablet. It seems to explain why my 64-bit systems were not affected, and why reverting compession fixed it too. Great job figuring this out.
I'll let you know soon.
thank you and regards, o.
> __mark_inode_dirty_flag(inode, flag, false); > } >
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