delay capable() check in ext4_has_free_blocks()
As reported by Eric Paris, the capable() check in ext4_has_free_blocks() sometimes causes SELinux denials. We can rearrange the logic so that we only try to use the root-reserved blocks when necessary, and even then we can move the capable() test to last, to avoid the check most of the time. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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@ -599,17 +599,12 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
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*/
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int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks)
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{
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s64 free_blocks, dirty_blocks;
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s64 root_blocks = 0;
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s64 free_blocks, dirty_blocks, root_blocks;
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struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
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struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
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free_blocks = percpu_counter_read_positive(fbc);
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dirty_blocks = percpu_counter_read_positive(dbc);
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if (!capable(CAP_SYS_RESOURCE) &&
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sbi->s_resuid != current->fsuid &&
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(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
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root_blocks = ext4_r_blocks_count(sbi->s_es);
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if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
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@ -623,13 +618,20 @@ int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks)
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}
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}
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/* Check whether we have space after
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* accounting for current dirty blocks
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* accounting for current dirty blocks & root reserved blocks.
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*/
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if (free_blocks < ((root_blocks + nblocks) + dirty_blocks))
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/* we don't have free space */
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return 0;
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if (free_blocks >= ((root_blocks + nblocks) + dirty_blocks))
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return 1;
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/* Hm, nope. Are (enough) root reserved blocks available? */
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if (sbi->s_resuid == current->fsuid ||
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((sbi->s_resgid != 0) && in_group_p(sbi->s_resgid)) ||
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capable(CAP_SYS_RESOURCE)) {
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if (free_blocks >= (nblocks + dirty_blocks))
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return 1;
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}
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return 0;
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}
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int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
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